Process for producing a moulding using a water-soluble casting mould and material system for the production thereof
View Patent ↗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 ).
1. A method for producing a molded part, comprising the following steps:
a) producing a water-soluble casting mold using a layering method, wherein the layering method is a powder bed-based layering method where particulate material is applied in thin layers and selectively printed upon with a computer-controlled print head;
b) sealing the surface of the casting mold with a sealing material including at least one water insoluble material;
c) generating a casting of the molded part by filling the casting mold with a free-flowing, hardenable material; and
d) dissolving the casting mold with the aid of an aqueous solution, characterized in that the casting mold is produced in a 3D printing method;
wherein the particulate material includes a sand, a gypsum, a metal, or a ceramic powder:
the sealing material penetrates pores between individual particles of the casting mold;
a material of the casting mold in the layering method includes a binder;
the hardenable material is capable of a binding action with the binder or the partiuclate material, and
the sealing material prevents the binding action.
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 an underpressure above an ambient pressure or an overpressure below the ambient pressure 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 is dissolved by immersion in a bath containing the heated aqueous solution.
5. The method of claim 4 , wherein the dissolution is accelerated by:
movements of the casting mold within the bath; or
the application of ultrasound.
6. The method according to claim 1 , characterized in that the hardenable material includes a casting polyamide.
7. The method of claim 1 , wherein the free-flowing, hardenable material is a hydraulically setting material.
8. The method of claim 1 , wherein the aqueous solution is a heated aqueous solution.
9. The method of claim 7 , wherein the water-soluble casting mold includes at least one water-soluble binder.
10. The method of claim 9 , wherein the at least one water-soluble binder includes at least one inorganic compound.
11. The method of claim 10 , 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.
12. The method of claim 9 , wherein the sealing material includes a water-insoluble material including a wax or a water-insoluble polymer.
13. The method of claim 12 , 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 above an ambient pressure or an overpressure below the ambient pressure 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 being accelerated by movements of the casting mold within the bath or by a temperature increase and/or by the application of ultrasound.
14. The method of claim 1 , wherein the water-soluble casting mold is produced from a material system including
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) the sealing material for sealing the surface of the casting mold.
15. The method of claim 14 , wherein the sealing material for sealing the surface of the casting mold includes a wax, at least one fatty acid, at least one water-insoluble polymer, stearyl alcohol and/or cetyl alcohol, or a mixture thereof.
16. The method of claim 15 , 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 above an ambient pressure or an overpressure below the ambient pressure 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 being accelerated by movements of the casting mold within the bath or by a temperature increase and/or by the application of ultrasound.
17. The method of claim 1 , wherein the dissolving of the casting mold is after the casting has solidified and the aqueous solution is temperature controlled.
18. The method of claim 1 , wherein the binding action includes a chemical reaction of the hardenable material with the binder or the partiuclate material, and wherein the sealing material prevents the chemical reaction.
19. The method of claim 1 , wherein the method includes a step of washing the water-insoluble material off of the molded part.
20. The method of claim 1 , wherein the hardenable material includes a free-flowing material that transitions to a hardened state by a polymerization reaction.
21. The method of claim 1 , wherein the casting mold has a rough surface and the sealing material smooths the surface.
22. The method of claim 1 , wherein the casting mold is cleaned and a surface is mechanically processed before the step of sealing.
23. The method of claim 1 , wherein the sealing material includes a wax, a fatty acid, a water-insoluble polymer, a stearyl alcohol, or a cetyl alcohol.
24. The method of claim 1 , wherein the binding action includes hardening by forming a crystalline structure.
25. A method of for producing a molded part, comprising the following steps:
a. producing a water-soluble casting mold using a layering method, wherein the layering method is a powder bed-based layering method where particulate material is applied in thin layers and selectively printed upon with a computer-controlled print head;
b. sealing the surface of the casting mold with a sealing material including a water insoluble material including at least one water insoluble material;
c. generating a casting of the molded part by filling the casting mold with a free-flowing, hardenable material; and
d. dissolving the casting mold with the aid of a heated aqueous solution, wherein the casting mold is produced in a 3D printing method;
the sealing material penetrates pores between individual particles of the casting mold;
a material of the casting mold in the layering method includes a binder;
the hardenable material is capable of a binding action with the binder or the partiuclate material, and
the sealing material prevents the binding action.
26. The method of claim 25 , 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 above an ambient pressure or an overpressure below the ambient pressure 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 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.