| 摘要 |
PURPOSE:To decrease the molding failures of ceramic or resin products, by detecting the positions of screw at the times when the filling of materials is completed and when the pressure in a mold is retained to the prescribed amount. CONSTITUTION:After the start of molding the following positions L of a screw 2 are compared by the signal processing circuit 12; the position L1=L at the time of completion of filling when a pressure sensor 11 gives a signal, the posi tion L2=L at the time of completion of retention after retention pressure is given in a definite time. When the difference DELTAL=L2-L1 is more than preset value, the quantity of back-flow is judged as more than specification and it is displayed by an alarming tool 15. Operator exchanges a check valve 8 in accordance with this alarm, and starts again molding at normal condition. Thus, because the quantity of the back-flow of resin material is detected with the changes of the positions of the screw 2, it is possible to find the frictional wear of the check valve 8 and prevent the molding failures substantially before the molding failures occur for the reason why the retention pressure in a cavity 5 is not sufficiently obtained owing to the increase of the quantity of back-flow. |
