The invention relates generally to a hollow body type melt core of the type comprising a low-melting point temperature metal alloy for producing a cavity in a structural part manufactured by means of injection molding.
Melt cores, which are designed as hollow bodies that are open on one side, are generally known (see German Patent 2251435, the contents of which are incorporated herein by reference). To reduce the cycle time taken up by the melting of the core, large-volume melt cores are typically produced as hollow bodies. In the known methods, the melt cores are hollowed out, for example, by means of slide valves, thereby necessitating that the recess thereby created must be sealed again by a slide valve on the die. Depending upon the particular manufacturing process employed, an opening is formed in the structural part in the area where the slide valve of the die seals the hollow body, and after the core is melted, this opening is sealed by a core-hole cover. The costs for the die are increased because of the slide valve that is employed to seal the cavity of the melt core. This has the overall effect of lengthening the time required to manufacture an injected structural part.
There remains a need to further develop a melt core of the previously known type, so that subsequent sealing by means of an additional slide valve in the die is no longer needed, and the cycle times for producing structural parts can thus be shortened and manufacturing cost are reduced.