| 摘要 |
PURPOSE:To reduce molding sink, mold shrinkage and residual stress and consequently carry out highly accurate molding by a method wherein comparatively low pressure, medium pressure and high pressure are applied to resin and temperature is raised and lowered between a first temperature, which is lower than the glass transition temperature of the resin under normal pressure, and a second temperature, which is higher than the glass transition temperature of the resin under comparatively low pressure, so as to interface pressure and temperature with each other. CONSTITUTION:To resin, comparatively low pressure of 30-200kgf/cm<2>, medium pressure of 200-600kgf/cm<2> and high pressure of 600-1,400kgf/cm<2> are applied. And, the temperature of cavity surface is raised and lowered between the temperature, which is lower than the glass transition temperature of the resin used by 5-20 deg.C under normal temperature, and the temperature, which is higher than the glass transition temperature of the resin used by 10-60 deg.C. The resin is filled at comparatively small pressure and compressed at high pressure at the time t1 so as to shift the glass transition temperature of the resin used up to about 130 deg.C in order to accelerate the solidification of the resin. Next, at the time t2, the raising of the temperature of the resin is started and, at the same time, the low pressure is applied to the resin. At the time t3, when the resin melts, the temperature of the resin is raised and, at the same time, the medium pressure is applied to the resin. Finally, at the time t4, when the temperature of the resin lowers to the temperature, which is lower than the glass transition temperature of the resin used under normal pressure by 5-10 deg.C, a mold is opened. |
