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.