METHOD AND DEVICE FOR PRODUCING THREE-DIMENSIONAL MODELS USING A BINDING AGENT SYSTEM

• US 20160263828A1
• Filed: 10/29/2014
• Published: 09/15/2016
• Est. Priority Date: 10/30/2013
• Status: Active Grant

• Current Assignee: Voxeljet AG
• Original Assignee: Voxeljet AG
• Inventors: Ederer, Ingo, Gnther, Daniel, Recknagel, Ulrich, Mgele, Florian
• Granted Patent: US 10,786,945 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B29C 64/165 using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber
• CPC Class Codes: B29C 64/245 Platforms or substrates support structures intended to be sacrificed after manufacture B29C64/40
• CPC Class Codes: B29C 64/295 Heating elements
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 70/00 Materials specially adapted for additive manufacturing
• CPC Class Codes: C09K 23/00 Use of substances as emulsifying, wetting, dispersing, or foam-producing agents

Abstract

The invention relates to a method, a device and a binding agent system for producing three-dimensional models.

Claims

1. A method for producing a component, wherein the component is a 3D molded body, comprising the steps of:

(a) applying a particle layer to a building platform in a first step with the aid of a powder coater;

(b) selectively applying a binder in a second step with the aid of a dosing device;

(c) subjecting the applied layer or layers to a heat treatment in another step with the aid of a heat source;

(d) lowering the building platform by the thickness of one layer, or raising the powder coater by the thickness of one layer;

wherein steps a) through d) are repeated until the component is built up, and the heat treatment (c) carried out after every second or additional layer application step.

2. The method according to claim 1, wherein the heat treatment is carried out at a temperature of 100°

C. to 170°

C.

3. The method according to claim 1, wherein

the particulate material is selected from the group comprising sands, ceramic powders, metal powers, plastics, wood particles, fibrous materials, celluloses lactose powders, and any combination thereof, and

the particulate material preferably is a dry, free-flowing powder, a cohesive, firm powder or a liquid-based dispersion.

6. A binder system, suitable for a 3D printing method, according to claim 1, comprising or including at least one adhesive, which is hardenable by the supply of heat, and a solvent.

7. The binder system according to claim 6, wherein the adhesive is a thermally secondarily cross-linkable prepolymerisate, and the solvent is one or multiple alcohols and/or water, preferably comprising or including a novolak and/or resol system and a solvent and possibly other additives, preferably comprising or including a coating resin system for the shell molding method, the solvent preferably being an alcohol, preferably ethanol and/or 2-propanol, and/or an aqueous solution, preferably water and 2-propanol, the other additives preferably being selected from the group comprising tensides and antifoaming agents, the solvent preferably being alcohol-based and preferably containing no more than 30% resin, preferably furthermore including up to 5% polyol, preferably glycol, propylene glycol or xylitol, preferably characterized by a viscosity between 5 and 40 mPas, preferably 8 and 20 mPas, at room temperature, preferably characterized by a surface tension of 20 to 40 mN/m, preferably 25 to 35 mN/m, at room temperature, preferably characterized by a vapor pressure of the binder system which is no higher than 55 hPa, particularly preferably no higher than 40 hPa.

8. The method of claim 1, wherein the heat treatment step is carried out at a temperature of 130°

C. to 160°

C.

9. The method of claim 8, wherein the heat treatment step is carried out after every second to seventh layer application.

10. The method of claim 9, wherein the heat treatment step is carried out after every fourth to sixth layer application.

11. The method of claim 8, wherein the heat treatment step is carried out after every fifth layer application.

12. The method of claim 8, wherein the particulate material is temperature-regulated on the building platform and having a temperature which is no less than 50°

C. to 70°

C.

13. The method of claim 8, wherein the binder is selectively applied with the aid of an ink-jet print head or a filament dispenser.

14. The method of claim 1, wherein the component is subjected to another heat treatment step.

15. The method of claim 14, wherein the additional heat treatment step is after a step of unpacking the component.

16. The method of claim 15, wherein the additional heat treatment step is at a temperature of 150°

C. to 200°

C.

17. The method of claim 16, wherein the preferably taking place after unpacking.

18. The method of claim 1, wherein the binder includes at least one adhesive, which is hardenable by the supply of heat, and a solvent.

19. The method of claim 1, wherein the binder includes a novolak and/or a resol system.

20. The method of claim 18, wherein the binder system includes a coating resin system for a shell molding method and the solvent includes an alcohol.

4. A device for 3D printing comprising:

(a) a powder coater,

(b) building platform,

(c) at least one dosing device for a binder,

(d) at least one heat source, and

(e) a lifting device (605) for lowering and raising the building platform (102) or the powder coater and the heat source, and

(f) a counting means for counting powder layers applied by the powder coater.

5. The device according to claim 4, wherein the device additionally includes a contact heater or a hot air device, the dosing device preferably being designed in the form of an ink-jet printing system, the dosing device preferably being designed in the form of a liquid filament dispenser.