I. Adjustment by Material's Core Thermal Stability Characteristics
High Heat-Resistant and Stable General-Purpose Materials (PP, PE, ABS, PS)
Core Material Characteristics: Thermal decomposition temperature is much higher than the conventional processing temperature; short-term overheating poses no significant degradation risk.
Recommended Heating Rate: 3~4℃/min, allowing 100% full power output throughout, maximizing the reduction of heating time.
Supporting Control: Only need to monitor the final temperature to ensure it does not exceed the material's recommended processing limit by 10℃; check the temperature every 20 minutes.
Medium Heat-Resistant Engineering Materials (PC, PA6, PA66, PMMA)
Core Material Characteristics: Overheating or prolonged exposure to high temperatures will cause molecular chain breakage and a decrease in mechanical properties.
Recommended Heating Rate: 2~3℃/min, rapid full-power heating up to 100℃; after 100℃, power is limited to 80% to avoid temperature overshoot and fluctuations.
Supporting Controls: Before heating, ensure the material is fully dry, with a moisture content ≤200ppm, to prevent localized hydrolysis caused by moisture during heating. Check the temperature every 10 minutes.
Highly Degradable Sensitive Materials (PVC, POM, PET, TPU)
Core Material Characteristics: Low degradation trigger temperature; rapid decomposition occurs even with short-term overheating, potentially leading to safety risks such as material spillage and corrosion.
Recommended Heating Rate: 1~1.5℃/minute; power limit is 60%~70% throughout; rapid heating is prohibited.
Supporting Controls: Once the temperature exceeds the material's safety threshold, check the temperature every 5 minutes, simultaneously monitoring odor and overflow status to identify early signs of degradation.
II. Targeted Adjustments Based on Material Specific Properties
High Viscosity, High-Filler Materials: Reduce the heating rate by 20% from the base rate to prevent uneven heating of the melt within the flow channel, resulting in poor filling and dispersion.
Fiberglass Reinforced Materials: The heating rate can be increased by 10% from the base value. Fiberglass itself poses no risk of thermal degradation, so the heating pace can be appropriately accelerated.
Transparent Optical Grade Materials: The heating rate should be reduced by 30% to ensure absolutely uniform temperature throughout the runner system, avoiding poor light transmission and stress marks caused by localized temperature differences.
III. Special Scenario Adjustment Rules
In high-humidity, rainy environments, the heating rate of all materials should be reduced by 20%, and the holding time at 100℃ should be extended to ensure sufficient moisture removal and prevent hydrolytic degradation.
When used with ultra-large multi-cavity hot runners with 64 or more cavities, the heating rate of all materials should be reduced by 30% above or below the base value to prevent excessive temperature differences between the inside and outside of the large-mass runner plate, which could lead to thermal deformation.
If the hot runner has previously experienced an over-temperature alarm, the heating rate of all materials should be reduced by 50%, and temperature stability should be continuously monitored. Once no abnormalities are confirmed, the heating rate should be gradually restored to the standard rate.
