JPS6469305A - Mold assembly - Google Patents

Abstract

PURPOSE:To obtain an excellent molded item without fine pores, crazing, strain and the like by a method wherein a large number of flexible planar coils, on each of which a temperature sensor and a temperature controlling device are provided, are arranged on the rear of a shell-like structure so as to control the heat release value of the flexible planar coils. CONSTITUTION:A plurality of flexible planar coils 7a-7g are wound round the rear of a shell-like structure so as to induction-heat every predetermined local parts, to which the respective planar coils 7a-7g are mounted, of the shell-like structure 1 up to the predetermined temperatures by passing high frequency current through the coils. The temperatures at the respective parts of the shell-like structure are detected with temperature sensors 8a-8g, which are provided corresponding to the respective coils, so as to control the mean application time of high frequency currents across the respective coils 7a-7g in response to the outputs of the temperature sensors in order to uniformize the temperature distribution of the shell-like structure 1. The amounts of local indication heatings of the shell-like structure 1 by the coils 7a-7g are increased and decreased by changing the mean application time to the coils 7a-7g through the changing of the width of pulses of the high frequency currents, which are supplied from a high frequency power source 9 to the coils 7a-7g and interrupted by an interrupting circuit 10 in the forms of pulse with comparatively low frequency.