Basic Visual and Dimensional Inspection Examine the full length of the sensor hole with an industrial borescope to make sure the repaired surface is smooth and level and to check for any remaining burrs, scratches, or distortion.
Verify that the inner diameter tolerance and coaxiality deviation are ≤0.05 mm by pushing a standard nylon "Go" gauge that matches the hole's nominal inner diameter smoothly and coaxially to the bottom of the hole without snagging or binding.
Check for Installation Compatibility
Insert a new armoured sheath, making sure that it fits snugly and without any looseness between the outer wall of the sheath and the inner wall of the hole, and that it is easy to insert and remove without binding. Check that the insulation resistance between the thermocouple poles and the sheath casing is ≥100 MΩ, which means there is no chance of an electrical leak.
Checking the Performance of Temperature Sensing After heating the hot runner to the specified operating temperature and keeping it there for half an hour, check the readings with a calibrated standard contact thermometer to make sure the difference between the temperature controller display and the actual temperature is 1°C.
To finish single-point calibration and update compensation settings, start the temperature controller's PID auto-tuning; make sure the temperature signal is not continuously drifting in one direction.
Check for Operational Stability Conduct three consecutive cycles of heating and cooling (from room temperature to the maximum working temperature) while keeping an eye on the temperature curve. Verify that the temperature uniformity deviation is ≤±1.5°C and that the temperature fluctuation is ≤±0.5°C with no random spikes. Once all indicators fulfil the necessary criteria, normal production can continue.
This inspection procedure ensures 100% compliance with repair precision criteria, eliminating injection moulding flaws brought on by placing defective equipment into production. It is completely in line with on-site hot runner maintenance and operating situations.
