Based on our previous discussion of the insulation characteristics and installation taboos of PTFE wires in humid environments within hot runner scenarios, the optimal sealing solution for PTFE wire joints in humid environments is as follows:
I. Core Sealing Solution
Joint Pre-treatment: After crimping, thoroughly clean any burrs from the wire core and wipe the joint surface with anhydrous ethanol to ensure the contact surface is clean and free of impurities.
First Layer of Sealing: First, apply a layer of adhesive-backed fluoroplastic heat shrink tubing. After heating and shrinking, hot melt adhesive completely fills the gaps, achieving a primary waterproof seal.
Second Layer of Reinforced Sealing: Apply an additional layer of thickened fluoroplastic heat shrink tubing, completely covering both ends of the inner layer by at least 5mm, forming a double-layer redundant protection.
Final Moisture-proof Reinforcement: Wrap the outer layer with PTFE tape for auxiliary sealing. Place the entire joint inside a waterproof insulating junction box and inject sealant for complete potting.
II. Key Precautions
Do not use ordinary PVC heat shrink tubing, as its temperature and moisture resistance is poor and it is unsuitable for the combined humid and high-temperature conditions of hot runner systems. After sealing, the joint must be left to stand in a humid environment for 24 hours. The insulation resistance must be retested and still ≥100MΩ for the seal to be considered合格 (qualified).
This method completely prevents moisture from entering the joint, ensuring long-term insulation stability in humid environments.
