Die-Casting Conditions for Pure Aluminum Heat Sink with Thin Fins

Heat sinks with thin and tall fins made from pure aluminum using die casting are in demand due to the higher thermal conductivity of pure aluminum compared to aluminum alloys. However, die casting of thin and tall fins using pure aluminum is considered difficult because of the poor castability of pure aluminum. Casting conditions suitable for pure aluminum heat sinks with tall and thin fins were identified from flow length tests using a narrow-gap spiral die. Based on these findings, casting of pure aluminum heat sinks with thin and tall fins was attempted. The casting conditions that extended the flow length of pure aluminum were different from the conventional theoretical conditions for aluminum alloy die casting. Discovery of this unique result was very useful for the production of pure aluminum heat sinks using die casting. Specifically, using the appropriate plunger speed and die temperature to extend the flow length was effective for filling the thin fins with molten metal. As a result, it was clarified that pure aluminum heat sinks with thin and tall fins, having a height of 50 mm, a draft angle of 0.5°, and a fin top thickness of 0.5 mm, could be successfully produced using die casting. The heat dissipation properties of the pure aluminum heat sink with thin and tall fins were also evaluated.