具体实施方式：
[0018]Illustrative examples of the devices, systems, and methods disclosed herein are provided below. An embodiment of the devices, systems, and methods may include any one or more, and any combination of, the examples described below. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth below. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Accordingly, the exemplary embodiments are intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the apparatuses, mechanisms and methods as described herein.
[0019]We initially point out that description of well-known starting materials, processing techniques, components, equipment and other well-known details may merely be summarized or are omitted so as not to unnecessarily obscure the details of the present disclosure. Thus, where details are otherwise well known, we leave it to the application of the present disclosure to suggest or dictate choices relating to those details. The drawings depict various examples related to embodiments of illustrative methods, apparatus, and systems for AM manufacturing.
[0020]When referring to any numerical range of values herein, such ranges are understood to include each and every number and/or fraction between the stated range minimum and maximum. For example, a range of 0.5-6% would expressly include the endpoints 0.5% and 6%, plus all intermediate values of 0.6%, 0.7%, and 0.9%, all the way up to and including 5.95%, 5.97%, and 5.99%. The same applies to each other numerical property and/or elemental range set forth herein, unless the context clearly dictates otherwise.
[0021]The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the particular quantity). When used with a specific value, it should also be considered as disclosing that value. For example, the term “about 2” also discloses the value “2” and the range “from about 2 to about 4” also discloses the range “from 2 to 4.”
[0022]The terms “media”, “web”, “web substrate”, “print substrate” and “substrate sheet” generally refers to a usually flexible physical sheet of paper, polymer, Mylar material, plastic, or other suitable physical print media substrate, sheets, webs, etc., for images, whether precut or web fed. The listed terms “media”, “print media”, “print substrate” and “print sheet” may also include woven fabrics, non-woven fabrics, metal films, carbon fiber reinforced material and foils, as readily understood by a skilled artisan. In additive manufacturing, a sheet may refer to a slice of a 3D object that is self-supporting or has a backing substrate that may be removed before a next sheet is added to a 3D object build.
[0023]The term “ink” as used herein may refer to printing matter deposited by an image forming device onto a web sheet or central rod supported cylinder to form an image on the sheet or cylinder. The listed term “ink” may include a sintering selectivity agent that is one of a sintering inhibitor to be deposited on the negative space or boundary of the pattern, and a sintering promoter to be deposited in the positive space of the pattern. Sintering ink may include an agent to deactivate the inhibitor, which may be placed throughout the bulk of the feedstock. The sintering ink may include a sintering inhibitor or a chemical that is a precursor to a sintering inhibitor.
[0024]The term ‘printing system“, “printing device” or “printer” as used herein encompasses any apparatus that performs a print outputting function for any purpose, such as a digital copier, scanner, image printing machine, xerographic device, digital production press, document processing system, image reproduction machine, bookmaking machine, facsimile machine, multi-function machine, 3D printer or the like and can include several marking engines, feed mechanism, scanning assembly as well as other print media processing units, such as paper feeders, finishers, and the like. A printing system can handle sheets, webs, marking materials, 3D feedstock and the like. A 3D printer can make a 3D object, and the like. A 3D printer may also be used to manufacture 2D, sheet-like, or surface-like objects. It will be understood that the structures depicted in the figures may include additional features not depicted for simplicity, while depicted structures may be removed or modified.
[0025]The term “controller” is used herein generally to describe various apparatus relating to the operation of one or more device that directs or regulates a process or machine. A controller can be implemented in numerous ways (e.g., such as with dedicated hardware) to perform various functions discussed herein. A “processor” is one example of a controller which employs one or more microprocessors that may be programmed using software (e.g., microcode) to perform various functions discussed herein. A controller may be implemented with or without employing a processor, and also may be implemented as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions. Examples of controller components that may be employed in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).
[0026]The examples further include at least one machine-readable medium comprising a plurality of instructions, when executed on a computing device, to implement or perform a method as disclosed herein. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of the computer-readable media.
[0027]Computer-executable instructions include, for example, instructions and data which cause a general-purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in stand-alone or network environments. Generally, program modules include routines, programs, objects, components, and data structures, and the like that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described therein.
[0028]As used herein, unless otherwise specified, the term “object” can also mean part, element, piece, or component in whole or a portion thereof. As used herein, an object refers to a 3D object to be individually built, or actually built, by a 3D printing system (printer). An object, as referred herein, may be built by successively adding layers so as to form an integral piece, or by continuously adding to a turning spiraled layer forming an outwardly growing cylinder. Some printers are capable of building, as part of the same print job, a plurality of independent pieces from a 3D model including a plurality of independent 3D objects. An object may include void spaces embedded in the object body.
[0029]Although embodiments of the invention are not limited in this regard, discussions utilizing terms such as, for example, “processing,”“computing,”“calculating,”“determining,”“using,”“establishing”, “analyzing”, “checking”, or the like, may refer to operation(s) and/or process(es) of a computer, a computing platform, a computing system, or other electronic computing device, that manipulate and/or transform data represented as physical (e.g., electronic) quantities within the computer's registers and/or memories into other data similarly represented as physical quantities within the computer's registers and/or memories or other information storage medium that may store instructions to perform operations and/or processes.
[0030]State of the art 3D printing (3DP) techniques such as Selective Laser Sintering (SLS), Stereolithography (SLA), Solid-Ground Curing (SGC), Multi-Jet Fusion (MJF), and Laminated Object Manufacturing (LOM) rely on a layer-by-layer ‘additive’ approach, wherein a part with the desired 3-dimensional geometry is created from the material to be 3D printed (hereinafter “active material” or “active 3D printing material” or “active material to be 3D printed”) by repeatedly developing 2-dimensional patterns (in the form of individual layers typically less than 100-500 micrometers thick) that are successively added on top of each—other thereby ‘building up’ the desired part. Other 3DP/AM techniques such as Fused Deposition Modeling (FDM) and Laser Engineered Net Shaping (LENS) rely on creating a 1-dimensional (line) pattern that is written into a 2D (X-Y) layer and the desired 3D geometry is realized by continually “building up” the X-Y layers in the vertical (Z) direction. In many 3DP/AM techniques, a sacrificial material (hereinafter “support material” or “supporting material”) may be added for each layer where the active 3D printing material was not deposited (to fill in the open areas/voids in the 2D pattern), before starting the subsequent (overlaid in the Z direction) layer so that overhangs in successive layers may b e reliably deposited and supported on top of the underlying layers and the desired 3D printed parts may be temporarily supported within the build volume, till they are released from the 3D printing stage for post-processing (if needed) and subsequent use in the desired application, for which they are being produced.
[0031]Laminated object manufacturing (LOM) is a method of high-speed additive manufacturing that can be used with sheet-like feedstocks incorporating a variety of materials including metals. In conventional LOM, the feedstock is formed into sheets that are cut out into cross sections of the designed part, and the sheets are laminated or fused together. Because the feedstock is 2D, in principle, printer design can be simplified by leveraging techniques from conventional paper printing. LOM techniques are compatible with high-speed additive manufacturing because the material is already fused in the plane of the cross section; patterning only needs to occur at the perimeter of the cross-section.
[0032]LOM processes compatible with sinterable feedstocks include depositing an adhesive or binder over the cross section of the layer, or cutting a layer at the perimeter of the cross section. In an adhesive process, the adhesive can be applied to a pre-formed sheet substrate containing the powder feedstock (i.e., powder embedded in a binder or on a porous substrate), or loose powder can be applied to the adhesive. Both the adhesive and cutting approaches have limitations. Printing an adhesive or binder over the cross section of a part is fundamentally slower than printing just at the boundaries. In addition, using an adhesive in addition to a feedstock substrate creates different powder density in-plane and through-plane, leading to part anisotropy. In other words, parts made from LOM are anisotropic and have weak shear planes between layers. Further, having two inactive materials (adhesive and substrate) complicates the binder removal step prior to sintering. Moreover, cutting a layer away at the perimeter limits part geometries to shapes with small overhangs and no floating planes.
[0033]Accordingly, as will be further appreciated, it may be useful to provide an Embedded High-speed Turning for Additive Layering (EHTAL) 3D printing system to allow significantly higher speed 3D printing of Additively Manufactured/3D printed parts. The EHTAL 3D printing system may include a continuously revolving roller on to which the patterned layer and any supporting material may be continuously added without having to resort to a back-and-forth or stop-and-go process. For example, the present techniques may include continuously adding on a layer in a concentric, spiral manner, and constructing to extend outwardly (e.g., “building out”) the diameter of the rotating cylinder from a starting central core. By continuously adding (e.g., material deposition to cover the pattern in the immediately preceding layer) and patterning active and support materials onto the surface of such a growing cylinder, it would be possible to fabricate the desired shapes (e.g., various 3D printed shapes/parts) embedded within the support material. In this way, the 3D printed part(s) may be thus constructed to “grow” layer by layer in a continuous spiraled manner, without having the “stop-and-go” methodology and constant layer deposition step direction change due to the back-and-forth motion of the development (layer patterning) system. Thus, so long as the outwardly growing cylinder keeps turning and patterned active and support materials are added in a continuous fashion to support the outward growth of the turning cylinder, the desired 3D Printed/Additively Manufactured components (parts) embedded within the support material can be fabricated at a high speed in a continuous fashion without having to stop the patterning process after each layer as is done in state of the art layered 3D printing/Additive Manufacturing systems—thereby significantly reducing process time and improving the overall 3D printing speed and 3D printing/fabrication throughput as well as enhancing overall system reliability. Moreover, the continuous spiral deposition on the outer curved surface of the outwardly growing cylinder does not result in the flat planes of weakness described above, and therefore can minimize fracture or slippage planes in the resulting 3DP/AM parts because the continuously deposited curved layers within the rotating cylinder provide improved structural stability.
[0034]In accordance with the present embodiments, it may be useful to describe EHTAL 3D printing systems, which are discussed in greater detail in U.S. Patent Publication No. US20200207015 to Pattekar et al. FIG. 1 is a diagram of an exemplary related art ETHAL 3D printing system 10 that may fabricate one or more 3DP/AM parts by using a sequential, pattern-wise deposition of anti-sintering agents (e.g., de-binding agents). In particular, the 3D printing system includes an active 3DP material that may be deposited (e.g., via a roller, spray, slit in a trough) as layer 12 onto a continuously revolving cylinder 20 via a carrier belt or ribbon 14, which may be referred to as a transfer belt. Specifically, a layer including the patterned active 3DP material layer 12 may be continuously deposited on the surface of the carrier ribbon 14, as the layer moves along with the ribbon. The active 3DP material layer 12 may be metal or plastic powder, Metal Injection Molding (MIM) starting material including a polydisperse metal powder and polymer binder, or other suitable material that is to be patterned into a 3D part to be fabricated in the desired geometry. Active materials for dense feedstock may include stainless steel alloys such as 17-4PH, carbonyl iron, 316, magnetic alloys, copper-nickel alloys, titanium, copper, alumina, zirconia, aluminosilicate minerals and glasses, polymer particles, and many others including various metals, metal alloys, ceramics, and plastics/polymers.
[0035]In examples, binder for the dense feedstock may be hydrophobic or hydrophilic, and it may contain thermoplastic or thermoset components. Some active binder materials include: polyethylene, polypropylene, polyoxymethylene, paraffin, carnauba wax, polypropylene oxide, polybutylene oxide (hydrophobic thermoplastics); polyethylene oxide, polypropylene carbonate, polybutylene carbonate, alginate, agar, cellulose, methylcellulose, methylcellulose-based compounds, solidum lignosulfonate, polyvinyl alcohol, polyvinyl butyral, polyacrylate salts, polylactic acid, (hydrophilic thermoplastics), and hydrophobic or hydrophilic UV-curable acrylate and methacrylate resins (thermosets).
[0036]Binders may include additional components such as surfactants to promote adhesion with the sinterable components (stearic acid, oleic acid, oleyl amine, fish oil, Pluronic surfactants, block copolymers of polyethylene oxide and polypropylene oxide, sodium dodecyl sulfate, molecules containing a hydrophobic moiety and a hydrophilic moiety such as a phosphate, sulfate, ammonium, carboxylates, or other amphiphilic molecules). Binders may include viscosity modifiers such as oligomers (short chain polymers) of the polymers listed above, glycerin, phthalate-containing molecules, dibutyl phthalate, dioctyl phthalate or solvents such as water, or organic solvents, such as toluene, xylenes, alkanes, decane, hexane, isopar, n-methylpyrrolidone, dimethylformamide, tetrahydrofuran, dimethylsulfoxide, acetophenone, and others.
[0037]The 3D printing system 10 further includes the carrier ribbon 14, a first roller 16, a second roller 18, the cylinder 20, an anti-sintering/de-binding agent jetting subsystem 22, and a transfer component 34 that transfers the active material 12 being 3D printed along with any embedded patterned anti-sintering/de-binding agent(s) 26, on to the outwardly growing cylinder. The cylinder 20 may include various 3D printed parts 28 which are illustrated by the exemplary shapes (e.g., the triangles, rectangles, trapezoids, parallelograms, etc.) within the cylinder.
[0038]As the rollers 16 and 18 rotate counterclockwise, the carrier ribbon 14 may move towards the right as shown in FIG. 1. The anti-sintering jetting subsystem 22 is a selective inhibition sintering mechanism that may spray, shoot, deposit, or otherwise apply a support material (e.g., anti-sintering agent 26) to the active material 12 that is on the surface of the carrier ribbon 14. The transfer component 34 may apply heat, light, mechanical vibration, or pressure at the contact between the ribbon 14 and the cylinder 20 to enable transfer of the active material 12 with the embedded patterned support material (e.g., anti-sintering agent 26) on to the surface of continuously rotating and outwardly growing spiraled cylinder. The cylinder 20 includes a core 24. Initially, the active material 12 with the embedded patterned anti-sintering agent 26 may be transferred to the core 24 and later onto the outer surface of the cylinder 20 as the cylinder is built. The core 24 may be attached to a rotating system (e.g., a rotating support axle, a motor that rotates the core), for example as discussed above.
[0039]The anti-sintering jetting subsystem 22 may perform a pattern-wise deposition of the anti-sintering agent 26 on to the active material layer 12 on ribbon 14. As illustrated in portion 30 of the active material layer 12, the anti-sintering agent 26 may be deposited (e.g., sprayed) onto the active material layer to form a pattern. The anti-sintering agent 26 is an ink that would impede the formation of permanent bond between the particles/components comprising the active material 12 that is being 3D printed in this system. Once the deposition of the patterned anti-sintering material and the active material being 3D printed is completed, the cylinder 20 may be cured, for example, by heating in an activation heater 38 (e.g., furnace, oven) to an appropriate sintering temperature (e.g., greater than about 400° C. for metal particles and 800° C. for ceramic particles). The activation heater 38 may include heating elements to achieve the target heating temperature for effective sintering, such as electrical (resistive) heating elements, combustible gas (burner) heating elements, or microwave/infrared or other (radiative) heating elements. Other curing approaches that may be used include mechanical (e.g., mechanical compaction/pressure application), chemical (e.g., chemical reactions leading to formation of permanent bonds between the constituents of the active material) and/or optical means (e.g., using lasers or directed infrared/ultraviolet light in order to cure/fuse the constituents of the active material).
[0040]The embedded anti-sintering agent 26 in cylinder 20 may form cut lines (e.g., de-binding borders 32) which act as separation points/de-binding boundaries upon sintering/curing of cylinder. After the curing/sintering step (e.g., by heating in a furnace or other suitable curing treatment to enable sintering/curing of cylinder 20), the anti-sintering agent patterned into cylinder would cause the formation of well-defined 3D printed geometrical shaped parts by forming appropriate de-binding boundaries 32 between contiguous regions inside the cylinder 20. This may occur by a mechanism of the formation, e.g., of a weak or porous solid, such as by the dehydration and solidification of applied sol-gel slurry to a brittle ceramic solid that may disintegrate into a powder and naturally fall away from the 3D printed parts 28 along the de-binding boundaries defined by the patterned anti-sintering agent 26. The de-binding or anti-sintering agents/materials for the related art 3D printed parts may include an applied polymeric material (e.g., Poly-alkylenecarbonates) that may decompose or degrade with the application of heat, or by other chemical means. This would produce gap/break-away de-binding borders 32 between the build and support structures and may also produce additional break-away borders within the support structures to promote ease of separation within the revolving cylinder 20. Other related art anti-sintering material may include, but are not limited to, a suspension of particles that includes a sol-gel slurry of silicon alkoxide/hydroxide, aluminum alkoxide/hydroxide, or metal alkoxide or hydroxide, a resin (e.g., a synthetic resin, epoxy resin) a polymeric/metal mixture, a polymeric/ceramic mixture and a polymeric/inorganic mixture, a dissolvable or dehydratable inorganic salt solution or slurry, of which at least one component of the solution or slurry may undergo degradation or decomposition with the application of at least one of heat, light, and/or a chemical agent.
[0041]In some related art examples, combinations of ceramic slurry, ceramic particles, and polymeric solutions may also be used as the de-binding agent. A solution or slurry of a metal halide or other non-reacting salt may be used as a de-binding agent, where upon dehydration or exposure to an appropriate solvent (e.g., water), the salt crystals remaining will fall away or dissolve to separate the 3D printed parts 28 and surrounding support structure. Once the revolving cylinder 20 with embedded 3D printed parts 28 is formed, the cylinder rotation may be stopped and the pre-sintering stage parts, for example, may be separated first and sintered in a furnace subsequently. In other examples, the entire cylinder 20 may be sintered in the furnace and the support structures may be removed thereafter by a variety of means, including but not limited to mechanical separation, chemically etching or dissolving the boundary between the parts of interest and support material, melting away the support material, ablating away the support material using optical (e.g., laser or directed infrared/ultraviolet light), etc.
[0042]The carrier ribbon 14, the rotation system for rotating the cylinder 20, the roller 16, the roller 18, the anti-sintering jetting subsystem 22, and the transfer component 34 may all be controlled by a control system/subsystem. For example, a computing device may synchronize the operation (e.g., the speed of rotation) of the carrier ribbon 14, the rotation system for rotating the cylinder 20, the roller 16, the roller 18, the anti-sintering jetting subsystem 22, and the transfer component 34, as understood by a skilled artisan.
[0043]FIG. 2 is a diagram of another EHTAL 3D printing system 40 that may fabricate one or more 3D parts by using a sequential deposition of the active material 12 being 3D printed and pattern-wise deposition of appropriate anti-sintering agents 26 (e.g., de-binding agents). The 3D printing system 40 includes an active material deposition subsystem 42, an anti-sintering agent deposition subsystem 44, and a cylinder 20. The cylinder 20 includes various 3D printed parts 28 which are illustrated by the shapes (e.g., the triangles, rectangles, trapezoids, parallelograms, etc.) within the cylinder.
[0044]The active material deposition system 42 may deposit (e.g., spray, shoot, deposit, extrude or otherwise mechanically apply) the active material 12 to be 3D printed onto the cylinder 20 to the surface (e.g., the outer surface) of the cylinder. The active material may comprise, e.g., an ultra-violet (UV) curable resin, or a slurry containing ceramic or metal/metal alloy particles, or a metal injection molding [MUM] slurry containing a mixture of polydisperse metal/metal alloy/ceramic powder & polymer binder. The dense feedstock layer may be subject to a fixing action, for example by a viscosity modifier 36 to transform the feedstock from a state which is easy to apply as layer to a state where the feedstock forms a solid or semi-solid self-supporting structure. The fixing can facilitate thinner layers to be applied (e.g., <100 microns, <50 microns, <10 microns), which may result in higher resolution parts. Examples of a viscosity modifier 36 include a heater drying solvent out of the feedstock to go from a low viscosity liquid to a dry, dense, solid powder-binder composite; a UV heater UV-curing a feedstock containing a UV-curable liquid binder resin; and after applying the feedstock as a liquid at or above room temperature, a cooler to form a solid at room temperature or below, as understood by a skilled artisan.
[0045]The anti-sintering agent deposition subsystem 44 (e.g., ink jet with nozzles, spray, etc), which is also a selective inhibition sintering mechanism that may also be referred to as the anti-sintering/de-binding agent jetting subsystem 22, may perform a pattern-wise deposition of an anti-sintering agent 26. For example, the subsystem 44 may spray the anti-sintering agent 26 onto the active material 12 in a pattern (e.g., a 2D pattern or shape) on the outer surface of the continuously rotating and outwardly growing cylinder. The anti-sintering jetting subsystem 22 may thus create an anti-sintering agent pattern on to the active material 12 that is continuously deposited on the surface of the cylinder 20 as the cylinder rotates in a continuous fashion (e.g., clockwise in FIG. 2). The active material 12 and the anti-sintering agent may be applied to the cylinder 20 sequentially. For example, the active material 12 may be applied or deposited onto the cylinder 20 first by the subsystem 42, and the anti-sintering agent 26 may be applied or deposited onto the cylinder thereafter by the anti-sintering jetting subsystem/print-head 22 as the cylinder rotates in a continuous, clockwise fashion, as indicated by the arrow in FIG. 2
[0046]The anti-sintering agent 26 may be applied to the active material to define boundaries between contiguous cured zones in the cylinder 20. The boundaries may be or may define de-binding regions that allow the 3D printed parts 28 to be separated from each other or separated from the rest of the material in the cylinder 20 (e.g., the active material that fills the space between the 3D printed parts 28). The anti-sintering agent, which is deposited onto the surface of the cylinder 20 as it turns and grows outwardly, may be composed of any material that, upon the application of heat (or other suitable physical/chemical mechanism) to sinter the 3D printed parts 28, may provide a de-binding/separation boundary 32 between the 3D printed parts and support material 46. This may occur by a mechanism of the formation of a weak or porous solid, such as by the dehydration and solidification of applied sol-gel slurry to a brittle ceramic solid that may dissolve into a powder and naturally fall away from the 3D printed parts 28.
[0047]In other words, during any time between ink deposition by the anti-sintering agent deposition subsystem 44 and early stages of sintering, the anti-sintering/de-binding agent 26 can undergo an optional activation process. For example, if the ink is a salt that is soluble when printed, it can be precipitated out by evaporating the solvent from the ink, and then thermally decomposed via a heater 38 (FIG. 2 (e.g., via a heater, heating element, laser, diode, oven)) into a ceramic particle as understood by a skilled artisan. Other anti-sintering ink materials may include an applied polymeric material (e.g., Poly-alkylenecarbonates) that may decompose or degrade with the application of heat, or by other chemical means. This would produce a boundary 32 to aid the separation of the 3D printed parts 28 and support structures 46 within the cylinder 20. The cylinder includes a core 24 (e.g., a starting core, a central core, a starting central core, etc.). Initially, the active material 12 may be transferred to the core 24 and later onto the outer surface of the cylinder as the cylinder is built, grown diametrically outward (i.e., grown by increasing the diameter spirally), etc. The core 24 may be attached to a rotating system (e.g., a rotating support axle, a motor that rotates the core, etc.).
[0048]As the active material 12 is continuously deposited on to the surface of the rotating and outwardly growing cylinder 20, the subsystems 42 and 44 may be continuously moved (translated) away from the axis of the rotating cylinder as its radius increases, so as to maintain an optimal distance (typically less than 10 millimeters) between the subsystems 42, 44 and the outer surface of cylinder in order to ensure reliable deposition of the active material and anti-sintering agents. In examples, the cylinder 20 may be translated rather than or in addition to subsystems 42 and 44. The relative spacing between subsystem 42 and 44 versus the build surface may also be maintained as understood by a skilled artisan. Moreover, the rotational speed of the cylinder 20 (e.g., number of revolutions per minute or RPM) may be continuously adjusted to maintain a fixed linear speed of the outer surface in order to maintain optimal deposition conditions for subsystems 42 and 44. In another example, the rotational speed of cylinder 20 may be kept fixed (i.e., not adjusted as above) and the print/deposition rate from subsystems 42 and 44 may be adjusted to track the speed of motion of the outer curved surface of the growing & continuously rotating cylinder.
[0049]In some related art examples, combinations of ceramic slurry, ceramic particles, and polymeric solutions may be used as the de-binding agent. A solution or slurry of a metal halide or other non-reacting salt may be used as a de-binding agent, where upon dehydration or exposure to an appropriate solvent (e.g., water) or other chemical, the salt crystals remaining will fall away or dissolve to separate the 3D printed parts 28 (with boundaries defined by the patterned anti-sintering agent from subsystem 44 and surrounding support structure. Once the revolving cylinder 20 with all the desired embedded 3D printed parts 28 is formed, the rotation of the cylinder may be stopped, and the pre-sintering stage parts may be separated along the boundaries 32 defined by the patterned de-binding agent, and subsequently sintered in a furnace. In another example, the entire cylinder 20 may be remov