How often should sensors be recalibrated after repair?

I. Calibration time requirements for mandatory initial calibration after repair

Immediate Calibration Requirement: Upon successful completion of the static insulation test after physical repair/replacement of the sensor, the initial recalibration should be conducted immediately under stable operating conditions with the hot runner temperature raised to 320℃ and sustained for 2 hours. It needs to be done urgently until production can be resumed.

Stability Verification After Initial Calibration: The stability verification must be performed by constantly maintaining the temperature for 1 hour after the initial calibration. The production can be officially resumed only when the temperature measurement error is stably controlled within ±1℃.

II. Routine Calibration Cycle Following Repair

Normal operating conditions of 8 hours per day and stable production: For repaired sensors the gap between the first two calibrations is reduced to 2 months. If the temperature measurement variation is < ±0.5℃ after two times calibration, then the standard calibration cycle of 3 months may be restarted. - Continuous high load production 24/7 - For repaired sensors the first two calibration intervals are shortened to one month. The normal calibration cycle of 1.5-2 months can be resumed after two consecutive calibrations with steady temperature variations and no drift.

III. Mandatory Calibration Trigger Cycle in Special Situations

If there was a heater leakage issue before the sensor was repaired, the temperature data should be compared and verified every two weeks for the first three months after the repair. Three successive successful comparisons reset the normal calibration cycle.

If the switch to high temperature engineering plastics like PEEK (above 350℃) after repair, a particular calibration must be performed before each process switch and this is not limited to a fixed cycle.

If product yield fluctuates abnormally owing to temperature for 3 consecutive days after the repair, recalibrate all sensors immediately without waiting for the fixed cycle.

IV. Rules of Dynamic Cycle Adjustment

A calibration log for fixed sensors will be established. If the temperature deviation is within ±0.5℃ for three consecutive calibrations, the calibration cycle of the sensor can be extended to a maximum of six months.

If one calibration shows a deviation in temperature greater than ±2℃, recalibrate promptly and abbreviate the next calibration cycle to 2 weeks. After two successive calibrations with a steady deviance, slowly return to the original cycle.