VULCANISATION (INCLUDING PRESSES, AUTOCLAVES AND CONTINUOUS VULCANISATION)

Moulding

Introduction
All vulcanising methods can cause burns. Insulate hot machine surfaces to prevent accidental contact where possible. Otherwise, warning signs and protective clothing (for lower arms as well as hands) are likely to be required.

Compression moulding
Compression moulding is the most common moulding technique used in the rubber industry. It involves pressing uncured rubber between heated moulds so that the rubber compound first fills the mould cavity before curing to produce the finished article. The presses are usually hydraulically or pneumatically powered and the moulds can be heated electrically, by steam, or by oil.
Compression moulding presses are generally vertical (the moving platen is raised or lowered in the vertical plane). The bottom platen can be up stroking or the top platen down stroking. Moulds may be fixed to both the platens, part fixed to a platen, or totally free to be drawn out of the press and loaded and unloaded on a press table. These loose moulds are usually charged (loaded) and stripped (unloaded) by hand. On fixed mould presses, mechanical devices, such as ejector pins or strippers will speed up the operation. This can reduce the need for close approach by the operator but can introduce additional trapping hazards. When thin sheets such as car mats and gaskets, are being moulded it is possible to mould several items per press cycle by using several sets of moulds. Each mould is placed between platens in a multi-daylight press - the number of daylights is the number of spaces between the platens.