Method for the layered construction of models

• US 8,122,939 B2
• Filed: 08/18/2011
• Issued: 02/28/2012
• Est. Priority Date: 06/17/2003
• Status: Active Grant

• Current Assignee: Exone GMBH (Desktop Metal, Inc.)
• Original Assignee: Rainer Hochsmann
• Inventors: Hochsmann, Rainer
• Primary Examiner(s): Kerns, Kevin P
• Application Number:
  US13/212,640
• Publication Number:
  US 20110308755A1
• Time in Patent Office: 194 Days
• Field of Search: 164/525, 164/23, 164/4.1, 164/456
• US Class Current: 164/456
• 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: 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 80/00 Products made by additive manufacturing
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

Described is a procedure for layered composition of models, whereby at least a first material is applied to an assembly platform, followed by selective application of a second material layer; these two application steps are repeated until the required model is achieved and both materials form a solid structure in an appropriate mixture ratio. The first material comprises a molding sand; the first and/or second material comprises a bonding agent encompassing a salt-crystal binder and/or protein binder.

Claims

1. A method for producing a metal casting mold comprising:

a) applying to an assembly platform a layer of a first material, the first material comprising moulding sand particles;

b) mixing a bonding agent into a second material;

c) selectively applying the second material and the bonding agent mixture to a cross-sectional area of the first material, in a sufficient dose so that the bonding agent binds the moulding sand particles together;

d) removing the second material through drying after an appropriate reaction time has lapsed;

e) lowering the assembly platform; and

f) repeating steps a)-e) until the metal casting mold is achieved and both the first material and the bonding agent form a solid structure in an appropriate mixture ratio;

wherein the bonding agent includes a salt-crystal binder, protein binder, or both.

2. The method according to claim 1, wherein the moulding sand particles are coated with the bonding agent after the step of removing the second material is complete.

3. The method according to claim 1, wherein the second material essentially comprises water.

4. The method according to claim 1, wherein the second material is applied by means of droplet generation.

5. The method according to claim 1, wherein the second material is applied by means of screen printing or spraying through a template.

6. The method according to claim 1, wherein the moulding sand particles comprise quartz sand, zircon sand, olivine sand and/or fireclay sand.

7. The method according to claim 6, wherein the bonding agent further comprises magnesium sulphate, sodium polyphosphate, proteins, or a combination thereof.

8. The method according to claim 7, wherein the second material is applied by means of droplet generation.

9. The method according to claim 7, wherein the second material is applied by means of screen printing or spraying through a template.

10. The method according to claim 6, wherein the salt-crystal, the protein binder, or both comprises 3 percent by weight water before the salt-crystal binder, the protein binder, or both is applied to the assembly platform.

11. The method according to claim 1, wherein the bonding agent further comprises magnesium sulphate, sodium polyphosphate, and/or proteins.

12. The method according to claim 1, further including the step of casting a metal casting from the metal casting mould.

13. The method according to claim 1, further including the step of coring a metal casting formed using the metal casting mould through immersion in a water bath.

14. The method according to claim 13, further including the step of recycling the sand particles after the metal casting mould is cored.

15. The method according to claim 1, wherein the second material is removed by applying microwave radiation heating or warm air.

16. The method according to claim 1, wherein the salt-crystal, the protein binder, or both comprises 3 percent by weight water before the salt-crystal binder, the protein binder, or both is applied to the assembly platform.

17. The method according to claim 1, further including the step of coating the first material with the bonding agent and the second material mixture prior to applying the first material to the platform.

18. The method according to claim 1, wherein the first material is untreated prior to the bonding agent and the second material mixture being applied.

19. The method according to claim 1, wherein after the first material has dried the bonding agent crystallizes to bind the first material together.

20. The method according to claim 1, wherein a computer-controlled pressure head selectively applies the bonding agent and the second material mixture to the layer of first material.