I. General Heating Stage Temperature Check Frequency
Ambient Temperature → Low-Temperature Preheating Stage
Temperature Range: Room temperature to 30°C below the material's heat distortion temperature
Check Interval: Every 30 minutes
Check Content: Record the heating rate of each channel, confirm no localized overheating, and temperature deviation ≤ ±5°C.
Medium-Temperature Transition Stage
Temperature Range: 30°C below the heat distortion temperature → Lower limit of the material's processing temperature
Check Interval: Every 20 minutes
Check Content: Confirm that the overall temperature of the hot runner is uniform, with no prolonged temperature stagnation, and temperature difference between channels ≤ ±3°C.
Production Temperature Holding Stage
Temperature Range: Lower limit of the processing temperature → Set production temperature and hold
Check Interval: Every 10 minutes
Check Content: Monitor temperature fluctuation range ≤ ±2°C, confirm that the temperature control system has no over-temperature alarms, and that temperature values are stable without fluctuations.
II. Temperature Inspection Intervals for High-Risk, Easily Degradable Materials
PVC Materials: The temperature inspection interval is uniformly 10 minutes throughout the entire heating phase. Once the temperature exceeds 160℃, the inspection interval is further shortened to 5 minutes to prevent rapid decomposition and release of corrosive gases due to overheating.
POM Materials: Before the temperature reaches 180℃, inspect every 20 minutes. After the temperature exceeds 200℃, the inspection interval is shortened to 5 minutes to prevent chain depolymerization and material spraying risks caused by overheating.
PET Materials: Before the temperature reaches 240℃, inspect every 20 minutes. After the temperature exceeds 260℃, the inspection interval is shortened to 8 minutes to prevent hydrolytic degradation at high temperatures that lead to performance decline.
PC Materials: Before the temperature reaches 280℃, inspect every 30 minutes. After the temperature exceeds 300℃, the inspection interval is shortened to 10 minutes to prevent black spots and silver streaks caused by overheating.
III. Temperature Check Adjustment Rules for Special Scenarios
During the rainy season/humid weather, the temperature check interval for all materials should be shortened by 30% to prevent moisture from accelerating material degradation and causing temperature anomalies.
For large multi-cavity hot runner systems, additional infrared temperature measurement checks should be performed on the surface of the runner plates, with an interval not exceeding 15 minutes, eliminating blind spots caused by localized hot spots.
If an over-temperature alarm occurs during the heating process, the temperature check interval for all subsequent stages should be shortened to 5 minutes, continuously monitored until the temperature has stabilized completely for 30 minutes without any abnormalities.
For newly installed or overhauled hot runner systems, the temperature check interval for the first two heating stages should be uniformly shortened by 50% to verify the stability of the temperature control system.
