| 摘要 |
PROBLEM TO BE SOLVED: To prevent the warpage, undulation or the like of a thin plate molded product by arranging a plurality of pin gates to a cavity and forming the upper and lower surfaces of the cavity so as to correct the deformation quantity of the cavity at the time of injection accompanied by the arrangement thereof. SOLUTION: A cavity 22 is formed between a fixed template 13 and a movable template 15 and a large number of pin gates 24 communicating with a runner 23 are arranged to an upper mold 14. The upper and lower surfaces 22a, 22b of the cavity 22 are respectively formed so as to expand toward the center part of the cavity 22 to be slightly curved. The expanding quantities of both of them are set so as to correspond to the deformation quantity of the cavity 22 at the time of injection expected by the arrangement of the pin gates 24. A molten resin injected from the respective pin gates 24 under pressure flows toward the center part of the cavity 22 while spreading in a ring shape. At this time, the center part of the cavity 22 expands to be deformed but, by the expanding formation of the cavity 22, a thin plate molded product having smooth upper and under surfaces can be molded. |
