| 摘要 |
<p>Die casting machine has a sprue for injecting molten metal into a die cavity and a plunger which is slidable in a sleeve connecting to another portion of the die cavity and which acts to compress metal injected into the cavity and serve as a feeder. Forward movement of the plunger to displace molten metal that has entered the die-cavity end of the plunger sleeve is started shortly, e.g. 0.5 sec., after the cavity is filled with metal, and plunger and sleeve dimensions are made such that the amount, V, of feeder metal displaced by the plunger is V = Po-P/Po Va + Po - P/Po Vb. K (where Va = amount of molten metal injected into die cavity and plunger sleeve; Vb = amount of metal in the sprue; Po = density of a product die-cast without imposition of plunger pressure; P = true density of the metal introduced into the die cavity; and K = empirical feeder coefficient = 0.3. is approx. 1.0). Products with good air-tightness qualities are obtained and there is no metal forced back into the sprue.</p> |
