Overmolding is an injection molding process where you cast a layer of resin (usually a rubber-like plastic called a TPE) over an already molded or machined material to give it properties that it would otherwise have.

While this process is cost-effective and helps provide excellent adhesion between materials, it requires proper planning. For example, engineers must select the right material to perform the function of the part and achieve maximum adhesion. This is one of the reasons why engineers must plan overmolding design guidelines correctly.

low-density polyethylene (LDPE) material is low-cost and is ideal for manufacturing secondary molded products such as valve components, food-grade items, storage chambers, and gas pipes. It also makes a great contribution to applications such as industrial food safety bagging, juice containers, medical prostheses, and extrusion molded components.

offer high performance and adaptability to molded products. These materials fall under the categories of thermoplastic vulcanizates, TPV, and some other related categories such as: thermoplastic polyolefin elastomers and styrene block copolymers. In addition to applications, TPEs are also very valuable in the manufacture of automotive sporting goods and footwear parts. Some common examples include air ducts, glass encapsulation, high/low pressure ducts, flippers, and sky-post handles.

has the lowest surface energy and is suitable for manufacturing parts such as threaded inserts and coupling parts manufacturing. Another high-performance engineering grade thermoplastic, polyetherimide (PEI), helps in engineering applications. High temperature resistance, the ability to mold really tight tolerance parts, customized solutions, and manufacturing high-standard scientific components are unique to this engineering grade plastic. In addition, whenever used in overmolding applications, it is usually overmolded onto a metal base part (substrate).

Hongsheng has been specialized in overmolding product customization for 20 years and has manufactured a large number of overmold tooling. Here is a Design For manufacturability Analysis (DFMA)of an overmolding product that our engineering team created before mold design and processing,making sure everything meets customer's expectation and applicable for mass manufacturing.