3D MULTI-STAGE METHOD

• US 20150273572A1
• Filed: 10/10/2013
• Published: 10/01/2015
• Est. Priority Date: 10/12/2012
• Status: Active Grant

• Current Assignee: Voxeljet AG
• Original Assignee: Voxeljet AG
• Inventors: Ederer, Ingo, Gnther, Daniel
• Granted Patent: US 10,052,682 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B22C 1/18 of inorganic agents B22C1/162 takes precedence
• CPC Class Codes: B22C 1/22 of resins or rosins
• CPC Class Codes: B22C 9/02 Sand moulds or like moulds for shaped castings
• 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 64/171 specially adapted for manufacturing multiple 3D objects
• CPC Class Codes: B33Y 70/10 Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
• CPC Class Codes: C04B 41/4584 Coating or impregnating of particulate or fibrous ceramic material C04B20/10, C04B35/628 take precedence
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

The present invention relates to a multi-stage method for producing one or multiple molded bodies, the method comprising the following steps: a) constructing one or multiple molded bodies in layers by repeatedly applying particulate material by the 3D printing method; b. a presolidification step for achieving a presolidification of the molded body; c. an unpacking step, wherein the unsolidified particulate material is separated from the presolidified molded body; d. a final solidification step, in which the molded body receives its final strength due to the action of thermal energy. The invention also relates to a device which may be used for this method.

Claims

1. A method for producing one or multiple molded bodies, wherein the method comprises the following steps:

a. constructing one or multiple molded bodies in layers by repeatedly applying particulate material by the 3D printing method;

b. a presolidification step for achieving a presolidification of the molded body;

c. an unpacking step, wherein the unsolidified particulate material is separated from the presolidified molded body; and

d. a final solidification step, in which the molded body receives its final strength due to the action of thermal energy.

2. The method according to claim 1, wherein the temperature in the final solidification step is from 110°

C. to 130°

C.

3. The method according to claim 1, wherein the particulate material is characterized by a single-phase coating or casing which includes one or multiple materials.

4. The method according to claim 3, wherein the coating or the casing is a binder.

5. The method according to claim 3, wherein the casing or coating comprises or includes thermoplastic polymers, soluble polymers, waxes, synthetic and natural resins, sugars, salts, inorganic network formers or water glasses.

6. The method according to claim 1, wherein the presolidification step takes place using a solvent comprising water, hydrocarbons, alcohols, esters, ethers, ketones, aldehydes, acetates, succinates, monomers, formaldehyde, phenol and mixtures thereof.

7. The method according to claim 3, wherein the binder contains polymerizable monomers.

8. The method according to claim 3, wherein the presolidified molded body has a flexural strength of more than 120 N/cm² and the molded body has a flexural strength of more than 250 N/cm² after the final solidification step;

wherein the material contained in the casing or coating contributes to the final strength or to the preliminary strength in the presolidification step and to the final strength in the final solidification step.

9. The method according to claim 3, wherein two different materials are contained in the casing or coating, the one material being essentially destined for the presolidification step and the other material essentially being destined for the final solidification step.

10. A device or device arrangement suitable for carrying out the method according to claim 1.

11. The method of claim 1, wherein

the molded body is subjected to one or multiple additional processing steps;

the molded body is solidified in the presolidification step to the extent that an unpacking from the unsolidified particulate material is possible, and the molded body essentially retains its shape defined in the 3D printing method;

the unpacking takes place manually or mechanically or in a robot-assisted manner;

the presolidified molded body (green body) has a flexural strength of more than 120 N/cm², preferably more than 200 N/cm², particularly preferably 120 to 400 N/cm² following the presolidification step;

the molded body has a flexural strength of more than 250 N/cm², preferably from 250 to 750 N/cm², preferably more than 750 N/cm², particularly preferably more than 1,000 N/cm², even more preferably more than 1,200 N/cm² after the final solidification step;

the presolidification step takes place without the introduction of additional thermal energy;

the presolidification step takes place using a solvent and/or a polymerization reaction;

the final solidification step takes place with the aid of heat treatment;

the body is heat-treated with the assistance of inert material.

12. The method of claim 11, wherein the presolidified molded body (green body) has a flexural strength of 120 to 400 N/cm² following the presolidification step;

and the molded body has a flexural strength of more than 750 N/cm² after the final solidification step.

13. The method of claim 1, wherein the temperature in the final solidification step is from 130°

C. to 150°

C.

14. The method of claim 1, wherein the temperature in the final solidification step is particularly preferably from 150°

C. to 200°

C.

15. The method of claim 2, wherein the temperature at the component is maintained within a time range of 2 to 24 hours.

16. The method of claim 15, wherein natural silica sand, kerphalite, cera beads, zircon sand, chromite sand, olivine sand, chamotte, corundum or glass spheres are used as the particulate material.

17. The method of claim 7, wherein the coating or casing contains materials for starting a polymerization with the binder.

18. The method of claim 9, wherein the coating or casing may preferably contain a color indicator which is activated by the binder.

19. The method of claim 18, wherein the one or multiple additional processing steps is/are selected from the group comprising polishing or dyeing.

20. The method of claim 11, wherein

the particulate material is characterized by a single-phase coating or casing which includes one or multiple materials;

coating or the casing is a binder;

the casing or coating comprises or includes thermoplastic polymers, soluble polymers, waxes, synthetic and natural resins, sugars, salts, inorganic network formers or water glasses;

the presolidification step takes place using a solvent comprising water, hydrocarbons, alcohols, esters, ethers, ketones, aldehydes, acetates, succinates, monomers, formaldehyde, phenol and mixtures thereof;

the coating or casing contains materials for starting a polymerization with the binder;

the presolidified molded body has a flexural strength of more than 120 N/cm² and the molded body has a flexural strength of more than 250 N/cm² after the final solidification step;

the material contained in the casing or coating contributes to the final strength or to the preliminary strength in the presolidification step and to the final strength in the final solidification step; and

two different materials are contained in the casing or coating, the one material being essentially destined for the presolidification step and the other material essentially being destined for the final solidification step.