System for Drying a Paste-Based Crafting Medium During Three-Dimensional Printing

Patent metadata

Field	Value
Publication number	US-2019337053-A1
Application number	US-201916403286-A
Country	US
Kind code	A1
Filing date	May 3, 2019
Priority date	May 4, 2018
Publication date	Nov 7, 2019
Grant date	—

Abstract

This invention relates to three-dimensional printing. This invention in particularly relates to a system for drying a paste-based crafting medium during three-dimensional printing and a method thereof. The system can comprise a dual printhead comprising a first dispensing nozzle for depositing the filament material for a mold layer in a flowable fluid form and a second dispensing nozzle for depositing the crafting medium, which is in a paste form. The system also includes a drying means which can be a heating system or a drying apparatus, that in some embodiments can be attached to the printhead. The three-dimensional imaging process for making objects, preferably metal objects or ceramic objects, on a layer-by-layer basis under the control of a data processing system is disclosed. The drying of the object or mold is crucial in the three-dimensional imaging process because it can affect the overall quality of the object. A solution to this problem is achieved in the present invention by using a drying step after finishing each layer of the object (both mold and paste). This is achieved in some embodiments by using a drying apparatus comprising a radiating heater and air circulation fan mounted on to the moving print head. The print head can repeatedly scan the printed layer and apply heat and air circulation to improve drying in a controlled manner. This system and method provides improved evenness in the drying and reduces the risk of cracks developing in the deposited object, and also reduces the risk of further problems during the subsequent processing steps to provide the finished object.

First claim

What is claimed is:

1 . A method for three-dimensionally printing a metal or ceramic object from a paste-based crafting medium comprising the steps of:
(a) depositing a layer of a crafting medium with a print head, and (b) drying the deposited layer from step (a) with a drying means, wherein steps (a) and (b) are performed prior to deposition of a further crafting medium layer.

2 . A method according to claim 1 wherein the drying step (b) is selected from,
(A) point drying of the deposited layer,
or (B) full area drying of the deposited layer.

3 . A method according to claim 1 wherein the drying means is provided by a drying head selected from a radiating heater, an infra-red heater, a circulating convective heater, a hot gas blowing heater, a contact heater, a resistance heater, or a microwave heater.

4 . A method according to claim 3 wherein the drying head follows (A) the same trajectory as the print head or (B) follows a trajectory that is different from that of the print head.

5 . A method according to claim 1 wherein the deposited layer of the crafting medium is heated to a temperature from about 20° C. to about 100° C. for deposition.

6 . A method according to claim 1 comprising drying the deposited layer from step (a) while simultaneously or subsequently decreasing the atmospheric pressure surrounding the crafting medium to facilitate said drying.

7 . A method according to claim 1 wherein the crafting medium comprises:
(i) from about 40% to about 80% by volume basis of a powder selected from metal powders, ceramic powders, and combinations, thereof;
(ii) from about 0.5% to about 10% by volume of a binder; and
(iii) from about 15% to about 60% by volume of an aqueous solvent.

8 . A method according to claim 1 wherein the crafting medium comprises:
(i) from about 40% to about 80% by volume basis of a powder selected from metal powders, ceramic powders, and combinations, thereof;
(ii) from about 0.5% to about 10% by volume of a binder; and
(iii) from about 15% to about 60% by volume of a non-aqueous solvent.

9 . A method according to claim 7 wherein the drying step (b) removes substantially all of the aqueous solvent from the deposited layer (a).

10 . A method according to claim 7 wherein the drying step (b) removes substantially all of the non-aqueous solvent from the deposited layer (a).

11 . A method according to claim 7 wherein the metal powder is selected from silver, gold, copper, tin, nickel, chromium, zinc, tungsten, cobalt, aluminum, molybdenum, boron, iron, titanium, vanadium, niobium, silicon, manganese, steel, metal alloys, and combinations thereof, or wherein the ceramic powder is selected from silicon carbide, boron carbide, aluminum carbide, tungsten carbide, titanium carbide, tantalum carbide, silicon nitride, boron nitride, aluminum nitride, titanium nitride, zirconium nitride, steatite, forsterite, alumina, zircon beryllia, magnesia, mullite, cordierite, aluminum titanate, zirconia, and combinations thereof.

12 . A method according to claim 7 wherein the binder is selected from organic binders, inorganic binders, and combinations thereof.

13 . A method according to claim 7 wherein said aqueous solvent is selected from water, or water in combination with one or more non-aqueous solvents selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, acetone, acetaldehyde, ethyl acetate, C2-C4 diols, glycerol, acetonitrile, and mixtures thereof.

14 . A method according to claim 8 wherein said non-aqueous solvent is selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, acetone, acetaldehyde, ethyl acetate, C2-C4 diols, glycerol, acetonitrile, and mixtures thereof.

15 . A method for three-dimensionally printing a metal or ceramic object from a paste-based crafting medium comprising the steps of:
(a) depositing a mold layer from a print head, (b) depositing a layer of a crafting medium with a print head within the confines of the mold layer, (c) drying the deposited layer from step (b) with a drying means, wherein steps (a), (b), and (c) are performed prior to deposition of a further crafting medium layer.

16 . A method according to claim 15 wherein the crafting medium deposited in step (b) is deposited at a volume in excess of the volume defined by the mold layer, and wherein the excess crafting medium deposited in step (b) is (A) removed prior to drying in step (c) or is (B) removed subsequent to drying in step (c).

17 . A method according to claim 15 wherein the mold layer comprises a thermoplastic polymer.

18 . A three-dimensionally printed article of manufacture prepared according to the method of claim 1 .

19 . A three-dimensionally printed article according to claim 18 prior to sintering.

20 . A system for continuously drying a paste-based crafting medium during three-dimensional printing of a metal or ceramic object comprising:
(a) a print head for depositing a layer of a crafting medium, and (b) a drying means for subsequently drying each deposited layer (a), wherein steps (a) and (b) are performed prior to deposition of a further crafting medium layer.

Assignees

• Addleap Ab
• Desktop Metal Inc

Inventors

• Moosberg Mats
• Barbati Alexander C

Classifications

• B29C64/40

  Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof · CPC title

• B22F12/10

  Auxiliary heating means · CPC title

• B22F10/50

  Treatment of workpieces or articles during build-up, e.g. treatments applied to fused layers during build-up · CPC title

• B22F12/90

  Means for process control, e.g. cameras or sensors · CPC title

• B22F3/24 Primary

  After-treatment of workpieces or articles {(B22F3/1146 takes precedence)} · CPC title