Enkeijoimononodaikasutoyoigata

摘要

PURPOSE:To eliminate intrapment of gas into a dicasting product and to cast the defectless product in a casting die for die casting having an approximately cir- cular cavity by forming a vent hole to the position where said hole is apart from a parting line and where the relation between a reference radius and angle is specified. CONSTITUTION:The vent hole 8 is formed in the position where the parting plane 2 of a cavity is not included in a casting die for the die casting having the cavity 3 of which the projected shape is approximately circular. More specifically, the hole 8 is formed in the position within the sectorial projection plane sandwiched by the reference radius running the central point of the cavity 3 and paralleling with the inflow direction of the molten metal into the cavity 3 from the runner, and the radius of the angle (180 deg.+3/2alpha-10 deg.) and the radius of the angle (180 deg.+3/2alpha+10 deg.) from the reference radius, where the angle between said reference radius and the radius running the sprue is designated as alpha(0 deg.=alpha90 deg.), and apart by =0.1 X radius from the parting line. The smooth venting of gas is assured by such die construction and the die casting product having high quality without blowhole defects is obtd.