Medical disposable and implant product molds operated in dust-free cleanrooms put forward ultra-strict hygiene, pollution-free and low-particle requirements for supporting hot runner thermocouples, completely different from ordinary industrial molds. Any metal shedding, coating peeling or organic volatile from sensors will contaminate medical-grade melt, resulting in whole batch product scrapping and failure to meet FDA and GMP production standards.
Material pollution control is the primary index for cleanroom dedicated thermocouples. Measuring junctions and sheath surfaces adopt mirror polishing treatment without burrs, rough edges or loose metal particles that may fall off into the flow channel. Ordinary carbon steel and recycled alloy raw materials are prohibited; only imported high-purity Inconel and 316L medical-grade stainless steel sheaths are allowed, with no surface electroplating coating that may peel under high temperature. Spring measuring rings use beryllium copper without surface oil anti-rust treatment; all accessories are degreased and cleaned before factory delivery to avoid organic volatile precipitation at high temperature.
Structure design eliminates dead corners that accumulate dust and plastic residue. Integrated seamless welding structure replaces split assembly with gaps; button measuring bases adopt fully enclosed circular smooth surfaces without tiny grooves storing carbonized plastic particles. Exposed tip micro probes for micro multi-cavity medical molds remove unnecessary thread gaps and positioning steps, reducing residue accumulation dead corners to the greatest extent.
Wire outer protective layers must use low-outgassing high-temperature PTFE sleeves instead of ordinary glass fiber braid. Conventional glass fiber will shed tiny fiber dust under repeated mold opening friction, polluting the cleanroom environment and melt. PTFE material produces almost no volatile substances at molding temperature, with smooth surface not easy to absorb dust, meeting Class 10000 cleanroom production standards. Double-layer stainless steel shielding mesh is polished without burrs to avoid metal chip shedding during wiring arrangement.
Precision and stability requirements are upgraded to Class 1 ultra-low drift standards. Medical raw materials such as PEEK, COC and medical PP have extremely narrow safe processing temperature windows, and thermocouple long-term temperature drift must be controlled within ±0.3℃. Un-grounded anti-interference structure is standard to prevent temperature fluctuation causing inconsistent melt viscosity and micro-defects such as tiny bubbles and black spots on transparent medical parts.
Cleanroom thermocouple maintenance rules are stricter than ordinary workshops. During quarterly disassembly cleaning, only alcohol non-woven cloth is allowed to wipe contact surfaces; abrasive cloth polishing is prohibited to avoid scratching the mirror finish and generating metal particles. Spare sensors must be stored in sealed dust-free packaging bags and taken out only before installation, avoiding exposure to workshop dust for a long time. Any thermocouple with surface scratch, coating peeling or loose shielding mesh must be scrapped immediately and cannot be reused on medical cleanroom molds.
