| 摘要 |
<p>Mouldings are produced by a pressure casting process using a destructible mould comprising a number of parts assembled onto a core such that the inside of the resulting mould defines the part to be moulded. Caps are fitted to the ends of the core to form a unit which is mounted in a chamber which can be placed under vacuum. The caps are sealed, the mould is placed under vacuum, and a synthetic material, esp. a silicone elastomer compsn, is injected into the mould cavity. The moulding unit is then removed from the chamber together with the moulding, the assembly is subjected to conditions whereby the mould is destroyed, the caps are released and the moulding is recovered. Pref. the mould core is an epoxy/glass bar; the mould parts are of polystyrene; the moulding material is a silicone elastomer; and the moulding chamber is of a transparent material such as PMMA or PVC. Process foruded high quality, bubble-free, perfect mouldings at high rates of prodn. the process is esp. useful for moulding high tension electrical insulators.</p> |
