DIECAST HEATSINK

A diecast heatsink uses the cast process by forcing molten metal under high pressure into a molded cavity. The molded cavity  of the diecast heatsink is created using a hardened tool steel die which is carefully machined into a predesignated shape.  The casting equipment and the metal dies represent large capital cost which tend to limit the process to high volume production applications.

Radian’s diecast heatsink utilizes a hot-chamber die casting process which relies upon a pool of molten metal to feed the die.  A pneumatic or hydraulic powered piston forces molten metal into the die. The advantages of this system include fast cycle times (approximately 15 cycles a minute).  Radian diecast heatsinks are primarily manufactured using aluminum based alloys (356.0, A380).

In the process to manufacture a diecast heatsink, two halves of a die are required in the die casting process. One half is called the “cover die half” and the other is called the “ejector die half”. A parting line is created on the part where the two die halves meet. The die is designed so that the finished casting will slide off the cover half of the die and remain in the ejector half as the die is opened. The ejector half contains ejector pins to push the casting out of the ejector die half.  In order to prevent damage to the casting, an ejector pin plate accurately drives all of the pins out of the ejector die at the same time and with the same force. The ejector pin plate also retracts the pins after ejecting the casting to prepare for the next shot.

Excess material such as metal extension can be removed from the ejected die cast heatsink through a secondary machining operation. Casting metal extension removal cost can be reduced if the amount of metal extension to be removed and the removal method to be employed are considered in the early stages of the design. For Multi-slide casting machine allow very complex designs but adds additional costs. For more information on the casting process we would recommend the following:

Radian can also provide rapid prototyping for a diecast heatsink using the same alloy without hard tooling which allows for addition changes to the mold.