Ceramic roller for powder spreading

Abstract

To provide a ceramic roller for powder spreading.SOLUTION: A system for additive manufacturing of a three-dimensional object includes a powder compaction apparatus having at least one compaction roller configured to spread and compact a powder material across a powder bed, and a printing apparatus configured to selectively bind or fuse the powder material. At least a portion of the at least one compaction roller is made from silicon carbide. The at least one compaction roller includes a work zone having a first end and a second end, a first bearing zone extending from the first end of the work zone, and a second bearing zone extending from the second end of the work zone. The work zone has a surface finish of less than 50 microinches Ra. At least one of the first bearing zone and the second bearing zone are formed monolithically with the work zone, or connected to the work zone via a joint.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a roller configured for use in additive manufacturing processes, and in particular to a ceramic roller for powder spreading and compression molding in additive manufacturing processes. Additionally, a method of manufacturing the roller is disclosed. [Background technology]

[0002] Additive manufacturing, also known as three-dimensional (3D) printing, is a manufacturing technique based on the controlled deposition of material in successive layers to define a 3D object. In some additive manufacturing processes, a roller is used to spread successive thin layers of powder material onto a build bed. The compacted powder material is then selectively fused, for example using a binder or a laser or other form of energy, to define a layer of the 3D object. The build bed is then lowered and the spreading / compaction molding process is repeated to generate another layer of powder material. The process of successively building multiple layers continues until the desired 3D object is formed.

[0003] The rollers used in the 3D printing machine are configured to rotate about their axis of rotation and to move laterally in a direction perpendicular to the axis of rotation. Such roller movement is configured to build up a layer of powder material with a uniform thickness (50 μm to 200 μm) and a desired packing density (typically expressed in units of g / cc and representing the geometric density of the powder material). The packing density achieved by the rollers is important in specifying the material properties of the printed 3D object, including but not limited to density, elastic modulus, strength, thermal conductivity, thermal expansion coefficient, and other material properties. Higher packing is desired to achieve better structural properties of the printed 3D object.

[0004] Conventional rollers used in 3D printing machines are made from metal or plastic. Such metal or plastic rollers wear over time, especially quickly when used to spread harder metal or ceramic powders. These rollers need to be replaced frequently (e.g., within a few weeks) when used to spread ceramic powders, such as silicon carbide, resulting in equipment downtime and high maintenance costs. Metal or plastic rollers additionally require a coating, such as a low friction polytetrafluoroethylene (PTFE) coating, to avoid powder adhesion or embedment.

[0005] Examples of conventional rollers include rollers made of aluminum (bare metal or coated with a PTFE coating) or alumina-coated steel. PTFE-coated aluminum rollers are expensive and require frequent replacement (approximately every 1-2 months), resulting in significant equipment downtime and very high costs. Alumina-coated steel rollers have undesirable surface roughness that results in low packing density. Thus, there is a need in the art for improved rollers for spreading powder material in 3D printing machines with improved powder density and extended roller life. Summary of the Invention [Means for solving the problem]

[0006] Non-limiting embodiments or aspects of a system for additive manufacturing of three-dimensional objects are disclosed herein. The system may include a powder compaction device including at least one compaction roller configured to spread and compact a powder material across a powder bed, and a printing device configured to selectively bond or fuse the powder material. At least a portion of the at least one compaction roller may be made of silicon carbide.

[0007] In some non-limiting embodiments or aspects, the silicon carbide can be reaction bonded silicon carbide.At least a portion of the at least one compression molded roller can have a surface finish of less than 50 microinches Ra.

[0008] In some non-limiting embodiments or aspects, the at least one compression molded roller can include a working area having a first end and a second end, a first bearing area extending from the first end of the working area, and a second bearing area extending from the second end of the working area. The working area can have a surface finish of less than 50 microinches Ra. The working area can be cylindrical with a circular cross section. At least one of the first bearing area and the second bearing area can be integrally formed with the working area.

[0009] In some non-limiting embodiments or aspects, at least one of the first bearing region and the second bearing region can be made of a different material than the working region. The working region can be made of silicon carbide and the first bearing region and the second bearing region can be made of metal. The first bearing region can be connected to a first end of the working region via a first connection and the second bearing region can be connected to a second end of the working region via a second connection. At least one of the first connection and the second connection can be one of a butt connection, a tongue and groove connection, a threaded connection, and a pin connection.

[0010] In some non-limiting embodiments or aspects, the compaction roller can be configured to rotate about the longitudinal axis and to traverse in a direction perpendicular to the longitudinal axis. The system can further include a powder feeder configured to feed a predetermined amount of powder material to a top surface of the powder bed.

[0011] In some non-limiting embodiments or aspects, a system for additive manufacturing of a three-dimensional object may include a powder compaction molding apparatus including at least one compaction molding roller configured to spread and compact a powder material across a powder bed, and a printing apparatus configured to selectively bond or fuse the powder material. The at least one compaction molding roller may include a cylindrical working area having a first end and a second end, a first bearing area extending from the first end of the working area, and a second bearing area extending from the second end of the cylindrical working area. The cylindrical working area may be made of silicon carbide and may have a surface finish of less than 50 microinches Ra.

[0012] In some non-limiting embodiments or aspects, the first bearing region can be connected to a first end of the working region via a first connection and the second bearing region can be connected to a second end of the working region via a second connection. At least one of the first connection and the second connection can be one of a butt connection, a tongue and groove connection, a threaded connection, and a pin connection.

[0013] In some non-limiting embodiments or aspects, a compression molding roller configured for use in a system for additive manufacturing of three-dimensional objects can include a cylindrical working region having a first end and a second end, a first bearing region extending from the first end of the working region, and a second bearing region extending from the second end of the cylindrical working region. At least the cylindrical working region can be made from silicon carbide, and the cylindrical working region can have a surface finish of less than 50 microinches Ra.

[0014] In some non-limiting embodiments or aspects, at least one of the first bearing region and the second bearing region can be integrally formed with the operating region.

[0015] In some non-limiting embodiments or aspects, the first bearing region can be connected to a first end of the working region via a first connection and the second bearing region can be connected to a second end of the working region via a second connection. At least one of the first connection and the second connection can be one of a butt connection, a tongue and groove connection, a threaded connection, and a pin connection.

[0016] Further embodiments or aspects of the disclosure are described in detail in one or more of the following appended claims.

[0017] Additional note 1: 1. A system for additive manufacturing of a three-dimensional object, comprising: The system, A powder compaction device including at least one compaction roller configured to spread and compact a powder material across a powder bed; a printing device configured to selectively bond or fuse the powder material; and Equipped with The system, wherein at least a portion of the at least one compression molded roller is made from silicon carbide.

[0018] Additional note 2: Silicon carbide is The system of claim 1, wherein the silicon carbide is reaction bonded.

[0019] Additional note 3: At least a portion of the at least one compression molding roller is 3. The system of claim 1 or claim 2 having a surface finish of less than 50 microinches Ra.

[0020] Additional note 4: At least one compression molding roller an active area having a first end and a second end; a first bearing region extending from a first end of the operating region; a second bearing region extending from a second end of the operating region; The system according to any one of claims 1 to 3, comprising:

[0021] Addendum 5: The operating area is 5. The system of claim 4 having a surface finish of less than 50 microinches Ra.

[0022] Addendum 6: The operating area is 6. The system of claim 4 or claim 5, which is cylindrical with a circular cross-section.

[0023] Addendum 7: At least one of the first bearing region and the second bearing region is The system according to any one of claims 4 to 6, which is formed integrally with the operating area.

[0024] Addendum 8: At least one of the first bearing region and the second bearing region is The system according to any one of claims 4 to 7, wherein the system is made from a material different from the operating area.

[0025] Addendum 9: The active area is made from silicon carbide; The system of any one of claims 4 to 8, wherein the first bearing region and the second bearing region are made of metal.

[0026] Addendum 10: The first bearing region is connected to the first end of the active region via a first coupling; The second bearing region The system according to any one of claims 4 to 9, wherein the system is connected to the second end of the operating area via a second connecting portion.

[0027] Addendum 11: At least one of the first connecting portion and the second connecting portion is 11. The system of claim 10, wherein the connection is one of a butt joint, a tongue and groove joint, a threaded joint, and a pin joint.

[0028] Addendum 12: Compression molding rollers, 12. The system of any one of claims 1 to 11, configured to rotate about the longitudinal axis and to move laterally in a direction perpendicular to the longitudinal axis.

[0029] Addendum 13: 13. The system of any one of claims 1 to 12, further comprising a powder feeder configured to feed a predetermined amount of powder material to an upper surface of the powder bed.

[0030] Addendum 14: 1. A system for additive manufacturing of a three-dimensional object, comprising: The system, A powder compaction device including at least one compaction roller configured to spread and compact a powder material across a powder bed; a printing device configured to selectively bond or fuse the powder material; and Equipped with At least one compression molding roller a cylindrical active area having a first end and a second end; a first bearing region extending from a first end of the operating region; a second bearing region extending from a second end of the cylindrical working region; Equipped with A system in which the cylindrical working region is fabricated from silicon carbide and has a surface finish of less than 50 microinches Ra.

[0031] Addendum 15: The first bearing region is connected to the first end of the active region via a first coupling; The second bearing region 15. The system of claim 14, connected to a second end of the working area via a second connection.

[0032] Addendum 16: At least one of the first connecting portion and the second connecting portion is 16. The system of claim 15, wherein the connection is one of a butt joint, a tongue and groove joint, a threaded joint, and a pin joint.

[0033] Addendum 17: 1. A compression molding roller configured for use in a system for additive manufacturing of three-dimensional objects, comprising: Compression molding rollers, a cylindrical active area having a first end and a second end; a first bearing region extending from a first end of the operating region; a second bearing region extending from a second end of the cylindrical working region; Equipped with at least a cylindrical working region is made from silicon carbide; A compression molded roller having a cylindrical working area with a surface finish of less than 50 microinches Ra.

[0034] Addendum 18: At least one of the first bearing region and the second bearing region is The compression molding roller according to claim 17, which is integrally formed with the operating region.

[0035] Addendum 19: The first bearing region is connected to the first end of the active region via a first coupling; The second bearing region The compression molding roller according to claim 17 or 18, which is connected to the second end of the operating area via a second connecting portion.

[0036] Addendum 20: At least one of the first connecting portion and the second connecting portion is 20. The system of claim 19, wherein the connection is one of a butt joint, a tongue and groove joint, a threaded joint, and a pin joint. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a side cross-sectional view of an additive manufacturing device according to an embodiment or aspect of the present disclosure.

[0038] [Diagram 2] 1 is a graph showing packing density as a function of time for various rollers used in an additive manufacturing device.

[0039] [Diagram 3] FIG. 1 is a plan view of a roller configured for use with an additive manufacturing device, according to an embodiment or aspect of the present disclosure.

[0040] [Figure 4] FIG. 13 is a plan view of a roller configured for use with an additive manufacturing device according to another embodiment or aspect of the present disclosure.

[0041] [Diagram 5] FIG. 13 is a plan view of a roller configured for use with an additive manufacturing device according to another embodiment or aspect of the present disclosure.

[0042] [Figure 6] FIG. 13 is a plan view of a roller configured for use with an additive manufacturing device according to another embodiment or aspect of the present disclosure.

[0043] [Figure 7A] 1 is a graph showing surface roughness for rollers made from various materials. [Figure 7B] 1 is a graph showing surface roughness for rollers made from various materials. [Figure 7C] 1 is a graph showing surface roughness for rollers made from various materials. [Figure 7D] 1 is a graph showing surface roughness for rollers made from various materials. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] Like reference numbers in FIGS. 1-7D represent the same components and elements wherever possible, unless otherwise noted.

[0045] As used herein, the singular terms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0046] For example, spatial or directional terms such as "left," "right," "inside," "outside," "upper," "lower," etc., are intended to refer to the embodiment or aspect illustrated in the drawings and are not intended to be limiting, as the embodiment or aspect may be in various alternative orientations.

[0047] All numbers used in the specification and claims are understood to be modified in all instances by the term "about." By "about" is meant plus or minus 25 percent of the stated value, for example, plus or minus 10 percent of the stated value. However, this should not be considered as a limitation to any analysis of values ​​under the doctrine of equivalents.

[0048] Unless otherwise stated, all ranges or ratios disclosed herein are understood to include the initial and final values, and any and all subranges or subratios subsumed therein. For example, a range or ratio described as "1 to 10" and "1 to 10" should be considered to include any and all subranges or subratios between a minimum value of 1 and a maximum value of 10 (inclusive), i.e., all subranges or subratios beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less. The ranges and / or ratios disclosed herein represent average values ​​across the specified ranges and / or ratios.

[0049] The terms "first," "second," and the like are not intended to denote any particular order or chronology, but rather are intended to denote different conditions, characteristics, or elements.

[0050] All documents mentioned herein are "incorporated by reference" in their entirety.

[0051] The term "at least" is synonymous with "greater than or equal to."

[0052] The term "not greater than" is synonymous with "less than or equal to."

[0053] Some non-limiting embodiments or aspects may be described herein in relation to a threshold value. As used herein, meeting a threshold may refer to a value being greater than the threshold, more than the threshold, higher than the threshold, equal to or greater than the threshold, less than the threshold, less than the threshold, lower than the threshold, equal to or less than the threshold, etc.

[0054] As used herein, "at least one of" is synonymous with "one or more of." For example, the phrase "at least one of A, B, or C" means any one of A, B, or C, or any combination of any two or more of A, B, or C. For example, "at least one of A, B, or C" includes only A, or only B, or only C, or A and B, or A and C, or B and C, or all of A, B, and C.

[0055] The term "including" is synonymous with "comprise (have)."

[0056] Referring to FIG. 1, a system 100 for additive manufacturing of three-dimensional (3D) objects is shown according to one non-limiting embodiment or aspect of the present disclosure. In some embodiments or aspects, the system 100 may be configured as a binder jetting system, where unbound powder material PM, also referred to herein as "powder" or "powder material", is spread onto a powder bed 102 as a very thin layer (50 μm to 200 μm), and a binder is selectively added to the powder material PM to bond the particles together, thereby forming a layer L of a solid object. After multiple layers L are built, the resulting 3D object may undergo further post-processing steps, such as sintering, to achieve desired strength and properties. Such further post-processing steps may be configured to reduce or eliminate gaps between particles of the powder material PM and to increase the density of the finished 3D object.

[0057] Although FIG. 1 and the following disclosure describe a binder jetting system, such as a metal binder jetting system, a ceramic binder jetting system, or a plastic binder jetting system, it should be understood that other embodiments of the system are not limited to the binder jetting system disclosed herein. For example, in some embodiments or aspects, the system 100 may be configured as a selective laser sintering or selective laser melting system. In such a system, the powder material PM is heated by a laser, causing the particles to fuse together to build a desired object layer by layer. In further embodiments, the system 100 relates to any additive manufacturing system configured to manufacture a 3D object from a powder material spread layer by layer.

[0058] Continuing with reference to FIG. 1 , the system 100 includes a powder feeder 104 configured to feed a predetermined amount of powder material PM onto an upper surface of a powder bed 102. The powder bed 102 is movable in the direction of arrow A after each layer L of powder material PM is spread, and a binder is provided to selectively bond unbound powder material PM. The powder feeder 104 may include a powder source 106 configured to accommodate a quantity of powder material PM and a feeding mechanism 108 configured to selectively feed a predetermined amount of powder material PM onto the powder bed 102. The feeding mechanism 108 may be configured to feed a pile of powder material PM configured to be flattened and compacted. In some embodiments, the powder source 106 may be a hopper and the feeding mechanism 108 may be a metering device configured to feed a predetermined amount of powdered material from the powder source 106.

[0059] In some embodiments, the powder material PM can be a metal powder material, such as, but not limited to, stainless steel, tungsten, cobalt, nickel, chromium, or rhenium. In other embodiments, the powder material PM can be a ceramic powder material, such as, but not limited to, silicon carbide (SiC), aluminum oxide, tungsten carbide, aluminum nitride, or silicon nitride. In further embodiments, the powder material PM can be a plastic powder material, such as, but not limited to, nylon, PBT (polybutylene terephthalate), PEEK (polyether ether ketone), or PP (polypropylene). In various examples, the powder material PM can have an average particle size of 0.1 μm to 2000 μm.

[0060] Continuing with reference to FIG. 1 , the system 100 may include a printing apparatus 110 configured to selectively dispense a binder onto the layer L of the powder material PM. The binder may be a liquid binder deposited onto the layer L of the powder material PM in a two-dimensional pattern representing a layer of the 3D object. In some embodiments, the binder may be a two-part binder including two components that react when combined to bond unbound powder material PM. In further embodiments, the binder may be an ultraviolet (UV) curable binder configured to bond unbound powder material PM upon exposure to UV light.

[0061] Continuing with reference to FIG. 1 , the system 100 further includes a powder compaction molding apparatus 112 configured to compact the powder material PM into a layer L of powder material PM before the binder is deposited. The powder compaction molding apparatus 112 includes at least one compaction roller 114 configured to spread and compact the powder material PM across the powder bed 102. In some embodiments, the at least one compaction roller 112 may be configured to rotate about a longitudinal axis 115 in the direction of arrow B and to move laterally in a direction perpendicular to the longitudinal axis 115 and parallel to a plane defined by the powder bed 102 in the direction of arrow C. The powder compaction molding apparatus 112 may include a drive mechanism 116 configured to drive the rotation and translation of the at least one compaction roller 112. In some embodiments, the drive mechanism 116 may be an electric motor.

[0062] Continuing with reference to FIG. 1 , the system 100 includes a controller 118 operably connected to at least one of the powder feeder 104, the printing device 110, and the powder compaction molding device 112. The controller 118 may include a processor 120 including a memory 122 including instructions that, when executed by the processor 120, control the operation of at least one of the powder feeder 104, the printing device 110, and the powder compaction molding / diffusion device 112. The controller 118 may be connected to one or more input devices 124 and / or output devices 126. The one or more input devices 124 may include, for example, a keyboard, a mouse, one or more buttons, one or more input terminals, or other input devices for inputting instructions to the controller 118. The one or more output devices 126 may include, for example, one or more displays, lights, or other output devices configured to output information regarding one or more parameters of the system 100, such as, for example, but not limited to, the progress of a 3D printing operation and / or the status of one or more components of the system 100.

[0063] In some embodiments, the controller 118 may be configured to control operation of the feeding mechanism 108 to feed a predetermined amount of powder material PM from the powder source 106. In further embodiments, the controller 118 may be configured to control operation of the printing apparatus 110 to feed a predetermined amount of binder to a selected location in the layer L of the powder material PM. In further embodiments, the controller 118 may be configured to control operation of the at least one compacting / spreading roller 114, e.g., rotation and / or translation of the at least one compacting / spreading roller 114 via operation of the drive mechanism 116.

[0064] When the powder compression molding device 112 spreads the powder material PM through the compression molding roller 114, it is desirable to increase the packing density, which represents how densely packed the particles of the powder material are. The packing density of the unbound powder material PM is important in determining the characteristics of the final 3D object, such as the object's density, elastic modulus, strength, thermal conductivity, thermal expansion coefficient, and other mechanical properties. Furthermore, it is desirable to have a uniform packing density across the powder bed 102 to prevent the 3D object from warping due to non-uniform shrinkage during the sintering process, for example. Thus, a denser packing of the powder material is desired to achieve better mechanical properties of the final 3D object. However, an increase in the packing density increases wear on the at least one compression molding roller 114. As described herein, the at least one compression molding roller 114 can be configured to spread the powder material PM into a layer L with a uniform thickness and high geometric density while providing a long service life through careful selection of the material of the at least one compression molding roller 114.

[0065] In some embodiments, at least a portion of the compaction roller 114 may be made from a ceramic material. In particular, at least a portion of the compaction roller 114 may be made from a silicon carbide (SiC) material selected for its hardness and resistance to wear and abrasion due to contact with the powder material PM. In some embodiments, the SiC material may be a reaction-bonded SiC material. The reaction-bonded SiC material is made by infiltrating molten Si into a SiC powder matrix. Examples of other forms of SiC include sintered SiC, hot-pressed SiC, and chemical vapor deposited SiC. With reference to FIG. 2, the compaction roller 114 made from a SiC material maintains powder packing density over several months of continuous use, whereas the powder packing density provided by the PTFE-coated aluminum roller decreases rapidly after only 1-2 months of use, requiring equipment to be shut down to replace the roller. Experimental data indicates that the compaction roller 114 made from a SiC material provides uniform packing density for more than 6 months of continuous use without appreciable degradation during use.

[0066] 3, the compaction molding roller 114 includes an operating region 128 including a first end 130 spaced apart from a second end 132 along a longitudinal axis 115. The operating region 128 is cylindrical with a circular cross-section. In some embodiments, the operating region 128 is configured to contact and compact the powder material PM during operation of the compaction molding roller 114. The compaction molding roller 114 further includes a first bearing region 134 extending axially from the first end 130 and a second bearing region 136 extending axially from the second end 132 of the compaction molding roller 128. The first bearing region 134 and the second bearing region 136 are axially aligned with the operating region 128 to maintain the cylindricality of the operating region 128. Each of the first bearing region 134 and the second bearing region 136 is configured to rotatably support the compression molding roller 114 on the powder compression molding apparatus 112 so that the compression molding roller 114 can rotate about the longitudinal axis 115 and translate in the direction of arrow C in FIG. 1. As shown in FIG. 3, each of the first bearing region 134 and the second bearing region 136 can include one or more bearing surfaces 139 for rotatably supporting the compression molding roller 114 on the powder compression molding apparatus 112. At least one of the first bearing region 132 and the second bearing region 134 can be integrally formed with the operating region 128. For example, the entire compression molding roller 114 including the operating region 128, the first bearing region 132, and the second bearing region 134 can be formed as one integral part made of a SiC material.

[0067] 4-5, the first bearing region 134 may be connected to the first end 130 of the operating region 128 via a first coupling 138. Similarly, the second bearing region 136 may be connected to the second end 132 of the operating region 128 via a second coupling 140. In this manner, the first bearing region 134 and the second bearing region 136 may be formed as separate components from the operating region 128. In some embodiments, at least one of the first bearing region 134 and the second bearing region 136 may be removably connected to the operating region 128 via the first coupling 138 and the second coupling 140, respectively. For example, at least one of the first coupling 138 and the second coupling 140 is one of a butt coupling, a tongue and groove coupling, a threaded coupling, and a pin coupling. As shown in Figures 5-6, one of the operating region 128 and the first bearing region 134 / second bearing region 136 may include a protrusion 150 configured to be received in a corresponding groove 152 in the other of the operating region 128 and the first bearing region 134 / second bearing region 136.

[0068] In further embodiments, at least one of the first bearing region 134 and the second bearing region 136 may be non-removably connected to the operating region 128 via the first coupling 138 and the second coupling 140, respectively. For example, the first bearing region 134 and the second bearing region 136 may be non-removably connected to the operating region 128 by adhesive bonding, soldering, brazing, diffusion bonding, and other bonding techniques that result in a non-removable connection of the first bearing region 134 and the second bearing region 136 to the operating region 128. The first coupling 138 and the second coupling 140 are configured to maintain alignment and concentricity of the operating region 128 and the first bearing region 134 and the second bearing region 136 relative to the longitudinal axis 115.

[0069] In some embodiments, the molded roller 114 may include a composite structure. For example, at least one of the first bearing region 134 and the second bearing region 136 may be made of a material different from that of the working region 128. For example, the working region 128 may be made of a SiC material, while the first bearing region 134 and the second bearing region 136 are made of a metal. This approach may reduce the overall cost of the molded roller 114 without reducing the performance characteristics of the working region 128. The working region 128 may be made of a simple cylinder or other shape including the first and second coupling portions 138, 140, and the first and second bearing regions 134, 136 may be machined to have a desired shape and to have the second and first coupling portions 138, 140.

[0070] The compression molded roller 114 may be manufactured by first forming the working region 128 in the desired shape and configuration, connecting the first bearing region 134 and the second bearing region 136 to the working region 128 via the first and second couplings 138 and 140, respectively, and machining the first bearing region 134 and the second bearing region 136 to the desired shape and configuration using the working region 128 as a reference datum. Such a manufacturing method ensures proper concentricity between the working region 128 and the first and second bearing regions 134 and 136.

[0071] In some embodiments, at least a portion of the molding roller 114 has a surface finish of less than 50 microinches Ra. For example, the working area 128 may have a surface finish of less than 50 microinches Ra. In some embodiments, the entire molding roller 114 may have a surface finish of less than 50 microinches Ra. Without intending to be bound by any theory, it has been found that a finer surface finish (i.e., a surface finish of less than 50 microinches Ra) of the molding roller 114 results in improved packing density of the powder material PM. Figures 7A-7C show the surface roughness for new rollers made from PTFE coated aluminum, alumina coated steel, and reaction bonded SiC, as measured on a Talysurf contact profilometer made by Taylor Hobson, Ltd. of Leicester, UK. Figure 7D shows the surface roughness of the PTFE coated aluminum roller used.

[0072] Although various embodiments or aspects have been described in detail for purposes of illustration and explanation, it is understood that such details are for the sole purpose and that the embodiments or aspects are not limited to the disclosed embodiments or aspects, but rather are intended to cover modifications and equivalent arrangements falling within the spirit and scope of the appended claims. For example, it is understood that the present disclosure contemplates that, to the extent possible, one or more features of any embodiment or aspect may be combined with one or more features of any other embodiment or aspect. Indeed, many of these features may be combined in a manner not specifically recited in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of possible embodiments includes each dependent claim in combination with each of the other claims in the claims. [Explanation of symbols]

[0073] 100 Systems 102 Powder bed 104 Powder feeding device 106 Powder source 108 Supply mechanism 110 Printing device 112 Powder compression molding equipment 112 Compression molding roller 112 Powder compression molding / diffusion device 114 Compression molding roller 114 Compression molding / spreading roller 115 Long axis 116 Drive mechanism 118 Control device 120 processors 122 Memory 124 Input Devices 126 Output Devices 128 Operating area 130 First end 132 Second End 132 first bearing area 134 First bearing area 134 Second Bearing Area 136 Second Bearing Area 138 First Connection 139 Bearing surface 140 Second Connection 152 Groove

Claims

1. 1. A system for additive manufacturing of a three-dimensional object, comprising: The system further comprises: A powder compaction device including at least one compaction roller configured to spread and compact a powder material across a powder bed; a printing device configured to selectively bond or fuse the powder material; and Equipped with wherein at least a portion of the at least one compression molding roller is made from silicon carbide.

2. The silicon carbide is The system of claim 1 which is reaction bonded silicon carbide.

3. At least a portion of the at least one compression molding roller is 10. The system of claim 1 having a surface finish of less than 50 microinches Ra.

4. The at least one compression molding roller is an active area having a first end and a second end; a first bearing region extending from the first end of the operating region; a second bearing region extending from the second end of the operating region; and The system of claim 1 , comprising:

5. The operating area is 5. The system of claim 4 having a surface finish of less than 50 microinches Ra.

6. The operating area is The system of claim 4 , which is cylindrical with a circular cross-section.

7. At least one of the first bearing region and the second bearing region is The system of claim 4 , integrally formed with the active area.

8. At least one of the first bearing region and the second bearing region is The system of claim 4 , wherein the active area is made of a different material.

9. the active region is made from silicon carbide; The system of claim 4 , wherein the first bearing area and the second bearing area are made from metal.

10. The first bearing region is connected to the first end of the active area via a first coupling portion; The second bearing region is The system of claim 4 , connected to the second end of the working area via a second connection.

11. At least one of the first connecting portion and the second connecting portion is The system of claim 10 , wherein the connection is one of a butt connection, a tongue and groove connection, a threaded connection, and a pin connection.

12. The compression molding roller, The system of claim 1 , configured to rotate about a longitudinal axis and to move laterally in a direction perpendicular to said longitudinal axis.

13. 10. The system of claim 1, further comprising a powder feeding device configured to feed a predetermined amount of the powder material to a top surface of the powder bed.

14. 1. A system for additive manufacturing of a three-dimensional object, comprising: The system further comprises: A powder compaction device including at least one compaction roller configured to spread and compact a powder material across a powder bed; a printing device configured to selectively bond or fuse the powder material; and Equipped with The at least one compression molding roller is a cylindrical active area having a first end and a second end; a first bearing region extending from the first end of the operating region; a second bearing region extending from the second end of the cylindrical working region; and Equipped with The system wherein the cylindrical working region is fabricated from silicon carbide and has a surface finish of less than 50 microinches Ra.

15. The first bearing region is connected to the first end of the active area via a first coupling portion; The second bearing region is The system of claim 14 , further comprising a second connection connected to the second end of the working area via a second connection.

16. At least one of the first connecting portion and the second connecting portion is 16. The system of claim 15, wherein the connection is one of a butt connection, a tongue and groove connection, a threaded connection, and a pin connection.

17. 1. A compression molding roller configured for use in a system for additive manufacturing of three-dimensional objects, comprising: The compression molding roller, a cylindrical active area having a first end and a second end; a first bearing region extending from the first end of the operating region; a second bearing region extending from the second end of the cylindrical working region; and Equipped with at least the cylindrical working area is made from silicon carbide; A compression molded roller, said cylindrical working area having a surface finish of less than 50 microinches Ra.

18. At least one of the first bearing region and the second bearing region is 20. The compression molding roller of claim 17, integrally formed with the working area.

19. The first bearing region is connected to the first end of the active area via a first coupling portion; The second bearing region is 20. The compression molding roller of claim 17, connected to the second end of the working area via a second connection.

20. At least one of the first connecting portion and the second connecting portion is 20. The system of claim 19, wherein the connection is one of a butt connection, a tongue and groove connection, a threaded connection, and a pin connection.

Images