PURPOSE: To prevent a molded product from running short of the filling quantity or generating voids by providing dummy cavities for respective cavities and making the filling time of resin almost equal.
CONSTITUTION: Totally eight cavities 1a-1h are provided at equal intervals on both sides of four runner 8. There is the difference of resin filling time between cavities 1a and 1b which are closest to a cull 7 and cavities 1g and 1h furthest therefrom. In the case that four cavities 1 are disposed in parallel, the filling quantity in the same length of time gets less and less as the distance between the respective cavities and a cull 7 gets longer, and the filling quantity is reduced by the unit of 1/4 of the volume of cavity 1 for respective cavities, which results in the longer filling time corresponding to said reduction ratio. In order to make the filling time to that of cavities 1g and 1h, which requires the longest filling time, therefore, dummy cavities 21a and 21b having the volume of 3/4 of that of the cavity 1 are annexed to the cavities 1a and 1b, dummy cavities 21c and 21d having the volume of 1/2 of that of the cavity are annexed to the cavities 1c and 1d, and dummy cavities 21e and 21f having the volume of 1/4 of that of the cavity are annexed to the cavities 1e and 1f. The shortage of filling or the generation of voids is eliminated by said arrangement.
TAKAHASHI FUMIHITO
KOBAYASHI HITOSHI
