Molten metal pouring time determining apparatus

摘要

A molten metal pouring time determining apparatus determines a proper time for pouring molten metal into a die. A mass of metal is placed in a melting pot. The melting pot and the metal mass are radio frequency (RF) induction heated with RF signal modulated with a low frequency signal. A light receiver receives light emitted by the metal mass heated in the melting pot and develops a received-light representative signal. A high-pass filter extracts a high frequency component developed by a sudden change in the received-light representative signal caused by the melting of the metal mass. A comparator develops an output signal when the output signal of the high-pass filter exceeds a reference signal. When the comparator output signal remains above the reference signal for a predetermined time period, a timer generates a molten metal pouring command signal.