Hot Stamping Die Apparatus

• US 20090320547A1
• Filed: 07/12/2007
• Published: 12/31/2009
• Est. Priority Date: 07/17/2006
• Status: Active Grant

• Current Assignee: Magna International Incorporated
• Original Assignee: Magna International Incorporated
• Inventors: Hansen, Monty, Shulkin, Boris, Hastilow, Bradford L., Judkins, James R., Janssen, Andreas G., Metz, Jim, Kotagiri, Seetarama S., Horton, Frank A.
• Granted Patent: US 8,215,147 B2
• Time in Patent Office: Days
• US Class Current: 72/342.3
• CPC Class Codes: B21D 22/022 by heating the blank or stamping associated with heat treatment C21D takes precedence
• CPC Class Codes: B21D 37/16 Heating or cooling
• CPC Class Codes: B21J 13/02 Dies or mountings therefor

Abstract

A hot forming die that includes a first die and a second die. The first die has a first die structure that is formed of a tool steel. The first die structure has a first die surface and a plurality of first cooling apertures. The first die surface has a complex shape. The first cooling apertures are spaced apart from the die surface by a first predetermined distance. The second die has a second die surface. The first and second die surfaces cooperate to form a die cavity. Related methods for forming a hot forming die and for hot forming a workpiece are also provided.

Claims

1. A method comprising:

providing a first die having a first die structure;

forming a first die surface on the first die structure, the first die surface having a complex shape;

forming a plurality of cooling channels in the first die structure, each of the cooling channels having a contour that generally follows the complex shape of the first die surface; and

forming a second die with a second die surface, the first and second die surfaces cooperating to form a die cavity.

2. The method of claim 1, wherein the first die structure includes a first die member and wherein forming the plurality of cooling channels comprises:

forming a plurality of slots in a surface of the first die member opposite the first die surface;

forming a plurality of filler plates; and

inserting each filler plate to an associated one of the slots, each filler plate cooperating with the associated one of the slots to form an inlet port and an outlet port.

3. The method of claim 2, further comprising:

providing a base having an cooling fluid inlet and a cooling fluid outlet;

securing the first die member to the base such that the cooling fluid inlet is coupled in fluid connection to the inlet ports; and

providing a flow of cooling fluid to the base, the cooling fluid entering the cooling channels from the inlet ports and exiting the cooling channels from the outlet ports.

4. The method of claim 1, wherein the first die structure includes a first member and a second member, the first member forming a first shell into which the second member is at least partially disposed.

5. The method of claim 4, wherein the first die structure includes an end member that is fixedly coupled to an associated end of the first member, the end member cooperating with the second member to fill the first shell.

6. The method of claim 5, wherein at least one cooling channel is formed between the first member and the end member.

7. The method of claim 6, wherein the second die surface is formed on a second die structure, and wherein the second die structure includes a first member and a second member, the first member of the second die structure forming a second shell into which the second member of the second die structure is at least partially disposed.

8. The method of claim 7, further comprising:

coupling at least a portion of the first shell to at least a portion of the second shell to form a shell assembly; and

heat treating the shell assembly.

9. The method of claim 8, wherein the at least the portion of the first shell is welded to the at least the portion of the second shell.

10. A hot forming die comprising:

a first die having a first die structure that is formed of a tool steel, the first die structure having a first die surface and a plurality of first cooling apertures, the first die surface having a complex shape, the first cooling apertures being spaced apart from the die surface by a first predetermined distance; and

a second die having a second die surface, the first and second die surfaces cooperating to form a die cavity.

11. The hot forming die of claim 10, wherein the second die has a plurality of second cooling apertures being spaced apart from the second die surface by a second predetermined distance.

12. The hot forming die of claim 10, wherein the first die structure includes a first member and a second member, the first member defining a first shell, the second member being at least partially received into the shell and cooperating with the first member to define at least a portion of the first cooling apertures.

13. The hot forming die of claim 10, wherein the first die structure further includes an end member, the end member cooperating with the first member to define another portion of the first cooling apertures, the end member being fixedly coupled to an end of the first member.

14. The hot forming die of claim 10, wherein the first die structure includes a die member and a plurality of filler plates, the die member defining a plurality of slots, each filler plate being received into an associated slot and cooperating with the slot to form an associated one of the first cooling apertures.

15. A method of hot forming a workpiece comprising:

providing a die with an upper die and a lower die, each of the upper and lower dies including a die structure that defines a die surface and a plurality of cooling channels, the die surface having a complex shape, the cooling channels being spaced apart from the die surface in a manner that generally matches a contour of the die surface, the die surfaces cooperating to form a die cavity;

heating a steel sheet blank;

placing the heated steel sheet blank between the upper and lower dies;

closing the upper and lower dies to form the workpiece in the cavity;

cooling the die structures of the upper and lower dies to quench the workpiece in the cavity; and

ejecting the quenched workpiece from the cavity.

16. A method comprising:

providing a first member that at least partially defines a first forming surface, the first member forming a shell;

forming a second member that is received into the shell, the second member at least partially supporting the first member, the first and second members cooperating to at least partially define a first die structure;

forming a second die with a second forming surface, the first and second dies cooperating to define a die cavity.

17. The method of claim 16, further comprising forming a cooling channel between the first member and the second member, a portion of the cooling channel being offset from the first forming surface in a direction that is parallel to a die action direction.

18. The method of claim 17, wherein the portion of the cooling channel is offset by a uniform spacing from the first forming surface.

19. A hot forming die comprising:

a first die having a first member and a second member, the first member at least partially defining a first forming surface, the first member forming a shell, the second member being received into the shell and at least partially supporting the first member; and

a second die having a second forming surface, the first and second dies cooperating to define a die cavity.

20. The hot forming die of claim 19, wherein a cooling channel is formed between the first member and the second member, a portion of the cooling channel being offset from the first forming surface in a direction that is parallel to a die action direction.

21. The hot forming die of claim 20, wherein the portion of the cooling channel is offset by a uniform spacing from the first forming surface.

22. A method comprising:

providing a die with an upper die and a lower die, each of the upper and lower dies including a die structure that defines a die surface having a complex shape;

placing a heated blank between the upper and lower dies;

closing the upper and lower dies to form, quench and cool a workpiece in the die;

removing the workpiece from the die; and

repeating each of the above three steps to produce additional workpieces at a rate of at least 120 workpieces per hour.

23. The method of claim 22, wherein the rate is at least 180 workpieces per hour.

24. The method of claim 22, wherein an austenite-to-martensite phase transformation occurs during the quenching of the workpiece over the entirety of the workpiece.

25. The method of claim 24, wherein the austenite-to-martensite phase transformation occurs within about 4 seconds of the closing of the upper and lower dies.

26. The method of claim 22, wherein the heated blank is formed of steel and wherein the workpiece is void of significant amounts of pearlite and bainite after it has been removed from the die.