Transfer moulding is a kind of ‘half-way house’ between compression and injection moulding. If the shape of the product does not lend itself to compression moulding or the product includes a bonded metal part which cannot be accurately located unless the cavity is fully closed, then a transfer mould is often the appropriate choice for prototype, low and medium volume production.
The defining feature of a transfer mould is the inclusion of an uppermost pot and plunger assembly connected by feeds and gates to the cavity. A piece of uncured rubber is placed in the pot whence the plunger forces the rubber through the feeds and gates into the cavity. The extra heat which the compound picks up as it flows through these narrow channels gives a shorter vulcanisation time. A transfer mould will cost more than the equivalent compression mould because of the additional transfer mechanism.
For regular large batch sizes it may be more appropriate to injection mould the product. At Elastomer Engineering we can offer our customers all types of moulding techniques.