Ceramic roller for powder dispersion

Abstract

A system for additive manufacturing of a three-dimensional object includes: a powder compaction apparatus having at least one compaction roller configured to scatter and compact a powder material on a powder bed; and a printing device configured to selectively bond or melt the powder material. At least a portion of the at least one compaction roller is made of silicon carbide. The at least one compaction roller includes a working region having a first end and a second end, a first support region extending from the first end of the working region, and a second support region extending from the second end of the working region. And the surface smoothness Ra of the working area is less than 50 micro inches. At least one of the first support region and the second support region is integrally formed with the working region, or is connected to the working region by a joint.

Description

Technical Field

[0001] The present disclosure relates to a roller configured for use in an additive manufacturing process, and more particularly to a ceramic roller for spreading and compacting powder in an additive manufacturing process. A method of manufacturing the roller is also disclosed. Background Art

[0002] Additive manufacturing, also known as three-dimensional (3D) printing, is a manufacturing technology based on the controlled deposition of materials in successive layers to define 3D objects. In some additive manufacturing processes, successive thin layers of powdered material are spread onto a build bed using rollers. The compacted powdered material is then selectively melted, for example using a binder or a laser or other form of energy, to define the layers of the 3D object. The build bed is then lowered and the spreading / compacting process is repeated to form another layer of powdered material. This process of continuously building multiple layers continues until the desired 3D object is formed.

[0003] The roller used in the 3D printing machine is configured to rotate around its axis of rotation and to traverse in a direction perpendicular to the axis of rotation. This roller motion is configured to build a layer of powder material with a uniform thickness (50 μm to 200 μm) and a desired packing density (usually expressed in g / cc, representing the geometric density of the powder material). The packing density achieved by the roller is crucial to determining 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. In order to obtain better structural properties for the printed 3D object, a higher stacking is desired.

[0004] Conventional rollers used in 3D printing machines are made of metal or plastic. Such metal or plastic rollers wear over time, and wear particularly quickly when used to spread harder metal or ceramic powders. These rollers have to be replaced frequently (e.g., within a few weeks) when used to spread ceramic powders (e.g., silicon carbide), resulting in equipment downtime and high maintenance costs. Metal or plastic rollers also require coatings (e.g., low-friction polytetrafluoroethylene (PTFE) coatings) to prevent powder adhesion or embedding.

[0005] Examples of conventional rollers include rollers made of aluminum (bare metal or coated with PTFE coating) or steel coated with aluminum oxide. PTFE-coated aluminum rollers are expensive and require frequent replacement (approximately 1-2 months), significantly increasing equipment downtime and costs. Aluminum oxide-coated steel rollers have an undesirable surface roughness, which results in low bulk density. Therefore, there is a need in the art for an improved roller for spreading powdered materials in a 3D printing machine, which has improved powder density and long roller life. Summary of the invention

[0006] Disclosed herein are non-limiting embodiments or aspects of a system for additive manufacturing of a three-dimensional object. The system may include: a powder compacting device having at least one compacting roller configured to spread and compact a powder material on 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 compacting roller may be made of silicon carbide.

[0007] In some non-limiting embodiments or aspects, the silicon carbide may be reaction-sintered silicon carbide.At least a portion of the at least one compacting roller may have a surface finish Ra of less than 50 micro-inches.

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

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

[0010] In some non-limiting embodiments or aspects, the compacting roller can be configured to rotate about the longitudinal axis and to traverse in a direction perpendicular to the longitudinal axis.The system can also include a powder dispensing device configured to dispense a predetermined amount of powder material onto 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 compacting device having at least one compacting roller configured to spread and compact a powder material on a powder bed; and a printing device configured to selectively bond or melt the powder material. The at least one compacting roller may include a cylindrical working area having a first end and a second end, a first support area extending from the first end of the cylindrical working area, and a second support 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 Ra of less than 50 microinches.

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

[0013] In some non-limiting embodiments or aspects, a compaction roller configured for use in a system for additively manufacturing a three-dimensional object may include a cylindrical working area having a first end and a second end, a first support area extending from the first end of the cylindrical working area, and a second support area extending from the second end of the cylindrical working area. At least the cylindrical working area may be made of silicon carbide, and the cylindrical working area may have a surface finish Ra of less than 50 microinches.

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

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

[0016] Additional embodiments or aspects of the present disclosure are described in detail in one or more of the following clauses:

[0017] Item 1: A system for additive manufacturing of three-dimensional objects, the system comprising: a powder compacting device, the powder compacting device including at least one compacting roller, the at least one compacting roller being configured to spread and compact powder material on a powder bed; and a printing device, the printing device being configured to selectively bond or melt the powder material; wherein at least a portion of the at least one compacting roller is made of silicon carbide.

[0018] Clause 2: The system of clause 1, wherein the silicon carbide is reaction-sintered silicon carbide.

[0019] Clause 3: The system of clause 1 or 2, wherein at least a portion of the at least one compacting roller has a surface finish Ra of less than 50 micro-inches.

[0020] Clause 4: The system of any one of clauses 1 to 3, wherein the at least one compaction roller comprises a working area having a first end and a second end, a first support area extending from the first end of the working area, and a second support area extending from the second end of the working area.

[0021] Clause 5: The system of clause 4, wherein the working area has a surface finish Ra of less than 50 microinches.

[0022] Clause 6: The system of clause 4 or 5, wherein the working volume is cylindrical with a circular cross-section.

[0023] Clause 7: The system of any of clauses 4 to 6, wherein at least one of the first support area and the second support area is integrally formed with the working area.

[0024] Clause 8: The system of any of clauses 4 to 7, wherein at least one of the first support region and the second support region is made of a different material than the working region.

[0025] Clause 9: The system of any of clauses 4 to 8, wherein the working region is made of silicon carbide, and wherein the first support region and the second support region are made of metal.

[0026] Clause 10: The system of any of clauses 4 to 9, wherein the first support area is connected to the first end of the working area via a first joint, and wherein the second support area is connected to the second end of the working area via a second joint.

[0027] Clause 11: The system of clause 10, wherein at least one of the first joint and the second joint is one of a butt joint, a tongue and groove joint, a threaded joint, and a pin joint.

[0028] Clause 12: The system of any of clauses 1 to 11, wherein the compaction roller is configured to rotate about a longitudinal axis and to traverse in a direction perpendicular to the longitudinal axis.

[0029] Clause 13: The system of any one of clauses 1 to 12, further comprising a powder dispensing device configured to dispense a predetermined amount of powder material onto a top surface of the powder bed.

[0030] Item 14: A system for additive manufacturing of three-dimensional objects, the system comprising: a powder compacting device, the powder compacting device comprising at least one compacting roller, the at least one compacting roller being configured to spread and compact powder material on a powder bed; and a printing device, the printing device being configured to selectively bond or melt the powder material; wherein the at least one compacting roller comprises a cylindrical working area having a first end and a second end, a first supporting area extending from the first end of the cylindrical working area, and a second supporting area extending from the second end of the cylindrical working area; wherein the cylindrical working area is made of silicon carbide and has a surface finish Ra of less than 50 microinches.

[0031] Clause 15: The system of clause 14, wherein the first support area is connected to the first end of the working area via a first joint, and wherein the second support area is connected to the second end of the working area via a second joint.

[0032] Clause 16: The system of clause 15, wherein at least one of the first joint and the second joint is one of a butt joint, a tongue and groove joint, a threaded joint, and a pin joint.

[0033] Item 17: A compaction roller configured for use in a system for additive manufacturing of three-dimensional objects, the compaction roller comprising: a cylindrical working area having a first end and a second end; a first support area extending from the first end of the cylindrical working area; and a second support area extending from the second end of the cylindrical working area, wherein at least the cylindrical working area is made of silicon carbide and wherein the cylindrical working area has a surface finish Ra of less than 50 microinches.

[0034] Clause 18: The compacting roller of clause 17, wherein at least one of the first support region and the second support region is integrally formed with the working region.

[0035] Clause 19: Compacting roller according to clause 17 or 18, wherein the first bearing zone is connected to the first end of the working zone via a first joint, and wherein the second bearing zone is connected to the second end of the working zone via a second joint.

[0036] Clause 20: The compaction roller of clause 19, wherein at least one of the first joint and the second joint 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 is a side cross-sectional view of an additive manufacturing apparatus according to an embodiment or aspect of the present disclosure;

[0038] Figure 2 is a graph showing the packing density of various rollers used in an additive manufacturing apparatus over time;

[0039] Figure 3 is a top view of a roller configured for use with an additive manufacturing apparatus according to an embodiment or aspect of the present disclosure;

[0040] Figure 4 is a top view of a roller configured for use with an additive manufacturing apparatus according to another embodiment or aspect of the present disclosure;

[0041] Figure 5 is a top view of a roller configured for use with an additive manufacturing apparatus according to another embodiment or aspect of the present disclosure;

[0042] Figure 6 is a top view of a roller configured for use with an additive manufacturing apparatus according to another embodiment or aspect of the present disclosure; and

[0043] Figures 7A-7D is a graph showing the surface roughness of rollers made of various materials.

[0044] exist Figure 1-7D In the present invention, like reference numerals refer to the same parts and elements, as appropriate, unless otherwise specified. DETAILED DESCRIPTION

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

[0046] Spatial or directional terms such as "left", "right", "inner", "outer", "upper", "lower" and the like refer to the embodiments or aspects shown in the drawings and are not to be considered limiting as the embodiments or aspects may assume various alternative orientations.

[0047] All numbers used in the specification and claims should be understood as being modified in all cases by the term "about". "About" means 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 limiting any numerical analysis under the principle of equivalents.

[0048] All ranges or ratios disclosed herein should be understood to include starting and ending values ​​and any and all subranges or subratios contained therein, unless otherwise specified. For example, a specified range or ratio of "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 (and including the end values); that is, all subranges or subratios start with a minimum value of 1 or greater and end with a maximum value of 10 or less. The ranges and / or ratios disclosed herein represent average values ​​of the specified ranges and / or ratios.

[0049] The terms "first", "second", etc. are not intended to refer to any particular sequence or chronology, but rather to different conditions, attributes 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 conjunction with a threshold value. As used herein, satisfying a threshold value may refer to a value greater than a threshold value, more than a threshold value, above a threshold value, greater than or equal to a threshold value, less than a threshold value, less than a threshold value, below a threshold value, less than or equal to a threshold value, equal to a threshold value, 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" refers to 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 A alone; or B alone; or C alone; or A and B; or A and C; or B and C; or all of A, B, and C.

[0055] The term "comprising" is synonymous with "including."

[0056] refer to Figure 1, a system 100 for additive manufacturing of a three-dimensional (3D) object according to a non-limiting embodiment or aspect of the present disclosure is shown. In some embodiments or aspects, the system 100 can be configured as a binder jetting system, in which an unbound powder material PM (also referred to herein as "powder" or "powder material") is spread on a powder bed 102 in the form of a very thin layer (50 μm to 200 μm) and a binder is selectively applied to the powder material PM to bond the particles together to form a layer L of a solid object. After building multiple layers L, the resulting 3D object can undergo additional post-processing steps (e.g., sintering) to achieve the desired strength and properties. Such additional post-processing steps can be configured to reduce or remove void spaces between particles of the powder material PM and increase the density of the final 3D object.

[0057] although Figure 1 The following disclosure describes a binder jetting system, such as a metal binder jetting system, a ceramic binder jetting system, or a plastic binder jetting system, but 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 can be configured as a selective laser sintering system or a selective laser melting system. In such a system, the powder material PM is heated by a laser so that the particles are melted together and the desired object is built layer by layer. In other embodiments, the system 100 relates to any additive manufacturing system configured to manufacture a 3D object from powder material dispersed layer by layer.

[0058] Continue to refer Figure 1 , the system 100 includes a powder dispensing device 104, which is configured to dispense a predetermined amount of powder material PM on the top surface of the powder bed 102. After each layer L of the powder material PM is spread and the binder is dispensed to selectively bond the unbonded powder material PM, the powder bed 102 can move in the direction of arrow A. The powder dispensing device 104 can have a powder source 106 configured to accommodate a large amount of powder material PM and a dispensing mechanism 108 configured to selectively dispense a predetermined amount of powder material PM on the powder bed 102. The dispensing mechanism 108 can be configured to dispense the powder material PM into a pile, which is configured to be flattened and compacted. In some embodiments, the powder source 106 can be a hopper, and the dispensing mechanism 108 can be a metering device configured to dispense a predetermined amount of powder 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 other embodiments, the powder material PM can be a plastic powder material, such as but not limited to nylon, PBT (polybutylene terephthalate), PEEK (polyetheretherketone) or PP (polypropylene). In various examples, the powder material PM can have an average particle size of 0.1 μm to 2000 μm.

[0060] Continue to refer Figure 1 , the system 100 may include a printing device 110 configured to selectively dispense a binder onto the layer L of powder material PM. The binder may be a liquid binder that is laid onto the layer L of powder material PM in a two-dimensional pattern representing a layer of a 3D object. In some embodiments, the binder may be a two-component binder comprising two components that react when combined to bond unbonded powder material PM. In further embodiments, the binder may be an ultraviolet (UV) curable binder that is configured to bond unbonded powder material PM when exposed to UV light.

[0061] Continue to refer Figure 1 , the system 100 also includes a powder compacting device 112, which is configured to compact the powder material PM into a layer L of powder material PM before laying the binding material. The powder compacting device 112 includes at least one compacting roller 114, which is configured to spread and compact the powder material PM on the powder bed 102. In some embodiments, the at least one compacting roller 112 can be configured to rotate around the longitudinal axis 115 in the direction of arrow B and to move transversely in the direction of arrow C and parallel to the plane defined by the powder bed 102 in a direction perpendicular to the longitudinal axis 115. The powder compacting device 112 can have a drive mechanism 116, which is configured to drive the rotation and translation movement of the at least one compacting roller 112. In some embodiments, the drive mechanism 116 can be an electric motor.

[0062] Continue to refer Figure 1, the system 100 has a controller 118 operably connected to at least one of the powder dispensing device 104, the printing device 110, and the powder compacting device 112. The controller 118 may have a processor 120 having a memory 122 containing instructions that, when executed by the processor 120, control the operation of at least one of the powder dispensing device 104, the printing device 110, and the powder compacting / dispersing device 112. The controller 118 may be connected to one or more input devices 124 and / or one or more 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 about one or more parameters of the system 100, such as, 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 the operation of the dispensing mechanism 108 to dispense a predetermined amount of powder material PM from the powder source 106. In further embodiments, the controller 118 may be configured to control the operation of the printing device 110 to dispense a predetermined amount of binder to a selected location on the layer L of the powder material PM. In further embodiments, the controller 118 may be configured to control the operation of at least one compacting / spreading roller 114, for example, via the operation of the drive mechanism 116 to control the rotation and / or translation of at least one compacting / spreading roller 114.

[0064] As the powder compacting device 112 spreads the powder material PM via the compacting roller 114, it is expected to increase the packing density, which represents the compactness of the particles of the powder material. The packing density of the unbonded powder material PM is crucial to determining the properties of the final 3D object, such as the density, elastic modulus, strength, thermal conductivity, thermal expansion coefficient and other mechanical properties of the object. In addition, it is expected to have a uniform packing density on the powder bed 102 to prevent the 3D object from warping due to, for example, non-uniform shrinkage during the sintering operation. Therefore, a higher powder material stacking is expected to obtain better mechanical properties for the final 3D object. However, the increase in packing density increases the wear on the at least one compacting roller 114. As described herein, the at least one compacting roller 114 can be configured to spread the powder material PM in a layer L having a uniform thickness and a high geometric density, while having a long service life by carefully selecting the material of the at least one compacting roller 114.

[0065] In some embodiments, at least a portion of the compacting roller 114 may be made of a ceramic material. In particular, at least a portion of the compacting roller 114 may be made of a silicon carbide (SiC) material, which is selected because of its hardness and resistance to wear caused by contact with the powder material PM. In some embodiments, the SiC material may be a reaction sintered SiC material. The reaction sintered SiC material is made by infiltrating a SiC powder preform with molten Si. Examples of other forms of SiC include sintered SiC, hot pressed SiC, and chemical vapor deposited SiC. Reference Figure 2 , the compaction roller 114 made of SiC material can still maintain the powder packing density in several months of continuous use, while the powder packing density produced by the PTFE-coated aluminum roller decreases rapidly in only 1-2 months of use, requiring the equipment to be shut down to replace the roller. The experimental data shows that the compaction roller 114 made of SiC material has a uniform packing density with no significant performance degradation when used continuously for more than 6 months.

[0066] refer to Figure 3 , the compacting roller 114 includes a working area 128 having a first end 130 spaced apart from a second end 132 along the longitudinal axis 115. The working area 128 is cylindrical with a circular cross-section. In some embodiments, the working area 128 is configured to contact and compact the powder material PM during operation of the compacting roller 114. The compacting roller 114 also has a first support area 134 extending axially from the first end 130 and a second support area 136 extending axially from the second end 132 of the working area 128. The first support area 134 and the second support area 136 are axially aligned with the working area 128 to maintain the cylindricity of the working area 128. Each of the first support area 134 and the second support area 136 is configured to rotatably support the compacting roller 114 on the powder compacting device 112 so that the compacting roller 114 can rotate about the longitudinal axis 115 and along Figure 1 Move in the direction of arrow C. Figure 3 As shown, each of the first support area 134 and the second support area 136 can have one or more support surfaces 139 for rotatably supporting the compacting roller 114 on the powder compacting device 112. At least one of the first support area 132 and the second support area 134 can be integrally formed with the working area 128. For example, the entire compacting roller 114 including the working area 128, the first support area 132 and the second support area 134 can be formed as a single integral piece made of SiC material.

[0067] refer to Figure 4-5, the first support area 134 can be connected to the first end 130 of the working area 128 via a first joint 138. Similarly, the second support area 136 can be connected to the second end 132 of the working area 128 via a second joint 140. In this way, the first support area 134 and the second support area 136 can be formed as separate components separate from the working area 128. In some embodiments, at least one of the first support area 134 and the second support area 136 can be removably connected to the working area 128 via the first joint 138 and the second joint 140, respectively. For example, at least one of the first joint 138 and the second joint 140 is one of a butt joint, a tongue and groove joint, a threaded joint, and a pin joint. Figure 5-6 As shown, one of the working area 128 and the first / second support areas 134 , 136 may have a protrusion 150 configured to be received in a corresponding recess 152 on the other of the working area 128 and the first / second support areas 134 , 136 .

[0068] In further embodiments, at least one of the first support region 134 and the second support region 136 can be irremovably connected to the working region 128 via a first joint 138 and a second joint 140, respectively. For example, the first support region 134 and the second support region 136 can be irremovably connected to the working region 128 via adhesive bonding, soldering, brazing, diffusion bonding, and other bonding techniques that will result in the first support region 134 and the second support region 136 being irremovably connected to the working region 128. The first joint 138 and the second joint 140 are configured to maintain alignment and concentricity of the working region 128 and the first support region 134 and the second support region 136 relative to the longitudinal axis 115.

[0069] In some embodiments, the compaction roller 114 can have a composite structure. For example, at least one of the first bearing area 134 and the second bearing area 136 can be made of a material different from the material of the working area 128. For example, the working area 128 can be made of a SiC material, while the first bearing area 134 and the second bearing area 136 are made of a metal. In this way, the overall cost of the compaction roller 114 can be reduced without reducing the performance characteristics of the working area 128. The working area 128 can be made into a simple cylindrical shape, or other shapes with a first portion of the first joint 138 and the second joint 140, while the first bearing area 134 and the second bearing area 136 can be machined to have a desired shape and a second portion of the first joint 138 and the second joint 140.

[0070] The compaction roller 114 can be manufactured by first forming the working area 128 into a desired shape and geometry; connecting the first support area 134 and the second support area 136 to the working area 128 via the first joint 138 and the second joint 140, respectively; and machining the first support area 134 and the second support area 136 into the desired shape and geometry using the working area 128 as a reference datum. This manufacturing method ensures proper concentricity between the working area 128 and the first support area 134 and the second support area 136.

[0071] In some embodiments, at least a portion of the compacting roller 114 has a surface finish Ra of less than 50 micro-inches. For example, the working area 128 may have a surface finish Ra of less than 50 micro-inches. In some embodiments, the entire compacting roller 114 may have a surface finish Ra of less than 50 micro-inches. Without wishing to be bound by any theory, it has been found that a finer surface finish of the compacting roller 114 (i.e., a surface finish Ra of less than 50 micro-inches) produces an improved packing density of the powder material PM. Figures 7A-7C Shown are the surface roughness of new rollers made from PTFE coated aluminum, alumina coated steel, and reaction sintered SiC, as measured on a Talysurf contact profilometer manufactured by Taylor Hobson, Ltd, Leicester, UK. Fig.7D The surface roughness of a used PTFE-coated aluminum roller is shown.

[0072] Although various embodiments or aspects have been described in detail for the purposes of illustration and description, it will be understood that such details are used for that purpose only, 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 that fall within the spirit and scope of the appended claims. For example, it will be 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. In fact, many of these features may be combined in ways not specifically recited in the claims and / or disclosed in the specification. Although each of the dependent claims listed below may be directly dependent on only one claim, the disclosure of possible implementations includes each dependent claim in combination with every other claim in the claim set.

Claims

1. A system for additive manufacturing of a three-dimensional object, the system comprising: a powder compacting apparatus comprising at least one compacting roller configured to spread and compact powder material onto a powder bed; and a printing device configured to selectively bond or fuse the powder material; Wherein, at least a portion of the at least one compacting roller is made of silicon carbide.

2. The system according to claim 1, wherein: The silicon carbide is reaction-bonded silicon carbide.

3. The system according to claim 1, wherein: At least a portion of the at least one compacting roller has a surface finish Ra of less than 50 micro-inches.

4. The system according to claim 1, wherein: The at least one compacting roller includes a working region having a first end and a second end, a first support region extending from the first end of the working region, and a second support region extending from the second end of the working region.

5. The system according to claim 4, wherein: The working area has a surface finish Ra of less than 50 microinches.

6. The system according to claim 4, wherein: The working area is cylindrical with a circular cross-section.

7. The system according to claim 4, wherein: At least one of the first support area and the second support area is integrally formed with the working area.

8. The system according to claim 4, wherein: At least one of the first support region and the second support region is made of a different material than the working region.

9. The system according to claim 4, wherein: The working area is made of silicon carbide, and wherein the first support area and the second support area are made of metal.

10. The system according to claim 4, wherein: The first support area is connected to the first end of the working area via a first joint, and wherein the second support area is connected to the second end of the working area via a second joint.

11. The system according to claim 10, wherein: At least one of the first joint and the second joint is one of a butt joint, a tongue and groove joint, a threaded joint, and a pin joint.

12. The system of claim 1, wherein: The compaction roller is configured to rotate about a longitudinal axis and to traverse in a direction perpendicular to the longitudinal axis.

13. The system of claim 1, further comprising a powder dispensing device configured to dispense a predetermined amount of the powder material onto a top surface of the powder bed.

14. A system for additive manufacturing of a three-dimensional object, the system comprising: a powder compacting apparatus comprising at least one compacting roller configured to spread and compact powder material onto a powder bed; and a printing device configured to selectively bond or fuse the powder material; wherein the at least one compacting roller comprises a cylindrical working area having a first end and a second end, a first support area extending from the first end of the cylindrical working area, and a second support area extending from the second end of the cylindrical working area, and Wherein, the cylindrical working area is made of silicon carbide and has a surface finish Ra of less than 50 micro-inches.

15. The system of claim 14, wherein: The first bearing area is connected to the first end of the cylindrical working area via a first joint, and wherein the second bearing area is connected to the second end of the cylindrical working area via a second joint.

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

17. A compaction roller configured to be used in a system for additively manufacturing a three-dimensional object, the compaction roller comprising: a cylindrical working area having a first end and a second end; a first support region extending from said first end of said cylindrical working region; and a second support region extending from said second end of said cylindrical working region, wherein at least the cylindrical working area is made of silicon carbide, and Wherein, the cylindrical working area has a surface finish Ra of less than 50 micro-inches.

18. The compacting roller according to claim 17, wherein: At least one of the first support area and the second support area is integrally formed with the cylindrical working area.

19. The compacting roller according to claim 17, wherein: The first bearing area is connected to the first end of the cylindrical working area via a first joint, and wherein the second bearing area is connected to the second end of the cylindrical working area via a second joint.

20. The compacting roller of claim 19, wherein: At least one of the first joint and the second joint is one of a butt joint, a tongue and groove joint, a threaded joint, and a pin joint.

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