Abstract: In this article, the temperature control system in injection molding machines was introduced. The key elements were illustrated in two main aspects: hardware and software, which affected the accuracy of temperature in the barrel, including PID optimizations of the operating system, measurements of thermocouples and heating coils. Detailed steps for improvements were given to diminish the temperature variation after heating up. Moreover, the presetting of PID parameters optimizes the efficiency of controlling process and reduces overshoot and settling time. Through the measurements of temperature after heating up at stable, the variation of the temperature achieves plus or minus 0.2 degree.

Key words: temperature control, thermocouples, all-electric injection molding machine