Influence of Mold Locking Force on Thermocouple Fixed State

Mold locking force has a subtle impact on the fixed firmness and operational stability of integrated hot runner thermocouples in injection molding manufacturing, in addition to being related to product formation and flash prevention. A locking force that is too high or too low will have many negative consequences.

Strong extrusion force acts on the entire hot runner structure when the mold locking force is very high. The inserted thermocouple bodies are easily squeezed by the minor compression deformation produced by the manifold and nozzle metal components. Probe bending displacement, thread loosening, extrusion damage to internal wire cores, destruction of the initial close contact condition, poor heat conduction, and unstable signal transmission are all consequences.

During injection pressure impact, there will be a small gap between the mold plates if the mold locking force is inadequate. The fastened thermocouples will gradually loosen and shift during repetitive vibration due to the minor vibration and offset caused by the hot runner location. Temperature data will fluctuate due to occasional virtual connection problems caused by long-term operation.

Furthermore, an unstable locking force will frequently result in minute alterations in the mold's internal space, increasing the complexity of the cold and hot alternating stress carried by thermocouples, hastening the metal fatigue aging of core wires, and reducing the total service life.

Setting the mold locking force within the typical reasonable range that corresponds with the product structure is the proper method. Avoid excessively hard extrusion in order to ensure solid mold closure and no flash. After modifying the locking parameters, periodically check the thermocouples' fastening condition, promptly re-lock any loose sections, and maintain the fixed state for an extended period of time.