Northern injection molding workshop ambient temperature sharply drops below 5℃ and even subzero temperature in deep winter; inconsistent linear shrinkage coefficient among thermocouple outer sheath, internal core alloy and magnesia filler causes concentrated internal tensile stress under sudden cold snap, cracking compact insulation layer and inducing damp invasion corrosion failure for conventional standard thermocouple matched with YUDO modular and domestic outdoor arranged hot runner equipment. Ordinary stainless steel sheath contracts rapidly under sharp low-temperature environment while internal magnesia insulation and core alloy shrink at much slower speed, huge internal deformation stress generates micro-cracks penetrating insulation structure; cold humid outdoor air invades along crack gaps and condenses into residual moisture inside thermocouple, which turns into high-pressure steam after subsequent hot runner heating, further expanding original crack size and worsening internal structural damage progressively.
Anti-cold-snap optimized customized thermocouple improves internal filling craft during production stage by adopting layered flexible buffered magnesia filling technology, reserving reasonable tiny deformation allowance inside insulation layer to absorb low-temperature shrinkage stress and avoid compact powder cracking under drastic cold contraction. Terminal and wire root transition position adds elastic insulation buffer sleeve specially developed for low-temperature working condition to concentrate dispersed cold stress away from core wire easily broken position. For outdoor exposed wiring section of thermocouple, outer insulation cable selects modified low-temperature resistant Teflon material which keeps flexible property under minus 30℃ without hardening and brittle fracture, replacing conventional fiberglass insulated wire prone to crack under freezing climate.
Before annual winter temperature drop comes, workshop completes targeted specification replacement for all thermocouple installed at draughty gate position and outdoor exposed hot runner layout according to anti-cold-snap design standard, establishing separate equipment ledger to record installation location and replacement date for subsequent follow-up performance tracking. Daily winter patrol inspection focuses on reading fluctuation data of low-temperature optimized thermocouple channels, accumulating long-term field operation data to revise next-year thermocouple purchasing specification and reasonably adjust anti-freeze configuration scope to balance product performance and procurement cost.
