Mold for injection molding of plastics using thin film electric heater

摘要

A mold includes a thin film electric heating employing voltage and current suppressed below values of an allowable voltage and an allowable current. The thin film electric heat includes a thin film electric resistor formed directly on a surface of the mold and is energized to effect heating. The resistor has a surface resistivity r, expressed by r= rho /t (where rho is the volume resistivity of the thin film electric resistor and t is the film thickness of the thin film electric resistor), within a range to achieve the heating function of the thin film electric heater while the values of voltage and current applied to the thin film electric heater are suppressed below the values of the allowable voltage and the allowable current.