| 摘要 |
PURPOSE:To make it possible to reduce residual stress in a short period of time by a method wherein a molded item is heated by high frequency dielectric heating with frequencies, which are available for the resin of the molded item. CONSTITUTION:A molded item is rapidly heated in a high frequency dielectric heating device with frequencies, which are available for the resin of the molded item, up to almost annealing temperature and, held at said temperature. Frequen cies available for heating depends upon the kind of resin and its additive and the like and the optimum frequencies are selected. For example, in the case of a resin molded item, which is singly or mainly made of polycarbonate resin, high frequency dielectric heating, the frequencies of which to be selected lie within the range of 10<8>-10<11>Hz is selected and its heating temperature is set to be publicly known annealing temperature in response to respective resins. Thus, residual stress can be removed in an extremely short period of time. Further, as the result of remarkable shortening of treatment time, the staining of the surface of the molded item with dust, dirt and the like is remarkably settled. |
