DISCONNECTION AND DEGRADATION DETERMINATION METHOD OF HEATER AND INJECTION MOLDING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a method for determining disconnection or a degradation condition for each heater with favorable accuracy without adversely affecting temperature control.SOLUTION: Two or more heaters (2) of an injection molding machine are supplied with electric power from a heater power source (5), and independently perform PWM control using a switch (4) that is individually disposed. A current sensor (6) is disposed in the heater power source (5). At timing in which only one heater (2) is turned ON in a control cycle of the PWM control, heater current of the heater (2) is obtained using the current sensor (6). In addition, when the heater current is smaller than a current threshold value that is preset in the heater (2), it is determined that the heater (2) is disconnected or degraded.