Plastic Injection Overmolding Mould

Overmolding, soft plastic product (TPU parts) covers hard plastic product (ABS parts). General soft plastic products appear in the position that can be touched by the hand, or play the role of appearance decoration.

Overmolding is a process of double plasitc injection molding, the product is made up of hard ABS or PC plastic parts and soft plastic parts (TPU or others). In the plastic injecton mold manufacturing, the first processing of injection molding hard plastic body, the main body of hard plastic mold design according to the normal design procedure, the external plastic (soft plastic material) mold design should be based on the hard plastic finished product as a reference, without considering the shrinkage rate. The core mold part, roughly the same as the hard plastic body, the front mold (cavity) is different from the hard plastic shape, in the production of hard part body, and then put the hard part body into the soft part mold, the external soft plastic materials injection cover the hard part.

In the design process, the most key point of attention is the sealing position, because the hard plastic product into the mold, will participate in the sealing, so the hard plastic and mold sealing position, we often need to do over cutting in the depth direction, the size of over cutting is 0.1-0.3, the plastic is thick, shrink large, over cutting slightly more.

In the position of non-sealing glue, often made to clearance , this position is very easy to cause problems. To avoid soft plastic outside the projector surface can be more than some, if in the projector surface, clearance not more than 0.2, even do not clearance, the size of the product is just enough. Otherwise the product will be unable to withstand and damage when injection molding.