Mechanical disassembly, grinding and repairing work of hot runner nozzle on domestic and Husky multi-cavity hot runner easily causes accidental scratch, extrusion damage and high-temperature flame burn to nearby installed thermocouple without standardized pre-protection measures, formulating unified maintenance pre-protection specification effectively lowers artificial damage induced premature scrap rate and saves accessory replacement cost. Before starting any nozzle mechanical repair construction, maintenance operators firstly wrap exposed probe and nearby sheath part of adjacent thermocouple with thick high-temperature resistant asbestos cloth or special heat insulation protective sleeve tightly to block welding flame splashing and grinding scrap high-temperature particle direct burn damage; fix wrapped protection material with high-temperature binding band to prevent falling off during construction operation. If nozzle disassembly needs large-range mold opening movement, check thermocouple outer wiring routing in advance and fix loose cable with wire clip to avoid wire pull, twist and sharp edge friction abrasion during mold displacement.
After finishing mechanical repair and before formal equipment recovery startup, remove all protection wrapping material and visually inspect sheath scratch, burn and terminal loose condition of protected thermocouple, implement insulation resistance spot-check with megohmmeter to screen hidden internal damage timely before production trial run. Workshop compiles maintenance pre-protection operation clause into mold repair management regulation, requiring construction operator to finish protection procedure and pass supervisor inspection confirmation before starting nozzle repair work. Monthly maintenance department counts man-made thermocouple damage quantity induced by unprotected repair operation, strengthening on-site operation training and supervision to reduce artificial accidental damage failure year by year.
