High-temperature engineering plastics including LCP, PEI, PEEK, and modified nylon are widely used in electronic communication, automotive new energy, precision medical, and aerospace fields. The manifold heating temperature for these resins needs to be stably controlled between 300°C and 400°C. Specialized thermocouple technologies are required for these demanding applications.
Type K for High-Temperature Stability. K-type sensors have a continuous service temperature range of 0–1100°C and stable signal linearity above 300°C, making them suitable for manifolds and long runners of high-temperature engineering plastics such as PEEK, PC, and enhanced nylon. Type K thermocouples offer strong oxidation resistance, low cost, and good linearity.
Type N for Ultra-High Temperatures. For processing temperatures from 380°C to over 420°C, Type N (Nicrosil-Nisil) thermocouples provide superior stability. Germany's Günther and EWIKON focus on ultra-high-temperature molding scenarios of engineering plastics such as PEEK and PA66+GF, selecting thermocouples that can stably work for a long time at melt temperatures above 380°C and effectively avoid signal drift caused by high-temperature oxidation.
Sheath Material Requirements. High-temperature thermocouples must withstand temperatures above 400°C for PEEK, PEI, and other high-performance engineering plastics. Inconel 600 or Haynes 230 sheaths provide the necessary oxidation resistance. Standard 316L stainless steel oxidizes rapidly at these temperatures and should not be used.
Brand-Specific Solutions. INCOE and HRSflow, which focus on engineering plastics, select high-temperature thermocouples suitable for PEEK, PPS, and other high-temperature materials. Each brand has its own requirements for thermocouple type, structure, installation position, and electrical parameters to match its dedicated temperature controllers.
Drift Prevention. At high temperatures, thermocouple drift accelerates dramatically. Regular calibration is essential-high-temperature sensors may drift 2–3°C per year at 350°C, compared to less than 1°C at 250°C. Premium sensors with stabilized alloys and advanced manufacturing techniques reduce drift rates significantly.
