| 摘要 |
PURPOSE:To improve the durability of molds even when the molds, which are manufactured easily at low cost, are employed, by a method wherein a mold clamping force applied to the parting faces of the molds is controlled to the necessary minimum during injection process or period ranging from the start of injection of molten material in the molds to its end. CONSTITUTION:The molten material 11 in an injection cylinder 10 is injected in the inner space 15 of clamped molds 14 by shifting a screw 12 in the cylinder toward a nozzle 13 side. A detecting means 16 to detect the mold clamping force applied to the parting faces of the molds, and a control part 17, which variably controls the mold clamping force of a mold clamping device 18 during the period ranging from the start of injection of molten material in the inner space to its end on the basis of signals sent from the detecting means are equipped. The control part 17 controls the detected mold clamping force applying to the parting faces of the molds from the start to the end of injection to nearly constant minimum necessary mold clamping force by changing the mold clamping force applying to the mold clamping device 18. As a result, injection molding can be done without applying load, which is beyond the necessary pressure, to the parting faces of the molds, so the durability of the molds is improved, even when the molds are made of material having lower resistance to surface pressure.
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