U.S. patent application number 15/245784 was filed with the patent office on 2017-03-02 for control of metallic electrohydrodynamic three-dimensional printing using feedback of surface characteristics.
The applicant listed for this patent is Desktop Metal, Inc.. Invention is credited to Ricardo Chin, Ric Fulop, Yet Ming-Chiang, Jonah Samuel Myerberg.
Application Number | 20170056967 15/245784 |
Document ID | / |
Family ID | 58097563 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170056967 |
Kind Code |
A1 |
Fulop; Ric ; et al. |
March 2, 2017 |
CONTROL OF METALLIC ELECTROHYDRODYNAMIC THREE-DIMENSIONAL PRINTING
USING FEEDBACK OF SURFACE CHARACTERISTICS
Abstract
A metallic electrohydrodynamic (EHD) three-dimensional printer
fabricates an object while surface characteristics of the object
are monitored. Sensors acquire data on surface characteristics, and
feedback related to these surface characteristics is used to adjust
the fabrication process, e.g., where the surface characteristics
deviate from a target surface shape.
Inventors: |
Fulop; Ric; (Lexington,
MA) ; Myerberg; Jonah Samuel; (Lexington, MA)
; Chin; Ricardo; (Shrewsbury, MA) ; Ming-Chiang;
Yet; (Weston, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Desktop Metal, Inc. |
Lexington |
MA |
US |
|
|
Family ID: |
58097563 |
Appl. No.: |
15/245784 |
Filed: |
August 24, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62208883 |
Aug 24, 2015 |
|
|
|
62212244 |
Aug 31, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 2999/00 20130101;
B22D 37/00 20130101; B33Y 30/00 20141201; B22D 11/01 20130101; B22D
39/00 20130101; B22F 3/1055 20130101; Y02P 10/295 20151101; Y02P
10/25 20151101; B33Y 70/00 20141201; B22D 11/18 20130101; B33Y
10/00 20141201; B22D 23/003 20130101; B22F 2003/1056 20130101; B33Y
50/02 20141201; B22F 2999/00 20130101; B22F 3/1055 20130101; B22F
3/115 20130101 |
International
Class: |
B22D 11/18 20060101
B22D011/18; B22D 11/01 20060101 B22D011/01 |
Claims
1. A method for additive manufacturing comprising: fabricating an
object based on a three-dimensional model with a printer, wherein
the printer is a three-dimensional metallic printer configured to
additively manufacture the object with a number of droplets of
liquefied metal as a build material using a metallic liquid
expeller; acquiring surface data from the object with one or more
sensors during fabrication, the surface data characterizing a
location on a layer of a build material of the object deposited by
the printer; estimating a target surface shape for the build
material at the location based on the three-dimensional model;
comparing the surface data to the target surface shape at the
location; and adjusting a fabrication process when a discrepancy is
identified between the surface data and the target surface
shape.
2. The method of claim 1, wherein the metallic liquid expeller is
configured to drive the droplets of liquefied metal by applying an
electrostatic field to a meniscus of the liquefied metal extending
from an outlet of the metallic liquid expeller of the printer.
3. The method of claim 1, wherein the surface data is acquired for
each one of the droplets of liquefied metal.
4. The method of claim 1, wherein the surface data is acquired for
a surface region about the location.
5. The method of claim 1, wherein the surface data is acquired for
a voxel about the location.
6. The method of claim 1, further comprising capturing process data
characterizing the droplets of liquefied metal.
7. The method of claim 6, wherein the process data includes at
least one of a volume of one of the droplets of liquefied metal and
an average volume of the droplets of liquefied metal.
8. The method of claim 6, wherein the process data includes at
least one of a dimension of one of the droplets of liquefied metal
and an average dimension of the droplets of liquefied metal.
9. The method of claim 6, wherein the process data includes at
least one of a velocity of one of the droplets of liquefied metal
and an average velocity of the droplets of liquefied metal.
10. The method of claim 6, wherein the process data includes at
least one of a temperature of one of the droplets of liquefied
metal and an average temperature of the droplets of liquefied
metal.
11. The method of claim 6, wherein the process data includes at
least one of a distance between an expeller of the printer and the
layer of the build material, a temperature of a build chamber of
the printer, and a temperature of a print bed of the printer.
12. The method of claim 1, wherein the one or more sensors include
at least one of a contact profilometer and a non-contact
profilometer.
13. The method of claim 12, wherein the one or more sensors include
an optical profilometer.
14. The method of claim 1, wherein the discrepancy includes a
depression at a position in the layer of the build material, and
wherein adjusting the fabrication process includes repeating a
deposition of droplets of liquefied metal at the position.
15. The method of claim 1, wherein the discrepancy includes a
protrusion at a position in the surface of the layer of the object,
and wherein adjusting the fabrication process includes omitting a
deposition of droplets of liquefied metal at the position while
fabricating a second layer of the object on the layer containing
the protrusion.
16. The method of claim 1, further comprising refinishing the
location on the layer of the object when the discrepancy between
the surface data and the target surface shape exceeds a
predetermined threshold.
17. The method of claim 1, further comprising sending a
notification to a user of the printer when the discrepancy between
the surface data and the target surface shape exceeds a
predetermined threshold.
18. The method of claim 1, further comprising acquiring parameter
data related to at least one parameter or condition of the printer
present during fabrication of the layer of the build material.
19. A computer program product comprising computer executable code
embodied in a non-transitory computer-readable medium that, when
executing on one or more computing devices in electronic
communication with a three-dimensional metallic printer configured
to additively manufacture an object based on a three-dimensional
model with a number of droplets of liquefied metal as a build
material using a metallic liquid expeller, performs the steps of:
acquiring surface data from the object with one or more sensors
during fabrication, the surface data characterizing a location on a
layer of a build material of the object deposited by the
three-dimensional metallic printer; estimating a target surface
shape for the build material at the location based on the
three-dimensional model; comparing the surface data to the target
surface shape at the location; and adjusting a fabrication process
of the three-dimensional metallic printer when a discrepancy is
identified between the surface data and the target surface
shape.
20. An additive manufacturing system including: a three-dimensional
metallic printer configured to additively manufacture an object
based on a three-dimensional model with a number of droplets of
liquefied metal as a build material using a metallic liquid
expeller; and a controller in electronic communication with the
three-dimensional metallic printer over a data network, the
controller including a processor and a memory, the memory bearing
computer executable code configured to perform the steps of
acquiring surface data from the object with one or more sensors
during fabrication, the surface data characterizing a location on a
layer of a build material of the object deposited by the
three-dimensional metallic printer, estimating a target surface
shape for the build material at the location based on the
three-dimensional model, comparing the surface data to the target
surface shape at the location, and adjusting a fabrication process
of the three-dimensional metallic printer when a discrepancy is
identified between the surface data and the target surface shape.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 62/208,883 filed on Aug. 24, 2015 and U.S.
Provisional Patent Application No. 62/212,244 filed on Aug. 31,
2015, where the entire content of each is hereby incorporated by
reference.
TECHNICAL FIELD
[0002] The present disclosure generally relates to additive
manufacturing, and more specifically to the three-dimensional
printing of metal objects.
BACKGROUND
[0003] Fused filament fabrication and the like are techniques for
fabricating three-dimensional objects from a thermoplastic or
similar material. Machines using this technique can fabricate
three-dimensional objects additively by depositing lines of
material in layers. While these polymer-based techniques have been
changed and improved over the years, the physical principles
applicable to polymer-based systems may not be applicable to
metal-based systems, which tend to pose different challenges. There
remains a need for three-dimensional printing techniques suitable
for metal additive manufacturing.
SUMMARY
[0004] An additive manufacturing system uses electrohydrodynamic
(EHD) printing techniques to form a metallic object based upon a
digital model. A metal build material is melted within a reservoir
and expelled through an outlet of an expeller in a controlled
manner using EHD force to modulate surface tension on a meniscus of
the liquid metal at the outlet of the expeller. Concurrently, a
positioning robotics system moves the expeller relative to a print
bed along a toolpath that forms the solidifying metal droplets into
a net shape according to the digital model.
[0005] In an aspect, an additive manufacturing system may include a
build chamber and an expeller. The expeller may include a
reservoir, a heater configured to maintain a metal within the
reservoir in a liquid form, and an outlet within the build chamber,
where the expeller is configured to modulate a release of the metal
in the liquid form from the outlet by applying an
electrohydrodynamic force to control a surface tension on the metal
at the outlet, thereby providing a supply of build material. The
additive manufacturing system may also include a print bed within
the build chamber, the print bed including a surface configured to
receive the supply of build material, a robotic positioning
assembly structurally configured to position the outlet relative to
the print bed within the build chamber, and a controller coupled to
the expeller and the robotic positioning assembly, the controller
operable to control the additive manufacturing system to fabricate
an object based on a digital model that provides a
three-dimensional representation of the object.
[0006] Implementations may include one or more of the following
features. The expeller may include an electrohydrodynamic (EHD)
device including one or more electrodes in communication with the
outlet, where one or more of a voltage difference or a capacitance
between the metal and the one or more electrodes is configured to
create an electrostatic field for modulating the surface tension of
the metal in the liquid form sufficient to expel a droplet of the
metal in the liquid form from the outlet. The additive
manufacturing system may further include a second expeller
configured to modulate a release of a second material in a liquid
form from a second outlet of the second expeller, thereby providing
a supply of a second build material. The second material may
include a support material, where the second expeller is configured
to deposit the support material for fabrication of a support for
the object. The second material may include a metal, the second
expeller including an electrohydrodynamic (EHD) device including
one or more electrodes in communication with the second outlet,
where one or more of a voltage difference or a capacitance between
the metal and the one or more electrodes is configured to create an
electrostatic field for modulating a surface tension of the metal
in a liquid form within the second outlet sufficient to expel a
droplet of the metal in the liquid form from the second outlet. The
second material may include one or more of a metal, a wax, a
polymer, and a salt. The build chamber may be is environmentally
sealed. The additive manufacturing system may further include a
deoxygenator in communication with the build chamber for removing
oxygen from the build chamber. The deoxygenator may include one or
more of an oxygen filter, an oxygen getter, an electrochemical
oxygen pump, and a cover gas. The heater may include an induction
coil. The release of the metal in the liquid form from the outlet
may be modulated by an inductor configured to control a magnetic
field around the outlet. The additive manufacturing system may
further include a sensor in communication with the controller, the
sensor configured to detect progress of fabrication of the object,
the controller configured to adjust at least one parameter of the
additive manufacturing system in response to the detected progress
of fabrication of the object. The additive manufacturing system may
further include a sensor in communication with the controller, the
sensor configured to monitor one or more of the surface tension and
a meniscus of the metal in the liquid form, the controller
configured to adjust at least one parameter of the additive
manufacturing system to control one or more of the surface tension
and the meniscus. The controller may be configured to apply a
voltage to the metal in the liquid form to control one or more of
the surface tension and the meniscus. The at least one parameter
may include a temperature of one or more of the metal in the liquid
form, at least a portion of a volume of the build chamber, and the
print bed. The at least one parameter may include a pressure
differential between the reservoir and the build chamber. The at
least one parameter may include an intensity of an electrostatic
field. The at least one parameter may include an amount or
concentration of an additive for mixing with the metal. The
additive manufacturing system may further include a temperature
control system for adjusting a temperature of one or more of the
heater, the print bed, and at least a portion of a volume of the
build chamber. The metal may include a metallic alloy.
[0007] A metallic electrohydrodynamic (EHD) three-dimensional
printer fabricates an object while surface characteristics of the
object are monitored. Sensors acquire data on surface
characteristics, and feedback related to these surface
characteristics is used to adjust the fabrication process, e.g.,
where the surface characteristics deviate from a target surface
shape.
[0008] In an aspect, a method for additive manufacturing includes
fabricating an object based on a three-dimensional model with a
printer, where the printer is a three-dimensional metallic printer
configured to additively manufacture the object with a number of
droplets of liquefied metal as a build material using a metallic
liquid expeller, acquiring surface data from the object with one or
more sensors during fabrication, the surface data characterizing a
location on a layer of a build material of the object deposited by
the printer, estimating a target surface shape for the build
material at the location based on the three-dimensional model,
comparing the surface data to the target surface shape at the
location, and adjusting a fabrication process when a discrepancy is
identified between the surface data and the target surface
shape.
[0009] Implementations may include one or more of the following
features. The metallic liquid expeller may be configured to drive
the droplets of liquefied metal by applying an electrostatic field
to a meniscus of the liquefied metal extending from an outlet of
the metallic liquid expeller of the printer. The surface data may
be acquired for each one of the droplets of liquefied metal. The
surface data may be acquired for a surface region about the
location. The surface data may be acquired for a voxel about the
location. The method may further include capturing process data
characterizing the droplets of liquefied metal. The process data
may include at least one of a volume of one of the droplets of
liquefied metal and an average volume of the droplets of liquefied
metal. The process data may include at least one of a dimension of
one of the droplets of liquefied metal and an average dimension of
the droplets of liquefied metal. The process data may include at
least one of a velocity of one of the droplets of liquefied metal
and an average velocity of the droplets of liquefied metal. The
process data may include at least one of a temperature of one of
the droplets of liquefied metal and an average temperature of the
droplets of liquefied metal. The process data may include at least
one of a distance between an expeller of the printer and the layer
of the build material, a temperature of a build chamber of the
printer, and a temperature of a print bed of the printer. The one
or more sensors may include at least one of a contact profilometer
and a non-contact profilometer. The one or more sensors may include
an optical profilometer. The discrepancy may include a depression
at a position in the layer of the build material, and adjusting the
fabrication process includes repeating a deposition of droplets of
liquefied metal at the position. The discrepancy may include a
protrusion at a position in the surface of the layer of the object,
and adjusting the fabrication process includes omitting a
deposition of droplets of liquefied metal at the position while
fabricating a second layer of the object on the layer containing
the protrusion. The method may further include refinishing the
location on the layer of the object when the discrepancy between
the surface data and the target surface shape exceeds a
predetermined threshold. The method may further include sending a
notification to a user of the printer when the discrepancy between
the surface data and the target surface shape exceeds a
predetermined threshold. The method may further include acquiring
parameter data related to at least one parameter or condition of
the printer present during fabrication of the layer of the build
material.
[0010] In an aspect, a computer program product includes computer
executable code embodied in a non-transitory computer-readable
medium that, when executing on one or more computing devices in
electronic communication with a three-dimensional metallic printer
configured to additively manufacture an object based on a
three-dimensional model with a number of droplets of liquefied
metal as a build material using a metallic liquid expeller,
performs the steps of acquiring surface data from the object with
one or more sensors during fabrication, the surface data
characterizing a location on a layer of a build material of the
object deposited by the three-dimensional metallic printer,
estimating a target surface shape for the build material at the
location based on the three-dimensional model, comparing the
surface data to the target surface shape at the location, and
adjusting a fabrication process of the three-dimensional metallic
printer when a discrepancy is identified between the surface data
and the target surface shape.
[0011] In yet another aspect, an additive manufacturing system
includes a three-dimensional metallic printer configured to
additively manufacture an object based on a three-dimensional model
with a number of droplets of liquefied metal as a build material
using a metallic liquid expeller, and a controller in electronic
communication with the three-dimensional metallic printer over a
data network, the controller including a processor and a memory,
the memory bearing computer executable code configured to perform
the steps of acquiring surface data from the object with one or
more sensors during fabrication, the surface data characterizing a
location on a layer of a build material of the object deposited by
the three-dimensional metallic printer, estimating a target surface
shape for the build material at the location based on the
three-dimensional model, comparing the surface data to the target
surface shape at the location, and adjusting a fabrication process
of the three-dimensional metallic printer when a discrepancy is
identified between the surface data and the target surface
shape.
[0012] Thermal parameters for an additive manufacturing process are
estimated using computer modeling, and these thermal parameters are
used to control the additive manufacturing process. For example,
the thermal parameters may be estimated based on bulk material
properties, object geometry, control signals to thermal components
of a system, and so forth.
[0013] In an aspect, a method includes fabricating a metallic
object on a print bed with a three-dimensional printer, estimating
a thermal parameter of the metallic object, and controlling the
three-dimensional printer during fabrication of the object
according to the thermal parameter.
[0014] Implementations may include one or more of the following
features. The three-dimensional printer may include a
three-dimensional metallic printer configured to additively
manufacture the metallic object with a number of droplets of
liquefied metal using a metallic liquid expeller. The metallic
liquid expeller may be an electrohydrodynamic expeller configured
to drive the droplets of liquefied metal by applying an
electrostatic field to a meniscus of the liquefied metal extending
from an expeller of the three-dimensional printer. Controlling the
three-dimensional printer may include controlling a mass of the
number of droplets. Controlling the three-dimensional printer may
include controlling a velocity of the number of droplets. The
three-dimensional printer may fabricate the metallic object using
fused filament fabrication. The thermal parameter may include a
thermal mass of the metallic object. The thermal parameter may
include a heat capacity of the metallic object. The thermal
parameter may include a surface temperature of the metallic object.
The surface temperature may be estimated based on one or more of a
shape of the metallic object, a bulk thermal property of a build
material used to fabricate the metallic object, and a control
signal for one or more of a build chamber temperature or a print
bed temperature. The surface temperature may be estimated based on
a thermal measurement of the print bed. The thermal parameter may
include a thermal resistivity of the metallic object. Controlling
the three-dimensional printer may include controlling a temperature
of a build chamber of the three-dimensional printer. Controlling
the three-dimensional printer may include controlling a deposition
rate of a metallic build material from an expeller of the
three-dimensional printer. Controlling the three-dimensional
printer may include controlling a temperature of the print bed.
[0015] In an aspect, a computer program product includes computer
executable code embodied in a non-transitory computer-readable
medium that, when executing on one or more computing devices in
electronic communication with a three-dimensional printer, performs
the steps of providing instructions for fabricating a metallic
object on a print bed with the three-dimensional printer,
estimating a thermal parameter of the metallic object, and
controlling the three-dimensional printer during fabrication of the
object according to the thermal parameter. The three-dimensional
printer may include a three-dimensional metallic printer configured
to additively manufacture the metallic object with a number of
droplets of liquefied metal using a metallic liquid expeller. The
metallic liquid expeller may be an electrohydrodynamic expeller
configured to drive the droplets of liquefied metal by applying an
electrostatic field to a meniscus of the liquefied metal extending
from an expeller of the three-dimensional printer.
[0016] In yet another aspect, an additive manufacturing system
includes a three-dimensional metallic printer configured to
additively manufacture a metallic object with a number of droplets
of liquefied metal using a metallic liquid expeller, and a
controller in electronic communication with the three-dimensional
metallic printer over a data network, the controller including a
processor and a memory, the memory bearing computer executable code
configured to perform the steps of fabricating the metallic object
on a print bed with the three-dimensional metallic printer,
estimating a thermal parameter of the metallic object, and
controlling the three-dimensional printer during fabrication of the
object according to the thermal parameter. The metallic liquid
expeller may be an electrohydrodynamic expeller configured to drive
the droplets of liquefied metal by applying an electrostatic field
to a meniscus of the liquefied metal extending from an expeller of
the three-dimensional printer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The foregoing and other objects, features and advantages of
the devices, systems, and methods described herein will be apparent
from the following description of particular embodiments thereof,
as illustrated in the accompanying drawings. The drawings are not
necessarily to scale, emphasis instead being placed upon
illustrating the principles of the devices, systems, and methods
described herein.
[0018] FIG. 1 depicts an additive manufacturing system.
[0019] FIG. 2 depicts an expeller of an additive manufacturing
system.
[0020] FIG. 3 depicts an expeller of an additive manufacturing
system.
[0021] FIG. 4 depicts a cutaway of an expeller including multiple
outlets.
[0022] FIG. 5 is a flow chart of a method for additive
manufacturing.
[0023] FIG. 6 is a flow chart of a method for controlling an
additive manufacturing process using estimated thermal
parameters.
[0024] FIG. 7 depicts a computer system.
DETAILED DESCRIPTION
[0025] The embodiments will now be described more fully hereinafter
with reference to the accompanying figures, in which preferred
embodiments are shown. The foregoing may, however, be embodied in
many different forms and should not be construed as limited to the
illustrated embodiments set forth herein. Rather, these illustrated
embodiments are provided so that this disclosure will convey the
scope to those skilled in the art.
[0026] All documents mentioned herein are incorporated by reference
in their entirety. References to items in the singular should be
understood to include items in the plural, and vice versa, unless
explicitly stated otherwise or clear from the context. Grammatical
conjunctions are intended to express any and all disjunctive and
conjunctive combinations of conjoined clauses, sentences, words,
and the like, unless otherwise stated or clear from the context.
Thus, the term "or" should generally be understood to mean "and/or"
and so forth.
[0027] Recitation of ranges of values herein are not intended to be
limiting, referring instead individually to any and all values
falling within the range, unless otherwise indicated herein, and
each separate value within such a range is incorporated into the
specification as if it were individually recited herein. The words
"about," "approximately," "substantially," or the like, when
accompanying a numerical value, are to be construed as indicating a
deviation as would be appreciated by one of ordinary skill in the
art to operate satisfactorily for an intended purpose. Ranges of
values and/or numeric values are provided herein as examples only,
and do not constitute a limitation on the scope of the described
embodiments. The use of any and all examples, or exemplary language
("e.g.," "such as," or the like) provided herein, is intended
merely to better illuminate the embodiments and does not pose a
limitation on the scope of the embodiments or the claims. No
language in the specification should be construed as indicating any
unclaimed element as essential to the practice of the
embodiments.
[0028] In the following description, it is understood that terms
such as "first," "second," "top," "bottom," "up," "down," and the
like, are words of convenience and are not to be construed as
limiting terms unless specifically stated to the contrary.
[0029] Described herein are devices, systems, and methods related
to three-dimensional printing, where a design, such as a
computer-aided drafting (CAD) file, is provided to a computer
operably connected to a three-dimensional printer (e.g., a
three-dimensional metal printer), and the object represented by the
design may be manufactured in a layer-by-layer fashion by the
three-dimensional printer.
[0030] In general, the following description emphasizes
three-dimensional printers using metal as a build material for
forming a three-dimensional object. More specifically, the
description emphasizes metal three-dimensional printers that
deposit metal for forming a three-dimensional object using, e.g.,
an electrohydrodynamic force to control delivery of a liquid metal
from an expeller. However, it will be understood that, unless
explicitly stated to the contrary or otherwise clear from the
context, the metal three-dimensional printers may also or instead
control delivery of a liquid metal build material using, e.g., a
gas feed, a piezoelectric drop-on-demand droplet generator, an
ultrasonic generator, and the like. Additionally, such printers may
usefully print with other materials, e.g., for support structures
or the like, alternately or concurrently with the deposition of
metal. Some of the techniques contemplated herein may also be
usefully adapted for use with metal three-dimensional printers
using fused filament fabrication or similar techniques where a bead
of material is extruded in a layered series of two dimensional
patterns as "roads," "paths," or the like to form a
three-dimensional object from a digital model.
[0031] Thus, although the devices, systems, and methods emphasize
metal three-dimensional printing using electrohydrodynamic forces,
a skilled artisan will recognize that many of the techniques
discussed herein, specifically techniques related to monitoring or
analyzing a three-dimensional build (e.g., during a physical build
process, before a physical build process, or after a physical build
process) may be adapted to three-dimensional printing using other
materials (e.g., thermoplastics and the like) and other additive
fabrication techniques including without limitation multijet
printing, stereolithography, Digital Light Processor ("DLP")
three-dimensional printing, selective laser sintering, and so
forth. Such techniques may benefit from the systems and methods
described below, and all such printing technologies are intended to
fall within the scope of this disclosure, and within the scope of
terms such as "printer," "three-dimensional printer," "fabrication
system," "additive manufacturing system," and so forth, unless a
more specific meaning is explicitly provided or otherwise clear
from the context.
[0032] Therefore, methods and techniques of the present disclosure
can be performed, unless otherwise indicated, in analogy to methods
known in polymer additive manufacturing, carbon fiber additive
manufacturing, and metal powder additive manufacturing, examples of
which are disclosed in U.S. Pat. No. 5,121,329; U.S. Pat. No.
5,503,785; U.S. Pat. No. 8,765,045; U.S. patent application Ser.
No. 13/343,651, filed Jan. 4, 2012; U.S. patent application Ser.
No. 13/587,002, filed Aug. 16, 2012; U.S. patent application Ser.
No. 13/949,946, filed Jul. 24, 2013; and U.S. patent application
Ser. No. 14/297,437, filed Jun. 5, 2014. All of the above, and any
other publications, patents, and published patent applications
referred to in this application are specifically incorporated
herein by reference in their entirety. In case of conflict, the
present specification, including its specific definitions, shall
control.
[0033] FIG. 1 depicts an additive manufacturing system. The
additive manufacturing system 100 shown in the figure may be
configured specifically for three-dimensional printing using a
metal build material such a metallic alloy. However, the additive
manufacturing system 100 may also or instead be used with other
build materials including plastics, ceramics, and the like.
[0034] The additive manufacturing system 100 may include a printer
101 having a build chamber 110, an expeller 120, a print bed 140, a
robotic positioning assembly 150, and a controller 160.
[0035] In general, the build chamber 110 may house the other
components of the additive manufacturing system 100 including,
e.g., the expeller 120, the print bed 140, and the robotic
positioning assembly 150, for forming an object 103 (e.g., a
three-dimensional object) within the build chamber 110. In an
aspect, the build chamber 110 is environmentally sealed, where the
build chamber 110 includes an enclosure 112 for environmentally
sealing a build volume 102 from an external environment 104. The
build chamber 110 being environmentally sealed may include a
substantially air-tight or hermetically sealed chamber. The
environmentally sealed build chamber 110 may be advantageous for
the manufacturing of metal objects from a liquid metal, e.g., where
an air-tight build chamber 110 can be purged of oxygen, or where an
inert gas (or other gases such as cover gases) can be added into
the build volume 102 in a controlled manner. The build chamber 110
being environmentally sealed may also or instead include a thermal
seal, e.g., a seal preventing an excess of heat transfer from the
build volume 102 to the external environment 104, and vice-versa.
The seal of the build chamber 110 may also or instead enable
control of a pressure included within the build chamber 102. To
maintain the seal of the build chamber 110, any openings in the
enclosure 112, e.g., for build material feeds, electronics, and so
on, may similarly include seals or the like.
[0036] The build chamber 110 may include a deoxygenator 114 in
communication with the build chamber 110 for purging/removing
oxygen from the build chamber 110. The deoxygenator 114 may include
without limitation one or more of an oxygen filter, an oxygen
getter, an electrochemical oxygen pump, a cover gas supply, an air
circulator, and the like. Thus, in implementations, purging the
build chamber 110 of oxygen may include one or more of applying a
vacuum to the build chamber 110, supplying an inert gas to the
build chamber 110, placing an oxygen getter inside the build
chamber 110, applying an electrochemical oxygen pump to the build
chamber 110, cycling the air inside the build chamber 110 through
an oxygen filter, and the like.
[0037] The build chamber 110 may include a temperature control
system 116 for maintaining or adjusting a temperature of at least a
portion of a volume of the build chamber 110 (the build volume
102). The temperature control system 116 may include without
limitation one or more of a heater, a coolant, a fan, a blower, or
the like. The temperature control system 116 may use a fluid or the
like as a heat exchange medium for transferring heat as desired
within the build chamber 110. The temperature control system 116
may also or instead move air (e.g., circulate air) within the build
chamber 110 to control temperature, to provide a more uniform
temperature, or to transfer heat within the build chamber 110.
[0038] The temperature control system 116, or any of the
temperature control systems described herein (e.g., the expeller's
temperature control system 126 or the print bed's temperature
control system 144) may include one or more active devices such as
resistive elements that convert electrical current into heat,
Peltier effect devices that heat or cool in response to an applied
current, or any other thermoelectric heating and/or cooling
devices. Thus, the temperature control systems discussed herein may
include a heater that provides active heating to the components of
the printer 101, a cooling element that provides active cooling to
the components of the printer 101, or a combination of these. The
temperature control systems may be coupled in a communicating
relationship with the controller 160 in order for the controller
160 to controllably impart heat to or remove heat from the
components of the printer 101. Thus, the temperature control
systems may include an active cooling element positioned within or
adjacent to the components of the printer 101 to controllably cool
the components of the printer 101. It will be understood that a
variety of other techniques may be employed to control a
temperature of the components of the printer 101. For example, the
temperature control systems may use a gas cooling or gas heating
device such as a vacuum chamber or the like in an interior thereof,
which may be quickly pressurized to heat the components of the
printer 101 or vacated to cool the components of the printer 101 as
desired. As another example, a stream of heated or cooled gas may
be applied directly to the components of the printer 101 before,
during, and/or after a build process. Any device or combination of
devices suitable for controlling a temperature of the components of
the printer 101 may be adapted to use as the temperature control
systems described herein.
[0039] It will be further understood that the temperature control
system 116 for the build chamber 110, the temperature control
system 126 for the expeller 120, and the temperature control system
144 for the print bed 140 may be included in a singular temperature
control system (e.g., included as part of the controller 160 or
otherwise in communication with the controller 160) or they may be
separate and independent temperature control systems
[0040] The build chamber 110 may include a pressure control system
118 for maintaining or adjusting a pressure of at least a portion
of a volume of the build chamber 110 (e.g., an air pressure of the
build volume 102). The pressure control system 118 may also or
instead be used to maintain or adjust a pressure of a reservoir
housing the liquid build material (e.g., liquid metal), e.g.,
relative to the pressure of the build chamber 110. Thus, the
pressure control system 118 may be part of the expeller 120 as
shown in the figure.
[0041] The expeller 120 (examples of which are shown in more detail
in FIGS. 2-4) may include a reservoir, a heater configured to
maintain a build material (e.g., a metal or metallic alloy) within
the reservoir in a liquid form, and an outlet 122 within the build
chamber 110. The components of the expeller 120, e.g., the
reservoir and the heater, may be contained within a housing 124 or
the like.
[0042] The expeller 120 or a component thereof may include or be
coupled with (e.g., electronically coupled) a temperature control
system 126 for maintaining or adjusting a temperature at the outlet
122 of the expeller 120 or some other location or component
thereof, e.g., the reservoir. The temperature control system 126
may include without limitation one or more of the heater, a
coolant, a fan, a blower, or the like.
[0043] The expeller 120 or a portion thereof may be movable within
the build chamber 110 by the robotic positioning assembly 150,
e.g., relative to the print bed 140. For example, the expeller 120
may be movable by the robotic positioning assembly 150 along a tool
path while depositing a build material (e.g., a liquid metal) to
form the object 103, or the print bed 140 may move within the build
chamber 110 while the expeller 120 remains stationary.
[0044] In general, the expeller 120 may be configured to deposit a
build material, e.g., a metal in liquid form, from the outlet 122.
In an aspect, the expeller 120 is configured to modulate a release
of the metal in the liquid form from the outlet 122 by applying an
electrohydrodynamic force to control a surface tension on the metal
at the outlet 122, thereby providing a supply of build material for
forming the object 103. In other words, a metallic liquid expeller
may be configured to drive droplets of liquefied metal from the
outlet 122 of the expeller 120 by applying an electrostatic field
to a meniscus of the liquefied metal extending from the outlet
122.
[0045] The expeller 120 may include or be connected to a feed 128
for build material, e.g., an opening for receiving a metal filament
or the like. Specifically, the feed 128 may receive the build
material into the reservoir for melting the build material into a
liquid form.
[0046] The expeller 120 may include an electrohydrodynamic (EHD)
device. The EHD device may include one or more electrodes coupled
in electronic communication with the outlet 122, and the EHD device
may be configured to drive droplets of liquefied metal from the
outlet 122 by applying an electrostatic field to a meniscus of the
liquefied metal extending from the outlet 122. In an aspect, a
voltage difference between the build material and the one or more
electrodes is configured to create the electrostatic field for
modulating the surface tension or meniscus of the liquid metal
sufficient to expel a droplet of the liquid metal from the outlet
122. In an aspect, a capacitance between the build material and the
one or more electrodes is configured to create the electrostatic
field for modulating the surface tension or meniscus of the liquid
metal sufficient to expel a droplet of the liquid metal from the
outlet 122.
[0047] Electrohydrodynamic forces are known for use, for example,
in two-dimensional printers or surface patterning or coating
systems where fine, atomizing sprays or streams can be usefully
created from an electrically charged meniscus of ink or other
printing material. Similar principles may be applied to create a
controllable stream of liquid metal droplets although, as described
herein, maintaining droplets of liquid metal that solidify upon
contact with a printed object, but not beforehand, may require
additional control of distance, velocity, and temperature of the
expelled liquid metal, as well as additional modeling, monitoring,
and/or feedback to ensure that a target three-dimensional shape is
being achieved.
[0048] In some implementations, the expeller 120 may include a
voltage regulator that applies an electrostatic field across a
meniscus of liquid metal at the outlet 122 of the expeller 120. For
steering and propulsion, a bias voltage may also be applied between
the outlet 122 and a print bed 140 or other location. In some such
implementations, the expeller 120 may include an EHD printing
device similar to that described in Y. Han et al., "Droplet
Formation and Settlement of Phase-Change Ink in High Resolution
Electrohydrodynamic (EHD) 3D Printing," JOURNAL OF MANUFACTURING
PROCESSES (2015), the contents of which are herein incorporated by
reference in their entirety. In some implementations in which the
expeller 120 comprises an EHD printing device, the capacitance
between the metal and an electrode may be designed to modulate the
surface tension of the liquid metal, where one or more of the
spacing between the outlet 122 and an electrode, the geometry of
the outlet 122 and an electrode, and the dielectric materials
between the outlet 122 and the electrode may be chosen or varied
based on a desired surface tension of the liquid metal. It will be
appreciated that an EHD process may generally be controlled to
eject discrete droplets or a continuous stream of liquid, or some
combination of these. Thus, a metallic EHD printer may usefully
switch between continuous and intermittent modes during
fabrication, e.g., by using a continuous stream to fill voids or
openings within an object being fabricated.
[0049] In some implementations in which the expeller 120 includes a
voltage regulator, the expeller 120 may further include an
electrode positioned below the outlet 122. Such an electrode may be
a torus or have some other suitable geometry. In such
implementations, the expeller 120 may create a voltage difference
between the metal build material and the electrode, thereby
expelling a drop of the liquid metal past or through the electrode
and onto the print bed 140. In some such implementations, the
electrode may be insulated.
[0050] In some implementations, the system further comprises a
plurality of electrodes positioned below a plurality of outlets
(see, e.g., FIG. 4). In such implementations, each electrode may
act as an independent expeller, allowing accretion to occur
simultaneously at multiple parts and/or locations of an object. In
some such implementations, more than one outlet in the plurality of
outlets may be associated with a single reservoir, allowing
multiple outlets or nozzles to share a single metal supply. In
other embodiments, different outlets may provide different
materials or material types, such as different metal alloys or
different build materials and support materials. In some
implementations in which the system comprises a plurality of
electrodes, the electrodes may be printed onto a ceramic printed
circuit board.
[0051] In alternate embodiments, the expeller 120 may also or
instead include an ultrasonic generator, or another device in which
the expeller 120 operates by acoustic droplet ejection where
acoustic energy is applied to the liquid build material. In some
such implementations, the expeller 120 generates ultrasonic waves.
In an aspect, the expeller 120 may also or instead include a
mechanical device, such as a valve, a plate with metering holes, or
some other suitable mechanism.
[0052] In some implementations, the expeller 120 may include a
piezoelectric material. As an illustrative example of such an
implementation, the expeller 120 may include the reservoir as
described herein, and a voltage may be applied to the expeller 120
to change the shape or volume of the reservoir and thereby expel a
quantity of the liquid metal. Thus, actuating the expeller 120 may
include applying a voltage to a piezoelectric material.
[0053] In some implementations, the expeller 120 may include an
induction coil. In such implementations, the expeller 120 may
magnetically control the release of the liquid metal. The induction
coil may be the same coil used as the heater for the expeller 120
in an embodiment, or it may be a different coil.
[0054] In some implementations, the expeller 120 may expel 400 pL,
500 pL, 600 pL, 700 pL, 800 pL, 900 pL, 1 nL, or some other
suitable volume of the liquid first metal at a time, e.g., per
ejection. In some implementations, the controller 160 may be
configured to select a volume of the liquid first metal to expel at
any given time. Thus, the expeller 120 may usefully deliver a
controllable droplet size according to, e.g., desired feature
sizes, print resolution, build time, or any other process
limitations or parameters.
[0055] The outlet 122 may be a hole or opening in the expeller 120
for expelling a build material. The outlet 122 may have a diameter
in the range of 10 .mu.m-1 mm, such as 10 .mu.m, 20 .mu.m, 30
.mu.m, 40 .mu.m, 50 .mu.m, 100 .mu.m, 1 nm, 1 mm, and so on.
[0056] In some implementations, the geometry of the reservoir
and/or the outlet 122 may be designed to affect the surface tension
of the liquid metal. In some implementations, the size of the
reservoir and/or the outlet may be designed to affect the surface
tension of the liquid metal.
[0057] The print bed 140 may be disposed within the build chamber
110 and include a surface 142 configured to receive the supply of
build material to form the object 103. The surface 142 may be rigid
and substantially planar, where the surface 142 is configured for
receiving liquid metal droplets released from the expeller 120.
[0058] The print bed 140 may be movable within the build chamber
110, e.g., by a positioning assembly (e.g., the same robotic
positioning assembly 150 that positions the expeller 120 or a
different positioning assembly). Specifically, in an aspect, the
print bed 140 is movable relative to the expeller 120, e.g., along
one or more axes. For example, the print bed 140 may be movable
along a z-axis (e.g., up and down--toward and away from the outlet
122 of the expeller 120), or along an x-y plane (e.g., side to
side, for instance in a pattern that forms the tool path or that
works in conjunction with movement of the expeller 120 to form the
tool path for fabricating the object 103). In an aspect, the print
bed 140 is rotatable.
[0059] The print bed 140 may include a temperature control system
144 for maintaining or adjusting a temperature of at least a
portion of the print bed 140. The temperature control system 144
may be wholly or partially embedded within the print bed 140. The
temperature control system 144 may include without limitation one
or more of a heater, coolant, a fan, a blower, or the like.
[0060] The robotic positioning assembly 150 may be structurally
configured to position the outlet 122 relative to the print bed 140
within the build chamber 110. The robotic positioning assembly 150
may include a Cartesian coordinate robot, a delta robot, or some
other suitable robot such as depicted in the figure.
[0061] The robotic positioning assembly 150 may position the outlet
122 relative to the print bed 140 by controlling movement of one or
more of the expeller 120 and the print bed 140. For example, in an
aspect, the expeller 120 is operably coupled to the robotic
positioning assembly 150 such that the robotic positioning assembly
150 positions the expeller 120. The print bed 140 may also or
instead be operably coupled to the robotic positioning assembly 150
such that the robotic positioning assembly 150 positions the print
bed 140. Or some combination of these techniques may be employed,
such as by moving the expeller 120 up and down for z-axis control,
and moving the print bed 140 within the x-y plane x-axis and y-axis
control. In some such implementations, the robotic positioning
assembly 150 may translate the print bed 140 along one or more
axes, and may rotate the print bed 140.
[0062] It will be understood that a variety of arrangements and
techniques are known in the art to achieve controlled linear
movement along one or more axes. The robotic positioning assembly
150 may, for example, include a number of stepper motors to
independently control a position of the expeller 120 or print bed
140 within the build volume 102 along each of an x-axis, a y-axis,
and a z-axis. More generally, the robotic positioning assembly 150
may include without limitation various combinations of stepper
motors, encoded DC motors, gears, belts, pulleys, worm gears,
threads, and the like. Any such arrangement suitable for
controllably positioning the expeller 120 or print bed 140 may be
adapted to use with the additive manufacturing system 100 described
herein.
[0063] The controller 160 may be coupled to (e.g., electronically
coupled to, or otherwise in communication with) one or more
components of the additive manufacturing system 100 for providing
control functionality thereto. For example, in an aspect, the
controller 160 may be coupled to the expeller 120 and the robotic
positioning assembly 150. The controller 160 may control aspects of
the expeller 120 such as a deposition rate of build material, an
amount of deposited build material, and so forth. The controller
160 may control aspects of the robotic positioning assembly 150,
such as the positioning of either or both of the expeller 120 or
the print bed 140 relative to one another. In general, the
controller 160 may be operable to control the additive
manufacturing system 100 to fabricate the object 103 based on a
digital model 106 that provides a three-dimensional representation
of the object 103.
[0064] In some implementations, the controller 160 may be further
configured to control a surface tension and/or a meniscus of the
liquid metal by controlling one or more of the liquid metal's
conditions. In such implementations, the controller 160 may be
further configured to: apply an AC voltage signal to the metal;
apply a DC voltage signal to the metal; vary the temperature of the
metal; control the composition, temperature, and/or pressure of the
atmosphere in the reservoir; control the composition, temperature,
and/or pressure of the atmosphere below the outlet 122; apply a
baseline EHD field; vary an EHD field; or otherwise suitably alter
the conditions of the liquid metal.
[0065] The controller 160 may thus be electrically coupled in a
communicating relationship with one or more of the various
components of the additive manufacturing system 100 as described
herein. In general, the controller 160 is operable to control the
components of the additive manufacturing system 100, such as the
expeller 120, the print bed 140, the robotic positioning assembly
150, the various temperature and pressure control systems, and any
other components of the additive manufacturing system 100 described
herein to fabricate the object 103 from the build material. The
controller 160 may include any combination of software and/or
processing circuitry suitable for controlling the various
components of the additive manufacturing system 100 described
herein including without limitation microprocessors,
microcontrollers, application-specific integrated circuits,
programmable gate arrays, and any other digital and/or analog
components, as well as combinations of the foregoing, along with
inputs and outputs for transceiving control signals, drive signals,
power signals, sensor signals, and the like. In one aspect, the
controller 160 may include a microprocessor or other processing
circuitry with sufficient computational power to provide related
functions such as executing an operating system, providing a
graphical user interface (e.g., to a display coupled to the
controller 160 or additive manufacturing system 100), convert
three-dimensional models into tool instructions, and operate a web
server or otherwise host remote users and/or activity through a
network interface 180 for communication through a network 182.
[0066] The additive manufacturing system 100 may further include
one or more sensors 170. In an aspect, the sensor 170 may be in
communication with the controller 160, e.g., through a wired or
wireless connection (e.g., through a data network 182). The sensor
170 may be configured to detect progress of fabrication of the
object 103, and to send a signal to the controller 160 where the
signal includes data characterizing progress of fabrication of the
object 103. The controller 160 may be configured to receive the
signal, and to adjust at least one parameter of the additive
manufacturing system 100 in response to the detected progress of
fabrication of the object 103.
[0067] In an aspect, the sensor 170 may be in communication with
the controller 160, where the sensor 170 is configured to monitor
one or more of the surface tension and a meniscus of the build
material (e.g., metal) in liquid form in the expeller 120. The
sensor 170 may be configured to send a signal to the controller 160
where the signal includes data characterizing one or more of the
surface tension and the meniscus. In response to receiving the
signal, the controller 160 may be configured to adjust at least one
parameter of the additive manufacturing system 100 to control one
or more of the surface tension and the meniscus.
[0068] In response to data or signals received from the one or more
sensors 170, the controller 160 may be configured to apply a
voltage to the build material--i.e., the liquid metal--to control
one or more of the surface tension and the meniscus.
[0069] The one or more sensors 170 may include without limitation
one or more of a contact profilometer, a non-contact profilometer,
an optical sensor, a laser, a temperature sensor, motion sensors,
an imaging device, a camera, an encoder, an infrared detector, a
volume flow rate sensor, a weight sensor, a sound sensor, a light
sensor, a sensor to detect a presence (or absence) of an object,
and so on.
[0070] As discussed above, the controller 160 may adjust a
parameter of the additive manufacturing system 100 in response to
the sensor 170. The parameter of the additive manufacturing system
100 adjusted by the controller 160 in response to data or signals
received from the one or more sensors 170 may include a temperature
of the build material (e.g., the liquid metal), a temperature of at
least a portion of a volume of the build chamber 110, and a
temperature of the print bed 140. The parameter may also or instead
include a pressure differential between the reservoir of the
expeller and the build chamber 110, or otherwise a pressure of a
portion of the build chamber 110 or the reservoir. The parameter
may also or instead include an intensity of an electrostatic field.
The parameter may also or instead include an amount or
concentration of an additive for mixing with the build material
(e.g., an additive for mixing with a metal build material).
[0071] In some implementations, the controller 160 may (in
conjunction with one or more sensors 170) may identify the build
material used in the additive manufacturing system 100, and may in
turn adjust a parameter of the additive manufacturing system 100
based on the identification of the build material including without
limitation at least one of the temperature of the build material,
actuation of the expeller 120, and a position of one or more of the
print bed 140 and the expeller 120 via the robotic positioning
assembly 150.
[0072] An example of an operation of the additive manufacturing
system 100 will now be discussed. In operation, to prepare for the
additive manufacturing of an object 103, a design for the object
may first be provided to a computing device 108. The design may be
a digital model 106 included in a CAD file or the like. The
computing device 108 may be any as described herein and may in
general include any devices operated autonomously or by users to
manage, monitor, communicate with, or otherwise interact with other
components in the additive manufacturing system 100. This may
include desktop computers, laptop computers, network computers,
tablets, smart phones, smart watches, PDAs, or any other computing
device that can participate in the system as contemplated herein.
In one aspect, the computing device 108 is integral with the
printer 101.
[0073] The computing device 108 may include the controller 160 as
described herein or a component of the controller 160. The
computing device 108 may also or instead supplement or be provided
in lieu of the controller 160. Thus, unless explicitly stated to
the contrary or otherwise clear from the context, any of the
functions of the computing device 108 may be performed by the
controller 160 and vice-versa. In another aspect, the computing
device 108 is in communication with or otherwise coupled to the
controller 160, e.g., through a network 182.
[0074] One or more of the computing device 108 and the controller
160 may include a processor 162 (and/or other processing circuitry)
and a memory 164 to perform the functionality described herein and
generally a variety of processing tasks related to management of
the additive manufacturing system 100 as described herein. The
processor 162 and memory 164 may be any as described herein or
otherwise known in the art. In general, the memory 164 may contain
computer code and may store data, e.g., data generated by other
components of the additive manufacturing system 100.
[0075] A first build material (e.g., a first metal) may be provided
to the feed 128 of the expeller 120, and the build chamber 110 may
be sealed and purged of oxygen. The first metal may be a wire or
filament, where the feed 128 may direct and move the wire into the
reservoir of the expeller 120, e.g., via a tube that is sealed to
the reservoir such that one or more of the composition, the
pressure, and the temperature of the interior of the reservoir may
be controlled. Once these preparatory steps have been completed,
the first metal may be melted within the reservoir of the expeller
120, or melted and directed into the reservoir. The connection
between the feed 128 and the reservoir may be designed to protect
the feed 128 from the heat of the liquid metal, such as by
thermally insulating a portion of the junction of the reservoir and
the feed 128 connection. As discussed herein, the first metal may
be melted by inductive heating, e.g., using a heater in the
expeller 120.
[0076] In some implementations, the feed 128 includes a metal wire.
In some such implementations, the wire may have a diameter of
approximately 80 .mu.m, 90 .mu.m, 100 .mu.m, 0.5 mm, 1 mm, 1.5 mm,
2 mm, 2.5 mm, 3 mm, or some other suitable diameter. In other
implementations, the feed 128 includes a metal powder.
[0077] The computing device 108 may identify how thick each layer
of the object 103 will be based on the first metal and the digital
model 106, and thus the computing device 108 may identify where and
how much liquid first metal should be expelled from the outlet 122
of the expeller 120 to manufacture each layer of the object 103 to
match the digital model 106 of the object 103. The computing device
108 may instruct the robotic positioning assembly 150 to configure
components of the additive manufacturing system 100 such that the
expeller 120 expels the liquid first metal onto the print bed 140
as part of a layer of the object 103. As depicted in the figure,
the expeller 120 may be attached to the robotic positioning
assembly 150 such that the robotic positioning assembly 150 moves
the expeller 120. In another aspect, the expeller 120 may have a
fixed location, and the robotic positioning assembly 150 may move
the print bed 140 relative to this fixed expeller 120. The
computing device 108 may control the robotic positioning assembly
150, the heater, and the expeller 120 to create a layer of the
object 103, and a subsequent layer of the object 103 on top of the
previously deposited layer, and continue until the object 103 is
complete. To create a layer, the computing device 108 may identify
an ordered pattern of liquid metal droplets to apply to generate
the layer. The computing device 108 may further identify a minimum
distance between droplets that will allow each droplet to cool
quickly and independently without imparting significant stress to a
printed part, and may manufacture a layer by applying droplets
spaced at least the minimum distance apart and applying adjacent
droplets only after the earlier droplets have had sufficient time
to cool.
[0078] In some implementations, the computing device 108 may
receive data from a sensor 170--for example, a contact
profilometer, an optical profilometer, or some other suitable
sensor system used to identify features of a surface during the
additive manufacturing process. As an illustrative example, the
additive manufacturing system 100 may include a Dense Tracking and
Mapping (DTAM) system, such as is described in R. A. Newcombe et
al., "DTAM: Dense tracking and mapping in real-time," 2011 IEEE
INTERNATIONAL CONFERENCE ON COMPUTER VISION (ICCV) (2011), the
contents of which are herein incorporated by reference in their
entirety. In such implementations, a sensor 170 may confirm whether
a layer has been formed correctly. If a portion of the layer is not
within an acceptable margin of error (for example, a depression is
too deep, there is a protrusion on a layer, porosity is too high,
or the like), the computing device 108 may control the additive
manufacturing system 100 to add more liquid metal or reduce the
amount of liquid metal used on subsequent layers to correct
deficiencies. In some implementations, the additive manufacturing
system 100 may also or instead inform a user of manufacturing
errors, adjust print parameters to correct errors, adjust output of
other materials used in a design based on any identified
discrepancies, or take other corrective action. In some
implementations, the sensor 170 may be used to identify aberrations
in the surface of the physical printed object 103 through a
comparison to a design of the object 103, and the additive
manufacturing system 100 may then be used to refinish the surface
of the object 103.
[0079] The computing device 108 may usefully calculate the thermal
mass of an object that is receiving a drop of liquid material,
particularly in the location where a droplet is expected to impact
the object. This may, for example, be based on the shape and size
of the object (which can be estimated at any point during
fabrication based on the CAD model or other digital design of the
object being used to control the fabrication process), as well as
the print bed 140 and any other materials between the print bed 140
and the expeller 120. Based on the thermal mass and any other
relevant thermal parameters such as thermal conductivity,
temperature, and so forth, the computing device 108 may adjust the
relative position of the expeller 120 and the print bed 140 using
the robotic positioning assembly 150, adjust the heat of the liquid
material, adjust the quantity of liquid material expelled (e.g.,
the size or frequency of droplets), adjust the velocity of liquid
metal droplets, adjust the temperature of the print bed 140, or
adjust any other suitable parameters of the additive manufacturing
system 100 in order to improve the consistency of the impact and
freezing process.
[0080] The additive manufacturing system 100 may include, or be
connected in a communicating relationship with, a network interface
180. The network interface 180 may include any combination of
hardware and software suitable for coupling the controller 160 and
other components of the additive manufacturing system 100 in a
communicating relationship to a remote computer (e.g., the
computing device 108) through a data network 182. By way of example
and not limitation, this may include electronics for a wired or
wireless Ethernet connection operating according to the IEEE 802.11
standard (or any variation thereof), or any other short or long
range wireless networking components or the like. This may include
hardware for short range data communications such as Bluetooth or
an infrared transceiver, which may be used to couple into a local
area network or the like that is in turn coupled to a data network
such as the Internet. This may also or instead include
hardware/software for a WiMax connection or a cellular network
connection (using, e.g., CDMA, GSM, LTE, or any other suitable
protocol or combination of protocols). Consistently, the controller
160 may be configured to control participation by the additive
manufacturing system 100 in any network 182 to which the network
interface 180 is connected, such as by autonomously connecting to
the network 182 to retrieve printable content, or responding to a
remote request for status or availability.
[0081] Examples of expellers of additive manufacturing systems will
now be discussed.
[0082] FIG. 2 depicts an expeller of an additive manufacturing
system. As shown in the figure, the expeller 200 may include a
build material feed 210, a reservoir 220, a heater 230, an outlet
240, and a casing 250.
[0083] The build material feed 210 may include a wire feed or the
like for receiving one or more wires or filament of build material
212. The build material feed 210 may also or instead include a
motor or the like to push the build material 212 into the reservoir
220. The build material feed 210 may also or instead be configured
to receive build material in different forms such as powder,
pellets, liquid, and the like. In an aspect, the build material 212
is a metal wire.
[0084] The reservoir 220 may be substantially sealed such that
melted build material can be contained within the controlled
environment of the reservoir 220. The reservoir 220 may be made of
metal. The metal may include a metal oxide such as an aluminum
oxide, sapphire, or some other suitable metal oxide. The metal of
the reservoir 220 may also or instead include one or more of
tungsten, a metal carbide (e.g., a tungsten carbide), a metal
nitride, and the like. The reservoir 220 may also or instead be
made of other materials, e.g., ceramic materials or the like.
[0085] In some implementations, one or more of the reservoir 220
and the outlet 240 may include a material selected to affect the
surface tension of the liquid metal build material. In some
implementations, one or more of the reservoir 220 and the outlet
240 include a surface treatment selected to affect the surface
tension of the liquid metal build material and/or the wettability
of the reservoir 220 by the liquid metal build material.
[0086] In some implementations, the reservoir 220 has a volume
between about 0.0001 mL and 1 mL. As an illustrative example, the
reservoir 220 may comprise a hole 0.08 mm in diameter and
approximately 20 mm deep. In some implementations, the reservoir
220 has a volume between about 0.0001 mL-0.04 mL. In some
implementations, the reservoir 220 has a volume between about 0.01
mL and 0.04 mL. In some implementations, the reservoir 220 has a
volume between about 0.1 mL-1 mL. Other volumes are also
possible.
[0087] The heater 230 may be configured to maintain a metal within
the reservoir 220 in a liquid form, or otherwise maintain a build
material 212 in the reservoir 220 at a desired temperature or a
desired physical state. The heater 230 may include an induction
coil as shown in the figure, where at least a portion of the
induction coil wraps at least partially around the reservoir 220.
The induction coil may also or instead be used for other purposes
besides heating. For example, in an aspect, release of the metal in
liquid form from the outlet 240 is modulated by an inductor such as
the induction coil, which is configured to control a magnetic field
around the outlet 240. The magnetic field may be adjusted (tuned)
for controlling the meniscus of the liquid metal at the outlet 240
for expelling the liquid metal. This may be used in addition to, or
in lieu of an EHD device for expelling metal droplets of build
material. Thus, in an aspect, the induction coil acts as the
expeller for the system.
[0088] The heater 230 may also or instead include one or more
heating blocks with resistive elements to heat the reservoir 220
with applied current, an inductive heater, or any other arrangement
of heaters suitable for creating heat within the reservoir 220 to
melt the build material 212.
[0089] The casing 250 may include a cover gas case or the like that
introduces a cover gas over the expeller 200. The casing 250 may
also or instead include an insulator, a protective casing, or the
like.
[0090] Thus, in some implementations, the system may include an
induction coil surrounding the reservoir, which is used to liquefy
the metal build material. In some such implementations, the
expeller 200 may be further configured to transmit an
identification signal to the controller, which may identify the
conductivity of the metal, identify the metal, identify the
diameter of the outlet 240, or provide other suitable information.
In such implementations, the controller may be further configured
to receive the identification signal, control the quantity of the
metal added to the reservoir 220 from the build material feed 210,
control the heater 230 (e.g., induction coil), and control at least
one of the expeller and the print bed based on the received signal,
which may include controlling the temperature of the print bed,
controlling the amount of liquid metal expelled by the expeller, or
performing other suitable tasks. In some implementations in which
the system includes an induction coil, the induction coil may for
example be a 0.5 kW induction coil, a 1.0 kW induction coil, or
some other suitable induction coil. When the system includes an
induction coil, one or more of the frequency of the induction
heating field, the magnitude of the induction heating field, and
the profile of the induced current in the liquid metal may be
varied to modulate a surface tension of the liquid metal.
[0091] FIG. 3 depicts an expeller of an additive manufacturing
system. As shown in the figure, the expeller 300 may include a
plurality of feeds 310, a tube interface 314, a reservoir 320, and
a heater 330.
[0092] The plurality of feeds 310 may include multiple conduits
(e.g., tubes or the like) for supplying a plurality of build
materials. One or more of the conduits may also or instead supply a
gas, one or more additives, wiring, and the like.
[0093] The tube interface 314 may be temperature controlled in an
aspect. For example, the tube interface 314 may be cooled.
[0094] The reservoir 320 may include separate reservoirs/containers
therein for containing different build materials, or the different
build materials may be mixed within a single
reservoir/container.
[0095] FIG. 4 depicts a cutaway of an expeller including multiple
outlets. As shown in the figure, the expeller 400 may include a
feed 410, a heater 430, and a plurality of outlets 440 fed by a
single reservoir 420.
[0096] In some implementations, there may be more than one outlet
440, and a controller or computing device may control the multiple
outlets 440 to simultaneously create multiple portions of a layer
of an object based on a digital design. As an illustrative example,
and as is depicted in the figure, multiple outlets 440 may be
connected to a single reservoir 420 heated by a single heater 430,
e.g., an induction coil. Each of the outlets 440 may include its
own EHD device 450 having one or more electrodes 452. In such
implementations, the controller may perform raster printing using
the multiple outlets 440 by translating the expeller 400 relative
to the print bed (or vice-versa) using the robotic positioning
assembly, actuating at least two of the EHD devices 450 while
translating and shifting one or more of the expeller 400 and the
print bed along a second axis orthogonal to the first axis.
[0097] As depicted in the figure, in an aspect, the reservoir 420
may be longer than its induction coil, thereby allowing for a feed
wire to remain connected to the liquid metal at the bottom of the
reservoir 420. In this manner, the feed wire may act as a first
electrode used to set the voltage of the liquid metal, and an array
of second electrodes 452 may be used for EHD printing from a
plurality of outlets 440. The second electrodes 452 in such an
implementation may be insulated to protect the electrodes 452 from
the heat of the liquid metal.
[0098] Implementations of expellers with multiple outlets will now
be discussed. Such implementations may be similar to the
embodiments discussed above with reference to FIGS. 1-4, but may
include additional outlets. The additional outlets may be the same
type of outlets as the outlets discussed above, or they may be
different outlets. The additional outlets may be positioned via the
same robotic positioning system as the outlets discussed above, or
by a separate robotic positioning system. Similarly, the additional
outlets may be controlled by the same controller discussed above,
or a separate controller.
[0099] An additive manufacturing system may include a build
chamber. The additive manufacturing system may include a first
expeller including a first reservoir, a first heater configured to
maintain a metal within the first reservoir in a liquid form, and a
first outlet within the build chamber. The first expeller may be
configured to modulate a release of the metal in the liquid form
from the first outlet by applying an EHD force to control a surface
tension on the metal at the first outlet, thereby providing a
supply of first build material. The additive manufacturing system
may include a print bed within the build chamber, where the print
bed includes a surface configured to receive the supply of first
build material, a robotic positioning assembly structurally
configured to position the first outlet relative to the print bed
within the build chamber, and a controller coupled to the first
expeller and the robotic positioning assembly. The controller may
be operable to control the additive manufacturing system to
fabricate an object based on a digital model that provides a
three-dimensional representation of the object.
[0100] The additive manufacturing system may include a second
expeller including a second outlet within the build chamber. The
second expeller may be configured to modulate a release of a second
material in a liquid form from the second outlet, thereby providing
a supply of a second build material. The second expeller and the
second outlet may be the same or similar to the first expeller and
the first outlet, respectively, or each of the second expeller and
the second outlet may be different from one or more of the first
expeller and the first outlet, respectively.
[0101] The second build material may include a support material,
where the second expeller is configured to deposit the support
material for fabrication of a support for the object. In an aspect,
the second build material includes one or more of a metal, a wax, a
polymer, and a salt.
[0102] The second build material may also or instead include a
metal, which may be the same as a metal that comprises the first
build material or different from the metal that comprises the first
build material. In an aspect, the second material includes a metal
and the second expeller includes an EHD device including one or
more electrodes in communication with the second outlet. In an
implementation, a voltage difference between the metal and the one
or more electrodes is configured to create an electrostatic field
for modulating a surface tension or meniscus of the metal in a
liquid form within the second outlet sufficient to expel a droplet
of the metal in the liquid form from the second outlet. In an
aspect, a capacitance between the metal and the one or more
electrodes is configured to create an electrostatic field for
modulating a surface tension or meniscus of the metal in a liquid
form within the second outlet sufficient to expel a droplet of the
metal in the liquid form from the second outlet.
[0103] Thus, as described above, in some implementations, a
three-dimensional printer may include a second expeller associated
with a second material, such as a wax, a second metal dissimilar
from the first metal, a polymer, a ceramic, or some other suitable
material. In such implementations, a computing device may control
the second expeller as well as the first expeller to generate
layers that include the first metal, the second material, or both.
As an illustrative example, if a layer of the first metal is so
thin that it would melt if a further drop of the first metal were
placed on top of it, the computing device may use the second
material to generate a thermal mass to support the thin layer
and/or to serve as a heat sink to draw heat away from the thin
layer. In some such implementations, expellers may be removable in
part or in their entirety--that is, one or more of a material feed,
a reservoir, an outlet, and an expeller may be replaced, e.g., when
a stock of material is being replaced, which may include changing
the material being used in manufacturing or simply refilling a
supply of material. In such implementations, the robotic
positioning assembly may include releasable connections for one or
more material feeds, reservoirs, and/or expellers. In such
implementations, one or more of the reservoir, the outlets, and the
expellers may be associated with a material, e.g., a metal or class
of metals. As an illustrative example, rather than using a
reservoir or an outlet that can be used for any metal, an expeller
that is optimized for use with steel may be used when manufacturing
steel objects while a print head that is optimized for use with
aluminum alloys may be used when manufacturing aluminum objects.
Thus, in some implementations in which the method comprises
supplying a second material to a second expeller, an embodiment
includes detaching the first expeller and attaching the second
expeller.
[0104] In some implementations, the system may include a second
expeller, where the including a second reservoir storing a second
material. The second expeller may be configured to modulate the
release of the second material from the second outlet, and the
second expeller may be operably connected to the controller, where
the controller is further configured to control the second expeller
based on a digital model or design. The second material may be a
wax, a second metal (which may or may not be dissimilar to the
first metal), a polymer, the first metal, or some other suitable
material. The controller may be further configured to operate the
first and second expellers simultaneously, independently of each
other, or in some other suitable fashion. In some implementations,
the controller may be configured to translate one or more of the
print bed or expeller assembly across at least a portion of a range
of motion along a first axis orthogonal to the first expeller,
actuate at least one of the first expeller and the second expeller
while or after translating the print bed or expeller assembly, and
shift the print bed or expeller assembly along a second axis
orthogonal to both the first axis and to the first expeller,
thereby allowing raster printing. In some implementations, the
controller may be configured to position the print bed or expeller
assembly based on a predetermined support design, actuate the
second expeller based on the predetermined support design (thereby
manufacturing the support), calculate a thermal mass of the
support, and adjust at least one of the temperature of the first
metal, the actuation of the first expeller, and the position of the
print bed or expeller assembly based on the thermal mass of the
support. In some such implementations, a technique includes
removing the design support, e.g., by raising the temperature of
the second material to a temperature higher than the melting point
of the second material but lower than the melting point of the
first material.
[0105] In some implementations in which the system includes a first
expeller and a second expeller, a first reservoir and a second
reservoir may be located within a single induction coil.
[0106] In some implementations, the system further includes a third
expeller with a third outlet, where the third expeller shares the
first reservoir with the first expeller, and the third expeller is
configured to interface with the third outlet and to modulate the
release of the liquid first metal from the third outlet. The system
may further include a fourth expeller, a fifth expeller, and so
on.
[0107] As described herein, one or more of the expellers may be
adapted for depositing metal. The metal may include aluminum, e.g.,
an aluminum alloy. The metal may also or instead include iron. For
example, the metal may include a ferrous alloy such as steel,
stainless steel, or some other suitable alloy. The metal may also
or instead include gold, e.g., a gold alloy. The metal may also or
instead include silver, e.g., a silver alloy. The metal may also or
instead include one or more of a superalloy, nickel (e.g., a nickel
alloy), titanium (e.g., a titanium alloy), and the like. Other
metals are also or instead possible.
[0108] In alternate embodiments, the expeller may include a gas
feed and a gas feed regulator, where the expeller supplies a
quantity of gas to the expeller to expel a quantity of liquid metal
(or other build material) from the outlet. In some such
implementations, the gas feed may supply nitrogen, argon, carbon
dioxide, or some other suitable gas.
[0109] FIG. 5 is a flow chart of a method for additive
manufacturing. The method may generally include controlling an
additive manufacturing system (e.g., a metallic EHD
three-dimensional printer) using feedback based on surface
characteristics. In this manner, a printed object may be
topographically monitored in real time, in addition to the real
time monitoring of other characteristics of the printed object or
the additive manufacturing system. Any such data may be used as
feedback for adjusting a current fabrication process, or for making
adjustments to subsequent fabrication processes.
[0110] As shown in step 502, the method 500 may include fabricating
an object based on a three-dimensional model with a printer. The
printer may be the same or similar to the printers/additive
manufacturing systems discussed herein. For example, the printer
may be a three-dimensional metallic printer configured to
additively manufacture the object using droplets of liquefied metal
as a build material, along with a metallic liquid expeller for
controllably propelling the droplets of liquefied metal toward an
object that is being fabricated. The metallic liquid expeller may
be configured to drive the droplets of liquefied metal using
electrohydrodynamic printing principles, e.g., by applying an
electrostatic field to a meniscus of the liquefied metal extending
from an outlet of an expeller or similar hardware.
[0111] The method 500 may be specifically advantageous to EHD
metallic three-dimensional printing because each droplet is subject
to a variety of forces during expulsion, travel, and impact, and
the resulting surface of an object may have variations and
non-uniformities rendering the object unsuitable for an intended
purpose. Against this backdrop, careful control of temperature,
velocity, and position may be used to generally improve uniformity
of deposition. At the same time, monitoring of the surface shape
may be used to identify locations where excess material is
accumulating (which may result in runaway accumulation, e.g., where
a surface projects into the droplet path) or to identify locations
where material is failing to accumulate, e.g., where the source
digital object model indicates that a structure should be present
but no material has been deposited.
[0112] The method 500 may also or instead be used for other
droplet-based three-dimensional printing, i.e., other than EHD
printing. Thus, while an EHD printer is described in the preceding
figures, these techniques may be usefully applied to a variety of
other techniques for additive manufacturing based on the additive
deposition of droplets of liquid metal to provide a target net
shape based on, e.g., a CAD model or other source digital model for
an object that is being fabricated.
[0113] As shown in step 504, the method 500 may include acquiring
surface data from the object with one or more sensors during
fabrication. In general, the surface data may characterize a
location on a layer of a build material of the object deposited by
the printer. The surface data may include information that
identifies inconsistencies or errors in fabrication, such as
depressions, protrusions, and the like. The surface data may thus
include a build height of a layer of the object at a particular
location. The surface data may also or instead include a surface
map of a top layer that is currently being fabricated.
[0114] The surface data may be acquired for each one of the
droplets of liquefied metal. The surface data may also or instead
be acquired for a surface region about the location on the layer of
build material of the object. The surface data may also or instead
be acquired for a voxel about the location on the layer of build
material of the object. Thus, each voxel may be analyzed and
compared to a digital model to determine whether the voxel is in
the correct location and whether the voxel includes the correct
characteristics. In another aspect, the impact location of a
droplet may be analyzed to determine whether adjustments should be
made, e.g., to droplet temperature, droplet velocity, build chamber
temperature, and so forth. For example, the shape of the impact
location may indicate that a droplet is freezing too soon, or too
late, or that the impact speed is too high, any of which might
leave characteristic physical features on the surface of the object
around the impact location. While it may be difficult to control
parameters like temperature on a droplet-by-droplet basis, the
environment within a build chamber may be continuously evaluated
and adjusted to keep the environment at or near an optimum
state.
[0115] The surface data may include one or more of a geometric
attribute, a thermal attribute, or a physical attribute, e.g., of
one or more droplets of liquefied metal or for an entire layer (or
portion of a layer) of a printed object. In an aspect, the surface
data includes the topography of the one or more droplets of
liquefied metal or for an entire layer (or portion of a layer) of a
printed object for detecting depressions, protrusions, and the
like. The surface data may also or instead include a porosity of
the surface of the layer of the object.
[0116] The surface data may be acquired on a predetermined basis,
e.g., where frequency of acquiring the surface data is based on one
or more of time, layer number, fabrication progress (e.g., percent
complete), and so forth. For example, the surface data may be
acquired for every layer, or every N layers. In an aspect, the
frequency for acquiring surface data is variable. For example, the
surface data may be acquired every N layers, but when a correction
or other remedial action is called for, the surface data may then
be acquired every layer until the correction is no longer needed.
The frequency for acquiring surface data may also or instead be
"active"--e.g., the frequency may be increased or decreased
depending on how much correction is called for in previous layers
of the build. Frequency may be a factor in the method 600 because
not acquiring surface data for every layer (and correcting every
layer) can minimize the build time. The frequency of acquiring
surface data may be based on the type of additive manufacturing
process, the type of object being fabricate, the build material,
time constraints, quality control parameters, and the like.
[0117] When evaluating characteristics of the object to be
fabricated (and supports), the characteristics at intermediate
stages of printing may also be considered. In some cases,
reasonable estimates may be achieved by looking at intermediate
shapes after N slices are printed. Such estimates may also or
instead be useful for techniques such as that described below in
method 600.
[0118] Sensors for acquiring surface data may include profilometer
such as a contact profilometer or a non-contact profilometer, or
any other device suitable for measuring or otherwise characterizing
the surface of the object being fabricated. The non-contact
profilometer may include an optical profilometer or a laser. The
one or more sensors may also or instead include a camera. The one
or more sensors may be positioned within the build chamber, or may
otherwise be in communication with the build chamber to detect
characteristics of a surface positioned within the build
chamber.
[0119] As shown in step 506, the method 500 may include estimating
a target surface shape for the build material at the location on
the layer based on the three-dimensional model. The target surface
shape may thus include model data related to a portion in the
digital model corresponding to the location on the layer of the
object. In other words, the target surface shape may include what
the three-dimensional model indicates should be present at the
location where surface data is acquired, and at the current time
within the build process. Thus, the digital source model may be
used to estimate an aggregate surface shape that is expected at a
particular moment during the build--specifically the moment when
the surface measurement is captured with the sensors. In another
aspect, the target surface shape may be based on other parameters
such as the expected pattern or surface shape that will be left by
droplets of EHD-propelled liquid metal when the system is operating
properly.
[0120] As shown in step 508, the method 500 may include comparing
the surface data to the target surface shape at the location on the
layer. The comparison may include identifying a discrepancy between
the surface data and the target surface shape. The discrepancy may
be compared to a threshold value, and if the discrepancy is greater
than the threshold value, action may be taken such that the
discrepancy between the surface data (or subsequent surface data)
and the target surface shape is lessened or eliminated. For
example, the threshold value may allow for normal process
variability that is expected for a properly working printer. The
corrective action may include adjusting a fabrication process as
explained below in step 514. Before an action is taken, however,
other data may be gathered by the system as explained below.
Gathering this additional data may assist in acquiring a complete
picture for the additive manufacturing process such that
appropriate action can be taken in response to an identified
discrepancy.
[0121] As shown in step 510, the method 500 may include capturing
process data. The process data may characterize one or more
droplets of liquefied metal. For example, the process data may
include a volume of one of the droplets of liquefied metal, or an
average volume of the droplets of liquefied metal. The process data
may also or instead include a dimension of one of the droplets of
liquefied metal, or an average dimension of the droplets of
liquefied metal. The process data may also or instead include a
velocity of one of the droplets of liquefied metal, or an average
velocity of the droplets of liquefied metal. The process data may
also or instead include a temperature of one of the droplets of
liquefied metal, or an average temperature of the droplets of
liquefied metal, e.g., when leaving the outlet of an expeller or
when impacting the surface of an object that is being fabricated.
The process data may also or instead include a time to deposit one
of the droplets of liquefied metal, or an average time for
depositing the droplets of liquefied metal. The process data may
also or instead include a composition of the droplets of liquefied
metal. The process data may also or instead include one or more of
a mass of the droplets of liquefied metal or a density of the
droplets of liquefied metal.
[0122] The process data may also or instead include information
regarding the additive manufacturing system, which might not be
directly related to characteristics of the one or more droplets of
liquefied metal, but may nonetheless affect the formation or
deposition of droplets of liquefied metal from an expeller. For
example, the process data may include at least one of a distance
between an outlet of an expeller of the printer and the layer of
the build material (or any other position information for the
expeller), a temperature of a build chamber of the printer, a
temperature of a print bed of the printer, a pressure of the build
chamber or a pressure difference between the expeller (or a
component thereof, e.g., a reservoir) and the build chamber, an
oxygen content of the build chamber, and so forth.
[0123] In general, the process data may be captured by one or more
sensors of the additive manufacturing system and sent to a
controller or the like for analysis.
[0124] As shown in step 512, the method 500 may include acquiring
parameter data. The parameter data may be related to at least one
parameter or condition of the printer present during fabrication of
the layer of the build material. The parameter data may thus
include print settings, or other settings for a system. The
parameter data may include a setting of the distance between an
outlet of an expeller of the printer and the layer of the build
material, a temperature setting of a build chamber of the printer,
a temperature setting of a print bed of the printer, a pressure
setting of the build chamber or a pressure setting for the
reservoir, an oxygen content setting of the build chamber, and so
forth. The parameter data may be acquired in addition to or in lieu
of the process data discussed above.
[0125] One or more of the surface data, the process data, and the
parameter data may be gathered, as discussed above, on a
droplet-by-droplet basis, a voxel-by-voxel basis, or on the basis
of another discrete unit of build material deposited by the
printer. One or more of the surface data, the process data, and the
parameter data may also or instead be gathered based on time--e.g.,
once per 0.100 seconds, once per 0.010 seconds, once per 0.001
seconds, or another unit of time.
[0126] As shown in step 514, the method 500 may include adjusting a
fabrication process when a discrepancy is identified between the
surface data and the target surface shape. The fabrication process
may be adjusted by a controller or the like as described herein or
otherwise known in the art. Adjustment of the fabrication process
may be based solely on the identification of the discrepancy
between the surface data and the target surface shape, solely on
the captured process data, or solely on the acquired parameter
data. The adjustment of the fabrication process may instead be
based on any combination of one or more of the discrepancy, process
data, parameter data, or other data. Additionally, any of the
discrepancy data, process data, parameter data, or other data may
be used to calculate other properties or characteristics of the
printed part or manufacturing system, which may then be used to
adjust the fabrication process.
[0127] Adjusting a fabrication process may include an adjustment of
any suitable process parameters relating to the fabrication
process. For example, adjusting the fabrication process may include
adjusting one or more of a temperature of the build material, a
temperature of a print bed of the printer, a temperature of a build
chamber of the printer, a distance between an outlet of an expeller
and a print bed of the printer, actuation of an expeller of the
printer, and so forth. Adjusting the fabrication process may also
include increasing or decreasing the amount of material deposited
in order to compensate for deviations between the expected shape of
an object (e.g., as indicated by the source digital model) and the
actual shape of the object. Thus for example, adjusting the
fabrication process may include adjusting a volume of build
material deposited in a predetermined portion of the layer of the
object, adjusting a quantity or output of a second build material
by the printer, repeating deposition within an area of the surface,
preventing deposition within an area of the surface, and so on.
Adjusting a fabrication process may also or instead include
adjusting any of the other parameters or settings discussed
herein.
[0128] By way of example, the discrepancy may include a depression
at a position in the layer of the build material. Based on this
discrepancy between the surface data and the target surface shape,
adjusting the fabrication process may include repeating a
deposition of droplets of liquefied metal at the position, i.e., to
fill the depression. In another example, the discrepancy may
include a protrusion at a position in the surface of the layer of
the object. Based on this discrepancy between the surface data and
the target surface shape, adjusting the fabrication process may
include omitting a deposition of droplets of liquefied metal at the
position while fabricating a second layer of the object on the
layer containing the protrusion--i.e., depositing droplets around
the protrusion in a subsequent layer, but not on top of the
protrusion to avoid exacerbating the protrusion.
[0129] The adjustment of the fabrication process may thus be a real
time adjustment that attempts to bring the printed object closer to
what the three-dimensional model shows.
[0130] As shown in step 516, the method 500 may include refinishing
a location on the layer of the object when the discrepancy between
the surface data for the location and the target surface shape
exceeds a predetermined threshold. A refinishing step may be
usefully performed where, for example, an appropriate amount of
material has been deposited, but poor process control has resulted
in generalized irregularities such as bumpiness from droplets that
freeze too early or spatter across the exposed layer that is being
fabricated. Refinishing may be particularly useful where, e.g., a
surface is so excessively varied that it becomes difficult to
fabricate a new layer on the surface, or where the surface is a
roof or other exterior surface of the fabricated object. Where
surface defects are particularly severe, the process may be paused
so that material can be removed from the surface, or the surface
can otherwise be prepared or treated to receive a new layer of
build material.
[0131] As shown in step 518, the method 500 may include sending a
notification to a user of the printer when the discrepancy between
the surface data and the target surface shape exceeds a
predetermined threshold. This may, for example, include a text
message, electronic mail notification, phone call, or computer
screen pop up alert notifying the user of an imminent or actual
build failure.
[0132] As shown in step 520, the method 500 may include recording
data. The recorded data may include one or more of the surface
data, the target surface shape (or a discrepancy between the
surface data and the target surface shape), the process data, the
parameter data, the adjustment taken to the fabrication process,
and so forth. The recorded data may also or instead include whether
an adjustment to the fabrication process was successful, e.g., for
remediating a discrepancy between the printed object and the
three-dimensional model. This information may be used, e.g., to
detect emerging maintenance needs for a machine, or to improve
future builds of the object by the same printer or similarly
configured printers. The recorded data may include data on every
droplet or every voxel. The recorded data may include many aspects
of the build history for an object. This may, for example, include
the source digital model, any input print parameters used for a
particular print job, as well as logging data obtained during the
print. In one aspect, this may include direct logging of parameters
such as temperature, pressure, etc. In another aspect, this may
include monitoring of deviations from the model, surface defects
that are detected, and so forth. In general, all of this data may
be temporally and spatially logged so that after an object is
created, the conditions during any moment and at any location
within the object can be reviewed. In general, this data may be
spatially stored at any suitable intervals such as for each liquid
droplet or voxel, or at temporal intervals such as once per second
or fraction thereof.
[0133] The recorded data may be useful for identifying patterns,
e.g., patterns related to where discrepancies tend to occur in a
layer of an object, patterns related to process data or parameter
data that tend to cause discrepancies or remediate discrepancies,
patterns related to adjustments in the fabrication process that
tend to remediate discrepancies or exacerbate discrepancies, and so
forth. The recorded data may reveal patterns that affect the
physical integrity of printed objects, thermal properties of
printed objects, geometric properties of printed objects, or other
characteristics of printed objects such as mass. Thus, the method
500 may include analyzing the recorded data to identify a pattern
where discrepancies exist.
[0134] The recorded data may be used for data analytics related to
the additive manufacturing of objects. For example, using the
recorded data or otherwise using disclosed techniques, failures or
defects can be traced back to where they occurred during
fabrication for accurate manufacturing analytics. By way of
example, using the data, a pattern can reveal that a certain type
of raw material used at a certain point in a manufacturing process
for a certain type of object is causing a failure or defect.
[0135] Using the method 500, defects in a printed object may be
detected and specific, detailed information may be gathered
including what the defect is, where the defect is, and what the
processing conditions and parameters were when the defect occurred.
Moreover, using the detailed information gathered by the techniques
described herein may yield a thermal budget on a voxel-by-voxel
basis, where the system obtains a time and temperature for each
voxel.
[0136] Using the method 500, a comparison between an expected mass
(using the three-dimensional model) and an actual mass (calculated
using the data gathered by the techniques described herein) may be
achieved. This may be particularly useful if a printed object
requires further finishing in which material will be removed. In a
similar manner, techniques may reveal how much build material was
extruded for a particular printer part (or portion of a particular
part), e.g., using the volume, mass, or density of the build
material on a voxel-by-voxel basis.
[0137] Thus, as described above, in some implementations, a method
may include identifying an expected surface of the predetermined
design, identifying a deviation in a surface of the object from the
expected surface, and adjusting at least one of the temperature of
the first metal, the actuation of the first expeller, and the
position of the robotic platform based on the identified deviation
to correct the identified deviation. In some such implementations,
the deviation may be identified with a contact profilometer, a
non-contact profilometer (e.g., an optical profilometer), or some
other suitable sensors. As an illustrative example, the method may
even out an undesirable depression in a surface by adding more of
the liquid first metal to the identified depression, or may correct
for an undesirable lump on a surface by reducing the amount of the
liquid first metal that would otherwise be supplied in forming a
layer on top of the surface.
[0138] In an implementation, a computer program product including
computer executable code embodied in a non-transitory
computer-readable medium that, when executing on one or more
computing devices in electronic communication with a
three-dimensional metallic printer configured to additively
manufacture an object based on a three-dimensional model with a
number of droplets of liquefied metal as a build material using a
metallic liquid expeller, may perform the steps of the method 500
above. For example, the computer program product may include
computer executable code that performs the steps of acquiring
surface data from the object with one or more sensors during
fabrication, the surface data characterizing a location on a layer
of a build material of the object deposited by the
three-dimensional metallic printer, estimating a target surface
shape for the build material at the location based on the
three-dimensional model, comparing the surface data to the target
surface shape at the location, and adjusting a fabrication process
of the three-dimensional metallic printer when a discrepancy is
identified between the surface data and the target surface
shape.
[0139] In an implementation, an additive manufacturing system may
include a three-dimensional metallic printer such as any of the
printers described herein. The three-dimensional metallic printer
may be configured to additively manufacture an object based on a
three-dimensional model with a number of droplets of liquefied
metal as a build material using a metallic liquid expeller. The
additive manufacturing system may further include a controller in
electronic communication with the three-dimensional metallic
printer over a data network. The controller may include a processor
and a memory, where the memory bears computer executable code
configured to perform the steps of acquiring surface data from the
object with one or more sensors during fabrication, the surface
data characterizing a location on a layer of a build material of
the object deposited by the three-dimensional metallic printer,
estimating a target surface shape for the build material at the
location based on the three-dimensional model, comparing the
surface data to the target surface shape at the location, and
adjusting a fabrication process of the three-dimensional metallic
printer when a discrepancy is identified between the surface data
and the target surface shape.
[0140] FIG. 6 is a flow chart of a method for controlling an
additive manufacturing process using estimated thermal parameters.
Some thermal properties are amenable to direct measurement during a
fabrication process, such as surface temperature where material is
being deposited. However, other thermal properties may be highly
relevant to consistent print quality but difficult to measure
directly. For example, the thermal mass of an object that is
receiving droplets of liquid metal may be relevant to the freezing
process by which the liquid metal converts to a solid, and the
thermal mass around the target surface may affect the size or
velocity of an optimized droplet that should be dispensed by the
expeller. Similarly, thermal conduction paths may significantly
affect the conversion of heat applied at a print bed into surface
temperature on a top layer being fabricated. These types of thermal
parameters may be usefully estimated during fabrication even in the
absence of direct physical measurement by using, e.g., physical
modeling or any other suitable techniques to draw accurate
quantitative inferences based upon known information about bulk
material properties, a current geometric shape of an object, and so
forth. Even where direct measurements are possible, estimation may
be used predictively, e.g., to predict a temperature at the surface
of the object at a point in time based on an indirect application
of thermal energy at, e.g., a heated print bed. More generally, an
estimated thermal parameter may be any parameter calculated or
estimated based on known thermal properties of the build material,
geometry of an object, and indirect sources of heat during the
fabrication process.
[0141] As shown in step 602, the method 600 may include fabricating
a metallic object on a print bed with a three-dimensional printer.
The three-dimensional printer may include any of the printers or
additive manufacturing systems described herein. For example, the
three-dimensional printer may include a three-dimensional metallic
printer configured to additively manufacture the metallic object
with a number of droplets of liquefied metal using a metallic
liquid expeller. The metallic liquid expeller may include an
electrohydrodynamic expeller configured to drive the droplets of
liquefied metal by applying an electrostatic field to a meniscus of
the liquefied metal extending from an outlet of an expeller of the
three-dimensional printer.
[0142] In another implementation, the three-dimensional printer may
fabricate the metallic object using fused filament fabrication. In
yet another implementation, the method 600 may be used for
non-metallic three-dimensional printing, e.g., the
three-dimensional printing of thermoplastics and the like. In other
implementations, the method 600 may be used for additional types of
three-dimensional printing including without limitation one or more
of binder jet printing, multijet printing, stereolithography, DLP
three-dimensional printing, selective laser sintering, and so
forth. In general, the method 600 may be used for an additive
manufacturing technique where a transfer of thermal energy is
relevant to the manufacturing process.
[0143] As shown in step 604, the method 600 may include estimating
a thermal parameter of the metallic object. In an aspect, the
thermal parameter includes a thermal mass of the metallic object.
The thermal parameter may also or instead include a heat capacity
of the metallic object. In another aspect, the estimated thermal
parameter may include a thermal conductivity of the metallic
object. In another aspect, the estimated thermal parameter may be
an estimated temperature at some location at the surface of or
within an interior of the object being fabricated, such as a
surface location where new build material is being deposited.
[0144] The thermal parameter may be related to a printing surface
or substrate of the metallic object in which droplets of liquefied
metal will be deposited, e.g., a previously deposited layer of the
metallic object. For example, the thermal parameter may include a
surface temperature of the metallic object. The surface temperature
may be estimated based on one or more of a shape of the metallic
object, a bulk thermal property of a build material used to
fabricate the metallic object, and a control signal for a thermal
component of the printer such as a control signal for a heater that
controls the build chamber temperature or a heater that controls a
print bed temperature. For example, an estimation of the surface
temperature may be made if known variables in an additive
manufacturing system include, e.g., the temperature of the print
bed (or a temperature setting of the print bed), the temperature of
the build chamber (or a temperature setting of the build chamber),
the height of the surface above the print bed (or an estimated
height), the amount of build material below the surface (or an
estimated amount of material), and a bulk thermal property of the
build material (e.g., a thermal resistivity or thermal conductivity
of the build material)--i.e., through heat transfer calculations.
In this manner, the surface temperature may be estimated based on
control signals sent to the print bed rather than direct
measurement of the surface temperature. This technique also permits
prospective or predictive estimation of the surface temperature of
the object at some future point in time based on a control signal
selected for the print bed or some other thermal element of the
printer. For example, the surface temperature of the object at a
location where material is to be deposited can be usefully
controlled using these techniques despite the potential for
significant latency between a change in the print bed temperature
and a resulting change in surface temperature for an object on the
print bed.
[0145] The thermal parameter may also or instead be estimated for
one or more supports for the metallic object.
[0146] As shown in step 606, the method 600 may include controlling
the three-dimensional printer during fabrication of the object
according to the thermal parameter. In an aspect where the
three-dimensional printer includes a three-dimensional metallic
printer configured to additively manufacture the metallic object
with a number of droplets of liquefied metal using a metallic
liquid expeller, controlling the three-dimensional printer may
include controlling a mass of the number of droplets. In such an
aspect, controlling the three-dimensional printer may also or
instead include controlling a velocity of the number of droplets.
Thus, in general, controlling the three-dimensional printer may
include controlling actuation of an expeller of the
three-dimensional printer based on, e.g., an estimated thermal mass
or surface temperature of an object at a location where material is
being deposited.
[0147] In an aspect, controlling the three-dimensional printer
includes controlling a temperature of a build chamber of the
three-dimensional printer. Controlling the three-dimensional
printer may also or instead include controlling a temperature of
the print bed. As noted above, control signals may be usefully
adjusted based on thermal modeling so that a target temperature is
maintained at the surface during deposition of metal. Controlling
the three-dimensional printer may also or instead include
controlling a temperature of the build material, or a pressure of a
reservoir storing liquid build material.
[0148] Controlling the three-dimensional printer may also or
instead include controlling a deposition rate of a metallic build
material from an expeller of the three-dimensional printer.
Controlling the three-dimensional printer may also or instead
include controlling a distance between an expeller and the print
bed of the three-dimensional printer. Controlling the
three-dimensional printer may also or instead include controlling a
volume of a discrete unit of build material to be deposited by the
three-dimensional printer (e.g., per layer or per other unit volume
or area).
[0149] Controlling the three-dimensional printer may also or
instead include controlling the composition of build material. For
example, where the build material is metal, controlling the
three-dimensional printer may include controlling an amount or
concentration of an additive for mixing with the metal.
[0150] Controlling the three-dimensional printer may also or
instead include adjusting a tool path for an expeller or print bed
of the three-dimensional printer to form the three-dimensional
object based on the estimated thermal parameter. Controlling the
three-dimensional printer may also or instead include sending a
notification to a user of the three-dimensional printer based on
the estimated thermal parameter, e.g., when there is a discrepancy
between the thermal parameter and a predetermined threshold.
[0151] The method 600 may be performed independent of any sensors
measuring aspects of the additive manufacturing system. In this
manner, a digital model of an object to be formed may be used to
gather information concerning physical properties of the object for
estimating the thermal parameter, along with temperature settings
of components of the additive manufacturing system. Thus, even
before an object is printed, the method 600 may estimate the
thermal mass of the object on a layer-by-layer basis. For example,
using the digital model, one or more printing surfaces may be
identified that include surfaces upon which build material will be
deposited by an expeller of the additive manufacturing system to
form the object. The thermal parameter may be estimated for each of
these surfaces, or for discrete portions of these surfaces, or for
a relevant three-dimensional volume around a location of
interest.
[0152] These techniques for estimation may also or instead be used
in a feedback manner to improve control over a printing process.
For example, based on this information, a discrete portion of the
object may be identified where there is a discrepancy between the
estimated thermal parameter for the discrete portion and a
predetermined threshold for the thermal parameter. Based on this
discrepancy, the fabrication process may be adjusted to compensate
for the discrepancy. For example, where a predicted surface
temperature becomes too low or too high, a heating system within
the printer may be adjusted accordingly to prevent excessive
excursions from target fabrication conditions.
[0153] By way of example, an analysis using the method 600 above
may include identifying that a layer of an object is estimated to
be cooler than a preferred substrate temperature when that layer
will act as the deposition surface for the next layer, e.g., based
on its height above a heated print bed. Thus, an adjustment may be
made to the additive manufacturing system when printing on this
layer based on the estimation, e.g., increasing the temperature of
the print bed. Similarly, heating of the build chamber of a
three-dimensional printer may be increased if it is estimated that
the substrate gets cooler as the height above the print bed is
increased for the printed object.
[0154] In an implementation, a computer program product including
computer executable code embodied in a non-transitory
computer-readable medium that, when executing on one or more
computing devices in electronic communication with a
three-dimensional printer, may perform the steps of the method 600
above. For example, the computer program product may include
computer executable code that performs the steps of providing
instructions for fabricating a metallic object on a print bed with
the three-dimensional printer, estimating a thermal parameter of
the metallic object, and controlling the three-dimensional printer
during fabrication of the object according to the thermal
parameter.
[0155] In an implementation, an additive manufacturing system may
include a three-dimensional metallic printer configured to
additively manufacture a metallic object with a number of droplets
of liquefied metal using a metallic liquid expeller, and a
controller in electronic communication with the three-dimensional
metallic printer over a data network. The controller may include a
processor and a memory, where the memory bears computer executable
code configured to perform the steps of fabricating the metallic
object on a print bed with the three-dimensional metallic printer,
estimating a thermal parameter of the metallic object, and
controlling the three-dimensional printer during fabrication of the
object according to the thermal parameter.
[0156] In some implementations, a method may include calculating a
thermal mass of a surface disposed beneath a first expeller, and
adjusting at least one of the temperature of a build material, the
actuation of the first expeller, and the position of one or more of
the expeller or the print bed based on the identified thermal mass.
In some such implementations, the method may further include
measuring or adjusting a temperature of the print bed, the build
chamber, or the build material.
[0157] In some implementations, a method may include an additive
manufacturing technique. In such aspects, the method may include
supplying a first metal to a first expeller, where the first
expeller includes a first reservoir, a first outlet, and a metal
feed. The method may include melting the first metal into the first
reservoir, moving a robotic positioning assembly based on a
predetermined design (such as a computer-aided design file), and
actuating a first expeller to release a quantity of the liquid
first metal from the first outlet based on the predetermined
design, thereby manufacturing an object. In some implementations,
the first expeller and the robotic positioning assembly are in an
air-tight chamber. In some such implementations, the method further
comprises one or more of applying a vacuum to the air tight chamber
and introducing an inert gas into the air-tight chamber.
[0158] In some implementations, a method includes applying one or
more voltages to each electrode in a plurality of electrodes
positioned below a plurality of outlets. In such implementations,
each electrode may act as an independent expeller, allowing a
system to build multiple portions of a design simultaneously. In
some such implementations, more than one outlet in the plurality of
outlets may be associated with a single reservoir, allowing
multiple expellers to share a single metal supply. In some
implementations, the electrodes may be printed onto a ceramic
printed circuit board.
[0159] In some implementations, a method includes altering one or
more conditions of a liquid metal to control its surface tension
and/or meniscus. In such implementations, the method may include
one or more of: applying an AC voltage signal to the metal;
applying a DC voltage signal to the metal; varying the temperature
of the metal; controlling the composition, temperature, and/or
pressure of the atmosphere in the reservoir containing the metal;
controlling the composition, temperature, and/or pressure of the
atmosphere below the first outlet; applying a baseline EHD field;
varying an EHD field; or otherwise suitably altering the conditions
of the liquid metal.
[0160] While various embodiments of the present disclosure have
been shown and described herein, it will be obvious to those
skilled in the art that such embodiments are provided by way of
example only. Numerous variations, changes, and substitutions will
now occur to those skilled in the art without departing from the
disclosure. For example, the first expeller may be mounted on a
robotic positioner capable of moving along a plane parallel to the
print bed, while the print bed may be mounted on a robotic
positioner capable of moving perpendicularly to the print bed,
towards and away from the first expeller. Likewise, the first
expeller may be capable of issuing a continuous stream of liquid
metal instead of or in addition to single drops of liquid metal.
Elements of an implementation of the systems and methods described
herein may be independently implemented or combined with other
implementations.
[0161] Having provided an overall context for various additive
manufacturing devices, systems, methods, and techniques, the
description now turns to a brief discussion of an example of a
computer system that may be used with any of the devices, systems,
methods, and techniques above.
[0162] FIG. 7 illustrates a computer system. Specifically, the
figure shows a representation of a computing system 700 that can be
used to implement or support any of the components of the devices,
systems, and methods described herein. A print engine controlling
any of the components of the devices, systems, and methods
described herein may be implemented on one or more computing
devices 710 having suitable circuitry. In certain aspects, a
plurality of the components of a print engine controlling any of
the components of the devices, systems, and methods described
herein may be included within one computing device 710. In certain
implementations, a component of a print engine controlling any of
the components of devices, systems, and methods described herein
may be implemented across several computing devices 710.
[0163] In general, the computer system 700 may include a computing
device 710 connected to a network 702, e.g., through an external
device 704. The computing device 710 may be or include any type of
device as described herein, e.g., with reference to FIG. 1 above.
By way of example, the computing device 710 may include any of the
controllers described herein (or vice-versa), or otherwise be in
communication with any of the controllers or other devices
described herein. For example, the computing device 710 may include
a desktop computer workstation. The computing device 710 may also
or instead be any suitable device that has processes and
communicates over a network 702, including without limitation a
laptop computer, a desktop computer, a personal digital assistant,
a tablet, a mobile phone, a television, a set top box, a wearable
computer (e.g., watch, jewelry, or clothing), a home device, just
as some examples. The computing device 710 may also or instead
include a server, or it may be disposed on a server.
[0164] The computing device 710 may be used for any of the devices
and systems described herein, or for performing the steps of any
method described herein. For example, the computing device 710 may
include a controller or any computing devices described therein. In
certain aspects, the computing device 710 may be implemented using
hardware (e.g., in a desktop computer), software (e.g., in a
virtual machine or the like), or a combination of software and
hardware, and the computing device 710 may be a standalone device,
a device integrated into another entity or device, a platform
distributed across multiple entities, or a virtualized device
executing in a virtualization environment. By way of example, the
computing device may be integrated into a controller or
three-dimensional printer.
[0165] The network 702 may include any network described above,
e.g., data network(s) or internetwork(s) suitable for communicating
data and control information among participants in the computer
system 700. This may include public networks such as the Internet,
private networks, and telecommunications networks such as the
Public Switched Telephone Network or cellular networks using third
generation cellular technology (e.g., 3G or IMT-2000), fourth
generation cellular technology (e.g., 4G, LTE. MT-Advanced, E-UTRA,
etc.) or WiMax-Advanced (IEEE 802.16m)) and/or other technologies,
as well as any of a variety of corporate area, metropolitan area,
campus or other local area networks or enterprise networks, along
with any switches, routers, hubs, gateways, and the like that might
be used to carry data among participants in the computer system
700. The network 702 may also include a combination of data
networks, and need not be limited to a strictly public or private
network.
[0166] The external device 704 may be any computer or other remote
resource that connects to the computing device 710 through the
network 702. This may include print management resources, gateways
or other network devices, remote servers or the like containing
content requested by the computing device 710, a network storage
device or resource, a device hosting printing content, or any other
resource or device that might connect to the computing device 710
through the network 702.
[0167] The computing device 710 may include a processor 712, a
memory 714, a network interface 716, a data store 718, and one or
more input/output devices 720. The computing device 710 may further
include or be in communication with peripherals 722 and other
external input/output devices 724.
[0168] The processor 712 may be any as described herein, and in
general be capable of processing instructions for execution within
the computing device 710 or computer system 700. The processor 712
may include a single-threaded processor or a multi-threaded
processor. The processor 712 may be capable of processing
instructions stored in the memory 714 or on the data store 718.
[0169] The memory 714 may store information within the computing
device 710 or computer system 700. The memory 714 may include any
volatile or non-volatile memory or other computer-readable medium,
including without limitation a Random Access Memory (RAM), a flash
memory, a Read Only Memory (ROM), a Programmable Read-only Memory
(PROM), an Erasable PROM (EPROM), registers, and so forth. The
memory 714 may store program instructions, print instructions,
digital models, program data, executables, and other software and
data useful for controlling operation of the computing device 700
and configuring the computing device 700 to perform functions for a
user. The memory 714 may include a number of different stages and
types for different aspects of operation of the computing device
710. For example, a processor may include on-board memory and/or
cache for faster access to certain data or instructions, and a
separate, main memory or the like may be included to expand memory
capacity as desired.
[0170] The memory 714 may, in general, include a non-volatile
computer readable medium containing computer code that, when
executed by the computing device 700 creates an execution
environment for a computer program in question, e.g., code that
constitutes processor firmware, a protocol stack, a database
management system, an operating system, or a combination of the
foregoing, and/or code that performs some or all of the steps set
forth in the various flow charts and other algorithmic descriptions
set forth herein. While a single memory 714 is depicted, it will be
understood that any number of memories may be usefully incorporated
into the computing device 710.
[0171] The network interface 716 may include any hardware and/or
software for connecting the computing device 710 in a communicating
relationship with other resources through the network 702. This may
include remote resources accessible through the Internet, as well
as local resources available using short range communications
protocols using, e.g., physical connections (e.g., Ethernet), radio
frequency communications (e.g., WiFi), optical communications,
(e.g., fiber optics, infrared, or the like), ultrasonic
communications, or any combination of these or other media that
might be used to carry data between the computing device 710 and
other devices. The network interface 716 may, for example, include
a router, a modem, a network card, an infrared transceiver, a radio
frequency (RF) transceiver, a near field communications interface,
a radio-frequency identification (RFID) tag reader, or any other
data reading or writing resource or the like.
[0172] More generally, the network interface 716 may include any
combination of hardware and software suitable for coupling the
components of the computing device 710 to other computing or
communications resources. By way of example and not limitation,
this may include electronics for a wired or wireless Ethernet
connection operating according to the IEEE 802.11 standard (or any
variation thereof), or any other short or long range wireless
networking components or the like. This may include hardware for
short range data communications such as Bluetooth or an infrared
transceiver, which may be used to couple to other local devices, or
to connect to a local area network or the like that is in turn
coupled to a data network 702 such as the Internet. This may also
or instead include hardware/software for a WiMax connection or a
cellular network connection (using, e.g., CDMA, GSM, LTE, or any
other suitable protocol or combination of protocols). The network
interface 716 may be included as part of the input/output devices
720 or vice-versa.
[0173] The data store 718 may be any internal memory store
providing a computer-readable medium such as a disk drive, an
optical drive, a magnetic drive, a flash drive, or other device
capable of providing mass storage for the computing device 710. The
data store 718 may store computer readable instructions, data
structures, digital models, print instructions, program modules,
and other data for the computing device 710 or computer system 700
in a non-volatile form for subsequent retrieval and use. For
example, the data store 718 may store without limitation one or
more of the operating system, application programs, program data,
databases, files, and other program modules or other software
objects and the like.
[0174] The input/output interface 720 may support input from and
output to other devices that might couple to the computing device
710. This may, for example, include serial ports (e.g., RS-232
ports), universal serial bus (USB) ports, optical ports, Ethernet
ports, telephone ports, audio jacks, component audio/video inputs,
HDMI ports, and so forth, any of which might be used to form wired
connections to other local devices. This may also or instead
include an infrared interface, RF interface, magnetic card reader,
or other input/output system for coupling in a communicating
relationship with other local devices. It will be understood that,
while the network interface 716 for network communications is
described separately from the input/output interface 720 for local
device communications, these two interfaces may be the same, or may
share functionality, such as where a USB port is used to attach to
a WiFi accessory, or where an Ethernet connection is used to couple
to a local network attached storage.
[0175] A peripheral 722 may include any device used to provide
information to or receive information from the computing device
700. This may include human input/output (I/O) devices such as a
keyboard, a mouse, a mouse pad, a track ball, a joystick, a
microphone, a foot pedal, a camera, a touch screen, a scanner, or
other device that might be employed by the user 730 to provide
input to the computing device 710. This may also or instead include
a display, a speaker, a printer, a projector, a headset or any
other audiovisual device for presenting information to a user. The
peripheral 722 may also or instead include a digital signal
processing device, an actuator, or other device to support control
or communication to other devices or components. Other I/O devices
suitable for use as a peripheral 722 include haptic devices,
three-dimensional rendering systems, augmented-reality displays,
magnetic card readers, user interfaces, and so forth. In one
aspect, the peripheral 722 may serve as the network interface 716,
such as with a USB device configured to provide communications via
short range (e.g., BlueTooth, WiFi, Infrared, RF, or the like) or
long range (e.g., cellular data or WiMax) communications protocols.
In another aspect, the peripheral 722 may provide a device to
augment operation of the computing device 710, such as a global
positioning system (GPS) device, a security dongle, or the like. In
another aspect, the peripheral may be a storage device such as a
flash card, USB drive, or other solid state device, or an optical
drive, a magnetic drive, a disk drive, or other device or
combination of devices suitable for bulk storage. More generally,
any device or combination of devices suitable for use with the
computing device 700 may be used as a peripheral 722 as
contemplated herein.
[0176] Other hardware 726 may be incorporated into the computing
device 700 such as a co-processor, a digital signal processing
system, a math co-processor, a graphics engine, a video driver, and
so forth. The other hardware 726 may also or instead include
expanded input/output ports, extra memory, additional drives (e.g.,
a DVD drive or other accessory), and so forth.
[0177] A bus 732 or combination of busses may serve as an
electromechanical platform for interconnecting components of the
computing device 700 such as the processor 712, memory 714, network
interface 716, other hardware 726, data store 718, and input/output
interface. As shown in the figure, each of the components of the
computing device 710 may be interconnected using a system bus 732
or other communication mechanism for communicating information.
[0178] Methods and systems described herein can be realized using
the processor 712 of the computer system 700 to execute one or more
sequences of instructions contained in the memory 714 to perform
predetermined tasks. In embodiments, the computing device 700 may
be deployed as a number of parallel processors synchronized to
execute code together for improved performance, or the computing
device 700 may be realized in a virtualized environment where
software on a hypervisor or other virtualization management
facility emulates components of the computing device 700 as
appropriate to reproduce some or all of the functions of a hardware
instantiation of the computing device 700.
[0179] The above systems, devices, methods, processes, and the like
may be realized in hardware, software, or any combination of these
suitable for a particular application. The hardware may include a
general-purpose computer and/or dedicated computing device. This
includes realization in one or more microprocessors,
microcontrollers, embedded microcontrollers, programmable digital
signal processors or other programmable devices or processing
circuitry, along with internal and/or external memory. This may
also, or instead, include one or more application specific
integrated circuits, programmable gate arrays, programmable array
logic components, or any other device or devices that may be
configured to process electronic signals. It will further be
appreciated that a realization of the processes or devices
described above may include computer-executable code created using
a structured programming language such as C, an object oriented
programming language such as C++, or any other high-level or
low-level programming language (including assembly languages,
hardware description languages, and database programming languages
and technologies) that may be stored, compiled or interpreted to
run on one of the above devices, as well as heterogeneous
combinations of processors, processor architectures, or
combinations of different hardware and software. In another aspect,
the methods may be embodied in systems that perform the steps
thereof, and may be distributed across devices in a number of ways.
At the same time, processing may be distributed across devices such
as the various systems described above, or all of the functionality
may be integrated into a dedicated, standalone device or other
hardware. In another aspect, means for performing the steps
associated with the processes described above may include any of
the hardware and/or software described above. All such permutations
and combinations are intended to fall within the scope of the
present disclosure.
[0180] Embodiments disclosed herein may include computer program
products comprising computer-executable code or computer-usable
code that, when executing on one or more computing devices,
performs any and/or all of the steps thereof. The code may be
stored in a non-transitory fashion in a computer memory, which may
be a memory from which the program executes (such as random access
memory associated with a processor), or a storage device such as a
disk drive, flash memory or any other optical, electromagnetic,
magnetic, infrared or other device or combination of devices. In
another aspect, any of the systems and methods described above may
be embodied in any suitable transmission or propagation medium
carrying computer-executable code and/or any inputs or outputs from
same.
[0181] It will be appreciated that the devices, systems, and
methods described above are set forth by way of example and not of
limitation. Absent an explicit indication to the contrary, the
disclosed steps may be modified, supplemented, omitted, and/or
re-ordered without departing from the scope of this disclosure.
Numerous variations, additions, omissions, and other modifications
will be apparent to one of ordinary skill in the art. In addition,
the order or presentation of method steps in the description and
drawings above is not intended to require this order of performing
the recited steps unless a particular order is expressly required
or otherwise clear from the context.
[0182] The method steps of the implementations described herein are
intended to include any suitable method of causing such method
steps to be performed, consistent with the patentability of the
following claims, unless a different meaning is expressly provided
or otherwise clear from the context. So for example performing the
step of X includes any suitable method for causing another party
such as a remote user, a remote processing resource (e.g., a server
or cloud computer) or a machine to perform the step of X.
Similarly, performing steps X, Y and Z may include any method of
directing or controlling any combination of such other individuals
or resources to perform steps X, Y and Z to obtain the benefit of
such steps. Thus method steps of the implementations described
herein are intended to include any suitable method of causing one
or more other parties or entities to perform the steps, consistent
with the patentability of the following claims, unless a different
meaning is expressly provided or otherwise clear from the context.
Such parties or entities need not be under the direction or control
of any other party or entity, and need not be located within a
particular jurisdiction.
[0183] It should further be appreciated that the methods above are
provided by way of example. Absent an explicit indication to the
contrary, the disclosed steps may be modified, supplemented,
omitted, and/or re-ordered without departing from the scope of this
disclosure.
[0184] It will be appreciated that the methods and systems
described above are set forth by way of example and not of
limitation. Numerous variations, additions, omissions, and other
modifications will be apparent to one of ordinary skill in the art.
In addition, the order or presentation of method steps in the
description and drawings above is not intended to require this
order of performing the recited steps unless a particular order is
expressly required or otherwise clear from the context. Thus, while
particular embodiments have been shown and described, it will be
apparent to those skilled in the art that various changes and
modifications in form and details may be made therein without
departing from the spirit and scope of this disclosure and are
intended to form a part of the invention as defined by the
following claims, which are to be interpreted in the broadest sense
allowable by law.
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