Based on our previous discussion of material identification, insulation resistance control, and regular testing of PTFE conductors in hot runner scenarios, the common faults of PTFE conductors in this scenario are as follows:
Insulation layer thermal aging and cracking: Prolonged operation at temperatures around 250℃, especially with conductors containing recycled materials, leads to rapid embrittlement and cracking of the insulation layer, causing a short circuit between the conductor core and the hot runner metal shell, burning out the heating coil.
Excessive distributed capacitance causing temperature control lag: Inferior doped conductors exhibit abnormally high dielectric constants, resulting in significantly excessive distributed capacitance. This exacerbates the low-pass filtering effect in the hot runner, causing severe lag in the temperature control signal, leading to localized overheating in the hot runner and triggering thermal shock cracking.
Sudden drop in insulation resistance and leakage: Insulation layer contaminated with oil or conductive dust, or after prolonged high-temperature aging, insulation performance deteriorates, causing insulation resistance to drop below the safety threshold, resulting in leakage faults and triggering the workshop's leakage protection trip.
Mechanical Damage to Wiring: The confined space within the hot runner system causes conductors to be subjected to prolonged compression, repeated thermal expansion and contraction, and bending, leading to fatigue fracture of the conductor core. This results in sudden temperature loss in the corresponding hot runner section, interrupting injection molding production.
Chemical Corrosion and Insulation Failure: Contact with corrosive additives volatilized during injection molding erodes and damages the PTFE insulation layer, causing insulation failure within a short period.
These failures directly impact the stable operation of the hot runner system. Using virgin PTFE conductors and regularly testing insulation resistance can effectively mitigate most of these problems.
