Custom Rubber Corp. has well over 100 years of institutional knowledge about transfer molding.
Similar to compression molding, transfer molding requires secondary raw material preparation into "pre-forms" that are loaded into a "pot." When the mold is closed, a "plunger" compresses the rubber in the "pot" and forces it through holes or sprues into the cavity to fill the part cavity.
The advantages of transfer molding over compression molding can include:
- Fewer and simpler pre-forms because one pre-form can fill hundreds of cavities.
- Tighter dimensional tolerance control because the mold is not held open by excess material spilling out of the cavity parting line; all the excess hold the "plunger" open from the "pot."
- 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 for compression molding or the injection screw and barrel in injection molding.
The primary disadvantage is increased waste; the "flash pad" or rubber left in the pot after transfer is typically cured and has to be recycled or thrown out.
Custom Rubber Corp. is an active member of the RMA (Rubber Manufacturer's Association) and one benefit to that membership is access to industry-specific operator training for all of our manufacturing methods. If you are interested in seeing a preview of the type of training all of our operators receive, you can visit the online site and learn a little about molded rubber.