# US 11,305,455 B2 · Xerographic 3D printing method for forming shaped objects

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- Number: US 11,305,455 B2
- Document ID: US11305455B2
- Status: Granted
- Kind: B2
- Application number: 16/139,459
- Filed: 2018-09-24
- Published: 2020-03-26
- Granted: 2022-04-19
- Earliest claimed: 2018-09-24
- Assignees: Xerox Corporation
- Applicants: Xerox Corporation
- Inventors: Christopher D. Blair; David C. Irving
- Web page: https://patentgrep.com/patent/US11305455B2

## CPC

- B22F 5/006: {of flat products, e.g. sheets (B22F3/1103 takes precedence; by using pressure rollers only see B22F3/18)}
- B22F 3/1021: {Removal of binder or filler (removal of binder from ceramics C04B35/638)}
- B28B 1/001: {Rapid manufacturing of 3D objects by additive depositing, agglomerating or laminating of material (selective deposition modelling of metallic powder B22F10/00; rapid manufacturing of 3D objects in general and in particular of plastics B29C64/00)}
- B29C 64/147: using sheet material, e.g. laminated object manufacturing [LOM] or laminating sheet material precut to local cross sections of the 3D object
- B32B 18/00: Layered products essentially comprising ceramics, e.g. refractory products
- C04B 35/6263: {characterised by their solids loadings, i.e. the percentage of solids}
- C04B 35/632: Organic additives
- C04B 35/638: Removal thereof
- C04B 35/64: Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F})
- B22F 2998/10: Processes characterised by the sequence of their steps
- B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy
- B33Y 10/00: Processes of additive manufacturing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 70/10: Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3208: Calcium oxide or oxide-forming salts thereof, e.g. lime
- C04B 2235/3215: Barium oxides or oxide-forming salts thereof
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3232: Titanium oxides or titanates, e.g. rutile or anatase
- C04B 2235/3244: Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
- C04B 2235/3418: Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
- C04B 2235/3821: Boron carbides
- C04B 2235/3826: Silicon carbides
- C04B 2235/3865: Aluminium nitrides
- C04B 2235/3873: Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/6026: Computer aided shaping, e.g. rapid prototyping
- Y02P 10/25: Process efficiency
- B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B28B: SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER (foundry moulding B22C; working stone or stone-like material B28D; shaping of substances in a plastic state, in general B29C; making layered products not composed wholly of these substances B32B)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A shaped ceramic or metallic object is formed by sectioning a model of a shaped body into 2-dimensional slices. For each slice, a toner material is electrostatically printed on a polymer sheet. The toner material includes solid particles. The printed sheets are assembled into a stack and the stack is depolymerized and sintered to form the ceramic object.

## Claims

### Claim 1

A method for forming a shaped object comprising:
sectioning a model of a shaped body into 2-dimensional slices;
for each slice, electrostatically printing a toner material on a respective flexible polymer sheet to form a printed sheet, the toner material comprising solid particles which form a ceramic or metal when sintered, the printing including feeding the polymer sheets from a print media source, which holds a supply of the polymer sheets, conveying the polymer sheets along a print media path to a marking engine where each polymer sheet is printed with a respective toner image, and fusing the toner image to the respective polymer sheet;
assembling the printed sheets one on top of the other into a stack, in the stack, each printed sheet comprising a respective polymer sheet and a toner image;
while applying pressure to the stack of printed sheets, depolymerizing the stack of printed sheets together to remove polymer of the polymer sheets from the stack; and
sintering the depolymerized stack to form the shaped object.

### Claim 2 (depends on 1)

The method of claim 1, wherein the particles in the toner material have an average diameter of less than 12 μm.

### Claim 3 (depends on 1)

The method of claim 1, wherein the polymer sheets each have a thickness which is greater than an average diameter of the ceramic-forming particles.

### Claim 4 (depends on 1)

The method of claim 1, wherein the polymer sheets have a thickness of at least 20 μm.

### Claim 5 (depends on 1)

The method of claim 1, wherein the polymer sheets comprise at least one polymer selected from the group consisting of polyoxymethylene, polyvinyl alcohol, polystyrene, polyvinylidene fluoride, polyvinyl acetals, unsaturated polycarbonates, saturated polycarbonates, polyvinylpyrrolidone, vinyl imidazole copolymers, polyamides, polyethers, polyesters, cyclic olefin copolymers, polyolefins, polyacrylates, polymethacrylates, polyacrylonitrile, and copolymers and mixtures thereof.

### Claim 6 (depends on 1)

The method of claim 1, wherein the solid particles comprise ceramic-forming particles which are formed of at last one refractory material selected from the group consisting of oxides, nitrides, carbides, hydroxides, silicates, and mixtures thereof.

### Claim 7 (depends on 6)

The method of claim 6, wherein the ceramic-forming particles are formed of at least one refractory material selected from the group consisting of alumina, aluminum hydroxide, aluminum nitride, silica, titanium dioxide, calcium oxide, magnesium oxide, barium oxide, zirconia, silicon carbide, silicon nitride, boron carbide, precursors which decompose on heating to form such refractory materials, and mixtures and compounds thereof.

### Claim 8 (depends on 1)

The method of claim 1, wherein the toner material comprises at least 40 wt. % of the solid particles.

### Claim 9 (depends on 1)

The method of claim 1, wherein the toner material comprises at least 80 wt. % of the solid particles.

### Claim 10 (depends on 1)

The method of claim 1, wherein the toner material comprises at least 5 wt. % of a binder material.

### Claim 11 (depends on 1)

The method of claim 1, wherein the binder material includes an organic polymer and optionally a least one of a charge control agent and a flow control agent.

### Claim 12 (depends on 11)

The method of claim 11, wherein the organic polymer in the binder is a same polymer as in the polymer sheets.

### Claim 13 (depends on 1)

The method of claim 1, wherein the depolymerizing includes chemically depolymerizing the stack in a gaseous, acid-containing atmosphere.

### Claim 14 (depends on 1)

The method of claim 1, wherein the depolymerizing includes applying pressure to the stack.

### Claim 15 (depends on 1)

The method of claim 1, wherein the stack includes at least 10 of the printed sheets.

### Claim 16 (depends on 1)

The method of claim 1, wherein the polymer sheets comprise at least one of a polyoxymethylene homopolymer and a polyoxymethylene copolymer.

### Claim 17

A method for forming a ceramic object comprising:
providing a print file in which a model of a ceramic body has been sectioned into 2-dimensional slices;
for each slice, printing a toner material on a polymer sheet to form a respective printed sheet, the toner material comprising at least 40 wt. % ceramic-forming particles and a binder comprising a polymer, the polymer sheet comprising at least one of a polyoxymethylene homopolymer and a polyoxymethylene copolymer;
assembling the printed sheets comprising the polymer sheets printed with toner material into a multilayer stack of printed sheets; and
depolymerizing the multilayer stack of printed sheets together to remove the polymer sheets; and
sintering the depolymerized stack to form the ceramic object.

### Claim 18 (depends on 17)

The method of claim 17, wherein: the polymer in the binder comprises at least one of a polyoxymethylene homopolymer and a polyoxymethylene copolymer.