26, September, 2011
If you take a close look at the products around you, you will notice that many are made of parts that have been assembled together. To make a plastic part for a product, the manufacturer has to first commission a mold-making company to design and produce a plastic injection mold. The mold begins as bars of chromium steel - a high-durability metal that can withstand repeated high pressure injection of plastic. Workers assemble several bars into a block called a mold base. They melt this base on a milling machine which shaves the bars to the right dimension to get a mold that's accurate to the 100th of a millimeter. A mold usually consists of two halves, each of which is comprised of several components. The factory drills strategically positioned holes in the bases for the guide pins and bushings to hold the components together when the plastic's injected. A grinder is then used to smooth and level all surfaces. This prepares the base for the high-precision machining operations...