deforming under load and then snapping back to almost original shape when the force is removed.
We Specialize in Small Rubber mouldings.
Common materials used :
Involves placing a properly shaped blank from the unvulcanized compound in each cavity of the mould.
The mould is then closed and placed in a hydraulic press. Under the applied pressure and heat the rubber will flow and completely
fill the mould cavity. The slight excess flows out through special groves. This excess is known as flash.
The mould remains closed under pressure for a prescribed period of time at a particular moulding temperature. Once this process is complete the mould is opened and the rubber moulding is removed.
A strip of the compound is fed into a heated cylinder and masticated by a screw, which then moves forward like a ram and forces this preheated stock through a nozzle into the mould cavities (Fig. 2.5c). As a result rubber mouldings can be vulcanized in very short times, usually reported in seconds (typical time is 30 seconds). Other advantages of injection moulding are reduced stock preparation costs and low cured scrap. However, both the moulds and the equipment are much more expensive than those used for compression and transfer moulding.
The postcure process usually lasts several hours (up to 24 hrs) at a considerably higher temperature than the vulcanization temperature in the press.
Postcure is carried out to improve one or more properties of the vulcanizate. Furthermore the decomposition products of the compounding ingredients are removed during the process.
Rubber to Metal Mouldings
O-Rings and Seals
Darac Ltd. Unit 9, Thesiger Close, Worthing, BN11 2RN, UK
Phone: 01903 331391
Company Reg: 03554943
VAT No. GB 717414935