Investment casting is one of the oldest manufacturing techniques still being used today. To put it in the simplest terms, it involves liquid metal being poured into a mold, typically made of ceramic, and allowed to harden and cool. The ceramic mold is then blasted away, and voila, there’s your metal part. The ceramic mold itself is usually formed by covering a wax pattern with ceramic material; the wax is then melted away and the ceramic mold is ready to hold a liquid metal alloy. It’s a lot of material used in the process of creating one final part, and while it’s effective, it has its drawbacks, namely cost and material waste.
Apple’s patent application involves using 3D printing to form the mold. At first glance, this doesn’t sound like anything new or patentable – 3D printing is being used to manufacture just about everything, so why not molds for investment casting? What’s interesting is what Apple intends to do with the molds, however. The molds, formed layer by layer, can be configured for the formation of amorphous alloys, or glasslike metals that are typically used in the manufacture of medical equipment or electronic components, as they have good conductive properties. Their formation depends on the rate of the liquid metal’s cooling.
“However, little has been shown regarding how to utilize and/or shape these alloy systems into structural components, such as those in consumer electronic devices,” states Patently Apple. “In particular, pre-existing forming or processing methods often result in high product cost when it comes to high aspect ratio products (e.g., thin sheets) or three-dimensional hollow products. Moreover, the pre-existing methods can often suffer the drawbacks of producing products that lose many of the desirable mechanical properties as observed in an amorphous alloy.”
If you’d like to delve deeply into Apple’s proposal, you can read the entire patent application here. One thing that is very clear is that Apple is very fond of 3D printing and intends to incorporate it into its manufacturing processes; whether that fondness will eventually lead to an actual 3D printer still remains to be seen. What do you think Apple’s intentions are? Discuss in the Apple 3D Molds forum over at 3DPB.com.