What Are the Long-Term Storage Preservation Standards for Spare Hot Runner Thermocouple Inventory?

Injection molding factories reserve a large number of thermocouple spare parts in the warehouse for emergency mold maintenance, but improper long-term storage will lead to sheath oxidation, wire insulation aging, spring elasticity attenuation and measuring junction corrosion even without formal installation on molds. Formulating unified inventory preservation standards can maintain the original precision and mechanical performance of stored thermocouples for more than 12 months, avoiding scrapping of a large number of spare parts due to storage damage. Warehouse environmental basic storage conditions. The spare parts warehouse must maintain constant temperature between 15℃–25℃ and relative humidity below 60%. Equip dehumidifiers and air conditioners for rainy and coastal high-humidity areas to prevent water vapor from corroding thermocouple metal sheaths and measuring junctions. Keep the warehouse away from chemical raw material storage areas such as plastic particles, flame retardants and PVC powder; volatile chlorine and sulfur gas will erode unprotected thermocouple probes and form corrosion layers on the measuring junction surface within several months. Place storage racks more than 30cm above the ground to avoid ground moisture penetrating packaging boxes, and keep away from window direct sunlight to prevent wire insulation layer aging and embrittlement under ultraviolet radiation. Classified sealed packaging standards for different types of thermocouples. All newly delivered thermocouples retain the original factory sealed anti-dust plastic packaging bags; for unpacked unused spare parts, re-seal with vacuum moisture-proof packaging bags filled with desiccant particles before storage. Classify storage by product model: separate K-type and J-type probes, distinguish button, spring ring, screw-in and miniature elbow thermocouples into independent labeled storage boxes. Wrap exposed measuring tips and threaded probes with foam anti-collision sleeves to avoid extrusion dent deformation during stacking storage. Integrated heater-thermocouple assemblies are stored in separate cartons with shock-absorbing cotton lining to prevent spring ring extrusion deformation under heavy stacking pressure. Storage operation forbidden behaviors that easily damage thermocouples. Do not stack heavy metal mold accessories and steel plates on top of thermocouple storage boxes; long-term heavy pressure will bend mineral insulated sheaths and form hidden alloy wire micro-cracks. Do not hang thermocouple wire harnesses vertically for long-term storage; the self-weight of the wire will pull the measuring tip joint loose, increasing contact resistance after installation. Avoid repeated bending of the same sheath position when sorting inventory; multiple folding will cause metal fatigue failure of internal alloy wires. Do not open the sealed packaging bag for long-term display without desiccant; expose probes to humid air for more than one week to start surface oxidation corrosion. Regular inventory rotation and pre-use inspection specifications. Implement first-in first-out inventory management, label each batch of stored thermocouples with incoming date, preferentially use the earliest incoming spare parts to avoid ultra-long storage exceeding 12 months. Conduct quarterly inventory spot checks: randomly take out samples from each storage box, check sheath surface for oxidation rust, test wire continuity and insulation resistance with a multimeter, and inspect spring ring elasticity for attenuation. Spare parts stored for more than 10 months must pass full insulation and precision calibration before being taken out of the warehouse for mold installation; probes with oxidation, low insulation resistance and spring deformation are sorted out and scrapped uniformly. Short-term emergency storage rules for disassembled reusable thermocouples. Thermocouples removed from molds during maintenance that are temporarily not reused must be cleaned of surface carbon deposits with alcohol cotton, dried thoroughly, wrapped in moisture-proof bags with desiccant and stored separately from new spare parts, marked with "recycled spare parts" labels. Do not store dirty un-cleaned used probes together with new thermocouples; residual plastic corrosive residues on the measuring base will contaminate adjacent new probes and accelerate corrosion damage of inventory spare parts. Strict implementation of the above storage preservation standards can reduce the scrap rate of warehouse thermocouple spare parts to less than 3%, cutting repeated spare part procurement costs for injection molding enterprises.