What are the countermeasures against corrosion from fluoroplastic decomposition products in hot runners?

I. Source Control: Reducing Decomposition Product Generation from the Material End Raw Material Drying Control: Fluoroplastics (such as PTFE and PFA) must undergo strict vacuum drying before molding, with the moisture content controlled below 0.01% to prevent moisture from accelerating fluoride decomposition at high temperatures. Precise Temperature Control: The actual operating temperature of the hot runner must be strictly controlled below the thermal decomposition threshold of the fluoroplastics to avoid localized overheating and reduce the generation of highly corrosive decomposition products such as HF at the source. Material Selection Optimization: Prioritize the use of modified fluoroplastic raw materials with higher thermal stability and add heat stabilizers to reduce the decomposition rate at high temperatures. II. Process Inhibition: Blocking Corrosion Paths and Contact Runner Surface Anti-corrosion Treatment: The melt contact area of ​​the hot runner is treated with Hastelloy coating or hard chrome plating to significantly improve resistance to fluoride corrosion and prevent rapid corrosion of ordinary H13 steel. Sealing Structure Upgrade: All hot runner joints and thermocouple mounting holes are sealed with high-temperature resistant fluororubber sealing rings to prevent decomposition products from leaking out and corroding surrounding wires and temperature control components. Insulation Material Upgrade: Ordinary PTFE insulated wires are replaced with fluorine-resistant PFA wires to prevent decomposition products from corroding the wire insulation and causing short circuits. III. Post-Corrosion Repair and Maintenance: Reducing the Impact of Corrosion Regular Cleaning and Maintenance: Every 3 months, the hot runner is shut down and disassembled. Residual fluorine-containing decomposition products are cleaned with anhydrous ethanol and a lint-free cloth to prevent long-term accumulation and accelerated corrosion. Specialized Post-Corrosion Repair: For thermocouple contacts showing green corrosion and corroded runner surfaces, polishing and passivation are performed. The temperature measurement accuracy of the K-type thermocouple probe is recalibrated to restore system performance. Corrosion Early Warning Mechanism: The MSE system monitors temperature deviation changes in each channel of the hot runner in real time. When abnormal drift occurs, potential corrosion from decomposition products is detected in advance to prevent sudden failures.