Core Accuracy Comparison Verification: Using a bipolar comparison approach, insert the calibrated Husky thermocouple and a Class II standard thermocouple within their metrological validity period together at the same isothermal measurement location in the hot runner. Conduct comparison testing at regularly used production temperature levels.
Maintain temperature field stability with temperature changes of ≤0.2℃/min. Measure at least four times in a forward-reverse cycle of standard-calibrated-standard. Calculate the average value to estimate the indicator error, and ensure that the error value falls within the acceptable accuracy range for the associated graduation number.
To verify low temperatures below 300℃, use a Class II standard mercury thermometer in an oil constant-temperature bath. Control the oil bath temperature change within ≤±0.1℃ to ensure low-temperature measurement accuracy satisfies standards.
Specific Performance Index Verification:
Insulation Resistance Verification: With a megohmmeter, measure the insulation resistance between the thermocouple sensing element and the protective tube. Check that the insulation resistance at room temperature is ≥100MΩ to prevent signal leakage and consequent measurement inaccuracies.
Thermal Response Verification: A rapid heating operation was performed on the hot runner to evaluate the thermocouples' temperature response speed, verifying that the temperature display responds promptly to actual temperature changes with minimal lag.
Stability Verification: The system was kept at a steady temperature for 2 hours at production temperatures, with temperature data taken every 15 minutes. There was no substantial drift in the thermoelectric potential value, and temperature swings were ≤ ±1℃.
System Operating Condition Linkage Verification: After configuring the calibration parameters, the Husky temperature controller's PID self-tuning program was launched, proving that the temperature control curve was stable, with no overshoot or oscillation.
The temperature control system met production requirements with no alarms, stable temperature data, and deviation from the actual hot runner temperature of ≤ ±1℃ during a three-cycle simulation of the injection moulding process.
A comprehensive calibration verification record was filled out, and the comparison data for each temperature point and performance test results were saved to create a traceable calibration verification report.
This verification technique fully complies with industrial metrology calibration standards and can 100% validate that Husky thermocouples' accuracy and performance after calibration meet the standards, preventing calibration failures that could have an impact on following production quality.
