Transfer molding is similar to compression molding, but has a transfer system on the top of the mold that feeds the rubber into cavities when the press is closed. The major difference between compression and transfer is that the uncured rubber is placed in a pot / ram combination built into the top of the mold. When pressure is applied by the closing of the press, the ram “transfers” the uncured rubber through small holes (sprues) in the pot directly into the cavities. The balance of the process is the same as is found in compression molding, except that, cure time is reduced due to preheating the rubber during the transfer process; finished parts are more consistent as the mold is closed prior to the transfer; and labor is reduced as preforms do not need to be loaded into the mold.
Minor Rubber’s transfer molding press capabilities for our compression line range from 12” x 12” to 85” x 108” with various press sizes in between.
Advantages of Transfer Molding
- Shorter production cycle than compression molding
- Less waste material and secondary trimming operations than compression molding
- Greater consistency of finished parts than compression molding
- Good for parts with inserts
Disadvantages to Transfer Molding
- Higher tool cost due to complexity of tool design
- Possible limitations on material and hardness
Looking for transfer molding services? Get a quote from Minor Rubber today!