How to Select the Right Thermocouple for Your Hot Runner System?

Selecting the right thermocouple for a hot runner system requires careful consideration of multiple factors. The first step is determining which thermocouple type is needed for temperature control. Type K and Type J thermocouples are the most common configurations in hot runner systems. Type K offers a wide temperature range from -200°C up to 1370°C and strong stability, making it the standard choice for premium systems. Type J is widely used in general applications with temperature ranges up to 800°C. For above 480°C, K-type thermocouples are recommended, while J-type is suitable for medium and low-temperature enclosed heating environments. High-end applications such as medical devices, optical parts, and precision connectors usually rely on imported brands for ultra-stable temperature control. General industrial parts can achieve reliable performance with mid-range brands while reducing procurement costs. The thermocouple probe diameter and length must match the mold's and installation depth. Standard diameters range from 0.5mm to 3.0mm, with Φ1.0 and Φ1.5 being most common. The measuring junction must be fully inserted into the hole to avoid leading to inaccurate readings. Connector types must match the temperature controller-DIN and mini-plugs are standard options. Sheath material selection is critical-Inconel and stainless steel sheaths provide excellent oxidation and corrosion resistance. The thermocouple type must match the temperature controller settings-J-type and K-type cannot be mixed. The wiring method must also be consistent, especially the positive and negative polarity. For cross-brand replacement, confirm the thermocouple alloy type, measuring point grounding mode, sheath material, and wire resistance in advance. Using genuine parts from authorized suppliers ensures authentic quality and after-sales support.