I. General Logic for Setting PID Parameters
P (Proportional Band): Determines the response speed of the temperature control system. A smaller value results in a faster response; too large a value can lead to heating lag, while too small a value can cause temperature oscillations.
I (Integral Time): Eliminates steady-state temperature deviation. A larger value weakens the integral effect; too small a value can cause overshoot.
D (Derivative Time): Predicts temperature change trends and suppresses temperature fluctuations. A larger value strengthens the derivative effect; too large a value makes it susceptible to interference from temperature measurement noise.
II. Specific PID Values for Different Materials
|
Material Classification |
Representative Material |
P-value (%) |
I-value (seconds) |
D-value (seconds) |
Adaptability Characteristics |
|
High Heat Resistance and Stable General-Purpose Materials |
PP, PE, ABS, PS |
8~12 |
120~180 |
20~40 |
Allows rapid heating, priority given to response speed, slight overshoot with no risk of degradation |
|
Medium Heat Resistance Engineering Materials |
PC, PA6, PA66, PMMA |
12~18 |
180~240 |
40~60 |
Balances response speed and temperature stability, avoids overshoot causing molecular chain breakage |
|
Highly Degradable and Sensitive Materials |
PVC, POM, PET, TPU |
18~25 |
240~360 |
60~90 |
Prioritizes temperature stability, completely eliminates the risk of over-temperature degradation |
|
Glass Fiber Reinforced Materials |
GF-PP, GF-PA66, GF-PET |
10~15 |
150~210 |
30~50 |
Fast thermal conductivity, can appropriately improve response speed |
Optical Grade Transparent Materials Optical grade PC, optical grade PMMA 20~30 300~420 80~120 The temperature difference throughout the flow channel must be controlled within ±2℃; temperature fluctuations are absolutely prohibited.
III. Step-by-Step Tuning Setting Method
Initial Parameter Import: Directly import the corresponding PID baseline values from the table above based on the processed material as the initial configuration.
Self-Tuning Trigger: When the hot runner temperature rises to 30℃ from the target temperature, the temperature control box automatically initiates PID self-tuning. The system generates adaptive parameters based on the actual load characteristics.
Manual Fine-tuning Optimization: If heating is delayed or the temperature fails to reach the set value for an extended period, decrease the P value by 10% and shorten the I value by 20%.
If the temperature overshoot exceeds 5℃, increase the P value by 15% and lengthen the I value by 25%.
If the temperature fluctuates frequently and slightly, increase the D value by 30% to suppress the fluctuation trend.
IV. Adjustment Rules for Different Cavity Numbers
Single-cavity/2-cavity small hot runner: Decrease the P value of all materials by 20% to improve the heating response speed.
For ultra-large multi-cavity hot runners with 64 or more cavities: the P-value of all materials is increased by 30% to avoid global temperature oscillations in large-mass runner plates.
In high-humidity environments: the I-value of all materials is extended by 20% to avoid frequent temperature fluctuations during dehumidification.
