Transfer Molding

Rubber transfer molding

Precision molded rubber parts.

Our rubber transfer molding process allows you to produce both rubber items bonded to metal surfaces, and precision molded rubber parts.

As with compression molding, preformed rubber is used in a designated weight. Instead of placing this material into an open mold, however, the preformed rubber is inserted it into a cavity located above the mold and a “plunger” is used to force the preform into the mold as it melts with the application of heat and pressure. The plunger remains in place over the mold for a specified period of time.

The advantages of transfer molding over compression molding can include:

  • Fewer and simpler pre-forms;
  • Tighter tolerance control because the mold is not held open by excess material spilling out of the cavity parting line;
  • Colored rubber parts benefit because pre-forms can be cut by hand from raw material sheets, significantly reducing the chance of contamination that can come from mechanical prep;
  • The primary disadvantage is increased waste; the flash pad or rubber left after transfer is typically cured and has to be recycled or thrown out.

Transfer molding is good for high precision applications, can accommodate over-mold or rubber bonded to metal or other material parts and is great for colored compounds of rubber.

Some disadvantages: Labor intensive compared to injection molding and higher tooling costs than compression tools.

Let a TMI expert help you decide what method is best for your rubber product.