group: Plastic injection
Product group: Plastic injection
Injection molding is the most common method of producing parts out of plastic material. It is an extremely versatile process that is capable of producing parts with a wide range of attributes. Melted granular plastic is fed by gravity from a hopper dryer into a heated barrel. As the granulates are slowly moved forward by a screw-type plunger, the plastic is forced into a heated chamber, where it is melted. As the plunger advances, the melted plastic is forced through a nozzle that rests against the mold, allowing it to enter the mold cavity through a gate runner system. The mold remains cold so that the plastic solidifies almost as soon as the mold is filled. Once the part is sufficiently cool, the mold opens and the part is ejected.
Over molding technic:
1. Specially designed molds allow previously molded parts to be reinserted in a second mold to allow a new plastic layer to form around the first part.
2. 2-shot or multi-shot molds are designed to over mold within a single molding cycle and must be processed on specialized injection molding machines with two or more injection units. This process is actually an injection process performed twice. In the first step, the base color material is molded into a basic shape. Then the second material of different color is injected into the remaining open cavities. Without such over molding procedure many of the products we take for granted today would not exist.