Transfer Molding is another method for molding thermoset materials where the design of the part is too complicated or unsuitable for compression molding. Transfer molding is often used when metal inserts, studs, connector pins, wear plates, electronic components or other parts are molded into the part.
With transfer molding, the mold is clamped closed first. The material charge is then loaded into a loading "pot" which is connected to the cavity with a short runner. The material is then "transferred" from the pot to the cavity via the runner under pressure exerted from a plunger that is hydraulically actuated against the material which has been loaded in the pot.