In it's simplest form, casting is a process by which molten metal is poured into a mold, allowed to cool and then the product is removed from the mold. That's the simple explanation, but doing it right is much more art than science. As a lapel pin manufacturer, we at StockPins.com take pride in making our cast pins right here in the USA using the finest materials available and decades of experience from dedicated team members.
As with any pin, it starts with the design and the design of the pin often dictates which manufacturing process is best. The cast process is great for dimensional designs - like our Great Job pin or this penguin lapel pin. Notice how the designs of these pins are 3D at multiple levels. Those rounded elements are well suited to the cast process (and would be much more difficult and sometimes impossible to achieve in the die struck process). The other design element is the finish. Our cast pins are created in the finest lead-free pewter but may be finished in gold, silver or other plated finishes. Pewter is a relatively soft metal and polishes well - it also takes a brushed or satin finish very well.
Once the pin is designed, it's time for our model makers to sculpt the 3D model of the pin. This is called the master model. While some manufacturers burn their models in magnesium we prefer to hand sculpt all our models. This allows our die makers to add extra detail that is not possible in a burned model. We feel this added attention to detail pays off by creating a superior product. We invest heavily in the master model - because that model is used to create the mold from which thousands of pins will be made.
The master model is then sunk in a rubber mold called the model mold. That mold will contain just one cavity - created from the master model. WIth each spin of the model mold, a casting is created. Depending upon the size of the product, we'll usually create a dozen or two castings from the model mold. Those castings are then placed onto rubber disks to create the production mold. The production mold will have anywhere from 12 - 36 cavities and each time metal is poured into the spinning production mold, 12-26 pins will be created.
Once the raw cast pins are removed from the production mold, they go through finishing processes - depending upon the desired look. They will all be deburred through a vibratory finishing process - but after that they may be plated (gold or silver) or they may be polished, they may take enamel color fills or a digital print with epoxy dome.