| 摘要 |
Die inserts and methods for use in high-pressure hot-chamber diecasting are disclosed which substantially eliminate sprue castings and greatly improve melt flow. The die inserts comprise (i) a heated sprue body insert (130, 258) adapted for location in the fixed dieblock (112) of a die set and having a sprue channel (136, 260) and (ii) a cooled sprue tip insert (132, 266) adapted mounting in the moving dieblock (114) of the die set. The sprue body and tip inserts are mounted coaxially so that their inner ends mate with one another in the region of the die parting-line (155) to conjointly form at least one curved transition channel (138, 262, 264) that connects the sprue channel (136, 260) with at least one runner channel (140, 254, 256) formed along the parting-line. The temperatures of the sprue body insert and the sprue tip insert are 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.
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