Long production runs-often lasting days or weeks-create extreme conditions for thermocouples. Many users notice gradual reading drift over time, even with quality sensors. What causes thermocouple drift during extended continuous operation?
High-temperature oxidation slowly changes the thermoelectric properties of sensor alloys, especially in Type K sensors above 300°C.
Chemical vapors from molten plastics and additives corrode the probe surface, altering thermal response.
Plastic infiltration and carbonization create an insulating layer on the probe, causing low-temperature drift.
Thermal fatigue from constant cycling weakens the junction, creating gradual signal change.
Insulation aging in high-temperature cables increases electrical leakage and signal drift.
Micro-movement from thermal expansion changes probe contact over months of operation.
Contamination buildup on the sensor tip changes heat absorption characteristics.
Long-term exposure to electromagnetic interference gradually affects signal stability.
Regular cleaning, calibration, and using high-temperature resistant thermocouples helps minimize drift during extended runs.
