| 摘要 |
PURPOSE:To improve the yield of an injection molding machine by making it possible to produce a molded product which is thinner in plate thickness and higher in accuracy by using conventional metal molds by such an arrangement wherein the injection and control of pressure preservation of high pressure injection molding higher than a specified pressure are controlled by the feedback value of a sensor which detects the pressure inside the mold. CONSTITUTION:Resin flows into from a sprus 3 and a molded product 4 is formed. At this time, along the flowing passage of resin, inside-mold pressure sensors 7a-7c are protrusively installed to a plate 6 and the pressure of a forming mold is detected by means of protruded pins 5a-5c and since forming filler rate is improved as injection pressure is raised in sequence from a normal pressure of 1,600kg/cm<2>, it is known that high pressure injection is effective for molding a product of thin thickness. Depend on the setting of molding conditions, the pressure inside the mold may rise abnormally and there is a risk that the metal mold may be damaged or accidentally opened. As a means for preventing such a trouble, the values of plural inside-mold pressure sensors are measured, and when they exceed a measured value, the pressure of an injection cylinder is detected and injection pressure to be impressed on the injection cylinder and its speed are detected and the injection speed of the injection cylinder is controlled. |
