WO2017014729A1

WO2017014729A1 - Selective distribution of build materials for additive manufacturing apparatus

Info

Publication number: WO2017014729A1
Application number: PCT/US2015/040964
Authority: WO
Inventors: Krzysztof Nauka; Fernando Juan
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2015-07-17
Filing date: 2015-07-17
Publication date: 2017-01-26

Abstract

In an example, an additive manufacturing apparatus includes gates to selectively allow distribution of different build materials from build material bins to form layers for a three-dimensional object. A controller may control the gates to selectively distribute the different build materials to a build area platform to form the layers. An ejection device may eject a solidifying agent onto each of the layers, and an energy source may apply energy onto the ejected solidifying agent of each layer to cause build material of the layer that is in contact with the ejected solidifying agent to solidify.

Description

SELECTIVE DISTRIBUTION OF BUILD MATERIALS FOR ADDITIVE

MANUFACTURING APPARATUS

BACKGROUND

[0001] Additive manufacturing systems, such as powder-based systems, may generate three-dimensional objects through implementation of a layer-by- layer fabrication process. For instance, portions of a powder-based build material may be solidified at each layer to form the three-dimensional objects. These types of systems have been used to build three-dimensional objects having relatively complex internal and external features.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Features of the present disclosure are illustrated by way of example and not limited in the following figure(s), in which like numerals indicate like elements, in which:

[0003] FIG. 1 shows a simplified isometric view of an additive manufacturing apparatus for generating a three-dimensional (3D) object, according to an example of the present disclosure;

[0004] FIGS. 2A-J show generating a 3D object, according to examples of the present disclosure;

[0005] FIGS. 3A-B show an additive manufacturing apparatus with more than two bins, according to examples of the present disclosure;

[0006] FIGS. 4A-4D show generating a 3D object from a build material blend, according to examples of the present disclosure;

[0007] FIG. 5 shown a recycling bin, according to an example of the present disclosure;

[0008] FIG. 6 shows a flow diagram of a method for generating a three- dimensional object, according to an example of the present disclosure; and

[0009] FIG. 7 shows controller, according to an example of the present disclosure.

DETAILED DESCRIPTION

[0010] For simplicity and illustrative purposes, the present disclosure is described by referring mainly to examples. The examples may be used in combination with each other. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be readily apparent however, that the present disclosure may be practiced without limitation to these specific details. In other instances, some methods and structures have not been described in detail so as not to unnecessarily obscure the examples of the present disclosure. As used herein, the terms "a" and "an" are intended to denote at least one of a particular element, the term "includes" means includes but not limited to, the term "including" means including but not limited to, and the term "based on" means based at least in part on.

[001 1] Additive manufacturing apparatuses, such as 3D printers, may generate 3D objects through implementation of a layer-by-layer fabrication process. Additive manufacturing refers to a process, such as a layer-by-layer fabrication process, for generating a 3D object for example by an additive manufacturing apparatus. According to example of the present disclosure, an additive manufacturing apparatus includes capability to generate a 3D object from different build materials through a selective distribution mechanism. The selective distribution mechanism may include movable structures (e.g., gates) that selectively allow distribution of different build materials from build material bins, which may include cartridges or any structure that can hold build materials, to create layers for the 3D object. Different layers can be comprised of different build materials provided from the build material bins. Also, a layer may be comprised of a blend of different build materials provided from the build material bins. Multiple layers are formed to create the 3D object.

[0012] The additive manufacturing apparatus may selectively distribute different build materials for each layer or blends of different material for each layer to generate a 3D object. For each layer of build material, a solidifying agent may be applied in a pattern representing a cross-section of the 3D object on the build material, and energy is applied to the solidifying agent located on the build material to cause the build material in contact with the solidifying agent to fuse together (i.e., solidify) to form the cross-section of the 3D object. Different build materials may be selectively distributed to form different cross- sections (e.g., layers) and generate a 3D object comprised of different build materials (e.g., different polymer composites) or blends. Reinforced plastic is an example of a polymer composite, which may include a mechanically "soft" polymer into which "hard" ceramic fibers or particles are incorporated. The resulting polymer composite is mechanically stronger that pure polymer and much lighter than metals of comparable strength. Also, advanced composites, instead of fibers, may contain other polymers, carbon nanotubes or graphene platelets, or metallic and semiconductor nanoparticles. Their additives may be selected to enhance mechanical strength, but could also provide ability to conduct current and heat, emit light, exhibit nonlinear optical properties, exhibit shape memory, or facilitate polymer biocompatibility.

[0013] Additive manufacturing, according to an example of the present disclosure can provide a fabrication process for many of the reinforced plastics, and minimize a miscibility gap among composite components. Many traditional composite blends are fabricated from a melt or solution, which may cause segregation when mixture solidifies. Unique characteristics of the additive manufacturing process can limit forces (diffusion) leading to segregation and allow fabrication of the composite blends unobtainable by traditional processes.

[0014] Also, the additive manufacturing process allows for the tailoring of structural composites. For example, two different build materials, such as build material a and build material b, having different strength properties can be deposited in a desired sequence to form different layers. For example, a 3D object can be created by depositing the following layers, each comprised of build material a or b, in the following sequence -a-a-a-b-a-a-b-b-a-a-a-. In another example, where "hard" b is deposited on the top and bottom of the layer to protect "soft" core, the deposited sequence of build materials is b-b-b-a-a-a-a- -a-a-a-a-a-b-b-b. [0015] With reference first to FIG. 1 , there is shown a simplified isometric view of an additive manufacturing apparatus 100 for generating a 3D object, according to an example. It should be understood that the apparatus 100 depicted in FIG. 1 may include additional components and that some of the components described herein may be removed and/or modified without departing from a scope of the apparatus disclosed herein. It should also be understood that the apparatus 100 depicted in FIG. 1 may not be drawn to scale and thus, the apparatus 100 may have a different size and/or configuration other than as shown therein.

[0016] As shown in FIG. 1 , the apparatus 100 includes a build area platform 102 that includes a build area surface on which a 3D object is to be generated from different build materials 104 and 105. The build area platform 102 may be removable. The build materials 104 and 105 may be stored in build material bins 130 and 131 , referred to as bins 130 and 131 . A bin is any structure, including a cartridge, that can hold material. A bin may be removable. The build materials 104 and 105 are selectively applied onto the build area platform 102 by a build material distributor 106. For instance, the build materials 104 and 105 may be raised to a slightly higher elevation in the bins 130 and 131 as compared to the build area platform 102 and the build material distributor 106 may move in the y-direction as denoted by the arrow 108 to distribute the build materials 104 and 105 onto the build area platform 102 to form layers of the 3D object being created. The build material distributor 106 may be a roller, blade, wiper or any other device suitable for spreading the build materials 104 and 105 over the build area platform 102. Also, the build area platform 102 may be moved in a downward direction as denoted by the arrow 1 10 to apply build material for another layer, and the process is repeated until all the layers for the 3D object are formed.

[0017] The apparatus 100 includes gates 140 and 141 . Any movable structure that can be used to control distribution of build materials from bins may be used. A gate refers to a movable structure. The gates 140 and 141 are movable structures that are movable to control distribution of the build materials 104 and 105 onto the build area platform 102. In an example, the gates 140 and 141 are movable between different positions. For example, when the gate 140 or 141 is in a first position, the gate facilitates or allows distribution of build material (e.g., build material 104 or 105) from a bin (e.g., bin 130 or 131 ) to the build area platform 102, and when the gate 140 or 141 is in a second position, the gate does not facilitate or prevents distribution of build material. For example, FIG. 1 shows gate 140 in the first position, e.g., a closed position, and gate 141 in the second position, e.g., an open position. For example, the gate 140 supports the build material 104 as the build material distributor 106 moves the build material 104 along the y-axis, from the build material bin 130, over the surface of the gate 140, and onto the build area platform 102. Gate 141 is in the second position, so any excess build material falls through the opening as the build material distributor 106 continues to move towards bin 131 along the y- axis. A catchment bin may be provided below gates 140 and 141 to catch excess build material. The build material distributor 106 can also move in the opposite direction along the y-axis to distribute build material 105 from bin 131 to the build area platform 102. For this scenario, gate 141 would be in the first position to allow distribution of the build material 105 from bin 131 to the build area platform 102, and gate 140 is would be in the second position so any excess build material falls through the opening as the build material distributor 106 continues to move towards bin 130 along the y-axis. Examples of controlling the gates 140 and 141 to control distribution of different build materials are further discussed below.

[0018] In an example, the gates 140 and 141 are moveable platforms that have a surface whereby build material can traverse or move over, such as in a direction of movement of the build material distributor. The gates 140 and 141 may be of any suitable size and shape to selectively allow or prevent distribution of the build material. The gates 140 and 141 are movably attached for example to a bin or the build area platform 102. In an example, the gates 140 and 141 are hinged, and the hinge may be controlled by controller 150 to control movement of the gates 140 and 141 . Other mechanisms may be used to control movement of the gates 140 and 141 to predetermined positions. For example, a sliding mechanism may be used to slide the gates 140 and 141 to an open or closed position. In another example, instead of being a platform to support the build material as it moves in the direction of the build area platform, a gate may be a movable structure that opens and closes to allow or prevent a build material from exiting a build material bin. For example, a build material bin may include an opening. The gate covers the opening in a closed position and is moved to an opened position to not cover the opening.

[0019] By way of example, two gates are shown and two build material bins are shown. The apparatus 100 may have more than two gates and more than two bins and may accommodate more than two build materials.

[0020] The apparatus 100 may also include a carriage 1 12 that may be movable in either or both of the x and y directions as denoted by the arrows 1 14. Although not shown, the carriage 1 12 may be supported on rods or other structures that enable the carriage 1 12 to move in the directions denoted by the arrows 1 14.

[0021] As shown, the carriage 1 12 may support an ejection device 120 and an energy source 126. The carriage 1 12 may thus modify the positions of these elements 120 and 126 to thus enable selective control over the placement of a solidifying agent with respect to the build area platform 102. In other examples, the elements 120 and 126 may remain relatively static with respect to the build area platform 102 in the x and y directions, and the build area platform 102 may move in the x and y directions. The energy source 126 may be positioned on another carriage (not shown), or coupled to move with the build material distributor 106. The energy source 126 may thus be separately movable from the ejection device 120.

[0022] As a further example, the printhead or printheads on the carriage

1 12 may be arranged in a page-wide array and the ejection device 120 may each extend substantially the entire width of the build area platform 102. In this example, the carriage 1 12 may be movable along one dimension (e.g., the y- axis) and the ejection device 120 may be selectively activated to apply solidifying agent at desired locations substantially across the width of the build area platform 102 without scanning the carriage 1 12 along a second dimension (e.g., the x-axis).

[0023] Discussed in greater detail below is a controller 150 that is to control operations of the various components depicted in FIG. 1 . Although not shown for purposes of clarity, the controller 150 may be in communication with each of the build material distributor 106, the carriage 1 12, the ejection device 120, the energy source 126 and the gates 140 and 141 , such as actuators controlling movement of the gates 140 and 141 .

[0024] According to an example, the build materials 104 and 105 are powder-based build materials. As used herein, the term powder-based build material is intended to encompass dry powder-based materials, wet powder- based materials, particulate materials, granular materials, etc. In other examples, the build materials 104 and 105 may be used with other suitable build materials, with suitable modification if appropriate. In still other examples, the build materials 104 and 105 may be any other suitable form of build material. By way of particular example, the build materials 104 and 105 are nylon plastic having particle sizes of about 50 microns on average.

[0025] According to a particular example, the build materials 104 and 105 are powdered thermoplastic materials. One suitable material may be Nylon 12, which is available, for example, from Sigma-Aldrich Co, LLC. Another suitable material may be PA2200, which is available from Electro Optical Systems EOS GmbH. In other examples, the build materials 104 and 105 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.

[0026] In still other examples, the build materials 104 and 105 may be liquids, pastes, or gels. Examples of the build materials 104 and 105 include polymeric semi-crystalline plastic materials with a wide processing window of greater than 5°C (i.e., the temperature range between the melting point and the re-crystallization temperature). In an example, the processing window ranges from 15°C to about 40°C.

[0027] Examples of suitable build materials 104 may include polyamides, polyethylene, polyethylene terephthalate (PET), and amorphous variations of these materials. Still other examples of suitable build materials 104 may include polystyrene, polyacetals, polypropylene, polycarbonate, polyester, polyurethanes, other engineering plastics, and blends of any two or more of the polymers listed herein. Core-shell polymer particles of these materials may also be used.

[0028] The build materials 104 and 105 may have a melting point ranging from about 55°C to about 450°C. Some specific examples of build materials having their melting point within this range include polyamides, such as nylon 1 1 , nylon 12, nylon 6, nylon 8, nylon 9, nylon 66, nylon 612, nylon 812, nylon 912, etc. As examples, polyamide 12 has a melting point of about 180°, polyamide 6 has a melting point of about 220°, and polyamide 1 1 has a melting point of about 200°.

[0029] The build materials 104 and 105 may also be a modified polyamide. In an example, the modified polyamide material is an elastomeric modified polyamide that melts at a lower temperature than nylon 12.

[0030] When the build materials 104 and 105 are in powder form, the build materials may be made up of similarly sized particles or differently sized particles. In an example, the build materials 104 and 105 include particles of three different sizes. In this example, the average size of the first particle is larger than the average size of the second particle, and the average size of the second polymer particle may be larger than the average size of the third polymer particle. The term "size", as used herein, refers to the diameter of a spherical particle, or the average diameter of a non-spherical particle (i.e., the average of multiple diameters across the non-spherical particle). In general, the average size of the particles of the build materials 104 and 105 may range from about 10 micrometers (μιη) to about 100 μιη. In some examples, the average size of the particles of the build materials 104 and 105 ranges from about 40 μιη to about 50 μιη. As an example of the different sizes for each of the particles, the average size of the first particle may be greater than 50 μιη, the average size of the second particle may be between 10 μιη and 30 μιη, and the average size of the third particle may be equal to or less than 10 μιη. In an example, the first polyamide particle is present in an amount ranging from about 70 percentage by weight (wt%) to about 95 wt%, the second polyamide particle is present in an amount ranging from about 0.5 wt% to about 21 wt%, and the third polyamide particle is present in an amount ranging from greater than 0 wt% up to about 21 wt%.

[0031] The apparatus 100 may perform an additive manufacturing process of fabricating a stack of layers with distinctly different compositions. FIGS. 2A-J show examples of creating layers for a 3D object comprised of different build materials, such as build materials 104 and 105. The examples are described with respect to being performed by the apparatus 100, and show the gates 140 and 141 in different positions to create different layers. All the components of the apparatus 100 are not shown in the examples in order to illustrate operations of the apparatus 100.

[0032] Build materials 104 and 105 for example are thermoset materials, such as different powder materials, stored at temperature(s) below their melting points in bins 130 and 131 . In FIGS. 2A-B, gate 141 is raised to a first position (e.g., closed) to allow spreading of the build material 105 from bin 131 onto heated build area platform 102 with the help of the build material distributor 106 travelling towards bin 130 along the y-axis. Gate 140 is in a second position (e.g., open) allowing excess build material 105 pushed by the build material distributor 106 to fall for example into a catching bin below (not shown).

[0033] FIG. 2C shows when spreading of the build material 105 is completed, and as a result build area platform 102 is covered with a uniform, thin (e.g., about 100 urn) layer of build material 105. Also, both gates 140 and 141 may be opened. In FIG. 2D printhead or carriage 1 12 may pass over build area platform 102 in a direction perpendicular to the movement of the build material distributor 106, and prints a pattern representing desired cross-section, which is a star-shape in this example, of the 3D object to be printed onto the surface of layer of build material 105. The printed pattern may be comprised of the solidifying agent which is ejected from the ejection device 120 to print the pattern.

[0034] FIG. 2E shows energy source 126 for example emitting light that is absorbed by the solidifying agent. The power of the energy source 126 may be selected to achieve a desired temperature of the solidifying agent close to or above the melting point of the build material 105, causing the star pattern to solidify. In FIGS. 2F-G, gate 140 is closed, and the build material distributor 106 travels towards bin 131 , spreading a thin layer of build material 104 onto the build area platform 102 that is covered with a layer of build material 105 including the star pattern. Excess build material 105 for example falls into a catching bin (not shown) under gate 141 .

[0035] In FIG. 2H the spreading of build material 104 is completed, and the build material distributor 106 is on the right side of bin 131 . Gates 140 and 141 may be opened. In FIG. 2I, the printhead with ejection device 120 prints another pattern of the solidifying agent, which may be commensurate with the previously printed pattern, to form another layer. In FIG. 2J, the energy source 126for example emits light that is absorbed by the solidifying agent. The power of the energy source 126 may be selected to achieve a desired temperature of the solidifying agent close to or above the melting point of the build material 104, causing the star pattern to solidify. At this point, the 3D printed object has two layers, the first made of build material 105 and the second of build material 104. The sequence can then be repeated until the printed object reaches the desired thickness. Also, the build materials may be deposited in a sequence other than alternating. For example, multiple layers of one build material may be formed, followed by multiple layers of another build material, depending on the desired composition of each section of the 3D object being created.

[0036] Densities of the solidifying agent used for materials 104 and 105, and the corresponding intensities and times of the illumination may be individually selected for each of the materials in accordance with the melting temperatures of each material. Similarly, a thickness of deposited layer may be different for different materials 104 and 105 in agreement with the design of the printed object.

[0037] More than two different build materials may be used by the apparatus 100 to create 3D objects. FIG. 3A shows an example where four build materials can be incorporated into 3D printed objects in a layer-by-layer fashion. For example, bins 130-133 may be affixed to a wheel 301 that is rotatable while build area platform 102 remains stationary. Bins 130 and 131 store build materials 104 and 105, and bins 132 and 133 store build materials 164 and 165. Rotation of the wheel 301 to place any of the bins 130-133 in directions of travel 108 of the build material distributor 106 enables applying of the build material stored therein to the build area platform 102. Another number of bins may be affixed to the wheel 301 in other examples. Also, movable support structures other than a wheel 301 may be used in other examples.

[0038] FIG. 3B shows an example, whereby an array of bins, such as bins 350-355, containing different materials 324-329 remains stationary while the build area platform 102 with corresponding elements, such as the materials distributor 106, ejection device 120 and energy source 126 (not shown), travels between the bins 350-356 supplying the desired build material and printing the subsequent layers of the 3D object, such as in accordance with a printing model describing the 3D object and build materials for the 3D object.

[0039] Additive manufacturing according to examples described herein may include forming layers comprised of a blend of build materials. FIGS. 4A-D show examples of forming layers comprised of a blend of build materials, which may be performed by the apparatus 100. All the components of the apparatus 100 are not shown for purposes of illustrating the forming of layers. As shown in FIG. 4A, bin 130 may include a mixing chamber 401 and containers 402 and 403 storing different build materials 410 and 41 1 . Build materials 410 and 41 1 are loaded into mixing chamber 401 where build materials 410 and 41 1 are mixed. A mechanism for loading build materials 410 and 41 1 into mixing chamber 401 is not shown but may include build material distributors similar to build material distributor 106 or other mechanisms. Also, the mixing chamber 401 may include a mixing blade or other mechanism for mixing materials. The loading and mixing may be controlled by the controller 150. A ratio of the build materials 410 and 41 1 loaded into the mixing chamber 401 is selected to provide the desired material effect. FIG. 4B shows spreading of the mixed build materials from the mixing chamber 401 onto the build area platform 102. In FIGS. 4C-D, a printhead with ejection device 120 prints a pattern, for example, with a solidifying agent representing cross-section of the 3D object being printed, and energy source 126 heats the printed pattern causing its solidification. Power applied to the energy source 126 is selected to provide solidification of the mixed build materials. More than two containers may be provided to allow for mixing more than two building materials.

[0040] FIG. 5 shows a recycling bin 501 to catch unused or un-solidified build material, which may be used in the apparatus 100. FIG. 5 shows a stack of layers comprised of different materials of a 3D object being created for example by the apparatus 100. In this example, the layers include a layer of build material 104, a layer of build material 105 and a layer of a blend of build materials 104 and 105. The recycling bin 501 catches the unused build material during the additive manufacturing process, such as represented by the arrow showing the direction of the build material as it falls into the recycling bin 501 . Multiple recycling bins may be used to catch unused build material in the apparatus 100. The build material caught by the recycling bin 501 may or may not be re-used. For example, layers of pure unused building material may be re-used, such as pure build material 104 or pure build material 105. If a blend is caught by the recycling bin 501 , then the blend may be re-used if the ratio of the build materials in the blend is the same as what is needed for another layer. However, if the ratio is different or is unknown, the blend may be discarded.

[0041] FIG. 6 illustrates an additive manufacturing method 600 according to an example. The method may be performed by the apparatus 100 including controller 150 by way of example. At 601 , gates 140 and 141 build material distributor 106 are controller by the controller 150 to selectively distribute different build materials from bins 130 and 131 to form layers of a 3D object. Different build materials can be deposited for different layers. Also, a build material blend may be created and deposited for a layer. The selection of build materials or a blend may be based on programmed instructions or a model defining the layers. Examples of the build materials are discussed above. According to an example, a 3D object is created according to a description which may be provided in a 3D model describing the 3D object. For example, the 3D model may be provided in a printer file, such as an STL (stereo lithography) file or another type of file. The 3D model may include, or instructions are provided along with the 3D model, that specify the build material for each layer of the 3D object and thickness, coalescing material density, and irradiation dose for energy provided the energy source 126. Based on this information, the controller 150 may determine the build material, thickness of the build material, coalescing material density, irradiation dose and pattern for each layer and controls the elements of the apparatus 100 to generate the layer according to this information. Data representing this information or at least a portion of the information may be stored in the apparatus 100 and is referred to as a "printing recipe". As indicated above, the build materials may be provided from different bins, and the build material for a layer may be comprised of a single build material or a blend of build materials. Also, different build materials may be specified for different layers and/or different ratios of blend materials may be specified for different layers.

[0042] At 602, for each layer, a solidifying agent is selectively deposited on the layer of the build material. The solidifying agent may be delivered to selected portions of the surface layer of the build material in a pattern defined by data derived from a model of a 3D object to be created. The solidifying agent may be a binder or a coalescing agent. According to examples, a binder may include sugar, starch, or other suitable forms of a glue. According to an example, the solidifying agent may be an ink-type formulation having carbon black, such as, for example, the ink formulation commercially known as CM991A available from the Hewlett-Packard Company. In an example, such an ink may additionally include an infra-red light absorber. In another example, such an ink may additionally include a near infra-red light absorber. In a further example, such an ink may additionally include a visible light absorber. Examples of inks having visible electromagnetic radiation enhancers are dye- based colored ink and pigment based colored ink.

[0043] At 603, for each layer, energy is applied to the solidifying agent on the surface of the build material. This causes the distributed build material positioned in contact with the deposited solidifying agent to solidify.

[0044] FIG. 7 shows a block diagram of the controller 150 and other hardware elements of the apparatus 100 depicted in FIG. 1 , according to an example. It should be understood that the controller 150 depicted in FIG. 7 may include additional elements and that in some examples some of the elements depicted therein may be removed and/or modified without departing from a scope of the controller 150. The controller 150 may be part of the apparatus 100 depicted in FIG. 1 or may be part of another entity that is separate from the apparatus 100 depicted in FIG. 1 , such as an entity that provides computing services for the apparatus 100.

[0045] The controller 150 may be a microprocessor, a micro-controller, an application specific integrated circuit (ASIC), or the like, and performs functions of the apparatus 100 described herein. In an example, the controller 150 is a processor that executes machine readable instructions 710 stored in a data storage 710 to perform processing function 71 1 . The processing functions may include but are not limited to controlling the material distributor 106, build area platform 102, ejection device 120, energy source 126, etc., to build a 3D object.

[0046] For example, the controller 150 may receive data, such as a 3D model, pertaining to a 3D object that is to be generated by the apparatus 100.

By way of example, the controller 150 may process the 3D model to generate slices of parallel planes of the model. Each slice may define a portion of a respective layer of build material that is to be solidified during an additive manufacturing process. The number of slices generated from the 3D model may have a thickness and build material specified in the 3D model or instructions provided with the 3D model. In this example, the data storage 702 may store information pertaining to each slice, such as information from the 3D model describing each slice including the pattern, thickness, build material, etc. In other examples, the slices may be generated by another computing device and the processor 202 may receive the generated slices.

[0047] The data storage 702 may include volatile and/or non-volatile storage devices, such as dynamic random access memory (DRAM), electrically erasable programmable read-only memory (EEPROM), magneto resistive random access memory (MRAM), memristor, flash memory, hard disk, removable storage media, or any other on which machine readable instructions or other data may be stored. The data storage 702 may store any information used by the apparatus 100 to print a 3D object.

[0048] The interface 204 may include hardware and/or software to enable the controller 150 to communicate control instructions 730 to the components of the apparatus 100 to generate a 3D object.

[0049] What has been described and illustrated herein are examples of the disclosure along with some variations. The terms, descriptions and figures used herein are set forth by way of illustration. Many variations are possible within the scope of the disclosure.

Claims

CLAIMS What is claimed is:

1 . An additive manufacturing apparatus to generate a three-dimensional (3D) object from different build materials on a build area platform, the apparatus comprising:

a build material distributor to distribute the different build materials for layers of the 3D object;

a plurality of gates to selectively allow distribution of the different build materials from a plurality of build material bins for the layers; and

a controller to control the plurality of gates and the build material distributor to selectively distribute the different build materials to form the layers, to control an ejection device to eject a solidifying agent onto each of the layers, and to control an energy source to apply energy onto the ejected solidifying agent of each layer to cause build material of the layer that is in contact with the ejected solidifying agent to solidify.

2. The apparatus of claim 1 , wherein the plurality of gates comprise structures that are movable to selectively distribute the build materials from the plurality of build material bins to the build area platform.

3. The apparatus of claim 2, wherein each of the movable structures, when in a first position, facilitates distributing a build material of the different build materials from one of the build material bins where the build material is stored to the build area platform, and when in a second position, prevents the build material from being distributed from the build material bin to the build area platform.

4. The apparatus of claim 3, wherein for each of the moveable structures, when in the first position, supports the build material as the build material is moved by the build material distributor over the moveable structure and onto the build area platform.

5. The apparatus of claim 4, wherein for each of the moveable structures, when in the second position, the build material is prevented from moving onto the build area platform via the moveable structure.

6. The apparatus of claim 1 , wherein the plurality of build material bins are affixed to a movable support structure, and the controller is to control movement of movable support structure to allow at least one the plurality of build material bins to be positioned for distributing its stored build material to the build area platform.

7. The apparatus of claim 1 , wherein the plurality of build material bins are stationary and the controller is to control movement of the build area platform to different positions corresponding to at least one the plurality of build material bins to for distributing stored build material to the build area platform.

8. The apparatus of claim 1 , wherein a build material bin of the plurality of build material bins comprises containers and a mixing bin, wherein build materials stored in the containers are loaded into the mixing bin to create a blend of the build materials that is distributable to the build area platform.

9. The apparatus of claim 1 comprising a recycling bin to catch build material from the build area platform not used in a layer of the 3D object.

10. The apparatus of claim 1 , wherein a bottom of each of the plurality of build material bins is movable in a vertical direction to allow the build material stored in the build material bin to be distributed by the build material distributor to the build area platform.

1 1 . The apparatus of claim 1 , wherein at least one of the layers comprises only one of the different build materials and at least one of the layers comprises a blend of at least two of the different build materials, and the controller is to determine a build material or build material blend, a thickness, a coalescing material density, and an irradiation dose for each of the layers based on a stored printing recipe.

12. The apparatus of claim 1 , wherein a ratio of build materials for different blends varies for different ones of the layers according to the printing recipe.

13. An additive manufacturing apparatus to generate a 3D object from build materials, the apparatus comprising:

a build material distributor to distribute the build materials for layers of the 3D object to a build area platform supporting the layers during generation of the 3D object;

a plurality of gates to selectively allow distribution of the build materials from a plurality of build material bins for the layers, wherein at least one of the plurality of build material bins includes containers to store different ones of the build materials and a mixing bin to store a blend of the ones of the build materials; and

a controller to control to loading the different ones of the build materials into the mixing bin according to a predetermined ratio to form the blend, to control the plurality of gates and the build material distributor to selectively distribute the build materials, including the blend, to form the layers, to control an ejection device to eject a solidifying agent onto each of the layers, and to control an energy source to apply energy onto the ejected solidifying agent of each layer to cause build material of the layer that is in contact with the ejected solidifying agent to solidify.

14. The apparatus of claim 13, wherein each of the gates, when in a first position, facilitates distributing a build material or the blend from the build material bin where the build material is stored to the build area platform, and when in a second position, prevents the build material or the blend from being distributed from the build material bin to the build area platform, and

wherein for each of the gates, when in a second position, the build material or the blend is prevented from moving onto the build area platform.

15. A method for generating a 3D object, the method comprising:

controlling a plurality of gates and a build material distributor of an additive manufacturing apparatus to selectively distribute different build materials from a plurality of build material bins storing the different build materials onto a build area platform to form layers of the 3D object;

for each layer, selectively depositing a solidifying agent on the layer of the build material; and

applying energy to the distributed build material and the deposited solidifying agent to cause the distributed build material positioned in contact with the deposited solidifying agent to solidify.