Insert Overmolding

Plastic Insert Overmolding: The process by which small parts of virtually any substance are combined into a single component through the injection of plastic into a cavity and around an insert piece placed into the same cavity. Some common applications are:

  • Metal bushings, levers, tubes, posts, threaded inserts, or studs
  • Electronic devices; current distribution parts, RFID housing, light bulb / LED connector
  • Medical devices; needle hubs,  tube valves, rehab products • Keys with electronics within the head
  • Tools; screwdrivers, wrenches, with soft grip handles
  • Knobs for appliances, switches or mechanical parts

The above mentioned products are representative of example insert molded products but do not by any means represent our full capabilities.

Overmolding Materials: Plastic Insert Molding is similar to the other processes at Mountain Mold and Die, in that it can be done with a wide variety of materials including:

  • polyethylene
  • polypropylene
  • polyvinyl chloride
  • thermoplastic elastomers


Benefits: Plastic Insert Molding is most often used as an efficient means of replacing common assembly methods due to the following benefits:

  • Reduced labor and assembly costs 
  • More reliability
  • Reduced size and weight 
  • More design options