Plastic leakage in hot runner systems is a serious issue that can damage molds, contaminate products, and cause extensive downtime. Leakage often occurs due to overheating, which expands components excessively or degrades seals, or due to uneven thermal expansion that creates gaps. Thermocouples prevent leakage by maintaining stable, controlled temperatures that avoid abnormal thermal expansion and material decomposition.
When a thermocouple fails or provides inaccurate readings, the corresponding heater may operate continuously, causing extreme overheating. This overheating softens or decomposes plastic, increasing pressure and pushing material into gaps between components. Over time, this leads to persistent leakage that is difficult to clean and repair. By maintaining accurate temperature control, thermocouples prevent the conditions that lead to leakage.
Thermocouples also help monitor thermal uniformity, ensuring that no single area of the manifold or nozzle becomes excessively hot. Balanced heating reduces uneven expansion that can break seals or distort components. In systems using valve pins, consistent temperature prevents material from solidifying or decomposing around the pin, which can also cause leakage. Regular inspection of thermocouple performance helps identify potential overheating issues before leakage occurs, protecting both the hot runner and the mold.
