| 摘要 |
A sprue bush (10) for an injection-moulding apparatus includes a hollow, inner core piece (20) of stainless steel, through which a through-channel (16) extends from the injection-moulding machine to the gate and around which there is arranged a helically wound electric heating element (32). The heating element (32) and the inner core piece (20) are cast with a highly conductive cast part (34) of copper and covered by an outer shell (40) of stainless steel. Fastened in the through-channel (16) is a spiral inner body (42) of steel, by which a rotating or swirling motion is imparted to the melt upon flowing through the gate into the mould cavity (18). This has the advantage that, by reducing the molecular orientation of the melt in one direction, the strength of the product increases and any threading of the melt upon opening the mould for ejecting the product is reduced. <IMAGE>
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