Hot sprue system for diecasting

摘要

A sprue insert-set which substantially eliminates sprue castings and improves melt-flow in high-pressure hot-chamber diecasting. The insert-set consists of (i) a heated sprue body insert for mounting in the fixed dieblock of a die set and (ii) a cooled sprue tip insert for mounting in the moving dieblock of the die set. The body and tip inserts are mounted so that their inner ends mate with one another in the region of the die parting-line to conjointly form a curved transition channel that connects the sprue channel in the body insert with a runner channel formed along the parting-line of the die set. The temperatures of the body insert and the top insert can be controlled so that the freeze-point occurs in the transition channel and the melt in the sprue channel is able to run back into the machine nozzle at the end each shot, thereby eliminating sprue castings.