Method of and apparatus for forming a unitary heat sink body

• US 5,562,146 A
• Filed: 02/24/1995
• Issued: 10/08/1996
• Est. Priority Date: 02/24/1995
• Status: Expired due to Fees

• Current Assignee: Wakefield Thermal Solutions, Inc. (The Heico Cos. LLC)
• Original Assignee: Wakefield Engineering, Inc.
• Inventors: Tremblay, Donald P., Madan, Nanak C., Harmon, Ronald A.
• Primary Examiner(s): Hail, III, Joseph J.
• Assistant Examiner(s): LIN, ING HOUR
• Application Number:
  US08/394,183
• Time in Patent Office: 592 Days
• Field of Search: 164/112, 164/332, 164/333, 164/334
• US Class Current: 164/112
• CPC Class Codes: B22D 19/0063 finned exchangers cylinders B22D19/0018

Abstract

A method of forming a unitary heat sink metal body by supporting one end of each plurality of flat metal plates or fins in a row so that the plates are spaced and parallel and casting a base about the freely extending ends of the plates. More specifically, the base is formed by die casting. Apparatus for carrying out the above method is also provided which includes a fixed base and a support for supporting a plurality of flat metal plates or fins in spaced parallel relationship so that one end of each plate engages the fixed base and the opposite end of each plate extends freely from the support. The freely extending ends of the plates are positioned within the cavity of a mold such as a die cast mold. The cavity of the mold is filled with molten metal for filling the spaces between the freely extending ends of the plates and forming the base of the heat sink when the molten metal solidifies.

Claims

1. A method of forming a unitary heat sink body for use in removal of heat from a heat generating electronic device, said body having a base and a plurality of spaced parallel fins extending from said base, said method comprising the following steps:

(a) supporting a first end of each of a plurality of flat plates in a row so that each plate is parallel to and spaced from adjacent plates and so that a second end of each of said plates which is opposite said first end extends freely;

(b) positioning the freely extending second ends of said row of plates in a substantially rectangular open cavity of a die casting mold;

(c) providing a seal between and around said plates at said cavity so that said cavity is completely closed by said seal and said plates;

(d) injecting molten metal into said cavity so that the free second end of each plate which is located within said cavity is completely surrounded by said molten metal;

(e) allowing said molten metal to solidify to form a rectangular base for supporting the second ends of said plates and thereby forming said unitary heat sink metal body having a base and projecting spaced parallel fins; and

(f) removing said unitary heat sink metal body from said cavity.

2. A method of forming a unitary heat sink body as recited in claim 1, wherein said method further comprises forming apertures in the freely extending ends of each of said plates prior to insertion of said freely extending ends into the cavity of said mold, whereby, when molten metal is injected into said cavity, said apertures will be filled with said molten metal to form a mechanical lock between the base and the fins of the heat sink metal body when the injected molten metal solidifies.

3. A method of forming a unitary heat sink body as recited in claim 1, wherein the freely extending ends of said plates are inserted partially into said cavity so that the freely extending ends of the plates are spaced from the surface of the cavity which faces said freely extending ends to enable molten metal to completely surround the portions of said freely extending ends which are located within said cavity.

4. A method of forming a unitary heat sink body as recited in claim 1, wherein the dimensions of the cavity and the opening to the cavity in a plane which is parallel to said opposing surface is greater than that of said row of plates so that the base of the heat sink body which is produced by said method has an outwardly extending ledge about the outer periphery of said row of fins of the heat sink metal body.

5. A method of forming a unitary heat sink body as recited in claim 1, wherein the first ends of said plates are supported by a base assembly which has a fixed outer surface which faces the cavity of said mold and which engages said first ends and a plurality of spaced bars which extend between said plates to maintain said plates in a spaced relationship.

6. A method of forming a unitary heat sink body as recited in claim 5, wherein said method further comprises utilizing a base assembly which has a fixed intermediate surface which surrounds said row of plates and which faces said cavity, said intermediate surface and said bars being utilized to provide a seal at said cavity.

7. A method of forming a unitary heat sink body as recited in claim 6, wherein the first ends of said plates are supported by a base assembly which has a base element and a spacing and sealing plate, said spacing and sealing plate being located between said mold and said base element and spaced from said base element, said fixed outer surface being located in said base element and said intermediate surface and said spaced bars being located in said spacing and sealing plate.

8. A method of forming a unitary heat sink body as recited in claim 6, comprising the step of adjustably locating the spacing and sealing plate at different fixed positions between the mold and base element relative to the base element to utilize plates which have different dimensions between their first and second ends.

9. Apparatus for forming a unitary heat sink body for use in removal of heat from a heat generating electronic device, said heat sink body having a generally rectangular base and a plurality of spaced parallel fins extending from said base, said apparatus comprising:

(a) supporting apparatus for supporting a plurality of generally rectangular flat plates of a heat conductive and heat dissipating material in a fixed position so that the plates are spaced and parallel and each plate has a freely extending end;

(b) a die cast mold which has a cavity and a generally rectangular opening to the cavity, said die cast mold being movable toward and away from the free ends of said plates between an inactive position in which the mold is substantially spaced from the plates and an active position in which the free ends of the plates extend into the cavity of the mold, said die cast mold having an aperture for enabling molten metal to be injected into said cavity; and

(c) sealing means for sealing the opening to said cavity around and between said plates so that when molten metal is injected into said cavity, the molten metal will enter the spaces between the free ends of the plates within the cavity for forming said base and for supporting said plates when the molten metal solidifies.

10. Apparatus for forming a unitary heat sink body as recited in claim 9, wherein width and length dimensions of said cavity and the opening to said cavity is greater than the length and width dimensions of said row of flat plates so that the base which is formed in said cavity has an outwardly extending ledge about the outer periphery of the fins which are formed from said plates.

11. Apparatus for forming a heat sink body as recited in claim 9, wherein said flat plates are metal.

12. Apparatus for forming a unitary heat sink body as recited in claim 9, wherein said supporting apparatus comprises:

(a) a fixed base which has a flat surface which faces said rectangular opening to the cavity of said die cast mold for engaging a first edge of each of said plates; and

(b) a spacing plate for maintaining said flat plates on said flat surface in said spaced parallel relationship so that the free ends of said flat plates face the cavity of said mold.

13. Apparatus for forming a unitary heat sink body as recited in claim 12, wherein said sealing means comprises a sealing surface on said spacing plate which faces said rectangular opening, said sealing surface being located between said flat plates and around the periphery of said plurality of flat plates so that said rectangular opening is completely closed by said flat plates and said sealing surface when the free ends of said flat plates are located within said cavity.

14. Apparatus for forming a unitary heat sink body as recited in claim 12, wherein said apparatus further comprises:

(a) a fixed frame which is fixed relative to said fixed base, said spacing plate being mounted on said fixed frame for movement toward and away from said opposing surface; and

(b) drive means operatively connected to said spacing plate for adjustably positioning said spacing plate relative to said opposing surface.

15. Apparatus for forming a unitary heat sink body as recited in claim 14, wherein said die cast mold is mounted on said fixed frame for movement toward and away from said opposing surface.

16. A method of forming a unitary heat sink body for use in removal of heat from a heat generating electronic device, said body having a base and a plurality of spaced fins which extend from the base, said method comprising the following steps:

(a) providing a first die member having a first face surface which contains a cavity;

(b) providing a second die member having a second face surface which has a socket which faces said cavity;

(c) interleaving a plurality of spacing plates with a plurality of fin plates so that one end of each fin plate extends freely beyond the spacing plates to form a plate cartridge in which fin plates alternate with spacer plates and said fin plates are aligned in a row, said fin plates being parallel and spaced from one another;

(d) inserting the plate cartridge within the socket so that said one end of each fin plate extends toward said cavity;

(e) moving one of said first and second die members toward the other of said first and second die members so that said first and second face surfaces abut and said one end of each fin plate extends into said cavity;

(f) injecting molten metal into said cavity so that said one end of each fin plates which is located within said cavity is completely surrounded by said molten metal;

(g) allowing said molten metal to solidify to form a base for supporting said one end of said fin plates and thereby forming a unitary heat sink body having a base and projecting spaced parallel fins; and

(h) removing said unitary heat sink metal body from said cavity.

17. A method of forming a unitary heat sink body as recited in claim 16, wherein said method further comprises:

(a) applying clamping pressure to said fin plates along the plane of each fin plate and parallel to the first face surface when the fin plates are located within the socket of the second die member; and

(b) applying clamping pressure to said fin plates transversely to the plane of each fin plate when the fin plates are located within the socket of the second die member.

18. A method of forming a unitary heat sink body as recited in claim 16, wherein the fin plates and the spacing plates in the plate cartridge are vertical when the cartridge is inserted within the socket of the second die member.

19. A method of forming a unitary heat sink body as recited in claim 16, wherein the fin plates and the spacing plates in the plate cartridge are horizontal when the cartridge is inserted within the socket of the second die member.

20. An injection die apparatus for forming a unitary heat sink body for use in removal of heat from a heat generating electronic device, said heat sink body having a base and a plurality of spaced parallel fins extending from said base, said injection die comprising:

(a) a first die member having a first face surface which contains a cavity;

(b) a second die member having a second face surface which faces said first face surface, said second face surface having a socket which faces said cavity;

(c) fin spacing and retaining means for maintaining a plurality of flat fin plates within said socket so that the fin plates are spaced in a row and so that each of said fin plates has a free end which extends beyond said second face surface toward said cavity; and

(d) one of said first and second die members being movable toward and away from the other of said first and second die members between an open position in which said first and second face surfaces are spaced from each other and a closed position in which said first and second face surface abut, said fins being insertable within said socket when said die members are in said open position so that when said die members are in said closed position, the free end of said fin plates extend into said cavity and said cavity is sealed by said second face surface and said fin spacing and retaining means, for enabling molten metal to be injected into said cavity and so that said molten metal enters the spaces between said fin plates to form said base for supporting said fin plates when said molten metal is allowed to solidify.

21. An injection die apparatus as recited in claim 20, wherein said die apparatus further comprises:

(a) first clamping means for applying pressure to said fin plates along the plane of each of said fin plates and parallel to said first face surface when said fin plates are located within said socket; and

(b) second clamping means for applying pressure to said fin plates transversely to the plane of each of said fin plates when said fin plates are located within said socket.

22. An injection die apparatus as recited in claim 21, wherein each of said first and second clamping means comprises:

(a) a first side wall of said socket;

(b) a second side wall of said socket which is mounted within said second die member for movement toward and away from said first side wall;

(c) biasing means for urging said second side wall away from said first side wall; and

(d) actuating means for moving said second side wall toward said first side wall against the bias of said biasing means.

23. An injection die apparatus as recited in claim 22, wherein said second side wall has an inner surface which faces said first side wall and an outer surface which faces away from said first side wall, said second face surface having an indent adjacent the outer surface of said second side wall and, wherein said actuating means comprises a projection on said first die member which extends toward said indent for engaging the outer surface of said second side wall and for moving said second side wall toward said first side wall when one of said first and second die members is moved to its closed position.

24. An injection die apparatus as recited in claim 20, wherein said fin spacing and retaining means comprises a cartridge for holding a plurality of fin plates so that the fin plates are spaced from one another and arranged in a row and the free ends of said fin plates extend beyond a first end of said cartridge, said cartridge having a second end which is opposite said first end, said socket being adapted to receive the second end of said cartridge.

25. An injection die apparatus as recited in claim 24, wherein said cartridge comprises:

(a) a plurality of spacing plates, each of said spacing plates having a first end edge at a first end of the spacing plate and a second end edge at a second end of the spacing plate which is opposite said first end edge, each of said spacing plates being adapted to retain one of said fin plates so that the free end of the fin plate extends beyond said second end edge; and

(b) holding means for aligning and connecting said spacing plates in a parallel stack so that said fin plates are parallel and aligned and spaced from one another in a row.

26. An injection die apparatus as recited in claim 25, wherein each of said spacing plates having a relatively thick portion adjacent said second end edge and a relatively thin portion adjacent said first end edge, said relatively thick and thin portions being separated by a transition surface which faces toward said first end edge, said fin having a broad side end, an end edge which is opposite said free end, said relatively thin portion being adapted to engage the broad side of one of said fin plates so that the end edge of said fin plates engages said transition surface, the combined thickness of one of said fin plates and the relatively thin portion of one of said spacing plates being equal to the thickness of the relatively thick portion of one of said spacing plates.

27. An injection die apparatus as recited in claim 26, wherein said holding means comprises at least one aperture in the relatively thick portion of each of said spacing plates and at least one retaining pin for extending through the apertures in said spacing plates.

28. An injection die apparatus as recited in claim 27, wherein said cartridge further comprises an end plate which abuts the last exposed fin plate in said row of fin plates which are combined with said spacing plates.

29. An injection die apparatus as recited in claim 25, wherein the second end edge of each of said spacing plates has a first profile configuration and said socket has an inner wall which is complementary with said first profile configuration.

30. An injection die apparatus as recited in claim 29, wherein one of said first and second profile configurations includes at least one projecting portion and the other of said first and second profile configurations includes at least one complementary recess portions.

31. An injection die apparatus as recited in claim 25, wherein said cartridge comprises:

(a) a plurality of spacing plates, each of said spacing plates having a first end edge at a first end of the spacing plate and a second end edge at a second end of the spacing plate which is opposite said first end edge, each of said spacing plates being adapted to retain one of said fin plates so that the free end of the fin plate extends beyond said second end edge, said spacing plates being interleaved with said fin plates; and

(b) a holder for supporting and aligning said spacing plates, said holder having a horizontal base for supporting said spacing plates and said fin plates and a vertical end wall which is fixed to said base, said end wall having a vertical alignment surface for engaging the first end edge of each of said spacing plates.

32. An injection die apparatus as recited in claim 31, wherein said second die member further comprises compression means for selectively compressing said cartridge transversely of the broad sides of said fin plates and said spacing plates.

33. An injection die apparatus as recited in claim 31, wherein each of said spacing plates has a relatively thick portion adjacent said second end edge and a relatively thin portion adjacent said first end edge, said relatively thick and thin portions being separated by a transition surface which faces toward said first end edge, said fin having a broad side end, an end edge which is opposite said free end, said relatively thin portion being adapted to engage the broad side of one of said fin plates so that the end edge of said fin plates engages said transition surface, the combined thickness of one of said fin plates and the relatively thin portion of one of said spacing plates being equal to the thickness of the relatively thick portion of one of said spacing plates.

34. An injection apparatus as recited in claim 33, wherein the relatively thick portion of each of said spacing plates has at least one aperture so that when all of said spacing plates are aligned and supported on said horizontal base, the apertures for all of the spacing plates are aligned to define a bore and wherein said second die member further comprises:

(a) a plunger which is mounted within said second die member for axial movement from an inactive position outside of said socket to an active position within said socket so that said plunger extends into the bore which is formed by the apertures in said spacing plates when the plunger is moved from its inactive position to its active position after said cartridge has been inserted within said socket; and

(b) drive means for moving said plunger between said active and inactive positions.

35. An injection die apparatus as recited in claim 31, wherein the second end edge of each of said spacing plates has a first profile configuration and said alignment surface has a second profile configuration which is complementary with said first profile configuration.

36. An injection die apparatus as recited in claim 35, wherein one of said first and second profile configurations includes at least one projecting portion and the other of said first and second profile configurations includes at least one complementary recess portion.

37. An injection apparatus as recited in claim 36, wherein the aperture in each of said spacer plates is rectangular and said plunger is rectangular in cross-section.

38. An injection apparatus as recited in claim 36, wherein said base has an upper surface for supporting said spacer plates and fin plates and said upper surface has a depression which is vertically aligned with said bore for receiving said plunger.

39. An injection apparatus as recited in claim 38, wherein said depression and the aperture in each of said spacer plates are rectangular and said plunger is rectangular in cross-section.

40. Apparatus for forming a unitary heat sink body for use in removal of heat from a heat generating electronic device, said heat sink body having a generally rectangular base and a plurality of spaced parallel fins extending from said base, said apparatus comprising:

(a) supporting apparatus for supporting a plurality of generally rectangular flat fin plates of a heat conductive and heat dissipating material in a fixed position so that the plates are parallel and spaced from one another and each fin plate has a freely extending end;

(b) a die cast mold which has a cavity and a generally rectangular opening to the cavity which faces the free ends of said fin plates;

(c) one of said die cast mold and said supporting apparatus being movable toward and away from the other of said die cast mold and said supporting apparatus between an inactive position in which the die cast mold is substantially spaced from said fin plates and an active position in which the fee ends of said fin plates extend into said cavity, said die cast mold having a passageway which leads to said cavity for enabling molten metal to be injected into said cavity; and

(d) sealing means for sealing the opening to said cavity around and between said fin plates so that when molten metal is injected into said cavity, the molten metal will enter the spaces between the free ends of the plates within the injection cavity for forming said base and for fixing said fin plates to the base when said molten metal solidifies.