Processes for making metal prototype parts

• US 5,109,589 A
• Filed: 03/11/1991
• Issued: 05/05/1992
• Est. Priority Date: 03/11/1991
• Status: Expired due to Term

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Cramer, Paul S., Parkos, Joseph J. Jr., Lomasney, Gary M.
• Primary Examiner(s): Gorski, Joseph M.
• Assistant Examiner(s): VO, PETER DUNG BA
• Application Number:
  US07/667,782
• Time in Patent Office: 421 Days
• Field of Search: 29/447, 29/458, 29/423, 29/424, 29/527.1-527.6, 29/DIG. 12, 29/904, 174/35 R, 204/2-9, 204/281, 264/22, 427/54.1
• US Class Current: 29/527.4
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C25D 1/10 Moulds; Masks; Masterforms
• CPC Class Codes: Y10S 29/012 Method or apparatus with electroplating
• CPC Class Codes: Y10T 29/49812 Temporary protective coating, impregnation, or cast layer
• CPC Class Codes: Y10T 29/49984 and casting
• CPC Class Codes: Y10T 29/49986 Subsequent to metal working
• CPC Class Codes: Y10T 29/49989 Followed by cutting or removing material

Abstract

Processes for making metal prototype parts are described. The key steps of the invention include: making a computer aided design (CAD) file of the prototype part; modifying such file a first time to produce a file of a first mandrel upon which the part will be formed; modifying such file a second time to produce a second mandrel upon which a metal anode will be formed, the anode and first mandrel then being used in an electroplating process to form the prototype. Stereolithographic techniques are preferred for making the mandrels out of polymeric materials.

Claims

1. A process for making a metal part having internal and external surfaces, and a thickness, comprising:

(a) making a first mandrel having a surface upon which said part is made, by forming and joining together adjacent cross sections of the first mandrel;

(b) making a second mandrel having a surface, upon which a metal anode is made, by forming and joining together adjacent cross sections of the second mandrel;

(c) depositing a layer of metal having a contacting surface which is in contacting relation with the surface of the second mandrel to form the metal anode;

(d) removing the metal layer from the surface of the second mandrel, and then assembling the first mandrel with respect to the metal layer such that the surface of the first mandrel and the contacting surface of the metal layer are in opposing relation to each other, and wherein said making and depositing steps are carried out such that said surfaces of the first mandrel and the metal layer are spaced apart a uniform amount greater than the part thickness;

(e) placing the assembly in an electroplating solution, making the first mandrel cathodic and the metal layer anodic, and plating a metal layer onto the surface of the first mandrel, wherein the thickness of the metal layer is greater than or equal to the part thickness; and

(f) removing the metal layer on the first mandrel from said mandrel.

2. The process of claim 1, wherein the step of making the first and second mandrels comprises:

(a) generating a computer file of each mandrel; and

(b) guiding, by means of the file, an energy beam onto a polymeric liquid medium to form and join together adjacent cross sections of each mandrel.

3. The process of claim 2, wherein the energy beam is of the ultraviolet frequency range, and the medium is a photosensitive liquid polymer.

4. The process of claim 2, where said guiding step is conducted such that each mandrel cross section has a section thickness between 25 and 625 microns.

5. The process of claim 1, wherein the process for depositing metal onto the surface of the second mandrel is selected from the group of processes consisting of electrolytic plating, electroless plating, physical vapor deposition chemical vapor deposition and combinations thereof.

6. The process of claim 5, wherein the process for depositing metal onto the surface of the second mandrel is selected from the group of processes consisting of electrolytic plating, electroless plating and combinations thereof.

7. The process of claim 6, wherein the process for depositing metal onto the surface of the second mandrel uses a consumable anode.

8. The process of claim 6, wherein the process for depositing metal onto the surface of the second mandrel uses a nonconsumable anode.

9. The process of claim 1, wherein the first mandrel and metal layer each have an axis, and are assembled coaxial with each other such that the first mandrel is positioned radially outward of the metal layer.

10. The process of claim 1, the first mandrel and metal layer are assembled coaxial with each other such that the first mandrel is positioned radially inward of the metal layer.

11. The method of claim 1, wherein the process for removing the metal layer from the first mandrel is selected from the group of processes consisting of combusting the mandrel, chemically dissolving the mandrel, embrittling the mandrel followed by fracturing the mandrel by force, and combinations thereof.

12. The method of claim 11, wherein said process comprises embrittling the mandrel followed by fracturing the mandrel by force.

13. The process of claim 1, further comprising the step of treating the surface of the metal part.

14. The process of claim 13, wherein said treating step comprises applying a coating to the part.

15. The process of claim 13, wherein said coating is selected from the group of coatings consisting of ceramic, metallic, organic, or inorganic coatings, and combination thereof.

16. The process of claim 1, wherein the first mandrel and metal layer each have an axis, and are assembled coaxial with each other such that the first mandrel is positioned radially outward of the metal layer.

17. The process of claim 1, wherein the first mandrel and metal layer each have an axis, and are assembled coaxial with each other such that the first mandrel is positioned radially inward of the metal layer.

18. A process for making a metal part having internal and external surfaces, and a thickness, comprising:

(a) generating a computer file of the part, wherein the part is comprised of adjacent cross sections;

(b) making a first mandrel from said computer file, wherein said first mandrel has a surface and is comprises of adjacent cross sections, each cross section of said first mandrel corresponding to a cross section of the part, wherein the first mandrel is made by forming and joining together adjacent ones of said mandrel cross sections, and wherein the surface of the first mandrel and the internal surface of the part are offset by an amount equal to zero;

(c) making a second mandrel from said computer file, wherein said second mandrel has a surface and is comprised of adjacent cross sections, each cross section of said second mandrel corresponding to a cross section of said part, wherein the second mandrel is made by forming and joining together adjacent ones of said cross sections, and wherein the surface of the second mandrel is offset from the external surface of the part a constant amount greater than zero;

(d) depositing a layer of metal onto the surface of the second mandrel, and then removing the metal layer from said surface, wherein the layer is comprised of adjacent cross sections, and each cross section of said metal layer corresponds to a cross section of the part, wherein the thickness of the layer is greater than the thickness of the part;

(e) assembling the first mandrel with respect to the metal layer such that corresponding cross sections of the mandrel and metal layer are aligned with each other, and such that at all cross sections, the surface of the first mandrel is spaced from the surface of the metal layer a uniform distance greater than the thickness of the part;

(f) depositing metal having the thickness of the part onto the surface of the first mandrel using the layer, to form the part on the surface of the first mandrel;

(g) removing the part from the surface of the first mandrel.

19. The process of claim 18, wherein the step of making the first and second mandrels comprises:

(a) generating a computer file of each mandrel by modifying the computer file of the part; and

(b) guiding, by means of the mandrel computer file, an energy beam onto a polymeric liquid medium to form and join together adjacent cross sections of each mandrel.

20. The process of claim 19, wherein the process for depositing metal onto the surface of the second mandrel is selected from the group of processes consisting of electrolytic plating, electroless plating, physical vapor deposition chemical vapor deposition and combinations thereof.

21. The process of claim 20, wherein the process for depositing metal onto the surface of the second mandrel is selected from the group of processes consisting of electrolytic plating, electroless plating and combinations thereof.

22. The process of claim 21, wherein the process for depositing metal onto the surface of the second mandrel uses a consumable anode.

23. The process of claim 21, wherein the process for depositing metal onto the surface of the second mandrel uses a nonconsumable anode.

24. The process of claim 19, wherein the energy beam is of the ultraviolet frequency range, and the medium is a photosensitive liquid polymer.

25. The process of claim 19, where said guiding step is conducted such that each mandrel cross section has a section thickness between 25 and 625 microns.

26. The method of claim 18, where the process for removing the metal layer from the first mandrel is selected from the group of processes consisting of combusting the mandrel, chemically dissolving the mandrel, embrittling the mandrel followed by fracturing the mandrel by force, and combinations thereof.

27. The method of claim 26, wherein said process comprise embrittling the mandrel followed by fracturing the mandrel by force.

28. The process of claim 18, further comprising the step of treating the surface of the metal part.

29. The process of claim 28, wherein said treating step comprises applying a coating to the part.

30. The process of claim 28, wherein said coating is selected from the group of coatings consisting of ceramic, metallic, organic, and inorganic coatings, and combinations thereof.

31. A process for making a metal part having internal and external surfaces, a thickness, and an axis, comprising:

(a) generating a computer file of the part, wherein the part is comprised of adjacent cross sections;

(b) making a first mandrel by modifying the computer file of the part to form a computer file of the mandrel, and guiding, by means of the mandrel computer file, an ultraviolet energy beam onto a photosensitive liquid polymeric medium to form and join together adjacent cross sections of the mandrel, wherein the first mandrel has a surface, an axis and is comprised of adjacent cross sections, and each cross section of said first mandrel corresponding to a cross section of the part, and wherein the surface of the first mandrel and the internal surface of the part are offset by an amount equal to zero;

(c) making a second mandrel by modifying the computer file of the part to form a computer file of the mandrel, and guiding, by means of the mandrel computer file, an ultraviolet energy beam onto a photosensitive liquid polymeric medium to form and join together adjacent cross sections of the mandrel, wherein the second mandrel has a surface, and axis and is comprised of adjacent cross sections, and each cross section of said second mandrel corresponding to a cross section of the part, and wherein the surface of the second mandrel is offset from the external surface of the part a constant amount greater than zero;

(d) plating a layer of metal onto the surface of the second mandrel, and then removing the metal layer from said surface by embrittling the mandrel and then fracturing the mandrel by force, wherein the layer is comprised of adjacent cross sections, and each cross section of said layer corresponds to a cross section of the part, wherein the thickness of the layer is greater than the thickness of the part;

(e) assembling the first mandrel in coaxial relation with the metal layer such that corresponding cross sections of the mandrel and the metal layer are aligned with each other, and such that the surface of the first mandrel is spaced from the surface of the layer a constant amount, and such that the first mandrel is radially inward of the metal layer;

(f) electroplating metal onto the surface of the first mandrel using the metal layer as an anode to form the part on the surface, the electrodeposited metal having a thickness equal to the part thickness; and

(g) removing the part from the surface of the first mandrel by embrittling the mandrel and then fracturing it by force.