Based on the previous focus on hot runner temperature monitoring system calibration and PID self-tuning, the following are practical PID parameter adjustment techniques:
Basic Parameter Adaptation: First, set the integral time (Ti) to 1.5 times the hot runner heating time and the derivative time (Td) to 1/4 of Ti to avoid large temperature fluctuations caused by initial parameters.
Overshoot Suppression Techniques: If the temperature overshoot is too large, first reduce the proportional gain P, then appropriately lengthen the integral time to quickly control the overshoot within 2℃.
Steady-State Fluctuation Optimization: If the steady-state temperature fluctuates frequently with small jumps, slightly increase the value of the derivative D to use the predictive effect of the derivative to offset the temperature fluctuations caused by the heating coil switching.
Differentiated Adjustment by Zone: The heating inertia in the hot runner nozzle area is small, so the P value should be appropriately lowered; the heat capacity in the manifold area is large, so the P value can be appropriately increased to achieve temperature stability across the entire area. These techniques can quickly optimize temperature control and stabilize the hot runner temperature accuracy within ±1℃.
