Casting Study: Drive Beck
The drive deck for Cherokee’s 5-1/4 in. WORM optical drive utilizes a ZA-12 graphite permanent mold casting. From the start, graphite permanent mold was the process of choice because of its economical tooling cost, good dimensional control, and low-volume economies. In this case, annual requirements run between 2,000 and 3,000 units. ZA-12 and graphite permanent mold casting satisfy two important manufacturing process requirements: stiffness and minimal machining. Previous experience with aluminium investment casting did not produce the required stiffness.
ZA-12’s high zinc content provides the deck with excellent sound and vibration dampening characteristics. The deck is cast square along all planes. The whole process is controlled to the point where the decks are ready for finish matching right out of the mold, eliminating preparatory machining. Three as-cast pads on the deck’s underside serve as machining locator points.