How to Repair an Aging Hot Runner Sensor

It is not possible to completely restore aging hot runner sensors to their original state; they can only be partially fixed and their lives prolonged. Repair techniques might be tried in accordance with the level of age. They usually only survive three to six months after repair, and replacement is ultimately advised:

1. Zero-Point Deviation/Slight Sensitivity Drift (Early Aging)

This is the most prevalent kind of mild aging, and recalibration compensation can fix it:

Using a soft copper sheet, gently scrape away any collected material and corrosion residue from the sensor head's surface, taking care not to scratch the diaphragm;

Recalibrate the zero point and full-scale range after heating to the working temperature, taking into account the system parameters' current drift;

Calibration will satisfy production standards and increase its lifespan by three to six months if the variance is minimal.

2. Moderate Aging/Mild Diaphragm Corrosion/Material Accumulation

Try buffing and cleaning the surface:

After removing the sensor, use anhydrous alcohol to wipe the diaphragm's surface. Use very fine metallographic sandpaper to carefully clean the diaphragm surface if the oxide layers are slightly corroded.

After polishing, recalibrate. After calibration, it can be used for two to three months if the sensitivity drops by no more than 8%.

3. Direct Replacement: Irreversible Aging

The following signs point to permanent aging for which there is no effective remedy:

Frequent signal fluctuations and disconnections indicate that the internal circuitry/amplifier has aged and become damaged; the diaphragm has cracked, deformed, or its sensitivity has decreased by more than 10%; seal leakage has happened and molten material has entered the internal components, damaging them.