PROCESS FOR PRODUCING A MOULDING USING A WATER-SOLUBLE CASTING MOULD AND MATERIAL SYSTEM FOR THE PRODUCTION THEREOF

• US 20150375419A1
• Filed: 02/18/2014
• Published: 12/31/2015
• Est. Priority Date: 02/28/2013
• Status: Active Grant

• Current Assignee: Voxeljet AG
• Original Assignee: Fluid Solids AG, Voxeljet AG
• Inventors: Gnchtel, Ingo, Gnther, Daniel, Karrer, Beat
• Granted Patent: US 10,343,301 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B28B 7/342 which are at least partially destroyed, e.g. broken, molten, before demoulding; Moulding surfaces or spaces shaped by, or in, the ground, or sand or soil, whether bound or not; Cores consisting at least mainly of sand or soil, whether bound or not
• CPC Class Codes: B28B 7/346 Manufacture of moulds
• CPC Class Codes: B28B 7/36 Linings or coatings, e.g. removable, absorbent linings, permanent anti-stick coatings; Linings becoming a non-permanent layer of the moulded articlelubricating surfaces of moulds, cores or mandrels B28B7/38
• CPC Class Codes: B29C 33/3842 Manufacturing moulds, e.g. shaping the mould surface by machining
• CPC Class Codes: B29C 33/52 soluble or fusible in particular used in injection moulding B29C45/4457
• CPC Class Codes: B29C 33/56 Coatings , e.g. enameled or galvanised; Releasing, lubricating or separating agents in-mould coating B29C37/0028; using or applying separating agents B29C37/0067
• CPC Class Codes: B29C 64/10 Processes of additive manufacturing
• 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

Abstract

A method for producing molded parts (16), a water-soluble casting mold (6) being produced in a first step using a layering method, in particular using a powder bed-based layering method. In a second step, the surface of the casting mold (6) is sealed with the aid of a material (9; 10). A casting of the molded part (16) is then formed by filling the casting mold (6) with a free-flowing, hardenable material (13), in particular a hydraulically setting material. After the casting has solidified, the casting mold (6) is dissolved with the aid of an aqueous solution (18), in particular a heated aqueous solution (18). The present application furthermore relates to a material system for producing a water-soluble casting mold (6), comprising at least one water-soluble material for building a casting mold (6) in a layering method, as well as comprising at least one material (9; 10) for sealing the surface of the casting mold (6).

Claims

1. A method for producing a molded parts, comprising the following steps:

a) producing a water-soluble casting mold using a layering method;

b) sealing the surface of the casting mold with a sealing material;

c) generating a casting of the molded part by filling the casting mold with a free-flowing, hardenable material; and

dissolving the casting mold with the aid of an aqueous solution, in particular a temperature-controlled aqueous solution after the casting has solidified;

characterized in that the casting mold is produced in a 3D printing method.

2. The method according to claim 1, characterized in that the surface of the casting mold is sealed by immersion in a bath, by being sprayed and/or by being brushed with the sealing material.

3. The method according to claim 1, characterized in that underpressure or overpressure is applied to the casting mold when it is filled with the free-flowing, hardenable material, and/or the casting mold is subjected to a shaking motion or a temperature increase.

4. The method according to claim 1, characterized in that the casting mold (6) is dissolved by immersion in a bath (17) containing the aqueous solution (18), the dissolution preferably being accelerated by movements of the casting mold (6) within the bath (17) or by a temperature increase and/or by the application of ultrasound.

5. The method according to claim 1, characterized in that the dissolution of the casting mold takes place in an autoclave.

6. The method according to claim 1, characterized in that the casting mold is sealed with the aid of a thermal resistant material having a special thermal resistance for using casting polyamide as the hardenable material.

10. A molded part produced according to a method according to claim 1.

11. The method of claim 1, wherein the layering method is a powder bed-based layering method.

12. The method of claim 11, wherein the free-flowing, hardenable material is a hydraulically setting material.

13. The method of claim 1, wherein the sealing material includes at least one water soluble material.

14. The method of claim 12, wherein the sealing material includes at least one water soluble material.

15. The method of claim 13, wherein the at least one water soluble material comprises at least one particulate material and at least one water-soluble binder.

16. The method of claim 15, wherein the at least one water-soluble binder includes at least one inorganic compound.

17. The method of claim 16, wherein the at least one water-soluble binder includes at least one polysaccharide, at least one salt and/or at least one water-soluble polymer, or a mixture thereof.

18. The method of claim 13, wherein the sealing material includes a wax, at least one fatty acid, at least one water-insoluble polymer, stearyl alcohol and/or cetyl alcohol, or a mixture thereof.

19. The method of claim 13, wherein

the surface of the casting mold is sealed by immersion in a bath, by being sprayed and/or by being brushed with the sealing material;

an underpressure or an overpressure is applied to the casting mold when it is filled with the free-flowing, hardenable material, and/or the casting mold is subjected to a shaking motion or a temperature increase; and

the casting mold is dissolved by immersion in a bath containing the aqueous solution, the dissolution preferably being accelerated by movements of the casting mold within the bath or by a temperature increase and/or by the application of ultrasound.

20. The method of claim 16, wherein

the surface of the casting mold is sealed by immersion in a bath, by being sprayed and/or by being brushed with the sealing material;

an underpressure or an overpressure is applied to the casting mold when it is filled with the free-flowing, hardenable material, and/or the casting mold is subjected to a shaking motion or a temperature increase; and

the casting mold is dissolved by immersion in a bath containing the aqueous solution, the dissolution preferably being accelerated by movements of the casting mold within the bath or by a temperature increase and/or by the application of ultrasound;

and wherein the sealing material includes a wax, at least one fatty acid, at least one water-insoluble polymer, stearyl alcohol and/or cetyl alcohol, or a mixture thereof.

7. A material system for producing a water-soluble casting mold comprising:

a) at least one water-soluble material for building a casting mold in a layering method, which comprises at least one particulate material as well as at least one water-soluble binder; and

b) at least one sealing material for sealing the surface of the casting mold.

8. The material system according to claim 7, characterized in that the sealing material for sealing the casting mold comprises a wax, at least one fatty acid, at least one water-insoluble polymer, stearyl alcohol and/or cetyl alcohol, or a mixture thereof.

9. A casting mold produced with the aid of a material system according to claim 7.