CASTING TIMING DETERMINING DEVICE, AND CASTING DEVICE

摘要

PROBLEM TO BE SOLVED: To detect the casting timing of a molten metal with high accuracy. SOLUTION: A metallic material is stored within a crucible 4, the crucible 4 is induction heated by an inverter 16 to output the voltage which is amplitude- modulated by the low-frequency signal with the high frequency signal which is amplitude-modulated by the low frequency signal, and the light emitted from a metal 8 in the crucible 4 is received by a photodiode 30 to generate the light- reception signal. The frequency component of the frequency higher than the low frequency signal is extracted from the light-reception signal by a low-frequency range cut-off filter 34. When the output signal of the low frequency range cut-off filter 34 is not less than the reference signal of a peak sample hold circuit 42, the voltage output signal is generated by a comparison circuit 40.