There are three main types of guide rails in CNC machining centers. According to the friction characteristics of the surface, they can be divided into three types: static pressure guide rails, sliding guide rails, and tumbling guide rails. The differences between these three guide rails are relatively large. Everyone must have a certain understanding of this matter when carrying out CNC machining.
An oil cavity is opened between the two working surfaces of the hydrostatic guide rail used in CNC machining. After entering the grease with a certain working pressure, a hydrostatic oil float can be generated, which makes the working surface of the guide rail in pure liquid friction, no damage, and good precision maintenance; at the same time, the friction index is also very low, which greatly reduces the output power of the drive; low-speed gear has no crawling, so the load-bearing can be large and the bending stiffness is good; in addition, the oil has the actual effect of absorbing vibration and good vibration resistance. Hydrostatic guide rails can be divided into hydrostatic guide rails and gas static pressure guide rails. The defect of the hydrostatic guide rail is that the structure is disordered, and the oil management system must be provided, and the cleanliness of the oil is required to be high. Hydrostatic guide rails are increasingly used on CNC lathes. The hydrostatic guide rail of CNC machine tool CNC punch press high-speed punch press can be divided into two types: open type and closed type.
The sliding guides used in CNC machining services have the advantages of simple structure, convenient production, good bending stiffness, and high vibration resistance. There are two common types of guide rail plastics: PTFE guide rail soft tape and epoxy resin wear-resistant guide rail coating. The characteristics of plastic-coated sliding rails are good friction characteristics, good wear resistance, stable fitness movement, good shock absorption, and good process performance. The disadvantage of the sliding guide rail is that the static friction index is large, and the dynamic friction index changes with the speed change, the friction damage is large, and it is easy to show a crawling state at low gears, and then the accuracy level of the fitness movement components is reduced. Therefore, in addition to economical and practical CNC lathes, in Other CNC lathes are no longer used. At this stage, most CNC lathes use plastic guide rails, that is, a layer of plastic film soft tape composed of plastic and other chemical materials is pasted on the friction surface of the sliding guide rail.
The rolling guide used in CNC machining is to place rolling bodies such as steel balls, rollers, and needle rollers in the middle of the guide surface, so that the sliding friction in the middle of the guide surface becomes the rolling friction. Compared with the sliding guide, the advantages of the tumbling guide are: the degree of comfort is improved, and the difference between the dynamic friction and the static friction index is very small, so the fitness movement is stable, and it is not easy to show crawling when the low-speed gear moves; the accuracy level is high, and the repeated accuracy level reaches 02μm; Low friction resistance, easy movement, small damage, good precision maintenance and long service life. However, the vibration resistance of the rolling guide is weak, and the safety protection requirements are relatively high. The disadvantage of the tumbling guide is that the vibration reduction is small and it is very easy to cause overshoot or shock, the bending stiffness is low, the production is difficult, and it is sensitive to dirt and track surface deviation. The CNC machining service of rolling guide rails is very suitable for places where the working components of CNC lathes require uniform movement, moving paths and high precision levels.