Failures and Removal Methods of Pilot Type Relief Valves for Injection Molding Machines

As the hydraulic system of the injection molding machine develops toward medium and high pressure, the pilot type relief valve is widely used in the control oil circuit of the hydraulic system of the injection molding machine.

In practice, in order to maximize its effectiveness, protect the control system, accurately and promptly diagnose and eliminate the failure of the pilot relief valve is a key link. Failure of the pilot relief valve can cause the injection molding machine to fail. According to the phenomenon, the reasons for the analysis were as follows: the spring of the pilot valve spool was broken; the Yin and Ni hole was blocked; the valve of the pilot valve was badly sealed; the main spool was stuck and so on. Corresponding exclusion measures are: replacement or flat washer in the break place for emergency use; cleaning and dredging; grinding or breaking the circuit for emergency use; grinding and cleaning.

Unstable pressure limit: The pilot-type pressure relief valve is unstable, which is characterized by a low or high pressure in the hydraulic system, an inability to actuate the hydraulic actuator, or bursts in the tubing, the pump body, and the valve body. Caused by this failure are: improper pressure adjustment; pilot valve spool spring bent or soft; dirty oil or oil flow is not smooth. Corresponding exclusion measures are: re-adjustment; correction, padding or replacement; replacement, cleaning. The pilot-type pressure relief valve is unstable as a gradual failure. The failure of the pilot relief valve is a sudden failure. After the failure is eliminated, the pressure of the injection molding machine system should be used to control the pilot relief valve. The pressure is adjusted again.