| 摘要 |
PURPOSE:To equalize the distribution of the residual stress of each section of a shape, and to obtain the injection-molded shape with no sink and warp by completely filling a die with a resin, decompressing resin pressure in the vicinity of a gate through a specific method and applying injection holding pressure again after a fixed time passes. CONSTITUTION:A melted resin 7 stored in the nose section of a screw 1 is injected and filled with high pressure into a die 4 by the advance of the screw 1. When pressure in the die 4 reaches to a set value, a reaching to the set value is detected by a die inside resin pressure sensor 15, and transmitted over a die inside set pressure gage 17. A signal is transmitted over a timer 18 from said pressure gage 17, and a solenoid valve 10 is changed over. Consequently, the screw 1 is retreated, and the distribution of resin pressure in the die, which is higher near a gate 8 and lower in the terminal section of a shape 5, on a filling is reversed while cooling is advanced. When the timer 18 times out, the solenoid valve 10 is automatically changed over again, and pressure oil is forwarded from an injection oil pressure cylinder 9 to apply injection holding pressure, thus completing molding. |
