| 摘要 |
PURPOSE:To mold in rapid cycle an axially symmetrical optical part excellent in the accuracies of axial symmetry and of shape by a method wherein molten resin is filled at the predetermined resin filling speed in a cavity, the temperature of which is held at a certain fixed temperature lower than the softening temperature of the resin, and dwelled until the temperature of the resin lowers to its flow temperature. CONSTITUTION:The temperature TM of a cavity is a fixed temperature lower than the softening temperature of resin used by 5-10 deg.C. Heating medium delivered from a temperature controlling device 8 passes through an anti-scaling device 9 and flows into temperature controlling flow paths 5 of a fixed bushing 6 and of a movable bushing 7 and into frame temperature controlling flow paths 15 of a fixed mold 1 and of a movable mold 2 so as to heat the molds and, after that, flows back to the temperature controlling device 8 again. When the temperature of the cavity rises and converges to TM deg.C + or - tolerance or DELTATb deg.C, an appliance controlling device 12 lowers the outputs of heaters of the temperature controlling device 8 to their steady outputs upon the receipt of the signals from temperature sensors 14 and fills resin delivered from an injection molder 13 in the cavity 3. The preferable filling time P is M/V=1.5sec or less, in which M(cm<3>) is the volume of the cavity and V(cm<3>/sec) is the filling speed of resin. The dwelling of the injection molder 13 is stopped, when the temperature of the resin lowers down to the flow temperature of the resin. |
