Dimensional Compatibility Risks
Residual burrs or localized deformation on the inner wall of the repaired hole can cause the sheathed probe to snag or jam during insertion; forced installation may re-scratch the wall and prevent the sheath from making full contact, leading to temperature measurement lag or drift.
Excessive coaxiality deviation in the hole causes radial misalignment of the probe, resulting in hard contact with the inner wall and significantly accelerated wear during long-term operation.
Temperature Measurement Performance Risks
Failure to calibrate accuracy after repair-while retaining old compensation parameters in the temperature controller-can lead to excessive measurement errors; this may cause localized overheating, carbon buildup, and material decomposition, resulting in defects such as black specks or yellow streaks on the molded parts.
Excessive clearance between the probe sheath and the hole reduces heat transfer efficiency and slows response times; the resulting heating lag in the control system can cause cosmetic defects like short shots or weld lines.
Insulation and Safety Risks
Inadequate cleaning of metal chips or grinding dust left after repair allows particles to adhere to the sheath's insulation layer; at high temperatures, insulation resistance drops rapidly, causing signal fluctuations and false alarms.
An excessively tight bending radius during installation damages the internal magnesium oxide insulation layer; insulation performance degrades at high temperatures, leading to leakage or short circuits and causing thermocouple failure.
Operational Stability Risks
Failure to verify heating/cooling cycles after repair leaves the thermal field unstable; unidirectional temperature drift during initial production can cause localized overheating, leading to resin leakage at the interface between the manifold and the hot nozzle.
Substandard surface roughness in the repaired hole allows carbon deposits to quickly embed in wall scratches; this causes repeated abrasion of the probe sheath, significantly shortening its service life.
Thoroughly screening and verifying all these risk factors before commencing production prevents secondary failures and ensures the long-term, stable operation of the hot runner system.
