Many small and medium-sized molding workshops lack professional dry-block temperature calibrator and laboratory inspection equipment for regular thermocouple verification on-site, so standardized rapid comparative calibration method against certified master reference thermocouple becomes the most feasible inspection scheme for installed sensors on Husky, YUDO and domestic in-production hot runner equipment. The core operation principle relies on fixing calibrated standard master thermocouple and tested sample probe tightly together inside the same hot runner mounting hole, enabling both probes to receive identical real working temperature from hot runner metal matrix simultaneously. Before calibration starts, maintenance personnel clean carbon deposit and oxide dirt on both probe surfaces to eliminate heat transfer barrier induced measuring error, then fix two probes side by side with high-temperature thermal conductive filler to guarantee consistent heat conduction condition.
Complete comparative inspection is divided into three temperature segments including low preheating temperature around 150℃, medium conventional forming temperature between 250~320℃ and high-temperature over 400℃ for engineering plastic hot runner, keep each temperature stage stable for more than 30 minutes to wait numerical reading fully stable before recording data. If reading deviation between tested thermocouple and standard master exceeds factory permissible tolerance ±1℃ for precision production channel, mark this component as drifting defective part and arrange replacement after order completion; ordinary commodity hot runner with wide process window allows slight deviation compensation via controller parameter fine-tuning temporarily.
Workshop needs to preserve one set of periodically certified master reference thermocouple specially for daily spot check and comparative calibration, send the master sample to third-party metrology institute for annual official calibration to maintain benchmark accuracy. This field comparison method effectively solves the calibration difficulty of factories without dedicated test instrument, reduces batch defective risk caused by long-term uncalibrated drifting thermocouple and improves daily on-site quality control efficiency of hot runner temperature system.
