Oxidation of hot runner connectors can lead to increased contact resistance, unstable signal transmission, abnormal temperature control, and even system shutdown, especially in high-temperature and high-humidity environments.
1. Degraded Electrical Performance
Increased Contact Resistance: Oxide layers (such as verdigris and silver sulfide) have high resistance, causing contact resistance to rise from the normal <10mΩ to tens or even hundreds of mΩ, leading to localized overheating.
Deteriorated Conductivity: Although silver sulfide itself has some conductivity, uneven oxidation can cause an imbalance in current distribution, resulting in hot spots and accelerated aging.
Signal Interference: Thermocouple circuits transmit micro-voltage signals; poor contact caused by oxidation can introduce noise or intermittent signals, causing temperature control box readings to fluctuate or malfunction.
2. Abnormal System Operation
Intermittent Circuit Breaks: The oxide layer may detach during vibration or insertion/removal, causing momentary power outages, manifesting as a sudden interruption of the heating circuit.
Temperature control malfunction: Abnormal temperature signals cause the temperature control system to misjudge the temperature, potentially triggering overheat protection or leading to uneven material temperature, affecting product quality.
Equipment downtime: Severe oxidation causes persistent poor contact, ultimately causing the injection molding machine to stop, affecting production cycle time.
3. Mechanical and structural risks
Difficulty in insertion and removal: Oxidation products accumulate between the pins and sockets, increasing friction and causing excessive insertion force or jamming.
Plating damage: Forcibly grinding or inserting/removing the oxide layer can easily damage the gold/silver plating, exposing the underlying copper or nickel, accelerating further oxidation.
4. Environmental factors exacerbating the problem: In the middle reaches of the Yangtze River, such as Wuhan and Xiaogan, it is currently the rainy season, with high humidity and sulfur-containing gases, which easily promotes the sulfidation of silver contacts and the oxidation of copper base components. If the connector is poorly sealed (e.g., O-ring aging), moisture intrusion will significantly accelerate the oxidation process.
