The commutation method in the system and commutation control parameters have decisive effects on commutation impact, and the planar grinding machine uses hydraulic transmission. Planning a new hydraulic commutation system has fired eyebrows. There are many ways to discuss the hydraulic transmission replacement measures of the planar grinder from the reverse approach and the perspective of the control strategy. 1. Select the reversing method of the stroke reversing valve: the reversal of the trigger on the spool, and is converted to the travel reversing valve. Automatic commutation is achieved using the stroke stop on the workbench. When the workbenger of the planar grinder is slowly moved, when the reversal valve reaches the intermediate orientation, regardless of the hydraulic cylinder or all the pressure oil, or it is turned back to the oil, or close, the hydraulic cylinder is two cavities. Without liquid pressure, it will cause the workbench to stop, so the reversing valve cannot reach the other end, and there is a so-called \”dead point\”. 2. Select the electromagnetic replacement valve for reversing method: Push the stroke switch by the stroke stop to declare the reversing signal, the stroke reversal valve is changed to the electromagnetic commutation valve. Making the electromagnet action into the slide valve commutation, avoiding \”dead point\”; but it is a switched hydraulic valve, which is open or closed according to the instruction, which is instantaneously turned on or blocked the return passage, such a hydraulic commutation system There is a big impact when commutation. 3. Select the electro-hydraulic replacement valve for reversing method: The pilot valve is not reversed, and the electromagnetic replacement valve is replaced with the electro-hydraulic-free replacement valve constitutes a new replacement method. The electro-liquid commutation valve consists of a pilot valve electromagnetic spool valve and a main valve hydraulic valve. Once the control oil is controlled, the main valve spool of the planar grinding machine moves to another working position according to the speed of predetermined, the main oil direction is changed, and the workbench will also be reversed, avoiding the reverse \”dead point.\” \”.