I. Core Temperature Determination Method
Contact Temperature Measurement: Use a contact surface thermocouple thermometer to directly measure the metal surface temperature of the hot runner's runner plate and nozzle mounting positions. Confirm that the temperature is ≤60℃, and that there is no significant rebound in the temperature readings after three consecutive measurements taken at 5-minute intervals. This indicates that cooling has been complete.
Non-Contact Temperature Measurement: Use an infrared thermometer at a distance of 15-20cm from the hot runner surface, avoiding ambient light interference. Scan all metal surfaces of the hot runner at multiple points. Confirm that the temperature is uniformly ≤60℃ across the entire area, with no localized high-temperature points. This indicates that cooling has been complete.
II. Mechanical Installation Verification Method
Operational Feel Determination: Wearing heat-resistant gloves, touch the hot runner junction box housing and fixed flange surface with bare hands. If there is no noticeable burning sensation and the component can be held and operated for an extended period, cooling has been complete.
Assembly Adaptability Determination: After the hot runner has cooled, mold closing and nozzle alignment installation can be completed smoothly without assembly jamming or misalignment due to thermal deformation. This indicates that cooling has been complete.
III. Auxiliary Methods for Electrical Performance Judgment
Insulation Resistance Retest: During the hot runner cooling process, the insulation resistance is retested every 15 minutes. When the insulation resistance is stable at ≥20MΩ and no longer increases with prolonged cooling time, it indicates that there is no residual high-temperature heat inside, signifying successful cooling.
Cold Junction Compensation Verification: The deviation between the cold junction compensation temperature display value of the Husky thermostat and the measured value of the ambient room temperature is ≤±2℃, indicating that the overall temperature of the hot runner has basically reached equilibrium with the ambient temperature, signifying successful cooling.
IV. Judgment Rules for Special Scenarios
For large multi-cavity hot runner systems, it is necessary to additionally measure the temperature of the pre-embedded temperature measuring point in the central area of the runner plate to confirm that the central temperature is ≤60℃, avoiding the false cooling phenomenon where the surface is cooled but the internal high temperature remains.
In high-humidity environments such as the plum rain season/return to spring, the judgment temperature for successful cooling can be relaxed to ≤50℃ to prevent high-temperature components from rapidly condensing and becoming damp upon contact with high-humidity air.
