Why is the smoothness of the reversing process of a CNC end face cylindrical grinder important?
CNC end face cylindrical grinder is a commonly used machine tool for mechanical processing. There are high requirements for motion stability, commutation accuracy, and commutation frequency. At present, CNC end face cylindrical grinders are developing towards large-scale production, and some workbenches have reached a reciprocating speed of 40m/min. The motion inertia of large grinding machines is large, and when they change direction, it will cause a sharp increase in back pressure, resulting in a reversal impact, which will have a catastrophic impact on the machine tool. Therefore, the problem of smooth reversal has become an important factor restricting the increase of grinding machine working speed and machining accuracy.
The reversing method and control parameters in the system have a decisive effect on the reversing impact, and hydraulic transmission is used. The design of a new hydraulic reversing system is urgently needed. Below, we will discuss the reversal impact problem of grinding machines from the perspective of reversal methods and control strategies.
1、 The mechanism of reversing impact:
Due to the fact that in its hydraulic system, when the hydraulic transmission changes direction. The directional valve port instantly closes, and the oil circuit suddenly disconnects, making it impossible to drain the oil in the return chamber.
The greater the kinetic energy, the greater the reversal impact. For CNC end face cylindrical grinders operating with high inertia, the commutation impact is significant, which not only affects the machining accuracy of the machine tool, but also hinders normal operation and service life.
2、 Introduction to commonly used hydraulic transmission reversing methods:
1. Adopting the directional method of stroke directional valve.
2. Adopting the direction change method of electro-hydraulic directional valve.
3. Adopting the directional method of electromagnetic directional valve.
The travel switch is driven by the travel block to send a direction change signal, and the direction change valve is changed to an electromagnetic direction change valve. Making the electromagnet move to push the slide valve to change direction can prevent "dead spots". However, it is a switch type hydraulic valve that opens or closes according to instructions, instantly connecting or cutting off the return oil channel. Such a hydraulic reversing system will have a significant impact during reversing.