Method of making a heat sink assembly, heat sink assemblies made therefrom, and illumants using the heat sink assembly

1. A method of making a heat sink assembly, comprising:

forming a heat sink assembly comprising a polymer heat sink around a metal insert, the polymer heat sink comprising a thermally conductive polymer material, wherein the heat sink assembly has a contact pressure between the polymer heat sink and the metal insert; and

increasing the contact pressure.

2. The method of claim 1 , wherein the metal insert in the heat sink assembly has an exposed inner surface and has an outer surface in contact with the polymer heat sink, wherein increasing the contact pressure comprises shot peening the inner surface.

3. The method of claim 1 , wherein forming the heat sink assembly comprises

heating a mold to a mold temperature;

subsequent to the mold attaining the mold temperature, introducing the metal insert to the mold, wherein the metal insert has an insert temperature of 30° C. to 70° C. when it is inserted into the mold; and

over-molding the metal insert with the thermally conductive polymer material.

4. The method of claim 3 , further comprising, after introducing the metal insert to the mold, closing the mold, and wherein the over-molding is performed in less than or equal to 10 seconds of the closing of the mold.

5. The method of claim 4 , wherein the over-molding is performed in less than or equal to 5 seconds of the closing of the mold.

6. The method of claim 3 , wherein the insert temperature is 35° C. to 65° C.

7. The method of claim 6 , wherein the insert temperature is 40° C. to 60° C.

8. The method of claim 7 , wherein the insert temperature is 45° C. to 55° C.

9. The method of claim 3 , wherein the metal insert has an exposed inner surface and has an outer surface in contact with the polymer heat sink, wherein increasing the contact pressure comprises shot peening the inner surface.

10. The method of claim 1 , wherein the contact pressure is increased by greater than or equal to 10%.

11. The method of claim 1 , wherein the contact pressure is increased by greater than or equal to 25%.

12. The method of claim 1 , wherein increasing the contact pressure comprises increasing the contact pressure to a point such that during use, a use contact pressure between the metal insert and the polymer heat sink is greater than zero.

13. The method of claim 1 , wherein the metal insert has a surface roughness, and further comprising reducing the surface roughness prior to forming the heat sink assembly.

14. The method of claim 13 , further comprising at least one of grinding or polishing the metal insert prior to forming the heat sink assembly.

15. A heat sink assembly made by the method of claim 1 .

16. A method of making a heat sink assembly, comprising:

forming a heat sink assembly comprising a polymer heat sink around a metal insert, the polymer heat sink comprising a thermally conductive polymer material, wherein the metal insert has an exposed inner surface and has an outer surface in contact with the polymer heat sink; and

shot peening the inner surface of the heat sink assembly.

17. The method of claim 16 , wherein forming the heat sink assembly comprises:

heating a mold to a mold temperature;

subsequent to the mold attaining the mold temperature, introducing the metal insert to the mold, wherein the metal insert has an insert temperature of 30° C. to 70° C. when it is inserted into the mold; and

over-molding the metal insert with the thermally conductive polymer material.

18. The method of claim 17 , further comprising, after introducing the metal insert to the mold, closing the mold, and wherein the over-molding is performed in less than or equal to 5 seconds of the closing of the mold.

19. A method of making a heat sink assembly, comprising:

reducing a surface roughness of a metal insert; and

subsequent to reducing the surface roughness, forming a heat sink assembly comprising a polymer heat sink around the metal insert, the polymer heat sink comprising a thermally conductive polymer material, wherein the metal insert has an exposed inner surface and has an outer surface in contact with the polymer heat sink.

20. A method of making a heat sink assembly, comprising:

heating a mold to a mold temperature;

subsequent to the mold attaining the mold temperature, introducing a metal insert to the mold, wherein the metal insert has an insert temperature of 30° C. to 70° C. when it is inserted into the mold;

closing the mold; and

in less than or equal to 10 seconds of closing the mold, over-molding the metal insert with a thermally conductive polymer material to form a heat sink assembly.

21. An illuminant, comprising:

a light emitting diode;

a heat sink assembly thermally connected to the light emitting diode, wherein the heat sink assembly comprises a metal insert in physical contact with a polymer heat sink at an interface, wherein after the heat sink assembly was formed, a contact pressure between the metal insert and the polymer heat sink was increased; and

a housing comprising a reflector, wherein the light emitting diode is located in the housing in optical communication with the reflector.