Calibrating the temperature compensation coefficient of a hot runner sensor can be done in two ways: on-site rapid calibration and standard accuracy calibration. Choose the method that best suits your needs. The specific steps are as follows:
1. On-site Rapid Calibration Method (Commonly used after sensor replacement, simple to operate)
Suitable for offsetting interchangeability errors after sensor swapping, no additional specialized equipment required:
Confirm Reference Conditions: Keep the mold closed, heating on, and all parameters stable for at least 30 minutes to allow the hot runner temperature to reach thermal equilibrium;
Record Current Display Temperature: After the temperature controller displays a stable temperature, record the current sensor display temperature, T<sub>display</sub>;
Compare with Actual Temperature Correction:
If there is an existing calibrated sensor at the same hole location, use the stable temperature of the existing sensor as the reference, T<sub>actual</sub>;
If there is no reference, use the set temperature when the product is qualified as the reference, T<sub>actual</sub>;
Adjust Compensation Coefficient: Calculate the compensation correction value:
ΔT = T<sub>actual</sub> − T<sub>display</sub>. Directly input the correction value ΔT in the sensor compensation/calibration interface of the temperature controller. Save the settings.
Verify the calibration results: After adjustment, wait 10 minutes for the temperature to stabilize. Confirm that the deviation between the displayed temperature and the reference temperature is within the allowable range. Calibration is now complete.
2. Standard Precision Calibration Method (Suitable for new model calibration and high-precision scenarios)
Using a standard thermocouple as a reference results in higher calibration accuracy:
Tools Preparation: A pre-calibrated first-class standard thermocouple (accuracy ≥ 0.1℃), and a high-precision instrument with temperature acquisition capabilities;
Test Hole Machining: Machining a test hole matching the standard thermocouple near the sensor mounting hole at the hot runner nozzle location, ensuring the bottom of the hole reaches near the sensor mounting position;
Temperature Stabilization: Turn on heating and raise the temperature to the commonly used production temperature. Hold for 30 minutes to allow the temperature to stabilize completely;
Data Recording: Record both the actual temperature T<sub>standard</sub> measured by the standard thermocouple and the displayed temperature T<sub>display</sub> of the sensor to be calibrated;
Compensation Coefficient Calculation and Setting: Correction Value
ΔT = T<sub>standard</sub> − T<sub>display</sub>. Input this correction value into the compensation parameters of the temperature controller and save it;
Verification: After re-stabilization, compare again. If the deviation is ≤ the allowable error for the corresponding scenario, the calibration is successful. If the deviation still exceeds the allowable limit, readjust.
