Two-Shot Overmolding for Challenging Molded Parts

The Two-Shot molding process is used to "over-mold" a plastic substrate with another plastic material within a single molding cycle. Specialized injection molding machines are used with two injection units. Two-Shot machines use a rotary platen to rotate the mold cavities between two positions. A substrate is molded using the mold cavity located in position #1 while the substrate made in the previous cycle is over-molded with a second plastic material using the mold cavity now rotated to position #2. Both parts, substrate and over-molded substrate, are molded simultaneously.

Le Sueur Incorporated specializes in Two-Shot molding. We have (3) state-of-the-art, 400 ton Two-Shot Injection Molding work centers. These work centers utilize dedicated robotics for the placement of molded-in inserts and part extraction.

Due to the complexity of the tooling used for Two-Shot molding, the associated tooling can be a sizeable investment. Over-molding via "hand transfer", where a substrate is produced prior in a separate molding machine, then robotically or manually placed in another mold and over-molded in another machine is commonly performed on products when production volumes do not support the investment in Two-Shot tooling.

When over-molding a plastic substrate, material compatibility is essential between the selected TPE and the substrate to obtain cohesion between the materials during the over-molding process, if so desired.

Le Sueur Incorporated provides plastic injection molding and aluminum casting solutions for projects of all sizes. We use a range of equipment and technology to accommodate your unique requirements and offer design engineering assistance and prototype services to help ensure your design requirements are met. Contact us today to learn more about our injection molding services.