Hydraulic press is a very common kind of forging press, the application of hydraulic press in the metal processing industry is very wide, hydraulic press abnormal or improper control logic, is the common cause of abnormal machining accuracy of CNC hydraulic press in production, find out the fault points and dispose of, hydraulic press can recover normal. Hydraulic press is a kind of special hydraulic oil as the working medium, the main engine and the control mechanism of two parts. The main part of the hydraulic press includes the body, the master cylinder, the ejector cylinder and the liquid filling device. If it is found that the operation of the hydraulic press does not respond, what is the cause of this situation?
1. Wear and tear
During the movement of mechanical parts such as hydraulic spool, valve sleeve, and valve body, friction is constantly generated during use, making the size, shape and surface quality of the parts change and fail. Electromagnetic reversing valve spool wear or deformation, will make the valve leakage and reduce the efficiency, and dirt is easy to enter the gap or deformation, so that the spool mechanical blockage phenomenon. If the matching gap between the spool and the valve hole is too large, pressure shock will occur. The wear of the pilot valve of the pressure reducing valve will make the valve work unstable and even cannot adjust the pressure. The pilot taper valve (or pilot small ball valve) at the relief valve is not tightly sealed due to wear, and the pressure can not be adjusted normally. The check valve of the one-way throttle (speed regulation) valve is partly worn, the seal is not strict, and some oil flow will flow away through the check valve, affecting the sensitivity of speed regulation.
2. Fatigue
Working under long-term variable load, the spring in the hydraulic valve will become soft, shorten the length of the spring or break the whole because of fatigue; The spool and seat will also be cracked, spalling or other damage due to fatigue. These can cause the valve to fail. The spring on the main slide or pilot valve of the relief valve is tired or broken, which will make the system pressure not meet the requirements. If the spring of the reversing valve is too soft or too short, it will affect the working position of the valve core and the normal reset, so that the system can not work normally.
3. Deformation
When the residual stress of the hydraulic valve parts in the processing process and the use process, the external load stress exceeds the yield strength of the parts material, the parts are deformed and can not complete the normal function and fail. Hydraulic relief valve spool bending deformation or spring deformation, will make the spool movement is not flexible, resulting in unstable system pressure. Unloading valve spool bending deformation will make the spool action slow, so that the system from unloading to working pressure or working pressure to unloading transition process slow. The bending deformation of the valve spool will make the valve reversing action difficult to carry out normally. Note that improper assembly may also cause deformation of parts, such as: the valve body deformation caused by the reversing valve assembly screw is too tight may make the spool stuck.
4. Corrosion
There is too much water or acid in the hydraulic oil, and after a long time of use, it will corrode the relevant parts in the hydraulic valve, making it lose its due accuracy and failure.
