| 摘要 |
PURPOSE:To evaluate the hardness of a resin in a die gate accurately by determining whether a pressure transmits to a cavity through the resin after it is retained in the gate for fixed time. CONSTITUTION:An upper die 5 and a lower die 6 are closed to throw a resin into an opening 7. Then, as a hydraulic device 3 is driven to lower a plunger 4, the resin is forced into a cavity 10 through a gate 9. When the resin pressure in the cavity reaches P1, the action of the hydraulic device stops, where the resin pressure becomes zero. After the time elapses by Xt, the hydraulic device 3 restarts to lower the plunger to increase the resin until it shows the highest value P2 by a pressure indication comparator 14. As the time Xt is prolonged, the resin in the gate 9 comes to be hardened where the resin pressure fails to rise again. The value Xt is varied by stages and the value P2 is read out at each time. Even if the time Xt is further extended, the value P2 can remain high. In this case, it should be determined that the resin is hard to be hardened in the gate 9, that is, poor appearance is hard to take place in the molded product. |
