Special high-temperature engineering plastics such as PEEK, LCP, PPS and PA46 are widely used in automotive high-temperature resistant parts, electronic insulation components and industrial precision parts. Their molding temperature is as high as 400°C to 450°C, far exceeding the long-term working limit of conventional medium and low temperature thermocouples. Ordinary thermocouples will rapidly oxidize, drift and fail in such extreme environments, while professional high-temperature resistant hot runner thermocouples rely on special alloy formulas and structural processes to adapt to ultra-high temperature working conditions.
High-temperature resistant thermocouples adopt imported Inconel alloy sheath and vacuum smelted nickel-chromium superalloy sensing core, which can maintain stable thermoelectric linearity for a long time above 450°C, without crystal structure changes and oxidation attenuation. The internal insulation uses high-purity magnesium oxide ceramic filling, which still maintains excellent insulation performance and pressure resistance under ultra-high temperature, avoiding signal leakage and short circuit failure. The whole body adopts laser seamless welding and fully sealed structure to isolate the erosion of high-temperature volatile gas and prevent internal alloy wire from being corroded and oxidized.
Conventional J-type thermocouples will completely lose measurement accuracy when working above 350°C for a long time, and ordinary K-type also has obvious drift above 400°C. High-temperature customized models optimize the alloy ratio, reduce high-temperature potential drift, and match the special compensation algorithm of the high-temperature controller to ensure that the temperature measurement error is controlled within ±0.5°C for a long time. It can accurately capture the subtle temperature changes of the runner, stabilize the melt viscosity of special engineering plastics, and avoid decomposition, carbonization and filling imbalance caused by ultra-high temperature deviation.
In addition, high-temperature resistant thermocouples are designed with high-temperature anti-aging leads and radiation protection structure, adapting to long-term high-temperature baking and harsh heat radiation environment of the runner. For molders producing special high-temperature plastics, blindly using ordinary thermocouples will lead to frequent failure, high scrap rate and repeated mold maintenance. Selecting matched high-temperature resistant thermocouples is the basic guarantee to give full play to the molding performance of special engineering plastics and stabilize long-term production.
