The web is full of diagrams and descriptions of injection molding so we won't get into it much here. Injection molding is one of the main ways that plastics are processed today. During the injection molding process, the material is fed into the machine through a hopper (it looks like a funnel) an is melted as it passes through the screw and then injected into a mold cavity. Once the melted plastic is in the mold, it cools to the shape of the mold cavity. In the past, finished parts needed further processing like cutting off the flashings or polishing the ejection pin contact points. Modern machines have solved most of these challenges through the use of hot runners and close cooperation with material suppliers to develop just the right material. Bosses, ribs, and screw threads can be formed during the one-step injection molding process. Websites www.protomold.com have a vast library of resources that can help you when choosing or designing your injection molded parts. If you're in the market for an injection molding machine, you can find them easily on websites like alibaba.com or you can contact us and we'll point you to some of the most respected manufacturers in Taiwan. Injection molded machines can process many types of plastic such as PP, PE, PET (pictured), ABS and more.