U.S. patent application number 17/645261 was filed with the patent office on 2022-04-14 for method of using a carriageless print head assembly for extrusion-based additive construction.
This patent application is currently assigned to R3 Printing, Inc.. The applicant listed for this patent is R3 Printing, Inc.. Invention is credited to Paul SIERADZKI.
Application Number | 20220111597 17/645261 |
Document ID | / |
Family ID | 1000006042365 |
Filed Date | 2022-04-14 |
View All Diagrams
United States Patent
Application |
20220111597 |
Kind Code |
A1 |
SIERADZKI; Paul |
April 14, 2022 |
METHOD OF USING A CARRIAGELESS PRINT HEAD ASSEMBLY FOR
EXTRUSION-BASED ADDITIVE CONSTRUCTION
Abstract
A method of using a carriageless print head assembly, in
extrusion-based additive construction is disclosed. The
carriageless print head features a cold end equipped with one or
more timing belt attachment slots and bores for receiving bearings
to achieve linear motion. The carriageless print head may be
optionally equipped with a fluid channel for aiding in the
regulation of the temperature of the print head cold end, and one
or more thermal monitors for monitoring the temperature of the cold
end of the print head.
Inventors: |
SIERADZKI; Paul; (Los
Angeles, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
R3 Printing, Inc. |
Wilmington |
DE |
US |
|
|
Assignee: |
R3 Printing, Inc.
Wilmington
DE
|
Family ID: |
1000006042365 |
Appl. No.: |
17/645261 |
Filed: |
December 20, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15694772 |
Sep 2, 2017 |
11235528 |
|
|
17645261 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B33Y 50/02 20141201;
B29C 64/106 20170801; B29C 64/364 20170801; B29C 64/393 20170801;
B29C 64/386 20170801; B29C 64/209 20170801; B33Y 30/00 20141201;
B29C 48/87 20190201 |
International
Class: |
B29C 64/364 20060101
B29C064/364; B29C 64/209 20060101 B29C064/209; B33Y 30/00 20060101
B33Y030/00; B33Y 50/02 20060101 B33Y050/02; B29C 64/386 20060101
B29C064/386; B29C 64/106 20060101 B29C064/106; B29C 64/393 20060101
B29C064/393 |
Claims
1. A computer-mediated method of performing extrusion-based
additive construction using a 3D printer equipped with a print head
having a thermal monitor and a receiver configured to receive a
bearing, comprising the steps of: a. beginning, by the 3d printer,
an extrusion-based additive construction; b. reading, by the
thermal monitor an operating temperature of the cold end; c.
assessing, whether the operating temperature is above a
predetermined temperature threshold; d. pausing, the construction;
and allowing the cold end to cool to a print resume threshold,
wherein the print resume threshold is equal to or below the
predetermined temperature threshold.
2. The computer-mediated method of claim 1, the print head
comprising: a cold end having a front end, a rear end, a left side,
a right side, a top surface extending from the front end to the
rear end and from the left side to the right side, a bottom surface
extending from the front end to the rear end and from the left side
to the right side; and a hot end configured to provide a melt zone,
the hot end being attached to the cold end.
3. The print head of claim 2, the cold end further comprising a
second receiver configured to receive a second bearing, wherein the
receiver is a first receiver and the bearing is a first
bearing.
4. A computer-mediated method of performing extrusion-based
additive construction using a 3D printer equipped with a print head
having a thermal monitor and an attachment slot, comprising the
steps of: a. beginning, by the 3d printer, an extrusion-based
additive construction; b. reading, by the thermal monitor an
operating temperature of the cold end; c. assessing, whether the
operating temperature is above a predetermined temperature
threshold; d. pausing, the construction; and allowing the cold end
to cool to a print resume threshold, wherein the print resume
threshold is equal to or below the predetermined temperature
threshold.
5. The computer-mediated method of claim 4, the print head
comprising a cold end having a front end, a rear end, a left side,
a right side, a top surface extending from the front end to the
rear end and from the left side to the right side, a bottom surface
extending from the front end to the rear end and from the left side
to the right side; and a hot end configured to provide a melt zone,
the hot end being attached to the cold end.
6. The computer-mediated method of claim 5, the cold end further
comprising a receiver configured to receive a bearing.
7. The computer-mediated method of claim 5, the cold end further
comprising a second attachment slot, wherein the attachment slot is
a first attachment slot.
8. The computer-mediated method of claim 6, the cold end further
comprising a second attachment slot, wherein the attachment slot is
a first attachment slot.
9. The computer-mediated method of claim 6, the cold end further
comprising a second receiver configured to receive a second
bearing, wherein the receiver is a first receiver and the bearing
is a first bearing.
10. The computer-mediated method of claim 8, the cold end further
comprising a second receiver configured to receive a second
bearing, wherein the receiver is a first receiver and the bearing
is a first bearing.
11. The computer-mediated method of claim 5, further comprising the
step of: e. resuming, the extrusion-based additive
construction.
12. The computer-mediated method of claim 5, further comprising the
step of: e. manually resuming, by a human operator, the
extrusion-based additive construction.
Description
CLAIM OF PRIORITY
[0001] This application is a continuation application of U.S.
patent application Ser. No. 15/694,772, filed Sep. 2, 2017,
entitled "Carriageless Print Head Assembly for Extrusion-Based
Additive Construction", the contents of which is hereby
incorporated by reference in its entirety.
NOTICE OF COPYRIGHTS AND TRADE DRESS
[0002] A portion of the disclosure of this patent document contains
material which is subject to copyright or trade dress protection.
This patent document may show and/or describe matter that is or may
become trade dress of the owner. The copyright and trade dress
owner has no objection to the facsimile reproduction by anyone of
the patent disclosure, as it appears in the Patent and Trademark
Office patent files or records, but otherwise reserves all
copyright and trade dress rights whatsoever.
FIELD OF THE EMBODIMENTS
[0003] The present disclosure relates generally to a carriageless
print head for use in extrusion-based additive construction. More
particularly, the present disclosure relates to a carriageless
print head which can be optionally configured to have cold end
temperature monitoring and liquid cooling of the print head.
BACKGROUND
[0004] In an extrusion-based additive construction ("EAC") 3D
printer, a desired object is formed by melting a continuous solid
material feed and selectively depositing the object layer-by-layer
onto a flat surface. The defining factors in the quality and
reliability of a 3D printer are the engineering and build quality
of a 3D printer's material feeding, melting, and layer deposition
mechanics.
[0005] EAC 3D printer material feeding, melting, and layer
deposition mechanics can be broken down into two main components:
the extruder; and the print head. The extruder is responsible for
the motion of the continuous solid material feed, therefore
controlling the amount and rate of which the material feed is
deposited onto the flat surface, often called a "build platform."
The print head is responsible for accepting the material feed
pushed into it by the extruder, and subsequently melting it to be
deposited onto a flat build surface. For this reason, the print
head is the only component of the material feeding, melting, and
layer deposition mechanics that must be in motion relative to the
EAC 3D printer in order to form the desired object.
[0006] Despite this truth, many existing EAC 3D printers mount the
extruder directly above the print head, resulting in the entire
assembly moving during the EAC. While this has some limited benefit
when a printed object is required to be flexible, it has a massive
detriment of meaningfully limiting the speed with which the
extruder/print head combination can create objects. Additionally,
this bulky and heavy combination reduces the size efficiency of the
printer, which is defined as the ratio of maximum printed-object
size to the size of the printer's chassis.
[0007] The fundamental principles behind the extruder and the print
head have not changed much since their inception. The print head
can be broken down into two halves that work in tandem to create
the ideal environment for EAC: a "hot end" and a "cold end."
Specifically, those components create an optimized structure for
feeding a continuous solid material feed into a melt zone, so that
the melted material feed can be subsequently deposited onto a
surface.
[0008] The hot end provides the "melt zone" and typically consists
of a nozzle, a metal block, a heater cartridge, a temperature
sensor, and a heat break. That is, the hot end provides the heat
necessary to melt the material feed such that it may be used in
EAC. The temperature sensor is typically either a thermistor or
thermocouple. The heat break serves as a connection point from the
hot end to the cold end and also provides for a heat transfer choke
point due to its particular mechanical shape.
[0009] The purpose of the cold end is to maintain the rigidity of
the material feed. Since the material feed is being pushed into the
hot end, its rigidity must be maintained else one risks a failure
to move it into the hot end due to an inability to
"push-on-a-rope." The hot end and cold end may be collectively
referred to as a "print head" though typically the print head for
an EAC 3D printer contains several additional components to aid in
the printing process though they are not essential. Firstly, the
print head is typically fastened to a carriage that contains linear
bearings (typically ball bearings) in order to achieve linear
motion. The carriage also typically contains mount points for
timing belts such that motion can be achieved by off-board
motors.
[0010] Additionally, the print head may also include an additional
fan and fan duct to facilitate the cooling of the top-most layer of
the object being constructed. This is beneficial because plastic
that has not yet cooled provides a poor foundation for subsequent
layers of the print. Without proper top layer cooling, an EAC 3D
printer can only print at a finite speed, well below the
capabilities of the other components. Additionally, cooling the
newly-extruded plastic also increases the `bridging` performance of
the printer. This means that with additional cooling of
newly-extruded plastic, features with steep overhangs or
unsupported spans of plastic may be better achieved.
[0011] In the vast majority of existing EAC 3D printers, the cold
end of the print head is air-cooled by radiating heat absorbed into
the surrounding environment, typically via active cooling with fans
and heatsinks and only in extreme cost-cutting edge cases, passive
radiation. In the construction of an air-cooled embodiment, there
is typically one heatsink, one pair of standoffs, one axial fan,
and one fan blade guard per hot end of the EAC 3D printer.
Therefore, for most EAC 3D printers with two hot ends, there are
two heatsinks, two pairs of standoffs, two axial fans, and two fan
blade guards, in addition to the bolts to fasten the assembly. This
large bill of materials for just the cooling subcomponent of the
EAC 3D print head is expensive to construct and is an inefficient
use of space.
[0012] While the weight and bill of materials (BoM) savings of a
passively-cooled EAC 3D print head is tempting, print heads
typically include some sort of cooling method to keep the cold end
cool for a fundamental reason. Over enough time, the cold end will
begin to absorb heat from the hot end due to heat diffusion. This
can lead to catastrophic failures of the EAC 3D printer as this
heat creep could cause a jam by heating the material feed to its
Glass Transition Temperature (Tg), (the temperature region where
the polymer transitions from a hard, glassy material to a soft,
rubbery material) thus causing a "pushing-on-a-rope" situation and
a subsequent jam.
[0013] There have been several attempts in the prior art to improve
certain components of an EAC 3D printer print head. However, these
components lack novel features disclosed herein and have yet to be
proposed in the unique combination disclosed herein, which yields
unexpectedly positive results in both weight reduction, size
footprint reduction, and reliability while simultaneously achieving
all goals already achieved by incumbent design.
[0014] The pursuit to reduce EAC 3D printer print head weight is
beneficial as currently it serves as a bottleneck in the EAC
process common to all types of EAC 3D printers. Put simply, even
minor reductions to the weight of the print head yield meaningful
improvements in the speed of EAC, so major reductions in weight
will result in substantial improvement over the prior art. This is
because of the first law of Newtonian physics that governs inertia:
an EAC 3D printer print head in motion will take significant force
to accelerate or decelerate accurately. Because of this, in order
to achieve accurate parts EAC 3D printers are programmed to print
slower than their theoretical limit. Additionally, the forces from
acceleration and deceleration are absorbed by the printer's
chassis, linear shafts, and belts, which cause vibrations. These
vibrations show in completed objects and present themselves as
surface artifacts in the print. Such surface features make EAC 3D
printing undesirable for cosmetic or end-use parts, but this can be
solved through superior print head design.
[0015] As such, there is a need for a print head that is capable of
incorporating all of the desired optional features currently
employed in the art, but has a smaller footprint and weighs less
than the print heads known in the art.
SUMMARY
[0016] An aspect of an example embodiment in the present disclosure
is to provide a carriageless print head for use in EAC 3D printing.
Accordingly, the present disclosure describes a print head, for use
in extrusion-based additive construction, including a cold end
having a front end, a rear end, a left side, a right side, a top
surface extending from the front end to the rear end and from the
left side to the right side, a bottom surface extending from the
front end to the rear end and from the left side to the right side,
and a receiver configured to receive a bearing, and a hot end
configured to provide a melt zone, the hot end being attached to
the cold end.
[0017] In some embodiments, the cold end includes a second receiver
configured to receive a second bearing, preferably where the
receiver is a first receiver and the bearing is a first
bearing.
[0018] The present disclosure also provides a print head, for use
in extrusion-based additive construction, including a cold end
having a front end, a rear end, a left side, a right side, a top
surface extending from the front end to the rear end and from the
left side to the right side, a bottom surface extending from the
front end to the rear end and from the left side to the right side,
and an attachment slot, and a hot end configured to provide a melt
zone, the hot end being attached to the cold end.
[0019] In some embodiments, the cold end includes a receiver
configured to receive a bearing.
[0020] In some embodiments, the cold end includes a second
attachment slot, preferably where the attachment slot is a first
attachment slot.
[0021] In some embodiments, the cold end includes a second receiver
configured to receive a second bearing, preferably where the
receiver is a first receiver and the bearing is a first
bearing.
[0022] In some embodiments, the print head includes a temperature
sensor configured to monitor a temperature of the cold end.
[0023] In some embodiments, the print head includes a temperature
sensor configured to monitor a temperature of a heat break
connected to the hot and the cold end.
[0024] In some embodiments, the print head includes a second
temperature sensor configured to monitor a second temperature of
the cold end, preferably where the temperature sensor is a first
temperature sensor and the temperature is a first temperature.
[0025] In some embodiments, the hot end and the cold end have a
unibody construction.
[0026] In some embodiments, the hot end, the cold end, the heat
break have a unibody construction.
[0027] In some embodiments, the first attachment slot is adjacent
to and aligned with the first receiver, and the second attachment
slot is adjacent to and aligned with the second receiver.
[0028] In some embodiments, the top surface is equipped with a
first slot which extends downwardly towards the bottom surface and
is configured to receive a first material feed.
[0029] In some embodiments, the attachment slot extends
substantially from the front end to the rear end, the first
receiver extends substantially from the front end to the rear end,
the second attachment slot extends substantially from the front end
to the rear end, and the second receiver extends substantially from
the front end to the rear end.
[0030] In an embodiment, the top surface includes a second slot
which extends downwardly towards the bottom surface and is
configured to receive a second material feed.
[0031] In an embodiment, the print head includes a first heat
break, preferably where the first heat break is proximate to the
first slot.
[0032] In an embodiment, the print head includes a second heat
break, preferably where the second heat break is proximate to the
second slot.
[0033] In an embodiment, the top surface includes a third slot
which extends downwardly towards the bottom surface and is
preferably configured to receive a cooling fluid, a fourth slot
which extends downwardly towards the bottom surface and is
preferably configured to expel a cooling fluid. In an embodiment,
the cold end includes a fluid channel having a perimeter,
preferably where the perimeter of the fluid channel is contained
within the cold end.
[0034] In an embodiment, the fluid channel intersects with the
third slot and the fourth slot, preferably where the fluid channel
extends from the third slot to the fourth slot.
[0035] In an embodiment, the fluid channel includes an opening on
either the first receiver or the second receiver, and a fluid
channel plug sized to seal the opening.
[0036] In an embodiment, the perimeter is bounded by the bottom
surface, the top surface, the front end, the rear end, the first
receiver and the second receiver.
[0037] The present disclosure also provides a computer-mediated
method of performing extrusion-based additive construction using a
3D printer equipped with a print head having a thermal monitor and
a receiver configured to receive a bearing, including the steps of:
beginning, by the 3d printer, an extrusion-based additive
construction; reading, by the thermal monitor an operating
temperature of the cold end; assessing, whether the operating
temperature is above a predetermined temperature threshold;
pausing, the construction; and allowing the cold end to cool to a
print resume threshold, preferably where the print resume threshold
is equal to or below the predetermined temperature threshold.
[0038] In an embodiment, the cold end further comprising a second
receiver configured to receive a second bearing, preferably where
the receiver is a first receiver and the bearing is a first
bearing.
[0039] The present disclosure also provides a computer-mediated
method of performing extrusion-based additive construction using a
3D printer equipped with a print head having a thermal monitor and
an attachment slot, including the steps of: beginning, by the 3d
printer, an extrusion-based additive construction; reading, by the
thermal monitor an operating temperature of the cold end;
assessing, whether the operating temperature is above a
predetermined temperature threshold; pausing, the construction; and
allowing the cold end to cool to a print resume threshold,
preferably where the print resume threshold is equal to or below
the predetermined temperature threshold.
[0040] In an embodiment, the print head includes a cold end having
a front end, a rear end, a left side, a right side, a top surface
extending from the front end to the rear end and from the left side
to the right side, a bottom surface extending from the front end to
the rear end and from the left side to the right side, and a hot
end configured to provide a melt zone, the hot end being attached
to the cold end.
[0041] In an embodiment, the cold end includes a receiver
configured to receive a bearing.
[0042] In an embodiment, the cold end includes a second attachment
slot, preferably where the attachment slot is a first attachment
slot.
[0043] In an embodiment, the cold end includes a second receiver
configured to receive a second bearing, preferably where the
receiver is a first receiver and the bearing is a first
bearing.
[0044] In an embodiment, the method includes the step of resuming,
the extrusion-based additive construction.
[0045] In an embodiment, the method includes the step of manually
resuming, by a human operator, the extrusion-based additive
construction.
[0046] Implementations may include one or a combination of any two
or more of the aforementioned features.
[0047] These and other aspects, features, implementations, and
advantages can be expressed as methods, apparatuses, systems,
components, program products, business methods, and means or steps
for performing functions, or some combination thereof.
[0048] Other features, aspects, implementations, and advantages
will become apparent from the descriptions, the drawings, and the
claims.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] In the drawings, like elements are depicted by like
reference numerals. The drawings are briefly described as
follows.
[0050] FIGS. 1A-1B show two embodiments of a carriageless EAC 3D
printer print head design with two differing linear motion shaft
systems.
[0051] FIG. 2 shows an alternative embodiment of an EAC 3D printer
print head design whereby linear motion is achieved through a
traditional bolt-on carriage.
[0052] FIGS. 3A-3C show various implementations of a top layer
cooling feature with the source of air off-board with respect to
the print head.
[0053] FIGS. 4A-4C show various implementations of a cold end
cooling feature with the components to dissipate heat to the
outside environment off-board with respect to the print head.
[0054] FIGS. 5A-5B show flow charts illustrating the logic of an
embodiment of the method of cold end thermal monitoring in
accordance with the present disclosure.
[0055] The present disclosure now will be described more fully
hereinafter with reference to the accompanying drawings, which show
various example embodiments. However, the present disclosure may be
embodied in many different forms and should not be construed as
limited to the example embodiments set forth herein. Rather, these
example embodiments are provided so that the present disclosure is
thorough, complete, and fully conveys the scope of the present
disclosure to those skilled in the art. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0056] FIGS. 1A and 1B illustrate two embodiments of a carriageless
print head in accordance with the present disclosure. Referring to
FIG. 1A, a carriageless print head 100 is provided. The
carriageless print head 100 is comprised of a cold end 102. The
cold end 102 has a front end 102A, a rear end 102B, a left side
102C, a right side 102D, a top surface 102E, and a bottom surface
102F. The top surface 102E constitutes the top surface of the cold
end 102, and the bottom surface 102F constitutes the bottom surface
of the cold end 102, where both the top surface 102E and the bottom
surface 102F extend from the first side 102C to the right side
102D, and from the front end 102A to the rear end 102B. The
carriageless print head 100 is also equipped with a first heat
break 136 attached to a first hot end 142 and a second heat break
138 attached to a second hot end 144. The first hot end 142 and the
second hot end 144 are proximate to the first slot and the second
slot, respectively.
[0057] Here, the top surface 102E is equipped with a first slot
116A and a second slot 116B. Both the first slot 116A and the
second slot 116B are configured to receive a material feed to be
used in the EAC process. Preferably, the first slot 116A and the
second slot 116B are press-fit quick release plungers, although
other types of attachment mechanisms are suitable. Optionally, the
top surface 102E is equipped with a cable passthrough 120, which
extends downwardly towards and through the bottom surface 102F,
such that a cable may be threaded through the cold end 102. In some
preferred embodiments, the top surface 102E features a bore for
thermal monitor 118 meant to receive a thermal monitor 400. The
thermal monitor 400 consists of at least one wire 402 and a
temperature sensor 404. The temperature sensor 404 may be a
thermocouple, thermistor, or any other type of electronic
temperature-sensing device that may be interpreted by a
microcontroller or similar computing device.
[0058] Preferably, the left side 102C and the right side 102D are
substantially symmetrical. The left side 102C is equipped with a
first receiver 112A and a first timing belt attachment slot 110A,
and the right side 102D is equipped with a second receiver 112B and
a second timing belt attachment slot 110B. By incorporating the
first receiver 112A and the second receiver 112B into the cold end
102, a good deal of space, weight, and mechanical complexity is
avoided when compared with solutions that exist in the prior art.
Specifically, the first receiver 112A and second receiver 112B
replace traditional ball bearings which provides for, greater
design freedom. In some embodiments, the second receiver 112B is
not present and only a single shaft is required to operate the
carriageless print head 100. Thanks to this arrangement, bearings
now take very little space outside of the size of the linear shafts
they slide against, allowing their placement to be within the cold
end 102. Optionally, one or more glide pads 150 may be employed to
help the first receiver 112A and the second receiver 112B slide
along a given shaft. Due to the proximate nature of the first
receiver 112A and the first timing belt attachment slot 110A, as
well as the proximity between the second receiver 112B and the
second timing belt attachment slot 112A allows the carriageless
print head 100 to be propelled along one or more linear shafts
inserted in the first receiver 112A and/or the second receiver
112B. Preferably, the first timing belt attachment slot 110A and
the second timing belt attachment slot 110B will be placed along
the centerline of the first receiver 112A and the second receiver
112B, respectively. This has the benefit of minimizing torque
during high acceleration of the carriageless print head 100. By
using cylindrical shafts, the overall cost of the 3D printer may be
reduced via the reduced cost of procuring the commonly used
cylindrical shaft.
[0059] As shown in FIG. 1B, the first receiver 112A and the second
receiver 112B may be shaped to work with non-cylindrical shafts. As
a non-limiting example, the embodiment shown in FIG. 1B shows the
first receiver 112A and the second receiver 112B in a configuration
to use a T-shaped shaft. Here the optional glide pads 150 are
shaped to interface with the T-shaped shaft as well as the first
receiver 112A and the second receiver 112B. T-shaped shafts are
desirable because they offer a balance between weight savings and
maximum unsupported span. For large-format EAC 3D printers, the
length of the linear shafts to span their large build platforms
poses an engineering problem: larger-diameter shafts add weight to
a system in motion, but smaller-diameter shafts cannot support the
weight of an EAC print head without significant
deflection--hindering the ability to print at very small layer
heights and introducing potential for resonant frequencies that
impact print quality. Accordingly, the embodiment of FIG. 1B could
be deployed in a large-scale EAC 3D printer and exhibit significant
weight savings, therefore achieving the goal of faster print speeds
and better printed-part-to-printer-size ratio, with the unexpected
outcome of reduced mechanical complexity in assembly of the EAC 3D
printer print head prior to installation in the EAC 3D printer.
Many other cross-sectional shapes of linear shafts are compatible
with the first receiver 112A and the second receiver 112B, the
first receiver 112A and the second receiver 112B just need to be
shaped complimentarily to the desired shaft. In some embodiments,
one or more glide pads 150 are inserted at the interface of the
first receiver 112A and the first shaft, as well as the interface
between the second receiver 112B and the second shaft. Again, in
some embodiments only the first receiver 112A is present and the
carriageless print head 100 operates using a single shaft.
[0060] Referring to FIG. 2, an embodiment of the print head 100 is
shown without the first receiver 112A or the second receiver 112B,
and is instead depicted with a traditional carriage 160. As can be
seen, the use of a separate carriage 160 to achieve linear motion
requires additional mechanical complexity in assembly of the final
product. In this embodiment, the use of the carriage 160 prevents
meaningful weight savings, and size savings, offered by the
embodiments shown in FIGS. 1A and 1B.
[0061] FIGS. 3A-3C show various embodiments of an air conduit 200
in accordance with the present disclosure. In FIG. 3A, the air
conduit 200 consists of a nipple 202, and an air duct 204. In this
embodiment, the air duct 204 is removably attached to the cold end
102. The nipple 202 allows the source of the air to be located
somewhere not on the cold end 102, allowing for meaningful size and
weight reduction of the carriageless print head 100.
[0062] Typically, in devices known in the prior art, air sources
employed in EAC 3D printing use an air source that is mounted on
the given print head in motion. These air sources may be either
radial fans or axial fans, and may also have an air duct to direct
airflow downwards towards newly-extruded plastic in order to avoid
cooling the hot end. These designs all bear the flaw of having the
moving mass of the air source and any optional duct on the print
head, which increases its size, reduces its speed due to its mass,
and potentially has an impact on print quality due to resonant
frequencies due to inertial mass.
[0063] In contrast, the embodiments shown in FIGS. 3A-3C employ
various off-board air sources for cooling the top layer of a
printed object. The nipple 202 preferably connects to an off-board
air source via a barbed-tube fitting, but could employ a
compression fitting, push-to-connect tube fitting, or other known
mechanical fastening agents for tubes that supply pressurized
airflow. The external air source may be an air compressor,
compressed air (or other pressurized gas) tank, chemical reaction,
motorized bellows, or even a fan capable of driving sufficient
pressure through a small-diameter tube.
[0064] Referring to FIG. 3B, the air conduit 200 is shown in an
integrated embodiment. That is, the air conduit 200 has been
integrated into the cold end 102. This achieves the goal of having
an off-board air source provide cooling air to the top layer. FIG.
3C shows a highly preferred embodiment where the air conduit 200 is
integrated with the cold end 102, but is also equipped with a
plurality of embedded fins 206 and the air duct 204 is optimized to
facilitate airflow therethrough. The plurality of embedded fins 206
create a uniform-velocity flow at the exit orifice, effectively
creating a `blade of air` to cool the top layer of the printed
part. This provides optimal performance to prevent over or
under-cooling localities of the printed part. The embodiment of the
air conduit 200 shown in FIG. 3C is also optimal in its placement
of the air duct 204: by situating the air conduit 200 between the
first slot 116A and the second slot 116B, the air duct 204 cools
newly-extruded filament material just as effectively regardless of
whether the first slot 116A or the second slot 116B is extruding
the material feed.
[0065] Referring to FIGS. 4A-4C, three embodiments of a water
channel 300 or a cooling fluid channel 300 are shown. In these
embodiments, the cold end 102 is cooled by liquid cooling. FIG. 4A
shows the water channel 300 is drilled from either the left side
102C or the right side 102D and subsequently plugged with cooling
fluid channel plug 302 to form a seal. Such a seal may take many
forms, such as a set screw, a set screw with thread lock, other
screw-type plugs, and deformable metal cooling circuit plugs.
Cooling fluid, preferably water, is circulated through the third
slot 114A and the fourth slot 114B, which are configured to allow
fluid to selectively pass through them.
[0066] FIG. 4B shows an embodiment where the cooling fluid channel
300 is completely contained within the cold end 102. This
embodiment provides benefits over the one shown in FIG. 4A because
there is no post-manufacture assembly required to seal the cooling
fluid channel, correspondingly no failure point for the cooling
fluid channel's seal, and lastly offers the greatest amount of
design freedom.
[0067] Shown in FIG. 4C is a highly preferred embodiment in
accordance with the present disclosure. This embodiment depicts a
cooling fluid channel 300 with a perimeter 304 where the connection
between the third slot 114A and the fourth slot 114B is not a
simple channel, but rather where the perimeter 304 constitutes a
completely customized internal envelope within the cold end 102. In
FIG. 4C we see that there is not only a channel to connect the
fluid inputs and fluid outputs, but this channel is expanded to
envelop other features internal to the carriageless print head 100.
By doing this, one no longer has to rely on the thermal
conductivity of the cold end 102.
[0068] In some embodiments, the carriageless print head 100 is
integrated with an embedded thermal monitor 400. In some
embodiments, the carriageless print head 100 is integrated with
multiple thermal monitors 400. By embedding the temperature sensor
404 in the top surface 102E, one now has a dedicated thermal
monitor 400 that can trigger protective action to prevent a jam or
other damage to the carriageless print head 100 typically caused by
long print jobs or times of peak printer usage with little rest
between jobs.
[0069] It is important to note that the presence of the thermal
monitor 400 alone is insufficient to prevent jams or damage caused
by heat creep into the cold end. For preventative/protective action
to be taken, accompanying software must be able to interpret the
data provided by the temperature sensor and trigger action
accordingly. Two proposed workflows for this process are shown in
FIGS. 5A and 5B.
[0070] "Cold Pause Mode" is defined as a mode in which an EAC 3D
printer pauses printing and disables the heaters in the hot end.
This allows the printer to cool safely and subsequently resume
printing without any damage or risk of completion to the printed
object. The process shown in FIG. 5A, is optimal for having
printers print continuously, pausing only to prevent heat-related
jamming or damage. The process shown in FIG. 5B takes a more
conservative approach in that upon detection of too much heat being
absorbed into the cold end, the printer is put indefinitely into
Cold Pause Mode until a human operator can diagnose the problem and
manually re-engage the printer to complete the print or to cancel
the print job entirely. The workflows disclosed in FIGS. 5A and 5B
may optionally have an alerting system to notify administrators of
the printers of the detected elevated temperatures in the cold end
102. It is also notable that while this logic may be embedded into
the printer's main firmware logic, it may also be present on an
external logic board. An external logic board would be beneficial
when the logic needs to be parsed by such an independent
microcontroller and only a stop/pause/cold pause signal can be sent
and accepted by the EAC 3D printer's primary controller board.
[0071] Referring to FIG. 5A, a method of monitoring the temperature
of a cold end of an EAC 3D printer 700 is shown. Here, the method
700 begins with step 702, and proceeds to step 704 where the
temperature of a thermal monitor configured to measure the
temperature of the cold is read. Then the method 700 proceeds to
step 706 where the method 700 assesses whether the read temperature
is above a cold pause threshold. If the read temperature is below
the cold pause threshold, the method proceeds to step 720 where the
EAC 3D printer is allowed to continue printing. However, if the
read temperature is above the cold pause threshold, the method
proceeds to step 708, where the EAC 3D printer enters a cold pause
mode, where the print job is stopped. From there, the method 700
proceeds to step 710 where the temperature of the thermal monitor
is reassessed, and in step 712 the method 700 determines if the
read temperature is still above the cold pause threshold. If so,
the method proceeds to step 716 where printing is paused, and
repeats step 710 again. If not, the method proceeds to step 714
where the EAC 3D printer is allowed to resume printing.
[0072] In FIG. 5A, there are two threshold variables that need to
be known: the Cold Pause Threshold and the Resume Print Threshold.
The Cold Pause Threshold variable is dependent on the material
being printed, specifically the material's Glass Transition
Temperature (Tg). In some embodiments the Cold Pause Threshold
would be equivalent to the material's Glass Transition Temperature
(Tg), though in other, preferred embodiments, the Cold Pause
Threshold should include some buffer to protect against
imperfections in the sensor, or other real-world environmental
variables. As an example, when printing in Acrylonitrile Butadiene
Styrene (ABS) plastic, whose Glass Transition Temperature (Tg) is
.about.105 degrees Celsius, an appropriate Cold Pause Threshold
could be 100 degrees Celsius, giving 5 degrees "buffer". To resume
printing, there would also be a Resume Print Threshold.
[0073] In many embodiments, it is to cool below the Resume Print
Threshold to prevent excessive pausing and re-starting. Therefore,
the Resume Print Threshold would be set to an arbitrary amount
below the Cold Pause Threshold. In the example of Acrylonitrile
Butadiene Styrene (ABS) plastic with a .about.105 degrees Celsius
Glass Transition Temperature (Tg) and a 100 degrees Celsius Cold
Pause Threshold, a Resume Print Threshold could be 95 degrees
Celsius.
[0074] In other embodiments, it may be preferential to the operator
that a printer remain paused until a human technician can diagnose
the cause of the overheating. This use case is illustrated in the
logic outlined in FIG. 5B. Here, the method 700 begins with step
702, and proceeds to step 704 where the temperature of a thermal
monitor configured to measure the temperature of the cold end 102
is read. Then the method 700 proceeds to step 706 where the method
700 assesses whether the read temperature is above a cold pause
threshold. If the read temperature is above the cold pause
threshold, the method 700 proceeds to step 708 where the EAC 3D
printer enters a cold pause mode, and then proceeds to step 722
where a human operator must manually resume printing. If the read
temperature is below the cold pause threshold, the method 700 will
proceed to step 720 where the EAC 3D printer is allowed to keep
printing. In FIG. 5B there is no need to set a separate Resume
Print Threshold because upon detecting the EAC 3D printer's print
head cold end temperature breaching the Cold Pause Threshold, the
printer is put in an indefinite Cold Pause.
[0075] It is understood that when an element is referred
hereinabove as being "on" another element, it can be directly on
the other element or intervening elements may be present
therebetween. In contrast, when an element is referred to as being
"directly on" another element, there are no intervening elements
present.
[0076] Moreover, any components or materials can be formed from a
same, structurally continuous piece or separately fabricated and
connected.
[0077] It is further understood that, although ordinal terms, such
as, "first," "second," "third," are used herein to describe various
elements, components, regions, layers and/or sections, these
elements, components, regions, layers and/or sections should not be
limited by these terms. These terms are only used to distinguish
one element, component, region, layer and/or section from another
element, component, region, layer and/or section. Thus, "a first
element," "component," "region," "layer" and/or "section" discussed
below could be termed a second element, component, region, layer
and/or section without departing from the teachings herein.
[0078] Features illustrated or described as part of one embodiment
can be used with another embodiment and such variations come within
the scope of the appended claims and their equivalents.
[0079] Spatially relative terms, such as "beneath," "below,"
"lower," "above," "upper" and the like, are used herein for ease of
description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
is understood that the spatially relative terms are intended to
encompass different orientations of the device in use or operation
in addition to the orientation depicted in the figures. For
example, if the device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the
example term "below" can encompass both an orientation of above and
below. The device can be otherwise oriented (rotated 90 degrees or
at other orientations) and the spatially relative descriptors used
herein interpreted accordingly.
[0080] Example embodiments are described herein with reference to
cross section illustrations that are schematic illustrations of
idealized embodiments. As such, variations from the shapes of the
illustrations as a result, for example, of manufacturing techniques
and/or tolerances, are to be expected. Thus, example embodiments
described herein should not be construed as limited to the
particular shapes of regions as illustrated herein, but are to
include deviations in shapes that result, for example, from
manufacturing. For example, a region illustrated or described as
flat may, typically, have rough and/or nonlinear features.
Moreover, sharp angles that are illustrated may be rounded. Thus,
the regions illustrated in the figures are schematic in nature and
their shapes are not intended to illustrate the precise shape of a
region and are not intended to limit the scope of the present
claims.
[0081] Attention is called to the fact, however, that the drawings
are illustrative only. Variations are contemplated as being part of
the disclosure.
[0082] In the present disclosure, where a document, act or item of
knowledge is referred to or discussed, this reference or discussion
is not an admission that the document, act or item of knowledge or
any combination thereof was at the priority date, publicly
available, known to the public, part of common general knowledge or
otherwise constitutes prior art under the applicable statutory
provisions; or is known to be relevant to an attempt to solve any
problem with which the present disclosure is concerned.
[0083] While certain aspects of conventional technologies have been
discussed to facilitate the present disclosure, no technical
aspects are disclaimed and it is contemplated that the claims may
encompass one or more of the conventional technical aspects
discussed herein.
[0084] The invention is described above with reference to block and
flow diagrams of systems, methods, apparatuses, and/or computer
program products according to exemplary embodiments of the
invention. It will be understood that one or more blocks of the
block diagrams and flow diagrams, and combinations of blocks in the
block diagrams and flow diagrams, respectively, can be implemented
by computer-executable program instructions. Likewise, some blocks
of the block diagrams and flow diagrams may not necessarily need to
be performed in the order presented, or may not necessarily need to
be performed at all, according to some embodiments of the
invention.
[0085] These computer-executable program instructions may be loaded
onto a general-purpose computer, a special-purpose computer, a
processor, or other programmable data processing apparatus to
produce a particular machine, such that the instructions that
execute on the computer, processor, or other programmable data
processing apparatus create means for implementing one or more
functions specified in the flow diagram block or blocks. These
computer program instructions may also be stored in a
computer-readable memory that can direct a computer or other
programmable data processing apparatus to function in a particular
manner, such that the instructions stored in the computer-readable
memory produce an article of manufacture including instruction
means that implement one or more functions specified in the flow
diagram block or blocks. As an example, embodiments of the
invention may provide for a computer program product, comprising a
computer-usable medium having a computer-readable program code or
program instructions embodied therein, said computer-readable
program code adapted to be executed to implement one or more
functions specified in the flow diagram block or blocks. The
computer program instructions may also be loaded onto a computer or
other programmable data processing apparatus to cause a series of
operational elements or steps to be performed on the computer or
other programmable apparatus to produce a computer-implemented
process such that the instructions that execute on the computer or
other programmable apparatus provide elements or steps for
implementing the functions specified in the flow diagram block or
blocks.
[0086] Accordingly, blocks of the block diagrams and flow diagrams
support combinations of means for performing the specified
functions, combinations of elements or steps for performing the
specified functions and program instruction means for performing
the specified functions. It will also be understood that each block
of the block diagrams and flow diagrams, and combinations of blocks
in the block diagrams and flow diagrams, can be implemented by
special-purpose, hardware-based computer systems that perform the
specified functions, elements or steps, or combinations of special
purpose hardware and computer instructions.
[0087] As the invention has been described in connection with what
is presently considered to be the most practical and various
embodiments, it is to be understood that the invention is not to be
limited to the disclosed embodiments, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the scope of the appended claims. Although specific
terms are employed herein, they are used in a generic and
descriptive sense only and not for purposes of limitation.
[0088] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined in the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal language of the claims.
[0089] In conclusion, herein is presented a carriageless print
head. The disclosure is illustrated by example in the drawing
figures, and throughout the written description. It should be
understood that numerous variations are possible, while adhering to
the inventive concept and spirit of the invention. Such variations
are contemplated as being a part of the present disclosure.
* * * * *