Key maintenance points for the heating system of injection molding machines:

Long term operation and frequent action of AC contactors can cause the main contacts to burn, damage, or have poor contact. Regular maintenance is essential. The long-term electrification operation of the contactor coil can also cause heating, deterioration, noise, etc., and requires frequent replacement.

The heating cylinder operates for a long time and has a certain service life. But common faults are short circuits in the power supply wires, burning out magnetic connectors or heating cylinder terminals. Short circuits in the power supply are often caused by human factors, such as pulling on the wiping machine, leaking glue during injection molding, and loose connection points. So, when replacing the heating cylinder, it should be installed firmly and the wiring should be reliable. First, tighten the wiring of the heating cylinder terminal, and then connect the power cord. After a few hours of operation, the heating cylinder is usually pre tightened again to avoid loosening of the connection points caused by thermal expansion and contraction.

The temperature controller is the core of the heating circuit. Its accuracy directly affects the quality of injection molded products, especially for plastics with high temperature requirements, otherwise the rubber material will be burnt, discolored or burned. The temperature controller collects the temperature signal of the heating cylinder, compares it with the set temperature signal, and controls whether to heat up or keep warm through the temperature controller.

Thermocouples are temperature sensing components that should be installed reliably, inserted into temperature detection holes at appropriate positions, and the thermocouple guide wire connection should also be firm and reliable. In general, there is a certain error in the temperature control table during use, and a thermometer can be used to measure and verify the accuracy of temperature control. The commonly used rubber material is generally error± It can also be used at 10 ℃.

The common malfunction of temperature controllers is control failure, mainly caused by burnt or sintered relay contacts in the meter, resulting in temperature failure and inaccurate temperature control. The large error range can be caused by a malfunction of the dial switch or deterioration of the performance of the integrated circuit inside the temperature gauge. It can also be caused by faults in internal circuits such as voltage regulator diodes, potentiometers, precision resistors, etc. A faulty temperature gauge also leads to loss of control.

To repair the heating circuit, you can start from the power supply part to the heating cylinder part for inspection, measure and adjust the circuit to determine the fault point and components, and then replace the damaged components before debugging and correction. When replacing components, attention should be paid to the model, shape, specifications, and parameters, especially the division number of the thermocouple, the power of the heating cylinder, and parallel installation. The nozzle heating cylinder should be protected from damage caused by adhesive leakage as much as possible.