Based on the previous focus on the need for safe replacement and subsequent calibration of damaged thermocouples in hot runner injection molding, the standard replacement steps for thermocouples in hot runner injection molding are as follows:
I. Pre-installation Safety Preparation
Disconnect the power supply to all heating rods in the hot runner system and activate air cooling to completely cool the runner to room temperature, avoiding the risk of melt spray and burns.
Verify that the new thermocouple's calibration number, length, and probe diameter are completely compatible with the original. Prepare the corresponding calibration compensation leads, standard temperature measuring gun, and other tools.
II. Removal and Cleaning of the Old Thermocouple
Unscrew the retaining cap at the end of the thermocouple and slowly pull out the damaged old thermocouple, avoiding scratching the inner wall of the mounting hole.
Clean any residual carbonized material and aged adhesive residue from the mounting hole, ensuring the channel is clear and free of foreign objects.
III. Installation and Fixing of the New Thermocouple
Push the new thermocouple probe completely into the bottom of the mounting hole, ensuring a tight fit between the probe and the temperature measuring surface of the runner, with no gaps or looseness.
Tighten the retaining cap appropriately to prevent probe displacement, while avoiding over-tightening that could damage the probe.
IV. Wiring and Accuracy Verification Connect the thermocouple to the temperature control box using the corresponding compensating wire, ensuring the positive and negative terminals are correctly connected.
Complete the freezing point benchmark calibration and multi-temperature zone comparison calibration. After confirming the temperature measurement deviation is ≤±2℃, reheat to purge any residual melt from the flow channel. Resume mass production after successful trial production verification.
This process safely completes thermocouple replacement, completely avoiding the potential risks of subsequent mismatched calibration numbers and inaccurate temperature measurements.
