EP3615250A1 - Frittage dans un four à micro-ondes de pièces obtenues par fabrication additive - Google Patents

Frittage dans un four à micro-ondes de pièces obtenues par fabrication additive

Info

Publication number
EP3615250A1
EP3615250A1 EP18790336.4A EP18790336A EP3615250A1 EP 3615250 A1 EP3615250 A1 EP 3615250A1 EP 18790336 A EP18790336 A EP 18790336A EP 3615250 A1 EP3615250 A1 EP 3615250A1
Authority
EP
European Patent Office
Prior art keywords
sintering
degrees
debinding
brown
powder
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP18790336.4A
Other languages
German (de)
English (en)
Other versions
EP3615250A4 (fr
Inventor
Gregory Thomas Mark
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Markforged Inc
Original Assignee
Markforged Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Markforged Inc filed Critical Markforged Inc
Publication of EP3615250A1 publication Critical patent/EP3615250A1/fr
Publication of EP3615250A4 publication Critical patent/EP3615250A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/001—Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
    • B22F10/10—Formation of a green body
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00—Processes of additive manufacturing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y70/00—Materials specially adapted for additive manufacturing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
    • F27B15/02—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B15/14—Arrangements of heating devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/04—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated adapted for treating the charge in vacuum or special atmosphere
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B5/00—Muffle furnaces; Retort furnaces; Other furnaces in which the charge is held completely isolated
    • F27B5/06—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B5/14—Arrangements of heating devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/12—Arrangement of elements for electric heating in or on furnaces with electromagnetic fields acting directly on the material being heated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D19/00—Arrangements of controlling devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D21/00—Arrangements of monitoring devices; Arrangements of safety devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
    • B22F10/10—Formation of a green body
    • B22F10/18—Formation of a green body by mixing binder with metal in filament form, e.g. fused filament fabrication [FFF]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
    • B22F10/40—Structures for supporting workpieces or articles during manufacture and removed afterwards
    • B22F10/43—Structures for supporting workpieces or articles during manufacture and removed afterwards characterised by material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
    • B22F10/40—Structures for supporting workpieces or articles during manufacture and removed afterwards
    • B22F10/47—Structures for supporting workpieces or articles during manufacture and removed afterwards characterised by structural features
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2207/00—Aspects of the compositions, gradients
    • B22F2207/11—Gradients other than composition gradients, e.g. size gradients
    • B22F2207/13—Size gradients
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
    • B22F2998/10—Processes characterised by the sequence of their steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/003—Apparatus, e.g. furnaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B33—ADDITIVE MANUFACTURING TECHNOLOGY
    • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y30/00—Apparatus for additive manufacturing; Details thereof or accessories therefor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • the part layer of green material may be deposited with a print head, and the portion of the first binder debound with a debinding head following a same trajectory as the print head.
  • a portion of the first binder is debound with a debinding head scanning across a part layer of green material. Following debinding all part layers of green material of the part, the entire part may be sintered.
  • the brown material may be further debound.
  • the entire part may be sintered.
  • the second binder may be pyrolysed during sintering to leave a loose layer of the release powder.
  • a method of reducing distortion in an additively manufactured part may include forming a shrinking or densification linking platform of successive layers of composite, the composite including a metal particulate filler in a debindable matrix.
  • the debindable matrix may include different components so as to be a one or two stage binder.
  • Shrinking or densification linking supports are formed of the same composite above the shrinking platform.
  • a desired part of the same composite is formed upon the shrinking platform and shrinking supports, substantially horizontal portions (e.g., overhangs, bridges, large radius arches) of the desired part being vertically supported by the shrinking platform (e.g., directly, via the shrinking supports, or via a release layer).
  • a method of reducing distortion in an additively manufactured part includes depositing, in successive layers, a shrinking platform formed from a composite, the composite including a metal particulate filler in a debindable matrix, and depositing shrinking supports of the same composite and above the shrinking platform.
  • An open cell structure including interconnections is deposited among cell chambers in the shrinking supports.
  • a desired part is deposited upon the shrinking platform and shrinking supports.
  • the shrinking platform, shrinking supports, and desired part are exposed to a fluid debinder to form a shape-retaining brown part assembly.
  • the fluid debinder is penetrated into the open cell structure to debind the matrix from within the open cell structure.
  • the shape-retaining brown part assembly is sintered to shrink at a rate common throughout the shape-retaining brown part assembly.
  • a method of reducing distortion in an additively manufactured part includes depositing, in successive layers, a shrinking platform formed from a composite, the composite including a metal particulate filler in a debindable matrix.
  • Shing supports of the same composite may be deposited above the shrinking platform.
  • parting lines as separation clearances may be formed dividing the shrinking supports into fragments separable along the separation clearances.
  • the fragments are formed as blocks separable from one another along a separation clearance contiguous within a plane intersecting the shrinking supports.
  • a lateral support shell of the same composite as the shrinking supports may be formed to follow a lateral contour of the desired part.
  • the lateral support shell may be connected to the lateral contour of the desired part by forming separable attachment protrusions of the same composite between the lateral support shell and the desired part.
  • parting lines may be formed dividing the lateral support shell into shell fragments separable along the parting lines.
  • the matrix may be debound sufficient to form a shape-retaining brown part assembly including the shrinking platform, shrinking support columns, lateral support shell, and desired part.
  • the lateral support shell may be separated into the shell fragments along the parting lines.
  • the shell fragments may be separated from the desired part.
  • a polymer-including material is deposited along a first contour tool path to form a perimeter path of a layer of the green part and to define an interior region within the perimeter path.
  • the material is deposited based on a second contour tool path to form an adjacent path in the interior region adjacent the perimeter path, The deposition of the adjacent path in the second direction stresses polymer chains in the material in a direction opposite to stresses in polymer chains in the material in the perimeter path, and reduces part twist caused by relaxation of the polymer chains in the part.
  • one of a start of deposition or a stop of deposition is adjusted to be located within the interior region of the layer.
  • the locations of the start point and the stop point define an arrangement selected from the group consisting of an open-square arrangement, a closed-square arrangement, an overlapped closed-square arrangement, an open-triangle arrangement, a closed-triangle arrangement, a converging- point arrangement, an overlapped-cross arrangement, a crimped- square arrangement, and combinations thereof.
  • a contour tool path between the start point and the stop point further defines a raster path that at least partially fills the interior region.
  • a digital solid model (e.g., 3D mesh or 3D solid) of the part is received, and the digital solid model is sliced into a plurality of layers.
  • a perimeter contour tool path is generated based on a perimeter of a layer of the plurality of layers, wherein the generated perimeter contour tool path defines an interior region of the layer.
  • An interior adjacent path is generated based on the perimeter contour tool path within the interior region.
  • a debindable composite is extruded including sinterable powder in a first direction based on the perimeter contour tool path to form a perimeter of the debindable composite for the layer.
  • a tool path is generated with a computer. Instructions for the generated tool path are transmitted to the controller, and a debindable composite is deposited from the deposition head while moving the deposition head along the generated tool path to form a perimeter path of a layer of the part.
  • the perimeter path may include a first contour road portion, and a second contour road portion, each of the first contour road portion and the second contour road portion crossing one another with an even number of X-patterns, forming an even number of concealed seams for the layer.
  • a debindable composite including a binder and a sinterable powder is deposited in a first direction about a perimeter.
  • An interior path is deposited along the perimeter in a direction retrograde the first direction. The deposition of the adjacent path stresses long-chain molecules in the binder in a direction opposite to stresses in the perimeter path, and reduces part twist during sintering caused by relaxation of the long-chain molecules in the part.
  • a composite material is fed including a binder matrix and a sinterable powder.
  • Successive layers of a wall of a part are deposited to form a first access channel extending from an exterior of the part to an interior of the part.
  • Successive layers of honeycomb infill in the interior of the part are deposited to form a distribution channel connecting an interior volume of the honeycomb infill to the first access channel.
  • the binder matrix is debound (e.g., dissolved) by flowing a debinding fluid through the first access channel and the distribution channel within the interior volume of the honeycomb infill.
  • a metal material including a binder matrix and sinterable powdered metal having an average particle diameter lower than 8 micrometers are fed, the metal material having a first sintering temperature.
  • a ceramic material is fed including a same binder matrix and a sinterable powdered ceramic, the ceramic material including a mixture of a first ceramic having a higher sintering temperature than the metal material with a second ceramic having a lower sintering temperature than the metal material, the ceramic material substantially matching a shrinking behavior of the metal material and having a second sintering temperature substantially in a same range as the first sintering temperature.
  • Layers of the metal material are formed by deposition upon a prior deposition of layers of the metal material, and layers of the metal material are formed by deposition upon prior deposition of layers of the ceramic material. At least a portion of the binder matrix is debound from each of the metal material and ceramic material.
  • a part so formed from the metal material and ceramic material is heated to the first sintering temperature, thereby sintering the first material and the second material.
  • Successive layers of a wall of a part are deposited to form a first access channel extending from an exterior of the part to an interior of the part, as well as to form a distribution channel connecting an interior volume of the honeycomb infill to the first access channel.
  • a binder matrix retaining sinterable powder is debound by flowing a debinding fluid through the first access channel and the distribution channel within the interior volume of the honeycomb infill.
  • a brown part integrally formed from a first powder having a first sintering temperature in a powder bed is placed within a crucible, the powder bed including a second powder having a second sintering temperature more than 300 degrees C higher than the first sintering temperature.
  • the second powder is agitated to fill internal cavities of the brown part. A weight of an unsupported portion of the brown part is continually resisted with the second powder.
  • the brown part is sintered at the first temperature without sintering the second powder to form a sintered part. The sintered part is removed from the powder bed.
  • At least a portion of the binder matrix from each green layer of first material is debound, to debind each green layer into a corresponding brown layer.
  • the part is placed integrally in a powder bed within a crucible, the powder bed including a third powder having a third sintering temperature more than 300 degrees C higher than the first sintering temperature.
  • the third powder is agitated to fill internal cavities among the brown layers, and a weight of an unsupported portion of the brown layers is continually resisted with the third powder.
  • the part is sintered at the first temperature without sintering the third powder to form a sintered part, and the sintered part is removed from the powder bed.
  • the desired part may be optionally tacked to the densification linking platform with small-cross sectional area (e.g., less than 1/3 mm diameter) connections of the metal composite material that penetrate the ceramic release layer vertically in order to ensure that the part shrinks in the same geometric manner as the densification linking platform that it is resting on.
  • the densification linking platform is optionally formed having a cross- sectional area in the shape of a convex shape (a polygon or curved shape without concavities), and/or in a symmetric shape having a centroid aligned with that of the part above.
  • the densification linking platform tends to densify and shrink in a regular or predictable manner due to its simple geometry, and if as the desired part is connected to the raft it decreases geometry specific part distortion that arises from the friction forces between the desired part and the
  • Fig. 17 is a depiction of elastic modulus vs. temperature showing an appropriate range for maintaining a sinterable additive manufacturing feedstock in a filament to permit spooling and transportation.
  • Figs. 37A-37H, 37J are schematic views representing seam and joint interaction in deposition walls and honeycombs.
  • Figs. 38A and 38B show FDM/FFF nozzle assemblies in cross section.
  • Fig. 40 shows a MIM material extrusion nozzle assembly in cross-section.
  • overhanging or jutting portions of a part may require removable and/or soluble and/or dispersing supports underneath to provide a facing surface for deposition.
  • removable and/or soluble and/or dispersing supports may also be helpful to prevent deformation, sagging, during mid- or post-processing - for example, to preserve shape vs. drooping or sagging in potentially deforming environments like high heat.
  • FIGs. 1A, IB through 40 in general show a Cartesian arrangement for relatively moving each print head in 3 orthogonal translation directions, other
  • respective filament feeds 1830 may be controlled by the controller 20 to supply one or more extrusion printheads 18, 18a, 18b, 1800.
  • a printhead board 110 optionally mounted on the compound printhead and moving therewith and connected to the main controller 20 via ribbon cable, breaks out certain inputs and outputs.
  • the temperature of the ironing tip 726 may be monitored by the controller 20 by a thermistor or thermocouple 102; and the temperature of the heater block holding nozzle of any companion extrusion printhead 1800 may be measured by respective thermistors or thermocouples 1832.
  • Fig. 3 depicts a flowchart showing a printing operation of the printers 1000 in Figs. 1A through 40.
  • Fig. 3 describes, as a coupled functionality, control routines that may be carried out to alternately and in combination use the co-mounted FFF extrusion head(s) 18, 18a, and/or 18b and/or a fiber reinforced filament printing head as in the CFF patent applications.
  • step S 10 determines in step S 10 whether the next segment to be printed is a fiber segment or not, and routes the process to S 12 in the case of a fiber filament segment to be printed and to step S 14 in the case of other segments, including e.g., base (such as a raft or shrinking/densification linking platform), fill (such as extruded or jet-bound model material, release material, or placeholder material), or coatings (such as sprayed or jetted release material).
  • base such as a raft or shrinking/densification linking platform
  • fill such as extruded or jet-bound model material, release material, or placeholder material
  • coatings such as sprayed or jetted release material
  • segment as used herein corresponds to "toolpath” and "trajectory”, and means a linear row, road, or rank having a beginning and an end, which may be open or closed, a line, a loop, curved, straight, etc.
  • a segment begins when a printhead begins a continuous deposit of material, and terminates when the printhead stops depositing.
  • All continuous fiber structures discussed herein, e.g., sandwich panels, shells, walls, reinforcement surrounding holes or features, etc., may be part of a continuous fiber reinforced part.
  • the 3D printer herein discussed with reference to Figs. 1A-40 may thereby deposit either fill material (e.g., composite with a debindable matrix containing metal, ceramic, and/or fibers), soluble (e.g., "soluble” also including, in some cases, debindable by thermal, pyrolytic or catalytic process) material, or continuous fiber.
  • fill material e.g., composite with a debindable matrix containing metal, ceramic, and/or fibers
  • soluble e.g., "soluble” also including, in some cases, debindable by thermal, pyrolytic or catalytic process
  • Commercially valuable metals suitable for printing include aluminum, titanium and/or stainless steel as well as other metals resistant to oxidation at both high and low temperatures (e.g., amorphous metal, glassy metal or metallic glass).
  • a thin sheet of metal - e.g., a raft - may be printed that will uniformly shrink with the part, and provide a "shrinking platform” or “densification linking platform” to hold the part and the related support materials in relative position during the shrinking or densification process.
  • green body supports may be printed from a thermal, soluble, pyrolytic or catalytically responsive material (e.g., polymer or polymer blend) and leave behind only removable byproducts (gases or dissolved material) when the green body supports are removed.
  • green body supports may optionally be printed from a matrix of thermal, soluble, or catalytic debindable composite material (e.g., catalytic including Polyoxymethylene - POM/acetal) and high melting point metal (e.g., molybdenum) or ceramic spheres, and leave behind a powder when debound.
  • Protrusions PI described herein, facing vertical, horizontal, or other direction, may be formed to be snapped by sharp or pulsed impact(s), e.g., having a contact surface cross-section of less than 1 ⁇ 2 mm.
  • the printing of green body supports GS l is continued upwards, in this case providing printing support to optionally angled (e.g., 10-45 degrees from vertical), sparse and/or branching sintering (e.g., shrinking or densification linking) supports SS I printed to later provide sintering support for an overhanging or cantilevered portion OH1, as well as building up a green body support GS 1 for printing support for the same overhanging or cantilevered portion OH1.
  • debinding includes removing a first binder component from the model material using a thermal process, a solvent process, a catalysis process, or a combination of these, leaving a porous brown body structure ("DEBINDING”), and may optionally include dissolving, melting, and/or catalyzing away the green body supports ("SUPPORT REMOVAL 1").
  • intervening between the shell structure and/or sintering supports are protrusions or ridges of model material interconnecting these to the part.
  • the same or a similar separation material intervenes between the brown body (e.g., as brown body assembly) and the build plate.
  • the brown body e.g., as a brown body assembly
  • the second stage debinding component of the model material may be pyrolysed during sintering (including, for example, with the assistance of catalyzing or other reactive agents in gas or otherwise flowable form).
  • a sintered body (e.g., as a sintered body assembly) can be removed from the sintering oven.
  • the supporting shell structure and the sintering supports can be separated or broken up along parting lines, and/or along separation layers, and or by snapping or flexing or applying an impact to protrusion connections, tacks or other specifically mechanically weak structures.
  • the separation layers are powderized and are readily removed. Should the green body supports be formed from the separation material, the green body supports are similarly powderized and may be readily removed.
  • Fig. 8 shows a variation of a part printed as in Fig. 4 or Fig. 6.
  • the part shown in Fig. 8 includes four overhanging or cantilevered sections OH2-OH5.
  • Overhang OH2 is a lower, thicker overhang under a cantilevered, thinner overhang OH3. While the lower overhang OH2 may in some cases be printed without sintering supports or even green- body supports as a self-supporting cantilever, it is below the long cantilever overhang OH3, which is sufficiently long, thin, and heavy that it may require both green body supports and sintering supports.
  • Overhang OH4 is a downward-leaning overhang, which generally must be printed with at least green body supports (because its lowest portion is otherwise unsupported, i.e., in free space, during printing) and in a form difficult to remove sintering supports printed beneath without drafting or parting lines (because rigid sintering supports would become locked in).
  • Overhang OH5 is a cantilever including a heavy block of model material, which may require both green body and sintering support.
  • the part shown in Fig. 8 includes an internal, e.g., cylindrical volume V2, from which any necessary sintering supports must be removed via a small channel.
  • the 3D shape of the part 14 of Fig. 8 is shown in Figs. 12 and 13.
  • the sintering supports SS3, SS4, and SS5 of Fig. 8) may be directly tacked (e.g., "tacked” may be contiguously printed in model material, but with relatively small cross- sectional area) to a raft RA2, to the part 14a, and/or to each other.
  • the sintering supports SS2 may be printed above, below, or beside a separation layer, without tacking. As shown, the sintering supports SS2 are removable from the orthogonal, concave surfaces of the part 14a.
  • similar sintering (e.g., shrinking or densification linking) supports SS3 are printed beneath the downward-leaning overhang OH4, and beneath heavier overhang OH5.
  • a parting line PL e.g., formed from separation material, and/or formed from a mechanically weakened separation structure (e.g., printing with a nearly or barely abutting clearance as described herein, or printing with a wasp- waisted, pinched, or perforated cross-section, or the like), or a combination of these (or, optionally, a combination of one or both of these with green body support material having little or no ceramic or metal content, should this be separately printed).
  • These material or mechanical separation structures, facilitating removal of the sintering supports may be similarly printed into the various sintering supports shown in Figs 4-7, 9, and throughout.
  • Fig. 9 is substantially similar to Fig. 8, but shows some variations in structure. Both variations in printing with and without reinforcement are shown, e.g., while Fig. 9 shows reinforcement structures CSPl therein, the remaining variant structures in the solid bodies, supports, and separation layers of Fig. 9 are optionally applicable to the non- reinforced structures of Fig. 8 and throughout.
  • a monolithic, form-fitting shell SH3 is printed of model material, separated from the part 14 by either release or separation layers SL2 and/or protrusions PI.
  • the monolithic shell SH3 has small open cell holes throughout to lower weight, save material, and improve penetration or diffusion of gases or liquids for debinding.
  • open cell holes may optionally be connected to access and/or distribution channels for debinding fluid penetration and draining, e.g., any of the structures of Figs. 25-31 may form, be formed by or be combined with the open cell holes.
  • This shell SH3 may surround the part 14 if sufficient parting lines or release layers are printed into the shell SH3 (e.g., instead of the structures SH4 and SH5 to the left of the drawing, a similar structure would be arranged), and if sufficiently form following, act as a workholding piece.
  • the release layer may be very thin, e.g., one 3D printing layer.
  • the release layer - having already had a first stage binder removed - is essentially powderized as the temperature is insufficient to sinter or diffusion bond the ceramic material. This enables the untacked sintering supports to be easily removed after sintering.
  • a role of tacked and untacked of sintering supports is to provide sufficient supporting points versus gravity to prevent, or in some cases remediate, sagging or bowing of bridging, spanning, or overhanging part material due to gravity.
  • the untacked and tacked sintering supports are both useful. Brown bodies, in the sintering process, may shrink by atomic diffusion, e.g., uniformly about the center of mass or centroid of the part. In metal sintering and some ceramics, typically this is at least in part solid-state atomic diffusion.
  • support or support structures or shells may be formed from model material following the form of the part in a lateral direction with respect to gravity, e.g., as shown in certain cases in Figs. 4-9.
  • the model material shells may be printed tacked to the base raft (which may be tacked to the part). They may be printed integral with, but separable from the base raft.
  • the base raft may be separable together with the model material shells.
  • These support structures may be offset from or substantially follow the lateral outer contours of the part, or may be formed from primitive shapes (straight or curved walls) but close to the part.
  • Fig. 10 shows the sintered body structure of Fig. 4 in top views
  • Fig. 11 shows a variation for the purpose of explanation.
  • support shells or other structures may be printed with separation or parting lines or layers between portions of the support structure.
  • the separation or parting lines or layers may be any separation structure described herein, including those described between the part and support structure.
  • Fig 11 crenellated or formed as a box joint (e.g., similar to PL-3 in Fig. 11), so as to resist separation, in some cases other than in a transverse direction. Parting lines may be printed nearly almost cut through the support shell (e.g., PL-2 in Fig. 11). Note that Fig 11 is depicted without protrusions PI, i.e., with only separation layers SL2 in the vertical direction, and largely monolithic, surrounding support shell SH.
  • Some soluble-pyrolysable binder combinations include polyethylene glycol (PEG) and polymethyl methacrylate (PMMA) (stearic acid optional, PMMA in emulsion form optional); waxes (carnauba, bees wax, paraffin) mixed with steatite and/or polyethylene (PE); PEG, polyvinylbutyral (PVB) and stearic acid.
  • Some pyrolysable second stage binders include: polyolefin resins polypropylene (PP), high-density polyethylene (HDPE); linear low-density polyethylene (LLDPE), and polyoxymethylene copolymer (POM).
  • Figs. 14 -16 differ in the orientation of the spools and the driving system of the filament.
  • spools are horizontally arranged on a lazy-susan type holder that permits rotation, and the filament drivers (including their, e.g., elastomer drive wheels) are arranged at a convenient location mid-way between the spools and the Bowden tubes. This mid-drive arrangement is suitable if the filament is not softened to an elastomer range in the heating chamber HC1.
  • Fig. 14 differ in the orientation of the spools and the driving system of the filament.
  • spools are horizontally arranged on a lazy-susan type holder that permits rotation
  • the filament drivers including their, e.g., elastomer drive wheels
  • debinding rather than debinding an entire part after printing, at least a portion of the debinding is performed while or after printing layers of the part and/or supports.
  • debinding may be performed by solvent, heating and/or applying vacuum evaporation or sublimation, catalysis, or other means of removing or decomposing a binder, in each case removing at least a part of the matrix material for subsequent processes such as sintering.
  • the first stage binder need only be retained so long as is necessary or useful for adhesion and shape retention versus these forces. In the case of molding, this would be at least until after the green part is formed, and in most cases until after the green part is removed from the mold. In the case of 3D printing, depending on the debinding system and binder material properties, the binder can be removed substantially immediately after deposition (e.g., if some first stage binder remains, and/or a second stage binder or other component retains structural integrity versus gravity and printing/processing forces). If sufficient structural integrity remains, a debinding head may continuously debind "behind" a deposited road that has solidified, or even one that has not yet solidified or cooled to solidification.
  • partial debinding may accelerate the overall process by increasing the available surface area for whole part debinding.
  • a partial debinding sweep may be conducted upon a printed layer or set of layers, temporarily exposing some surfaces to debinding fluid (gas or liquid).
  • each of the print heads 180, 180a is shown in Fig. 18, each of the print heads 180, 180a
  • a debinding head DBHl for a solvent or catalytically debindable first material may include a spray, droplet, or jet of solvent or catalyst fluid, aerosol, or gas (optionally warmed, heated, or recycled).
  • the debinding head DBHl may include or add a waste or fume collection vacuum or extractor FEl.
  • An additional head-borne or whole chamber process may accelerate (e.g., by gas flow, vacuum, or heat) removal of the debinding solvent following the debinding step.
  • the apparatus feeds a first filament including a binder matrix and sinterable spherized and/or powdered first material having a first sintering temperature, e.g., the model material.
  • a green layer of first material is deposited or partially deposited, at least in some cases upon a brown layer of first material that has already been debound. In other cases it may be deposited upon a layer of sintering support or green body support material. At least a portion of the binder matrix is then removed from the green layer or portion thereof of first material to debind each green layer into a corresponding brown layer.
  • the part is a brown part and may be sintered the part at the first sintering temperature.
  • Green layers of model material are deposited upon a by deposition upon a build plate or prior deposition of a brown layer (previously debound layer-by-layer as discussed herein) or separation material, and at least a portion of the binder matrix from each green layer is debound to convert that layer or layers into a corresponding brown layer.
  • Layers of the separation material are deposited upon a build plate or first or second material, and layers of first material by deposition upon prior deposition of model material or separation material as appropriate, to permit sintering supports to be later removed or build up separation material.
  • the part may be sintered at the first sintering temperature but below the second material.
  • binder compositions may contain a first stage binder of 50-70 vol.-% of hydrocarbon solvent-soluble wax or fatty acid components.
  • the first stage binder may include low-melting binder components, such as higher alkanes, petrolatum, paraffin waxes and fatty acid esters and other compatible liquid plasticizers to increase the flexibility of the polymeric binder system. These components may improve spool winding on small-diameter spools and to resist impact during handling and shipping (including in colder ambient temperatures, e.g., below freezing), and may also increase the rate of extraction during the solvent debinding step.
  • the alkane, ester or its blend or a blend with a medium-size fatty acid has a measurable vapor pressure at ambient or higher temperature, but below the melting or dissolution point of the polymer binder, it can conveniently be removed from the blend by simply exposing the green part to low pressure environment, preferable at an elevated temperature, but at least initially at a temperature lower than the melting or dissolution temperature of the polyolefin binder.
  • the sublimation or evaporation of the binder component will generate microporosity in the binder phase of the green part, thus facilitating subsequent thermal debinding of the green part and preventing its dimensional distortion due to the expansion of the trapped gaseous decomposition products.
  • the volatile binder component should have a vapor pressure at ambient temperature low enough so as not to vaporize to a significant degree during normal handling and use of the material in the open atmosphere. Volatile binder loss during long-term storage may be effectively prevented by storing the pellets, extruded filament or the like in sealed gas- and organic vapor-impermeable multilayer packaging.
  • Polyolefin binders include polyethylene, polypropylene or their copolymers, as described with a wax component including a proportion of naphthalene, 2-methylnaphthalene. Sublimation of naphthalene during storage can be prevented by using an appropriate vapor impermeable packaging material such as an aluminum-polymer laminate, yet naphthalene can be relatively rapidly removed from the green part by moderate heating under low pressure, for example, in a vacuum oven at temperatures below the melting point of naphthalene and thus remove it without melting the binder phase.
  • the fine powder preferably alumina, or the like
  • the fluidized bed of fine powder provides either or both of resistance or buoyancy.
  • the system may alternate between fluidized state and a non-fluidized state, and/or the flow rate of the fluid (gas) can further be modulated to achieve varying degrees of powder mobility.
  • the powder in the bed continually resists weights of unsupported portions of the brown part (e.g., unsupported portions 23-12).
  • the powder in order to promote flow, and prevent entrapment of powder in orifices and compartments of the part, the powder may be substantially spherically shaped. Further, the powder bed can be fluidized to reduce viscosity through fluid inlet and/or distributor plate 23-9. Further optionally, the crucible 23-1 is positioned in a substantially gas-tight chamber 23-7 that seals the furnace to prevent the ingress of oxygen - which is usually detrimental to the physical properties of metallic powders during the sintering process. A refractory lining 23-5 is shown, which isolates the high- temperature crucible 23-1 from the (preferably stainless steel) walls of the furnace.
  • Fluidizing e.g., creating a fluidized bed
  • the initial ramp before necking
  • a hood guard 23-11 shaped to exclude powder directly above the contour of the part may reduce or eliminate the weight of a hood or stagnant cap of non-fluidized powder that may reside above the part.
  • This hood or stagnant cap may reduce overall buoyancy or buoyancy in particular locations (see, e.g.,
  • the hood guard 23-11 may also serve the role of a supporting hanger 23-10, and the part may be suspended via the hood guard 23-11.
  • the hood guard 23-11 may be "sacrificial", e.g., generated during printing but disposed of or recycled following sintering.
  • a gas outlet 8 may allow the exhaust of the sintering process to be removed from the oven.
  • the outlet 8 may be used to pull a vacuum on the furnace (e.g., use a vacuum pump to lower the ambient pressure toward vacuum) to remove a significant portion of the oxygen from the environment prior to flowing the inert or reducing gas for sintering and/or fluidizing the bed.
  • Flowing gas through the powder agitates the powder in addition to fluidizing the powder.
  • a fluidized bed may allow the part to contract or shrink during sintering without the powder exerting any resistance.
  • Fig. 23B shows one overall schematic of the process.
  • the part 14, together with at least its green body supports is printed in a 3D printer as described.
  • the green body including all of these, optionally still bound to a higher melting temperature material - ceramic or other material build plate 16, may be transferred to a debinding chamber (optionally, the debinding chamber is integrated in the 3D printer or vice versa).
  • a debinding chamber optionally, the debinding chamber is integrated in the 3D printer or vice versa.
  • green body supports may be removed during debinding. Accordingly, as shown in Fig.
  • debinding STG-2A debinds the model material, leaving a porous brown body structure ("DEBINDING"), and may optionally include dissolving, melting, and/or catalyzing away the green body supports ("SUPPORT REMOVAL").
  • sintering supports may remain even with the powder bed or fluidized powder bed technique, but may be, e.g., placed in fewer locations or support only longer spans.
  • a brown body is transferred to a sintering chamber or oven (optionally combined with the printer and/or debinding chamber).
  • the sintering chamber or oven is filled with a powder, as described, that will not sinter at the sintering temperature of the brown body (e.g., alumina powder surrounding n aluminum or steel brown body to be sintered.
  • a powder as described, that will not sinter at the sintering temperature of the brown body (e.g., alumina powder surrounding n aluminum or steel brown body to be sintered.
  • the brown body uniformly shrinks by approximately 20%, closing internal porous structures in the brown body by atomic diffusion.
  • the alumina powder bed does not sinter, but either resists sag and slumping of spans and overhangs, and/or provides buoyancy for spans and overhangs.
  • the powder and part may be more uniformly heated by the circulation of fluidizing with a gas.
  • a sintered body can be removed from the sintering oven. Some alumina powder may remain in internal cavities and can be washed away STG-4A and/or recovered.
  • a fused silica tube used for sintering may be formed from very pure silica (e.g., 99.9% Si02), and a crucible for holding the workpiece or part may be made from a similar material.
  • the optical transparency of fused silica may correlate to its microwave transparency and/or its coefficient of thermal expansion.
  • a more optically transparent fused silica may have a lower degree of crystallization, and the crystal structures may scatter both light and RF.
  • Penetration depth (d) is the distance from the surface of the material at which the field strength reduces to 1/e (approximately 0.368) of its value at the surface. The measurements in this table are taken at or around 20 degrees C. As temperature increases, the penetration depth tends to decrease (e.g., at 1200 degrees C, the penetration depth may be 50-75% of that at 20 degree C).
  • An atmosphere after initial debinding to clean away lubricants or remnant binder, but before sintering may be oxidizing (nitrogen saturated with water or with added air) through water to high temperature metal for example, optionally deposited with a similar (primary) matrix or binder component to the model material. After sintering, the release layer may become highly saturated, or by use of air additions. Temperatures may be 200- 750C with dew point of 0 to 25C.
  • An atmosphere in sintering, especially for stainless steels or some tool steels, may be highly reducing, e.g., pure Hydrogen, with dew point of -20 to -40C.
  • Nitrogen/hydrogen mixtures (3-40%) or Nitrogen/ammonia may be used, and hydrocarbons may add back surface carbon or prevent its loss.
  • Atmospheres in post- sintering may be cooling (at very low Oxygen levels, e.g., 10-50ppm) at a rate of, e.g., 1- 2 degrees C per second, and/or may be recarbonizing with a hydrocarbon-including atmosphere (forming some CO) at e.g., 700-1000°C range for steels.
  • one candidate microwave generator 113-1 for assisting or performing sintering may generate 2.45 GHz frequency microwaves at a power output of 1-10 kW.
  • the generator, oscillator or magnetron 113-1 may be connected to a waveguide 113-2 with an open exit.
  • a circulator 113-3 and dummy load 113-4 e.g., water
  • a tuner device may change the phase and magnitude of microwave reflection to, e.g., cancel or counter reflected waves.
  • one technique and material variation method may involve supplying a material (pellet extruded, filament extruded, jetted or cured) containing a removable binder as discussed herein (two or one stage) and greater than 50% volume fraction of a powdered metal having a melting point greater than 1200 degrees C
  • the powdered metal may have which more than 50 percent of powder particles of a diameter less than 10 microns, and advantageously more than 90 percent of powder particles of a diameter less than 8 microns.
  • the average particle size may be 3-6 microns diameter, and the substantial maximum (e.g., more than the span of +/-3 standard deviations or 99.7 percent) of 6-10 microns diameter.
  • the particle size distribution may be bimodal, with one mode at approximately 8 micron diameter (e.g., 6-10) microns and a second mode at a sub-micron diameter (e.g., 0.5 microns). The smaller particles in the second mode assist in early or lower temperature necking to preserve structural integrity.
  • the fused tube 113-5 may be sealed by a fused silica plug or plate 113-6 (and/or a refractory or insulating plug or plate).
  • the internal air may be evacuated, and may be further replacing internal air with a sintering atmosphere (including vacuum, inert gas, reducing gas, mixtures of inert and reducing gas).
  • Microwave energy may be applied from the microwave generator 113-1 outside the sealed fused tube to the brown part. In this case, because the small particles may lower the sintering temperature, the brown part of steel may be sintered in this furnace at a temperature lower than 1200 degrees C.
  • the material having a removable binder and greater than 50% volume of a powdered steel (or other metal) is supplied with more than 50 percent of the powder particles have a diameter less than 10 microns, advantageously more than 90 percent having a diameter equal to or less than substantially 8 microns.
  • the material may be additively deposited with a nozzle having an internal diameter smaller than 300 microns, which provides fine detail but is 10-20 times the diameter of the larger particles of the powder (preventing jamming).
  • the binder is removed to form a brown body and the brown part loaded into the fused tube, e.g., amorphous silica, having a thermal expansion coefficient lower than lxlO-6/°C, and the is sealed and the atmosphere therein replaced with a sintering atmosphere.
  • Radiant energy e.g., radiant heat from passive or active susceptor rods or other resistive elements, and/or microwave energy
  • Heating elements e.g., the resistive heater and/or susceptor 113-7 and/or the microwave generator 113-1) are placed outside the fused tube 113-5 and outside any sintering atmosphere within the fused tube 113-5 so as not to contaminate the sintering atmosphere.
  • a controller e.g., 113-12
  • the controller 113-12 may be operatively connected to the heating elements 113-7 and/or 113-1 and the internal atmosphere regulator.
  • the controller 113-12 may sinter first material (aluminum) brown parts within a first sintering atmosphere ( ⁇ 0.001 percent oxygen in nitrogen) at first sintering temperature higher than 500 degrees C and less than 700 degrees C.
  • the controller may sinter second material (stainless steels) brown parts within a second sintering atmosphere (e.g., inert or reducing atmosphere) at a second sintering temperature higher than 1000 degrees C but less than 1200 degrees C.
  • a second sintering atmosphere e.g., inert or reducing atmosphere
  • An (optical) pyrometer 113-13 may be used to observe sintering behavior through the seal.
  • the oven 113 is held in an appropriate microwave reflective enclosure 113-14 and is insulated with appropriate insulation 113-15 and refractory material 113-16.
  • interconnected channels may be printed between infill cells or honeycomb or open cells in the part interior, that connect to the part exterior, and a shell (including but not limited to a support shell) may have small open cell holes, large cells, or a honeycomb interior throughout to lower weight, save material, and improve penetration or diffusion of gases or liquids (e.g., fluids) for debinding.
  • a shell including but not limited to a support shell
  • These access channels, open cells, and other debinding acceleration structures may be printed in the part or supports (including shrinking/densification supports or shrinking/densification platform). All or some of the channels/holes may be sized to remain open during debinding (including but not limited to under vacuum), yet close during the
  • the 3D printer may deposit a wall or successive layers of a wall, the wall having an access channel extending from an exterior of the part to an interior of the part.
  • the access channel permits fluid to enter the interior (e.g., between positive and negative contours of a cross-section of the part). As shown, e.g., in Figs. 26A-31, it is not necessary that the entirety of the interior of a part be interconnected to reduce the debinding time.
  • a wall-penetrating access channel and interconnected honeycomb may be connected to route fluid to a location within a specified distance of the deepest interior region of a part; or to set a specified distance of a wall or walls of the part to a nearest fluid-filled chamber.
  • the routing channels CHI may connect during debinding to a matching one, several or array of debinding fluid supply channels (e.g., as shown in Fig. 25). Alternatively, or in addition, fluid flow through the routing channels may be promoted via circulation, heating, or agitation in an immersed bath of debinding fluid. Agitation may be forced fluid, mechanical, inductive, magnetic, or the like.
  • the raft or shrinking platform RA1 is otherwise similar to that discussed with reference to Fig. 5B.
  • the channels CH2 and CH3 are angled through infill and walls of the part, which can increase the length of a channel and/or decrease the number or degree of turns in the fluid flow. In this manner - by changing the length or straightness of channels CH2 or CH3 - fluid flow throughout the channels CH2 and CH3 part can be balanced for evenness or
  • Figs. 27 and 28 show a side sectional view, substantially similar in description to Figs. 4, 6, 8 and 9 (common reference numbers being similarly described) , in which the honeycomb cavities/infill are formed as vertical, columnar prism shapes.
  • Distribution channels CH3 e.g., approximately 20 shown
  • the distribution channels CH3 are shown distributed about many layers to interconnect some, many, or all infill or honeycomb cells. No channels are shown extending into overhangs OH2 or OH4, which may not be thick enough to need additional debinder fluid flow.
  • sintering support or form-fitting shell SH3 may also be filled with infill cells, and may or may not additionally include channels access or distribution channels CH2 or CH3 (none shown in Fig. 27).
  • Fig. 27 does not show the optional access channel CH2, i.e., showing the case where the distribution channels CH3 by themselves increase debinding speed.
  • the access channels CH2 shown in other Figures and described herein may be applied to the structure of Fig. 27.
  • Fig. 28 shows access channels CH2 which provide ingress and egress for fluid flow into the distribution channel CH3 interconnected honeycomb cells.
  • Fig. 29 shows a side sectional view, substantially similar in description to Figs. 4, 6, 8, 9, 27, and 28 (common reference numbers being similarly described) in which the distribution channels cavities/infill are formed in an aligned, and/or angled, manner throughout the columnar prism shapes. As discussed, changing the diameter, length and/or straightness of the channels CH3, or depositing obstacles or baffles within them, may increase or decrease resistance to flow.
  • the sintering support or shell structures SH3 and SH4 also include access channels CH2 to permit fluid flow therethrough (both an inlet and outlet).
  • Fig. 30 shows a side sectional view, substantially similar in description to Figs. 4, 6, 8, 9, 27, 28 and 29 (common reference numbers being similarly described) in which the distribution channels CH3 throughout cavities/infill are formed in an aligned, and/or angled, manner throughout cellular (octahedral as one example) polyhedron stacked shapes, and in which access channels CH2 are provided in three locations in this section.
  • wall thicknesses may be maintained substantially constant (e.g., within 5% of thickness) throughout - e.g., the exterior wall or shell thickness of the part being the same as the interior walls of the infill, and/or either being the same as walls forming distribution or access channels, and/or any of these being the same thickness as walls forming the sintering support structures or shrinking platform.
  • Fig. 31 shows a side sectional view, a closer view of the exemplary part of the process diagram of Fig. 25, substantially similar in description to Figs. 4, 6, 8, 9, 27, 28 29, and 30 (common reference numbers being similarly described), in which the distribution channels CH3 throughout cavities/infill are formed in an aligned, and/or angled, manner throughout cellular prism shapes, and in which access channels CH2 are provided in two locations in this section.
  • the distribution channels pass near to, adjacent to, or proximate to the portion of the part interior farthest from, deepest within, or thickest TH with reference to a negative or positive contour or wall of the part.
  • the uppermost region of the part shown in Fig. 31 does not include channels, as the part interior is close enough to debinder fluid flow such that it may be expected that the uppermost region of the part may debind in an acceptable time.
  • successive layers of honeycomb infill may be deposited in the interior of the part to form a plurality of distribution channels CH3 connecting an interior volume of the honeycomb infill to the first access channel CH2, at least some of the plurality of distribution channels CH3 being of different length from other of the distribution channels CH3.
  • companion ceramic sintering supports may be printed using a ceramic composite material that behaves dimensionally similarly to the metal model material but does not sinter together with it.
  • CSS may sinter according to any particular temperature profile suitable for sintering the part' s model material, the material of the ceramic sintering support shrinks by a particular amount and in some cases along a particular density profile (e.g., starting and ending density, starting and ending temperatures, shape of the curve between) according to at least the composition of the ceramic sintering support material.
  • the amount of final shrinkage should be the same.
  • the amount of shrinkage of the ceramic sintering support material should be less than that of the part model material until the final shrinkage amount is reached.
  • the ceramic sintering support material may begin to shrink at a lower temperature or earlier at the same temperature.
  • a candidate first ceramic material e.g., a-alumina or other alumina, having a sintering temperature above that of the part model material may have its sintering temperature lowered and/or its shrinkage amount changed by (i) reducing average particle size ("APS") or (ii) mixing in a compatible second or third lower temperature sintering material (e.g., silica, or yttria- silica-zirconia). These mixed materials would also be sintered.
  • APS average particle size
  • a compatible second or third lower temperature sintering material e.g., silica, or yttria- silica-zirconia
  • a non- sintering filler that sinters at a significantly higher temperature may be mixed (which will generally decrease the amount of shrinking or densification).
  • homogeneous materials having a smaller APS will start densifying at lower temperatures and will attain a full density at a lower temperature than the larger APS materials.
  • the sintering temperature, shrinking amount or the degree of densification can be changed by changing the particle size distribution ("PSD", e.g., for the same average particle size, a different proportion or composition of larger and smaller particles).
  • PSD particle size distribution
  • gaps may be printed side-to-side, in the vertical direction or horizontal direction, together with green body supports and/or a separation layer between each ceramic sintering support and the part (including between adjacent ceramic sintering supports). Gaps may be printed adjacent convex or concave part shapes or contours. In addition, gaps may be printed adjacent convex or concave part shapes or contours where a surface of the part and a surface of a ceramic support follow respective paths that would, without the gap, interfere during shrinking. In the case of vertical gaps, a small amount (e.g., a few mm) of unsupported span of part material is stiff enough to resists gravity-caused slump during sintering.
  • a separation layer in the gap including remnant powder (spheres) following debinding will permit substantially free horizontal or diagonal sliding of the ceramic support during sintering.
  • substantially differing shrink rates or other differences in bulk density curve over time e.g.
  • differing starting or ending positions, differing curve shapes may require some rearranging of some sintering supports following debinding, such that the shrink rate profile of the model material to the sintering support material be matched to within 5 percent of the bulk density of the model material over rising and constant temperature portions of a sintering temperature ramp.
  • Exemplary measurements would be (i) via an optical or electromagnetic sensor, measuring a property such as opacity, color, capacitance, inductance representative of an amount of material debound (ii) via a mechanical or fluid-responsive sensor (optionally connected to an optical or electromagnetic element), measuring a property such as natural frequency, viscosity, or density or (iii) via a chemical sensor (optionally connected to an optical or electromagnetic element) measuring a chemical change such as pH, oxygen content, or the like.
  • a property such as opacity, color, capacitance, inductance representative of an amount of material debound
  • a mechanical or fluid-responsive sensor optionally connected to an optical or electromagnetic element
  • measuring a property such as natural frequency, viscosity, or density
  • a chemical sensor optionally connected to an optical or electromagnetic element measuring a chemical change such as pH, oxygen content, or the like.
  • step S346 post draining or partial draining, a measurement may be taken to gauge to progress of debinding and set a subsequent stage trigger or instruction for the next cycle.
  • the sensor applicable may be similar or the same as that described with reference to step S344.
  • the part weight may be measured (before and after a debinding cycle) via a load cell, etc.
  • the changing part weight may be recorded (e.g., as a profile) and used to determine the time, temperature, and/or agitation of a subsequent cycle.
  • the profile of weight change may also be employed to model an exponential decay constant relating to the maximum removable binder per part weight and set a termination cycle count or time based on the exponential decay constant (e.g., terminating at a time or cycle count for 90-95% removed material by weight based on the exponential decay rate).
  • step S347 cycles may repeats until complete ("N CYCLES” being determined by predetermined count or time, by direct or indirect measured feedback as described above, or other modeling).
  • N CYCLES being determined by predetermined count or time, by direct or indirect measured feedback as described above, or other modeling.
  • the green part has become a brown part, and may be actively or passively dried or otherwise post-processed in preparation for sintering.
  • the green parts may be formed from a curable and/or debindable photopolymer including a sinterable powder, as well as optionally a second stage binder (either a debindable, e.g., pyrolysing photopolymer or thermoplastic).
  • a debindable e.g., pyrolysing photopolymer or thermoplastic
  • different additive manufacturing processes can include a matrix in liquid (e.g., SLA) or powder (e.g., SLS) form to manufacture a composite material including a matrix (e.g., debindable plastic) solidified around the core materials (e.g., metal powder).
  • a matrix in liquid e.g., SLA
  • powder e.g., SLS
  • Many methods described herein can also be applied to Selective Laser Sintering which is analogous to stereolithography but uses a powdered resin for the construction medium as the matrix as compared to a liquid resin.
  • the reinforcement might be used for structural, electrical conductivity, optical conductivity, and/or fluidic conductivity properties.
  • a stereolithography process is used to form a three dimensional part, the layer to be printed being covered with resin, cured with UV light or a laser of a specified wavelength, the light used to cure the resin sweeping over the surface of the part to selectively harden the resin (matrix) and bond it to the previous underlying layer.
  • Fig. 35 depicts an embodiment of the stereolithography process described above. Description of Figs. 1A and IB herein would be recognized by one of skill in the art as consistent with Fig. 35 (despite differences in reference numbers).
  • a part 1600 is being built on a platen 1602 using stereolithography.
  • the part 1600 is immersed in a liquid resin material 1604 contained in a tray 1606.
  • the liquid resin material may be any appropriate photopolymer (e.g., debindable composite including a primary debindable component and optionally a secondary debindable component and a sinterable powder).
  • a laser 1612 is directed to cure the resin.
  • the laser may be generated by a source 1616 and is directed by a controllable mirror 1618.
  • Extrusion type and other deposition 3D printers employ various printing approaches for completing perimeters, in particular for reducing seams resulting from extruding a closed perimeter path. Any path point not on a perimeter path is in an interior region, because the perimeter path constitutes the outermost path points (e.g., a new path that forms part of the outer perimeter renders previous paths to be interior regions).
  • printing paths may form a seam with a butt joint or other than a butt joint (or example, overlapping, self-crossing, interlocking).
  • a butt joint or other than a butt joint (or example, overlapping, self-crossing, interlocking).
  • one segment and one seam is preferred because fewer seams tend to have superior aesthetics, sealing, and dimensional stability.
  • wall or shell contour paths in contrast to "raster" fill paths) have been deposited in a same rotational direction - either clockwise or counterclockwise. Paths are printed in the same clockwise or counterclockwise direction even if a perimeter path branches to the interior. This simplifies and speeds printing as perimeter paths can be continuously printed without reflex angle turns (e.g., turns of less than 180 degrees) from the current heading.
  • brown parts may be dimensionally consistent with the deposited green part, but may display a twist around a vertical axis after sintering.
  • the second stage polymer binder may be considered to be heated to a level where residual stress can relax, causing the twist, as deposition stress built into the brown part is relaxed.
  • long chain molecules that compose the second stage binder polymer may be strained along the printing direction. When heated to a relaxing temperature, the molecules may pull back, potentially causing a macroscopic twist in the part as pulls among many layers accumulate.
  • One countermeasure for twist is to print roads in a counteracting or retrograde direction.
  • the three most common categories of roads are shells or walls, which are printed to form the perimeter of a sliced interior or exterior contour; "raster" fill, which is printed to fill interior volume in a solid manner, and infill honeycomb, which is printed to fill interior volume in a honeycomb.
  • the shape of shells or walls may change completely from one layer to the next. Accordingly, it is optionally advantageous to print first and second sets of opposing direction walls or shells within one layer, so as to avoid layer- to layer comparison which may be more complex.
  • One approach is to print each outer perimeter or negative contour inner perimeter with a companion, parallel, adjacent wall or shell road.
  • the length of the companion or offsetting road is not necessarily precisely the same, especially for small positive and negative contours (e.g., for a 3mm diameter feature, the length of the perimeter road vs. a companion road may differ by 25 or 30%, while at 30 mm the length of the companion road may be 5% or less difference). In such a case an amount of overlap determined according to the difference in perimeter lengths may be effective at removing twist.
  • a twisting effect from the relaxation of residual stress may not be as pronounced because raster rows may include some retrograde paths.
  • differences in path length among raster rows and turns may be more pronounced.
  • Overlap determined according to a difference in directional lengths e.g., including straight rows as well as end-of-row turns
  • raster-like or cellular patterns may be printed in tile patterns that each include main paths and parallel retrograde paths to relieve twisting stress relaxation within the tile and/or among tiles.
  • Fig. 36B may be considered a different version of the layer of Fig. 36A, or may be considered to depict an adjacent layer (Fig. 36B is depicted a smaller outer perimeter than Fig. 36 A, such as would be the case for an adjacent layer sloping to a peak).
  • an adjacent perimeter path 376 in an adjacent layer may be alternatively or also deposited in a retrograde direction with respect to the perimeter path 371, and other paths such as raster fill 378 or honeycomb infill 377 may also be printed in a retrograde direction with respect to parallel paths in an adjacent layer 374, 373 respectively.
  • an adjacent road or deposition 376 may be deposited wider or at a higher rate than a perimeter path 375 (or narrower).
  • the changed width or deposition rate may offset the twist tendency of two adjacent depositions (on either side) in the same layer.
  • a first tool path for a layer of the part may be received by the controller, the received first tool path including a perimeter contour segment 371.
  • a second tool path 372 may be receive for a layer of the part by the controller, including an interior region segment adjacent the perimeter contour segment.
  • the deposition head may be moved (including directed movement of a beam or ray of light or electromagnetic energy) in a pattern that follows the perimeter contour segment of the received first tool path to produce a perimeter path 371 of a debindable composite including sinterable powder, and in a pattern that follows the interior region segment of the received second tool path to produce an interior adjacent path 372 of the debindable composite, wherein the perimeter path 371 and the adjacent path 372 are deposited in retrograde directions so that directions of residual stress within a binder of the debindable composite are opposite in the perimeter path and the adjacent path. As shown in Figs. 37A-37H and 37J, this may also apply between adjacent layers, where the adjacent path 376 is in an adjacent layer.
  • a digital solid model may be received for the part (e.g., a 3D mesh such as an STL file or a 3D solid such as a NURBS, parasolid, IGES file).
  • the digital solid model may be sliced (by, e.g., a computer or a cloud-based computing service) into a plurality of layers.
  • a perimeter contour tool path 371 may be generated based upon a perimeter of a layer of the plurality of layers, wherein the generated perimeter contour tool path defines an interior region of the layer.
  • An interior adjacent path 372 may be generated based on the perimeter contour tool path within the interior region.
  • a debindable composite may be deposited including sinterable powder in a first direction based on the perimeter contour tool path to form a perimeter 371 of the debindable composite for the layer.
  • the debindable composite may be extruded in a second direction based on the perimeter contour tool path to form an interior adjacent path 372 of the debindable composite for the layer.
  • the deposition of the perimeter contour tool path 371 and the interior adjacent path 372 may be traced in retrograde directions to one another so that directions of residual stress within a binder of the debindable composite are opposite in the perimeter contour tool path 371 and the interior adjacent path 372.
  • a start point of the perimeter contour tool path 371 and a stop point of the perimeter contour tool path 371 may be adjusted to locations within the interior region.
  • building a part with an deposition-based additive manufacturing system having a deposition head and a controller may include receiving a first tool path for a layer of the part by the controller, wherein the received first tool path comprises a contour segment.
  • a second tool path may be received for a layer of the part by the controller, and wherein the received second tool path overlaps the first tool path over more than 70 percent, preferably at least 90 percent of a continuous deposition length of the second tool path.
  • the deposition head may be moved in a pattern that follows the first tool path to produce a perimeter path 371 of a debindable composite for the layer, and also moved in a pattern that follows the second tool path in a retrograde direction to the first tool path to produce a stress-offsetting path 372 adjacent the perimeter path of debindable composite.
  • Directions of residual stress within a binder of the debindable composite may be opposite in the perimeter path 371 and the stress- offsetting path 372.
  • the second tool path may be continuously adjacent or overlap the first tool path within the same layer, and may include interior region path within the same layer.
  • the second tool path is continuously adjacent over at least 90 percent of the first tool path within an adjacent layer, and may include a perimeter path of the adjacent layer.
  • the method in a method for building a part with a deposition-based additive manufacturing system having an deposition head and a controller, includes generating a tool path with a computer. Instructions may be generated for the generated tool path to the controller. A debindable composite may be deposited from the deposition head while moving the deposition head along the generated tool path to form a perimeter path of a layer of the part. As shown in Fig.
  • the perimeter path may include a first contour road portion 378, and a second contour road portion 379, each of the first contour road portion and the second contour road portion crossing one another with an even number of X-patterns, forming an even number of concealed seams for the layer.
  • a deposition-based additive manufacturing system having a deposition head and a controller may move the deposition head along a first tool path segment 380 to form a perimeter road portion 371 for a layer of the part.
  • the deposition head may be moved along a direction changing tool path segment 381; and moved along a second tool path segment 382 to form a stress- balancing road portion 372 adjacent to the perimeter road portion 371.
  • the direction changing tool path segment 381 may include a reflex angle
  • nozzle structure can be used to improve printing properties of the metal powder composite feedstocks discussed herein.
  • Metal powder composite feedstocks such as MIM (Metal Injection Molding) feedstocks, are a composite material, as discussed herein, including sinterable metal powder and a binder, may be designed to facilitate MIM-specific processes.
  • certain feedstocks can be adapted for extrusion-type 3D printing, e.g., Fused Deposition Modeling or Fused Filament Fabrication ("FDM" or "FFF", terms for generic extrusion-type 3D printing).
  • Traditional extrusion feedstocks are not formed in the same manner as MIM feedstocks, and include thermoplastic material that melts or softens.
  • other materials intended for injection molding or the green-to-brown part process are often included in the feedstock - typically waxes, but including other low melting point and low viscosity materials.
  • the higher viscosity (vs. lower viscosity of wax-including MIM feedstocks) and lower thermal conductivity (vs. high metal powder content of MIM feedstocks) of FDM/FFF thermoplastic filament may require a larger melt zone to get the material to a suitable temperature and thus suitable viscosity to flow.
  • Bubbles may be formed in many ways - for example gas dissolution from the solid phase, i.e. small amounts of moisture making steam.
  • micro bubbles may coalesce in the nozzle that entered the feedstock filament in a feedstock
  • manufacturing phase e.g., bubbles in pellet material converted into filament that are not removed during this process, or bubbles introduced during filament production.
  • air may be pulled into the system during a retract step following steady printing (an extrusion type 3D printer may be set to "retract", i.e., reverse the filament drive direction, by a small amount - e.g., 1-5 mm - following steady printing or during a non-printing nozzle translation to relieve pressure in the melt zone).
  • bubbles may be caused by deformation due to the filament extruder hob (e.g., caused by any of grabbing teeth, pressure, or heating) [0255]
  • An additional benefit of the present system is decreasing the volume of melt for a practically sized heater block and nozzle system, providing more responsive extrusion control.
  • the material may be heated in the print head to 180-230 C to promote adhesion.
  • the melt zone instead of reducing the volume of the melt zone using a long, thin melt channel (e.g., 1: 10 width- height aspect ratio for diameter and a volume of 20 mm A 3, the melt zone may be a short 1:2 aspect ratio and a volume of 20 mm A 3 - e.g., 3 mm of melt zone height, 1.5 mm of melt zone diameter.
  • MIM metal (or ceramic) powder loading by volume
  • separation layer material in small powder sizes (e.g., less than 1 um diameter) of alumina ceramic may tend to sinter at steel sintering temperatures. As the size of powder increases slightly to 2 um, the separation layer may become chalk-like. Accordingly, 15-35% powder by volume with a powder diameter of 5 um or higher for alumina or similar ceramic powder loaded in a MIM binder (e.g., wax-polyethylene, as discussed herein) may perform well as a separation layer.
  • MIM binder e.g., wax-polyethylene, as discussed herein
  • 10-20% powder by volume with a powder diameter of 2 um or lower (or 1 um or lower) for alumina or similar ceramic powder loaded in a MIM binder may perform well as a separation layer. Further, these may be combined (e.g., some particles smaller than 1 um and some particles larger than 5 um).
  • a conventional FDM/FFF filament or melt chamber may be approximately 1.7-3 mm, and in the present invention the melt chamber may be 0.6 - 1 mm in diameter for a tip outlet diameter of 0.1-0.4 mm (for a filament diameter of 1.0-2 mm).
  • the volume of the melt chamber (the heated substantially cylindrical chamber of constant diameter extending from adjacent the nozzle tip to a melt interface) the may be approximately 15- 25 mm A 3 vs. a melt chamber in conventional FDM/FFF of approximately 70 mm A 3.
  • an FDM/FFF nozzle assembly may include a nozzle 38-1 including part of the cylindrical melt chamber 38-2 having a larger diameter and a transition to the nozzle outlet 38-3.
  • the transition may be smooth (tapered 38-4, as in Fig. 38A) or stepped 38-5 (as in Fig. 38B).
  • Both the nozzle 38-1 and a heat break 38-5 are tightened (e.g., screwed) into a heater 38-6 block to abut one another, the heat break 38-5 including the remainder of the cylindrical melt chamber.
  • the heat break 38-5 includes a narrow waist made of a lower heat conductivity material (e.g., stainless steel) to provide the melt interface via a sharp temperature transition between the top portion of the heat break 38-5 (which is cooled via the heat sink) and the lower, conductively heated portion of the heat break 38-5.
  • the melt interface between the solid filament 38-8 and the liquefied material in the melt chamber 38-2 is typically near the narrow waist (adjacent above or below, or within).
  • an FDM/FFF nozzle assembly may include a melt chamber of approximately 1.8 mm diameter and 10 mm height, a volume of about 70 mm A 3, vs. a nozzle outlet of approximately 0.25-0.4 mm diameter.
  • a cartridge heater 38-6 in Fig. 38A
  • a coiled inductive heater 38- 6 in Fig. 38B
  • a PTFE insert 38-9 may provide resistance to filament jamming.
  • a MIM material extrusion nozzle assembly may include a melt chamber 39-2 of approximately 0.6-1 mm diameter and 10 mm height, a volume of about 20 mm A 3, vs. a nozzle outlet 39-3 of approximately 0.1- 0.4 mm diameter.
  • a narrowing insert 39-11 may be used to convert an FDM nozzle for MIM material extrusion (e.g., the melt chamber volume vs. nozzle outlet size or filament relationships described herein are related to MIM material dimensions during extrusion, not necessarily the specific nozzle, heat break, or insert parts).
  • the melt chamber volume vs. nozzle outlet size or filament relationships described herein are related to MIM material dimensions during extrusion, not necessarily the specific nozzle, heat break, or insert parts).
  • the binder jetting example printer 1000J and associated processes may be used.
  • a binder may be jetted as a succession of adjacent 2D layer shapes onto a sinterable metal or ceramic powder bed in successive layers of powder feedstock, the powder bed being refilled with new or recycled feedstock and
  • differing amounts of binder may be jetted depending on whether a 2D layer shape segment being formed is an external wall, internal wall, or honeycomb wall, or internal bulk material (or depending on the printing location relative to such perimeters or areas). This results in differing (optionally a continuous or stepwise gradient) of volume fraction proportions of binder to powder, e.g., from 90% binder to 100% powder through 50:50 up to 10% binder to 90% powder. For example, a higher volume fraction of binder may be located on an outer shell (and/or inner shell), progressively reducing inward toward, e.g., area centroids.
  • a release material (including another powder that does not sinter at the sintering temperature of the feedstock powder) may also be applied in a
  • complementary 2D shape e.g., jetted in a binder, extruded in a binder
  • the external shell 2D shapes are deposited in each candidate layer on top of the preceding powder (e.g., bound powder, unbound powder, and/or release material) layer, then a subsequent layer of unbound powder feedstock is wiped on.
  • a doctor blade 138 may be used to slice the top of the 2D shell shape off (leveling) or a silicon roller / blade 138 may be used to slice the top of the 2D shell shape off - the silicon roller / blade may accept some deformation, e.g., deform to accommodate the bump of the plastic tolerance above the printing plane.
  • the part may be anchored part with (e.g., solvent removed) binder to a ground plane (e.g., build plate) and/or parts to each other (e.g., in the Z axis, when printing one on top of another).
  • a ground plane e.g., build plate
  • the powder bed is refilled and releveled/wiped (with a doctor blade 138, roller, wheel or other powder leveling mechanism) flush with the green part shape, the release material shape, and/or the free space placeholder material shape.
  • a surface finishing mechanism flattens or shapes (rolling, shaving, ironing, abrading, milling) a recent or a most recent layer of green part shape, release material shape, and/or placeholder material shape before the powder bed is refilled about them.
  • each of the green part, sintering supports, intervening release material, and placeholder free space material are built up in successive layers, and in 3D space may take essentially any interlocking 3D forms.
  • the green part is formed as a recognizable 3D object, with separation material forming planes, arches, hemispheres, organic shapes or the like separating the 3D object from columns of sintering supports below, leading down to a shrinking platform as described herein, which is adhered to a build platform via placeholder material and/or bound composite tacks.
  • desired free space may be filled with placeholder material and/or unbound sinterable powder.
  • placeholder material and/or unbound sinterable powder may be deposited bound composite honeycomb or lattice or the like containing or entraining either or both of the placeholder material or unbound sinterable powder.
  • a mold shape defining the outer skin of the 3D object may be formed of the placeholder material.
  • a skin shape forming the outer skin of the 3D object may be formed of the bound composite.
  • the 3D green part(s) together with sintering supports, release shapes, and placeholder or adhesive shapes is removed from the powder, and cleaned of remaining unbound powder.
  • Unbound powder may be removed from the surroundings of the 3D green part(s) and sintering supports via outlets formed in the bound composite, or left entrained within the desired green part.
  • the green part and its sintering supports may be handled as otherwise described in this disclosure. Bound composite outer and inner walls and internal honeycomb walls will be debound as described to form the brown part assembly. Release material will be debound as described, become separation powder for removing the sintering supports, and is retained for sintering and removed following sintering.
  • Placeholder material may be debound (including in a solvent, catalytic, or thermal process) or even, if a different material from the binder, removed before or after debinding.
  • high temperature placeholder material that retains its shape at high heat but may be disassembled by further vibration, mechanical, radiation, or electrical processing (e.g., carbon or ceramic composite ) may be retained through sintering.
  • a material may be supplied (pellet extruded, filament extruded, jetted or cured) containing a removable binder as discussed herein (two or one stage) and greater than 50% volume fraction of a powdered metal having a melting point greater than 1200 degrees C (including various steels, such as stainless steels or tool steels).
  • the powdered metal may have which more than 50 percent of powder particles of a diameter less than 10 microns, and advantageously more than 90 percent of powder particles of a diameter less than 8 microns.
  • the average particle size may be 3-6 microns diameter, and the substantial maximum (e.g., more than the span of +/-3 standard deviations or 99.7 percent) of 6-10 microns diameter.
  • Smaller, e.g., 90 percent of less than 8 microns, particle sizes may lower the sintering temperature as a result of various effects including increased surface area and surface contact among particles. In some cases, especially for stainless and tool steel, this may result in the sintering temperature being within the operating range of a fused tube furnace using a tube of amorphous silica, e.g., below 1200 degrees C. Smaller diameter powder material may be additively deposited in successive layers to form a green body as discussed herein, and the binder removed to form a brown body (in any example of deposition and/or debinding discussed herein).
  • a "sintering temperature" of a material is a temperature range at which the material is sintered in industry, and is typically a lowest temperature range at which the material reaches the expected bulk density by sintering, e.g., 90 percent or higher of the peak bulk density it is expected to reach in a sintering furnace.
  • Heneycomb includes any regular or repeatable tessellation for sparse fill of an area (and thereby of a volume as layers are stacked), including three-sided, six-sided, four-sided, complementary shape (e.g., hexagons combined with triangles) interlocking shape, or cellular.
  • Cells may be vertical or otherwise columns in a geometric prism shape akin to a true honeycomb (a central cavity and the surrounding walls extending as a column), or may be Archimedean or other space-filling honeycomb, interlocking polyhedra or varied shape "bubbles" with a central cavity and the surrounding walls being arranged stacked in all directions in three dimensions. Cells may be of the same size, of differing but repeated sizes, or of variable size.
  • Shells and “layer” are used in many cases interchangeably, a “layer” being one or both of a subset of a “shell” (e.g., a layer is an 2.5D limited version of a shell, a lamina extending in any direction in 3D space) or superset of a “shell” (e.g., a shell is a layer wrapped around a 3D surface).
  • Shells or layers are deposited as 2.5D successive surfaces with 3 degrees of freedom (which may be Cartesian, polar, or expressed "delta”); and as 3D successive surfaces with 4-6 or more degrees of freedom.
  • 3D printer meaning includes discrete printers and/or toolhead accessories to manufacturing machinery which carry out an additive manufacturing sub-process within a larger process.
  • a 3D printer is controlled by a motion controller 20 which interprets dedicated G-code (toolpath instructions) and drives various actuators of the 3D printer in accordance with the G-code.
  • G-code toolpath instructions
  • Deposition head may include jet nozzles, spray nozzles, extrusion nozzles, conduit nozzles, and/or hybrid nozzles.
  • “Filament” generally may refer to the entire cross-sectional area of a (e.g., spooled) build material.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • General Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Dispersion Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Powder Metallurgy (AREA)

Abstract

La présente invention concerne un procédé consistant à : réaliser une alimentation en une première pièce brune et d'une seconde pièce brune, chacune des première et seconde pièces brunes étant formée à partir d'un matériau dans lequel plus de 50 pour cent de particules de poudre d'un second métal en poudre ont un diamètre inférieur à 10 microns, dans un premier mode, charger la première pièce brune dans un tube fondu, et augmenter progressivement la température à l'intérieur du tube fondu dans une proportion supérieure à 10 °C par minute mais inférieure à 40 °C par minute jusqu'à une première température de frittage située dans la plage allant de 500 à 700 °C, et dans un second mode, charger la seconde pièce brune dans le tube fondu, et augmenter progressivement la température à l'intérieur du tube fondu dans une proportion supérieure à 10 °C par minute mais inférieure à 40 °C par minute jusqu'à une seconde température de revenu de frittage de 1 000 à 1 200 °C.
EP18790336.4A 2017-04-24 2018-04-24 Frittage dans un four à micro-ondes de pièces obtenues par fabrication additive Withdrawn EP3615250A4 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US201762489410P 2017-04-24 2017-04-24
US201762505081P 2017-05-11 2017-05-11
US201762519138P 2017-06-13 2017-06-13
US201762545966P 2017-08-15 2017-08-15
US201762575219P 2017-10-20 2017-10-20
PCT/US2018/029129 WO2018200515A1 (fr) 2017-04-24 2018-04-24 Frittage dans un four à micro-ondes de pièces obtenues par fabrication additive

Publications (2)

Publication Number Publication Date
EP3615250A1 true EP3615250A1 (fr) 2020-03-04
EP3615250A4 EP3615250A4 (fr) 2021-02-24

Family

ID=63919078

Family Applications (2)

Application Number Title Priority Date Filing Date
EP18791940.2A Withdrawn EP3615253A4 (fr) 2017-04-24 2018-04-24 Frittage dans un four à micro-ondes de pièces obtenues par fabrication additive
EP18790336.4A Withdrawn EP3615250A4 (fr) 2017-04-24 2018-04-24 Frittage dans un four à micro-ondes de pièces obtenues par fabrication additive

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP18791940.2A Withdrawn EP3615253A4 (fr) 2017-04-24 2018-04-24 Frittage dans un four à micro-ondes de pièces obtenues par fabrication additive

Country Status (2)

Country Link
EP (2) EP3615253A4 (fr)
WO (2) WO2018200515A1 (fr)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210069784A1 (en) 2018-05-04 2021-03-11 Addleap Ab A method of generating a mold and using it for printing a three-dimensional object
CN109608750B (zh) * 2018-12-07 2021-03-12 哈尔滨工业大学 一种具有光致振动性能的3d打印线材及其制备和使用方法
DE102018132938A1 (de) * 2018-12-19 2020-06-25 Volkswagen Aktiengesellschaft Verfahren zur generativen Herstellung wenigstens eines Gegenstands, Verwendung eines Druckkopfs und Kraftfahrzeug
EP3725435A1 (fr) * 2019-04-17 2020-10-21 Siemens Aktiengesellschaft Fabrication d'un objet métallique
US11738519B2 (en) 2019-05-03 2023-08-29 Raytheon Technologies Corporation Systems and methods for support material removal
GB201907714D0 (en) * 2019-05-31 2019-07-17 Renishaw Plc Metal powder bed additive manufacturing apparatus and methods
CN110076335B (zh) * 2019-06-14 2021-04-06 珠海天威飞马打印耗材有限公司 三维成型丝料及fdm三维成型方法
JP6624626B1 (ja) * 2019-07-29 2019-12-25 アサヒ・エンジニアリング株式会社 電子部品のシンタリング装置
CN111307809B (zh) * 2020-02-24 2021-01-12 浙江大学 小管道气液两相流相分布光学检测系统和方法
CN115007860A (zh) * 2020-04-30 2022-09-06 山东威尔斯通钨业有限公司 钨基高比重合金制备用骨架及其使用方法
DE102021100057A1 (de) * 2021-01-05 2022-07-07 Xerion Berlin Laboratories GmbH Vorrichtung zur Herstellung metallischer und/oder keramischer Teile

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1080562A (fr) * 1977-02-10 1980-07-01 Frederick D. King Methode et appareil de fabrication de fibres optiques par depot active par plasma dans un tube
US4276072A (en) * 1977-06-07 1981-06-30 International Telephone And Telegraph Corporation Optical fiber fabrication
DE3735879C2 (de) * 1987-10-23 1995-07-20 Leybold Ag Verfahren und Vorrichtung zum Sintern von keramischen Rohlingen
US6814926B2 (en) * 2003-03-19 2004-11-09 3D Systems Inc. Metal powder composition for laser sintering
US20060166158A1 (en) * 2005-01-25 2006-07-27 Norbert Abels Laser shaping of green metal body to yield an orthodontic bracke
US7942987B2 (en) * 2008-06-24 2011-05-17 Stratasys, Inc. System and method for building three-dimensional objects with metal-based alloys
JP5763055B2 (ja) * 2009-06-02 2015-08-12 ビーエーエスエフ ソシエタス・ヨーロピアＢａｓｆ Ｓｅ 多孔性の金属焼結成形体の製造方法
WO2015006697A1 (fr) * 2013-07-11 2015-01-15 Heikkila Kurt E Particule modifiée en surface et produits extrudés frittés
EP3247688A4 (fr) * 2015-01-23 2018-01-24 Hewlett-Packard Development Company, L.P. Matériaux suscepteurs pour impression 3d à l'aide d'un traitement micro-ondes

Also Published As

Publication number Publication date
WO2018200512A1 (fr) 2018-11-01
EP3615253A4 (fr) 2021-02-24
WO2018200515A1 (fr) 2018-11-01
EP3615253A1 (fr) 2020-03-04
EP3615250A4 (fr) 2021-02-24

Similar Documents

Publication Publication Date Title
AU2017372858B2 (en) Additive manufacturing with heat-flexed material feeding
EP3548257B1 (fr) Procédé de réduction des distortions dans une pièce produite par méthode additive
US20210197493A1 (en) Sinterable separation material in additive manufacturing
EP3634724B1 (fr) Déliantage rapide par l'intermédiaire de canaux de fluide internes
EP3615250A1 (fr) Frittage dans un four à micro-ondes de pièces obtenues par fabrication additive
US20200114422A1 (en) Method for minimizing stress-related deformations in 3d printed and sintered parts
EP3810360A1 (fr) Matériau de séparation apte à être fritté en fabrication additive
WO2019079704A2 (fr) Espace libre interne d'impression 3d
EP3819049B1 (fr) Procédé de minimisation de déformations liées au stress dans des pièces imprimées et frittées en 3d

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20191122

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
A4 Supplementary search report drawn up and despatched

Effective date: 20210122

RIC1 Information provided on ipc code assigned before grant

Ipc: B29C 31/04 20060101ALI20210118BHEP

Ipc: B33Y 10/00 20150101ALI20210118BHEP

Ipc: B29B 11/16 20060101ALI20210118BHEP

Ipc: B33Y 30/00 20150101ALI20210118BHEP

Ipc: B29C 67/00 20170101AFI20210118BHEP

Ipc: B33Y 40/00 20200101ALI20210118BHEP

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20210820