U.S. patent application number 15/324944 was filed with the patent office on 2017-07-20 for generating a three-dimensional object.
This patent application is currently assigned to Hewlett-Packard Development Company, L.P.. The applicant listed for this patent is David CHANCLON, Alejandro Manuel DE PENA, Comas ESTEVE, Hewlett-Packard Development Company, L.P.. Invention is credited to David CHANCLON, Esteve COMAS, Alejandro Manuel DE PENA.
Application Number | 20170203513 15/324944 |
Document ID | / |
Family ID | 55443000 |
Filed Date | 2017-07-20 |
United States Patent
Application |
20170203513 |
Kind Code |
A1 |
CHANCLON; David ; et
al. |
July 20, 2017 |
GENERATING A THREE-DIMENSIONAL OBJECT
Abstract
According to one example, there is provided a system for
generating a three-dimensional object. The system comprises a
carriage to move bi-directionally along a first axis relative to a
support platform. The carriage is to receive, or have installed
thereon, a plurality of modules each to perform an operation from a
set of operations to generate a layer of a three-dimensional
object. The system further comprises a controller to cause relative
movement between the carriage and the support platform along the
first axis, and to control, during the relative movement, operation
of the modules to perform the set of operations in a predefined
order.
Inventors: |
CHANCLON; David; (Sant Cugat
del Valles, ES) ; DE PENA; Alejandro Manuel; (Sant
Cugat del Valles, ES) ; COMAS; Esteve; (Sant Cugat
del Valles, ES) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CHANCLON; David
DE PENA; Alejandro Manuel
ESTEVE; Comas
Hewlett-Packard Development Company, L.P. |
Sant Cugat del Valles
Sant Cugat del Valles
Sant Cugat del Valles
Houston |
TX |
ES
ES
ES
US |
|
|
Assignee: |
Hewlett-Packard Development
Company, L.P.
Houston
TX
|
Family ID: |
55443000 |
Appl. No.: |
15/324944 |
Filed: |
July 10, 2014 |
PCT Filed: |
July 10, 2014 |
PCT NO: |
PCT/EP2014/064870 |
371 Date: |
January 9, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2014/050841 |
Jan 16, 2014 |
|
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15324944 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B33Y 40/00 20141201;
B33Y 10/00 20141201; B33Y 30/00 20141201; B29C 64/205 20170801;
B29C 64/165 20170801; B33Y 50/02 20141201; B29C 64/40 20170801;
B29C 64/393 20170801 |
International
Class: |
B29C 67/00 20060101
B29C067/00; B33Y 50/02 20060101 B33Y050/02; B33Y 40/00 20060101
B33Y040/00; B33Y 10/00 20060101 B33Y010/00; B33Y 30/00 20060101
B33Y030/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 16, 2014 |
EP |
PCT/EP2014/050841 |
Claims
1. A system for generating a three-dimensional object, comprising:
a carriage to move bi-directionally along a first axis relative to
a support platform, the carriage to receive, or have installed
thereon, a plurality of modules each to perform an operation from a
set of operations to generate a layer of a three-dimensional
object; and a controller to: cause relative movement between the
carriage and the support platform along the first axis; and
control, during the relative movement, operation of the modules to
perform the set of operations in a predefined order.
2. The system of claim 1, wherein the controller is to control the
modules to perform the set of operations in the predefined order
during a single pass of the carriage over the support platform in a
first direction.
3. The system of claim 1, wherein the controller is to control the
modules to perform the set of operations in the predefined order
over more than one pass of the carriage over the support
platform.
4. The system of claim 2, wherein the controller is to control the
modules to perform the set of operations in the predefined order
during each pass in either direction along the first axis.
5. The system of claim 4, wherein the carriage comprises a pair of
modules each to perform the same operation, and wherein the
controller is to control one of the pair of modules to operate
during a first pass in a first direction, and to control the other
one of the pair of modules to operate during a second pass in a
second direction.
6. The system of claim 2, wherein one module is a build material
distributor to form a layer of build material on the support
platform and wherein one module is an agent distributor to
selectively deposit drops of agent on a formed layer of build
material in accordance with control data.
7. The system of claim 6, wherein the agent distributor is to
deposit drops of a chemical binder agent.
8. The system of claim 6, wherein the agent distributor is to
deposit drops of a coalescing agent, and wherein one of the modules
is an energy source to apply energy to a layer of build
material.
9. The system of claim 8, wherein the one of the modules is an
agent distributor to deposit drops of a coalescence modifier
agent.
10. A method of operating a system to generate a three-dimensional
object, comprising: controlling a carriage, on which are mounted,
or on which may be received, a plurality of modules to perform
operations to generate a layer of a three-dimensional object, to
move bi-directionally along a first axis over a support; and whilst
the carriage is moving, controlling the modules to perform
operations from a set of operations in a predefined order.
11. The method of claim 10, further comprising controlling the
modules to perform operations from the set of operations during a
single pass of the carriage over the support.
12. The method of claim 10, further comprising controlling the
modules to perform operations from a first sub-set of the set of
operations during a pass in a first direction of the carriage over
the support, and to perform operations from a second sub-set of the
set of operations during a pass in a second direction of the
carriage over the support.
13. The method of claim 10, wherein the set of operations includes:
forming a layer of build material on the support; and depositing
agent at selected locations on a formed layer of build
material.
14. The method of claim 13, wherein the set of operations further
includes: applying energy to a formed layer of build material.
15. A system for generating a three-dimensional object, comprising:
a carriage to move bi-directionally in a first axis relative to a
support platform, the carriage to receive, or have installed
thereon, a build material distributor to form a layer of build
material on the support platform and an agent distributor to
selectively deposit drops of agent on a formed layer of build
material in accordance with control data; and a controller to:
cause relative movement between the carriage and the support
platform along a first axis; and control the build material
distributor and the agent distributor to operate in a predefined
order.
Description
BACKGROUND
[0001] Additive manufacturing systems enable the generation of
three-dimensional objects on a layer-by-layer basis.
[0002] The time to produce a three-dimensional object using such
systems is related to the speed at which layers of build material
may be formed and selectively solidified.
BRIEF DESCRIPTION
[0003] Examples will now be described, by way of non-limiting
example only, with reference to the accompanying drawings, in
which:
[0004] FIG. 1 is an illustration of an additive manufacturing
system according to an example;
[0005] FIG. 2 is a flow diagram outlining a method of operating an
additive manufacturing system according to an example;
[0006] FIG. 3 is a side view of an additive manufacturing system
according to an example;
[0007] FIG. 4 is a side view of a portion of an additive
manufacturing system according to an example;
[0008] FIG. 5 is a side view of a carriage arrangement according to
an example;
[0009] FIGS. 6a to 6d are side views of carriage arrangements
according to various examples;
[0010] FIG. 7 is a side view of a portion of an additive
manufacturing system according to an example;
[0011] FIG. 8 is a side view of a carriage arrangement according to
an example; and
[0012] FIG. 9 is a side view of a carriage arrangement according to
an example.
DETAILED DESCRIPTION
[0013] Some additive manufacturing systems generate
three-dimensional objects through the selective solidification of
successive layers of a build material, such as a powdered build
material. Some such systems may solidify portions of a build
material by selectively depositing an agent to a layer of build
material. Some systems, for example, may use a liquid binder agent
to chemically solidify build material where the liquid binder agent
is applied.
[0014] Other systems, for example, may use liquid energy absorbing
agents, or coalescing agents, that cause build material to solidify
when suitable energy, such as infra-red energy, is applied to build
material on which an energy absorbing or coalescing agent has been
applied. The temporary application of energy may cause portions of
the build material on which coalescing agent has been delivered, or
has penetrated, to absorb energy. This in turn causes these
portions of build material to heat up above the melting point of
the build material and to coalesce. Upon cooling, the portions
which have coalesced become solid and form part of the
three-dimensional object being generated.
[0015] Other systems may use additional agents, such as coalescence
modifier agents, in conjunction with coalescing agents. A
coalescence modifier agent is agent that serves, for example, to
modify the degree of coalescence of a portion of build material on
which the coalescence modifier agent has been delivered or has
penetrated.
[0016] The production of a three-dimensional object through the
selective solidification of successive layers of build material may
involve a set of defined operations. Generally the defined
operations have to be performed sequentially, in a predefined
order.
[0017] A first process may, for example, be to form a layer of
build material from which a layer of the three-dimensional object
is to be generated. A subsequent process may be, for example, to
selectively deposit one or multiple agents to selected portions of
a formed layer of build material. In some examples, a further
subsequent process may be to supply energy to build material on
which an agent has been deposited to solidify the build material in
accordance with where the agent was deposited.
[0018] Repetition of these processes enables a three-dimensional
object to be generated layer-by-layer, through selective
solidification of portions of successive layers of build
material.
[0019] Generation of three-dimensional objects with an additive
manufacturing system may be somewhat time-consuming. Examples
described herein, however, provide an additive manufacturing system
that enable three-dimensional objects to be produced in a
time-efficient manner by providing an additive manufacturing system
that may perform different ones of the above-mentioned processes in
an efficient manner. For example, in some examples some or all of
the processes may be performed at, or substantially at, the same
time.
[0020] Referring now to FIG. 1, there is shown a simplified
isometric illustration of an additive manufacturing system 100
according to an example.
[0021] The system 100 comprises a support platform 102 on which a
three-dimensional object may be generated. The system 100 further
comprises a carriage 104 that is movable bi-directionally along the
y-axis, in a first direction 122 and in a second direction 123,
over the support platform 102. In one example the support platform
102 is not moveable, and hence remains static, in the x-axis. In
one example the carriage 104 is movable along one or multiple
carriage supports (not shown) that may, for example, extend along
the y-axis above the support platform 102.
[0022] The carriage 104 may have installed thereon, or may receive,
multiple modules that may be used during the generation of a
three-dimensional object. In the example shown in FIG. 1 three such
modules are illustrated: a build material distributor 106; an agent
distributor 108; and an energy source 110. In other examples, as
described further below, the carriage 104 may have installed
thereon, or may receive, additional, fewer, or different modules.
For example, if a chemical binder agent is distributed from the
agent distributor 108 then in one example no energy source module
110 may be present.
[0023] The support platform 102 is mounted on a support element
105, such as a piston, movable in the z-axis, for example such that
the support platform 102 may be moved downwards in a stepwise or a
continuous motion as each layer of a three-dimensional object is
generated. The support platform 102 is surrounded by an open
housing 103 (shown in dashed lines). The support platform 102 is
movable from a position in which the support platform 102 is
generally flush with the uppermost surface of the housing 103, to a
position in which the support platform is substantially within the
housing 103. The height of the housing 103, and the length of
vertical travel of the support platform 102 within the housing
generally dictates the maximum height of a three-dimensional object
that may be generated with the additive manufacturing system
100.
[0024] The operation of the additive manufacturing system 100 is
generally controlled by an additive manufacturing system controller
112. The controller 112 comprises a processor 114, such as a
microprocessor or microcontroller, coupled to a non-transitory
computer readable memory 116, for example through a communications
bus (not shown). The memory 116 stores additive manufacturing
system control instructions 118 which are machine readable
instructions that, when executed by the processor 114, cause the
controller 112 to control the additive manufacturing system 100 as
described herein in various examples in accordance with control
data 120.
[0025] The control data 120 is data that may be derived from, for
example, a digital model of a three-dimensional object. For
example, the control data 120 may define, for each layer of build
material to be processed, the locations at which drops of the, or
of each agent, are to be deposited.
[0026] Operation of the additive manufacturing system 100,
according to an example, will now be described with additional
reference to the flow diagram of FIG. 2.
[0027] In this example, the defined operations to be performed, and
the order in which they are to be perform is: [0028] 1) Form layer
of build material; [0029] 2) Deposit agent at selection locations
on formed layer of build material; and [0030] 3) Apply energy to
the formed layer of build material
[0031] At block 202 the controller 112 controls the carriage 104 to
move along the y-axis.
[0032] At block 204, as the carriage 104 is moving along the y-axis
the controller 112 controls at the modules installed on the
carriage 104 to perform the defined operations in the predefined
order.
[0033] In one example the controller 122 controls all of the
defined operations to be performed in the predefined order during a
single pass of the carriage 104 over the support 102. For example,
as the carriage 104 moves in a first pass in the first direction
122, the controller 112 controls the build material distributor 106
to form a layer of build material on the support 102, controls the
agent distributor 108 to deposit drops of an agent at selected
locations on the formed layer 404 of build material, and controls
the energy source 110 to apply energy 408 to the formed layer 404
on which drops of agent may have been deposited.
[0034] In one example the energy source 110 is suitable to apply a
substantially uniform amount of energy across a portion of a layer
of build material.
[0035] In another example, a first sub-set of the set of the
defined operations may be performed in a first pass over the
support 102, and a second sub-set of the set of operations may be
performed in a second pass over the support 102. For example, the
controller 112 may control the energy source 110 to operate during
a second pass of the carriage over the support 102 in the second
direction 123.
[0036] The decision to perform all or some of the defined
operations in one or in multiple passes may be based on various
considerations. For example, one consideration is the way in which
the different modules are arranged on the carriage 104. Another
consideration may be based on specific details of the additive
manufacturing system 100.
[0037] For example, the carriage arrangement of FIG. 1 only allows
the defined operations to be performed in the predefined order at
the same time during a single pass when the carriage is moving in
the direction 122. The carriage arrangement of FIG. 1 does,
however, also allow the defined operations to be performed in
predefined order over multiple passes. For example, the modules 106
and 108 may be operated in a first pass in the first direction 123,
and the module 110 may be operated in a second pass in the second
direction 123.
[0038] In one example, as illustrated in FIG. 3, the build material
distributor 106 comprises a spreader, such as a wiper blade or
roller, to spread a volume of build material from a build material
store 301 across the support platform 102 to form a layer of build
material on the support platform 102.
[0039] It should be noted, however, that the first layer of build
material is formed directly on the surface of the support platform
102, whereas subsequent layers of build material are formed on a
previously formed layer of build material. Accordingly, it will be
understood that the notion of `forming a layer of build material on
the support platform`, as used herein, may refer to forming an
initial layer directly on the support platform 102, or may refer to
forming a layer of build material on a previously formed layer of
build material, according to the specific context. Similarly, the
notion of the `surface of the support platform`, as used herein, is
intended to refer either to the top surface of the support platform
(when no layer or layers of build material is/are formed thereon),
or may refer to the surface of a layer of build material on the
support platform, according to the specific context.
[0040] In the example shown in FIG. 3 the build material store 301
comprises an open housing 302 within which is provided a movable
platform 304 mounted on a moveable element 306 such as a piston.
Build material 308 is provided on the platform within the housing
302. When a new layer of build material is to be formed, the
movable platform 304 is raised such that a small volume of the
build material 308 is raised above the top level of the housing
302. As the carriage 104 is moved in the first direction 122, the
raised volume of build material 308 is spread by the build material
distributor 106 over the surface of the support platform 102
forming a layer of build material on the support platform 102. The
general thickness of the formed layer may depend, for example, on
the height difference between the top of the housing 103, and the
top of the support element 102 (or the top of any layers of build
material formed thereon).
[0041] In one example the thickness of the layer of build material
formed by the build material distributor 106 may be in the range of
about 90 to 110 microns, although in other examples thinner or
thicker layers of build material may be provided. The surface of
the formed layer of build material is parallel to the y-axis (as
shown in FIG. 1), and in an example may be substantially
horizontal.
[0042] As previously mentioned the build material distributor 106
may form a first layer of build material directly on the support
102, and may form subsequent layers of build material on a
previously formed layer of build material. When a new layer of
build material is formed atop a previously formed layer of build
material the thickness of new layer may vary slightly depending the
surface profile of the previously formed layer.
[0043] In one example, the build material distributor 106 is a
passive element, such that no specific control thereof has to be
made. In other words, controlling the carriage 104 to move in the
first direction 122 is sufficient to control the build material
distributor 106 to form a layer of build material.
[0044] In another example, the build material distributor 106 may
be an active element. For example it may comprise, or may be
coupled to, a build material hopper (not shown) that may be
controllable to feed, for example under gravity or under mechanical
pressure, a volume of build material in front of the build material
distributor 106 as it moves in the first direction 122. In another
example the build material distributor 106 may comprise a motorized
roller controllable to rotate in a direction counter to the first
direction 122 (e.g. the roller may be controller to rotate in a
counter-clockwise direction when the carriage is moving in the
first direction 122).
[0045] As shown in FIG. 4, as the carriage 104 is moved in the
first direction 122 a substantially level layer 404 of build
material is progressively formed by the build material distributor
106. A complete layer of build material is only formed, however,
once the carriage 104 has moved completely across the support
platform 102.
[0046] In one example an agent distributor may be a printhead, such
as thermal or a piezo printhead. Such printheads may be the same or
similar to those used in inkjet printing systems. In other examples
an agent distributor may be a spray nozzle or an array of spray
nozzles.
[0047] In the example shown in FIG. 1 only a single agent
distributor 108 is shown, which may, for example, be used to
distribute drops of a suitable binder agent or coalescing agent at
selected location on the layer 404. The locations may be selected,
for example, based on the control data 120, as previously
mentioned. For example, the control data 120 may be based on an
image of a slice of a three-dimensional object that is to be
generated. In another example, the agent distributor 108 may be
configured to deposit drops of multiple agents at selected
locations on the layer 404. In an example the agent distributor 108
may selectively deposit drops of a coalescing agent, and may also
independently and selectively deposit drops of a coalescence
modifier agent on the layer 404.
[0048] The energy source 110 may be any suitable energy source for
emitting any suitable form of electromagnetic radiation. The type
of energy source, and hence the form of electromagnetic radiation
emitted thereby may be chosen, for example, based on the type of
build material, the type of agent(s), or any appropriate factor.
Examples of suitable energy sources may include: ultra-violet light
sources; infra-red light sources; visible light sources; microwave
energy sources; a heating roller, ultra-sound sources, and laser
light sources.
[0049] The controller 112 controls the appropriate synchronization
of operation of each of the modules installed on the carriage 104.
For example, the controller 112 may only control the agent
distributor 108 to selectively deposit drops of an agent when the
agent distributor 108 is positioned above a section of the formed
layer 404 of build material.
[0050] The order in which the modules 106, 108 and 110 are arranged
in the carriage 104 may be modified in some examples, as
illustrated in FIG. 5. For example, in some examples it may be
useful to separate the build material distributor 106 from the
energy source 110, for example by positioning the build material
distributor 106 in between. This, for example, may help shield the
build material distributor 106 from energy emitted by the energy
source 110.
[0051] In the example described above where all of the defined
operations are performed during a single pass of the carriage 104,
to generate a subsequent layer of a three-dimensional object the
carriage 104 has to be moved in the direction 122 back to the
right-hand side (as illustrated in FIG. 1) of the support platform
102, during which time the modules 106, 108, and 110 are not
operated. In one example, the time when the carriage 104 is
returning to the right-hand side of the support platform 102 may be
used to perform other operations, which may include, for example;
printhead maintenance operations; heating operations; moving the
support platform; or the like.
[0052] The controller 112 may control the additive manufacturing
system 100 to operate in different ways, depending for example, on
particular requirements.
[0053] In one example, the controller 112 may control the carriage
104 shown in FIG. 5 to move from the right-hand side of the support
102 to the left-hand side of the support 102 in the first direction
122. In a first pass in the direction 122 the controller 112 may
control the build material distributor 106 to form a layer of build
material, may control the agent distributor 108 to deposit drops of
agent at selective locations on the formed layer of build material.
The controller 112 may then control the carriage 104 to move in the
direction 123 to the right-hand side of the support 102 without the
modules 106, 108, or 110 being operated. In subsequent passes in
the direction 122, the controller 112 may control the energy source
110 to apply energy to layer of build material formed in the
previous pass and on which agent may have been deposited by the
agent distributor 108. The controller 112 may then control the
build material distributor to form a new layer of build material.
The controller 112 may then control the agent distributor to
deposit drops of agent at selective locations on the formed layer
of build material. This configuration may be useful, for example,
where a lapse of time is desired between the depositing of agent
onto the layer of build material and the application of energy
thereto.
[0054] Additional speed advantages may be obtained by enabling a
layer of a three-dimensional object to be generated whilst the
carriage 104 is moving both in the direction 122 and in the
direction 123. Hereinafter this is referred to a bi-directional
processing.
[0055] To enable bi-directional processing, some of the modules may
be installed in duplicate on the carriage 104, as illustrated in
FIGS. 6a to 6d. In one example some of the modules may be
duplicated and be arranged in a generally symmetrical configuration
around a non-duplicated module. In other examples, however, each of
the modules may be duplicated. In other examples a non-symmetrical
configuration of modules may be provided.
[0056] FIG. 6a illustrates a carriage arrangement 600, comprising a
number of different modules. Each of the modules is to perform one
of the defined operations, for example as described earlier. A
single module 602 is provided in the middle of the carriage 600. On
each side of the module 602 is provided a respective one of
duplicated modules 604a and 604b. At each extremity of the carriage
600 is a respective one of duplicated modules 606a and 606b.
[0057] During operation, the controller 112 controls the
non-duplicated module 602 to operate whilst the carriage is moving
in both the direction 122 and in the direction 123. The controller
112 controls one pair of each of the duplicated modules to operate
whilst the carriage is moving in the direction 122, and controls
the other one of the pair of each of the duplicated modules to
operate whilst the carriage is moving the direction 123.
[0058] For example, in a first pass in the direction 122 the
controller 112 controls the modules 602, 604b, and 606b to operate,
and in a second pass in the direction 123 the controller 112
controls the modules 602, 604a, and 606a to operate. Thus, the
controller 112 may control different ones of the modules on the
carriage 104 to operate depending on the direction in which the
carriage 104 is moving.
[0059] In this way, all of the defined operations may be performed
in the predefined order whilst the carriage is moving in either the
first direction 122 or in the second direction 123.
[0060] Some specific examples are additionally shown in FIGS. 6b to
6e. It will be understood, however, that the examples described
herein are purely illustrative in nature and are in no way
limiting. For example, other configurations and arrangements of
modules may be possible that allow each of the different processes
to be performed in the predefined order.
[0061] Referring now to FIG. 6b, there is a shown an example
carriage arrangement, in which a single energy source 110 is
provided between a pair of agent distributors 108a and 108b. At the
extremity of the carriage is provided one of pair of build material
distributors 106a and 106b. In operation, the controller 112
controls the carriage to move from the right-hand side of the
support 102 to the left-hand side of the support 102 in the first
direction 122. In a first pass in the direction 122 the controller
112 may control the build material distributor 106a to form a layer
of build material, may control the agent distributor 108a to
deposit drops of agent at selective locations on the formed layer
of build material, and may control the energy source 110 to apply
energy to the layer of build material. In a return pass in the
direction 123, the controller 112 may control the build material
distributor 106b to form a layer of build material, may control the
agent distributor 108b to deposit drops of agent at selective
locations on the formed layer of build material, and may control
the energy source 110 to apply energy to the layer of build
material.
[0062] Referring now to FIG. 6c, there is a shown an example
carriage arrangement, in which a single agent distributor 108 is
provided between a pair of energy sources 110a and 110b. At the
extremity of the carriage is provided one of a pair of build
material distributors 106a and 106b. In operation, the controller
112 controls the carriage to move from the right-hand side of the
support 102 to the left-hand side of the support 102 in the first
direction 122. In a first pass in the direction 122 the controller
112 may control the build material distributor 106a to form a layer
of build material, may control the agent distributor 108 to deposit
drops of agent at selective locations on the formed layer of build
material, and may control the energy source 110b to apply energy
thereto. In a return pass in the direction 123, the controller 112
may control the build material distributor 106b to form a layer of
build material, may control the agent distributor 108 to deposit
drops of agent at selective locations on the formed layer of build
material, and may control the energy source 110a to apply energy
thereto. In one example, the energy sources 110a and 110b may be
operated at different energy intensities or wavelengths during each
pass, for example, such that one energy source may be used as a
pre-heater whilst the other energy source is apply energy suitable
to cause solidification of build material on which an appropriate
agent has been deposited.
[0063] In some examples an agent distributor, such as the agent
distributor 108a or 108b, may be able to selectively and
independently deposit drops of multiple agents, such as drops of a
coalescing agent and a coalescence modifier agent.
[0064] Referring now to FIG. 6d, there is a shown an example
carriage arrangement, in which a two pairs of agent distributors
108a and 108b, and 109a and 109b, are provided between a single
energy source 110. The first pair of agent distributors 108a and
108b may deposit drops of a first agent, such as a coalescing
agent. The second pair of agent distributors 109a and 109b may
deposit drops of a second agent, such as a coalescence modifier
agent. At the extremity of the carriage is provided one of a pair
of build material distributors 106a and 106b. In operation, the
controller 112 controls the carriage to move from the right-hand
side of the support 102 to the left-hand side of the support 102 in
the first direction 122. In a first pass in the direction 122 the
controller 112 may control the build material distributor 106a to
form a layer of build material, may control the agent distributor
108a to deposit drops of a first agent at selective locations on
the formed layer of build material, may control the agent
distributor 109a to deposit drops of a second agent at selective
locations on the formed layer of build material, and may control
the energy source 110 to apply energy to the layer of build
material. In a return pass in the direction 123, the controller 112
may control the build material distributor 106b to form a layer of
build material, may control the agent distributor 108b to deposit
drops of a first agent at selective locations on the formed layer
of build material, may control the agent distributor 109b to
deposit drops of a second agent at selective locations on the
formed layer of build material, and may control the energy source
110a to apply energy to the layer of build material.
[0065] In one example, to enable bi-directional distribution of
build material the additive manufacturing system 100 may be
provided with a pair of build material stores 301a and 301b, as
illustrated in FIG. 7. For example, when the carriage 104 moves in
the first direction 122, build material from the build material
store 301a is used to form a layer of build material on the support
platform 102, and when the carriage 104 moves in the direction 123,
build material from the build material store 301b is used to form a
layer of build material on the support platform 102.
[0066] As previously mentioned, in an example where a chemical
binder agent is distributed from the agent distributor 108 no
energy source module 110 may be present on the carriage 104, as
illustrated in FIG. 8. In this example the carriage 104 may
comprise a build material distributor module 106 and an agent
distributor 108. In one example such a carriage may be controlled
to generate a layer of a three-dimensional object in a single pass
whilst moving in a single direction, such as the direction 122.
During a return pass the agent distributor 108 and build material
distributor 106 are not operated.
[0067] In one example such a carriage may be controlled to generate
a layer of three-dimensional object over two passes, for example a
first pass in the direction 122 the build material distributor 106
may be operated, and in a second pass in the direction 123 the
agent distributor 106 may be operated. In another example more than
two passes may be used.
[0068] In a further example, as illustrated in FIG. 9, the carriage
104 may be arranged to comprise a build material distributor 106 on
either side of which is arranged one of a pair of agent
distributors 108a and 108b. This configuration enables, for
example, a layer of a three-dimensional object to be generated
whilst the carriage 104 is moving either in a direction 122 or in a
direction 123.
[0069] The example additive manufacturing systems described herein
provide a scalable solution for additive manufacturing systems. For
example, by having all of the main modules of an additive
manufacturing system positioned on a single carriage enables all
data, power, and agent connections to be routed to a single
carriage. This may help simplify the design and manufacture of such
systems. Furthermore, the size of objects that may be generated
with such a system may be easily increased in the y-axis by
extending the length of the support platform 102 and extending the
length of the carriage bars on which the carriage 104 moves.
[0070] Although the examples described herein provide a carriage
which moves over a fixed support platform, in other examples the
carriage 104 may be fixed and the support platform 102 may be
movable along the y-axis. In other examples, any suitable relative
movement between the carriage 104 and the support platform 102 may
be provided.
Description of Materials
[0071] To enable the methods and systems to manufacture a
three-dimension object as described herein to function the
properties of the build material, coalescing agent, and coalesce
modifier agent need to be carefully chosen.
[0072] Some examples of suitable materials are given below.
Build Material
[0073] According to one example a suitable build material may be a
powdered semi-crystalline thermoplastic material. One suitable
material may be Nylon 12, which is available, for example, from
Sigma-Aldrich Co. LLC. Another suitable material may be PA 2200
which is available from Electro Optical Systems EOS GmbH.
[0074] In other examples any other suitable build material may be
used. Such materials may include, for example, powdered metal
materials, powdered composited materials, powder ceramic materials,
powdered glass materials, powdered resin material, powdered polymer
materials, and the like.
Coalescing Agent
[0075] According to one non-limiting example, a suitable coalescing
agent may be an ink-type formulation comprising carbon black, such
as, for example, the ink formulation commercially known as CM997A
available from Hewlett-Packard Company. In one example such an ink
may additionally comprise an infra-red light absorber. In one
example such an ink may additionally comprise a near infra-red
light absorber. In one example such an ink may additionally
comprise a visible light absorber. Examples of inks comprising
visible light enhancers are dye-based colored ink and pigment-based
colored ink, such as inks commercially known as CE039A and CE042A
available from Hewlett-Packard Company.
Coalescence Modifier Agent
[0076] As described above, a coalescence modifier agent acts to
modify the effects of a coalescing agent. It has been demonstrated
that different physical and/or chemical effects may be used to
modify the effects of a coalescing agent.
[0077] For example, and without being bound by any theory, in one
example a coalescence modifier agent may act to produce a
mechanical separation between individual particles of a build
material, for example to prevent such particles from joining
together and hence preventing them from solidifying to form a
portion of a generated three-dimensional object. An example
coalescence modifier agent may comprise a liquid that comprises
solids. Such an agent may be, for example, a colloidal ink, a
dye-based ink, or a polymer-based ink.
[0078] Such an agent may, after being delivered to a layer of build
material, cause a thin layer of solids to cover or partially cover
a portion of build material, for example after evaporation of any
carrier liquid, and hence may act as a coalescence modifier agent
as described herein.
[0079] In one example such a coalescence modifier agent may
comprise solid particles that have an average size less than the
average size of particles of the build material on which it is to
be delivered. Furthermore, the molecular mass of the coalescence
modifier agent and its surface tension should be such that it
enables the coalescence modifier agent it to penetrate sufficiently
into the build material. In one example such an agent should also
have a high solubility such that each drop of agent comprises a
high percentage of solids.
[0080] In one example a salt solution may be used as a coalescence
modifier agent.
[0081] In another example an ink commercially known as CM996A ink
and available from Hewlett-Packard Company may be used as a
coalescence modifier agent. In another example an ink commercially
known as CN673A ink and available from Hewlett-Packard Company has
also been demonstrated to work as a coalescence modifier agent.
[0082] In another example, and without being bound by any theory, a
coalescence modifier agent may act to modify the effects of a
coalescing agent by preventing build material from reaching
temperatures above its melting point. For example, it has been
demonstrated that a fluid that exhibits a suitable cooling effect
may be used as a coalescence modifier agent. For example, when such
an agent is delivered to build material the energy applied to the
build material may be absorbed by the coalescence modifier agent
causing the evaporation thereof, which may help prevent build
material on which the coalescence modifier agent has been delivered
or has penetrated from reaching the melting point of the build
material.
[0083] In one example an agent comprising a high percentage of
water has been demonstrated as a suitable coalescence modifier
agent.
[0084] In other examples other types of coalescence modifier agent
may be used.
[0085] An example of a coalescence modifier agent that may increase
the degree of coalescence may include, for example a suitable
plasticizer. Another example of a coalescence modifier agent that
may increase the degree of coalescence may include, for example, a
surface tension modifier to increase the wettability of particles
of build material.
[0086] It will be appreciated that examples described herein can be
realized in the form of hardware, or a combination of hardware and
software. Any such software may be stored in the form of volatile
or non-volatile storage such as, for example, a storage device like
a ROM, whether erasable or rewritable or not, or in the form of
memory such as, for example, RAM, memory chips, device or
integrated circuits or on an optically or magnetically readable
medium such as, for example, a CD, DVD, magnetic disk or magnetic
tape. It will be appreciated that the storage devices and storage
media are example of machine-readable storage that are suitable for
storing a program or programs that, when executed, implement
examples described herein. Accordingly, examples provide a program
comprising code for implementing a system or method as claimed in
any preceding claim and a machine readable storage storing such a
program.
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