Advantages and Disadvantages of CNC machining different guide rails

There are three main types of guide rails in the CNC machining center. According to the conflicting nature of the contact surface, it can be divided into three types: static pressure guide rail, sliding guide rail, and rolling guide rail. The differences between these three types of guide rails are quite big. Everyone must have something to do when performing CNC machining. Understand, the editor will briefly introduce their advantages and disadvantages to you.

1. There is an oil cavity on the working surface of the two guide rails of the liquid static pressure guide rail. After the lubricating oil with a certain pressure is introduced, a static oil film can be formed, so that the surface of the guide rail operation is in pure liquid conflict without causing wear, and accuracy retention Good; together, the conflict coefficient is also very low, which greatly reduces the driving power; low speed without crawling, large load-bearing ability and good stiffness; in addition, the oil has vibration absorption effect and good vibration resistance. The static pressure guide rail can be divided into liquid static pressure guide rails and gas static pressure guide rails.

2. The sliding guide rail has the advantages of simple structure, easy production, good stiffness and high vibration resistance. There are two types of polytetrafluoroethylene guide rail soft belt and epoxy wear-resistant guide rail coating. The characteristics of plastic-on-plastic sliding guides are good conflict characteristics, good wear resistance, stable movement, good vibration damping and good processability.

3. The rolling guide is a rolling element such as balls, rollers, and needles between the guide rail surfaces, so that the sliding conflict between the guide rail surfaces becomes a rolling conflict. Compared with sliding guides, the advantages of rolling guides are: high activity, and the coefficients of dynamic conflict and static conflict are very different, so they move smoothly and are not prone to crawling when moving at low speed; (high positioning accuracy, repeat positioning accuracy can be Up to 02um; small conflict resistance, easy movement, small wear, good precision retention, and long life. However, the tumbling guide rail has poor vibration resistance and high protection requirements.

What are the shortcomings of the three?

1. The disadvantage of static pressure guide rails is that they are messy in structure and need an oil supply system, and the cleanliness of oil is high. Static pressure guide rails are becoming increasingly widely used in machine tools. The liquid static guide rails of CNC turret punch press can be divided into two categories: open type and closed type.

2. The disadvantage of sliding guide rail is that the static collision coefficient is large, and the dynamic collision coefficient changes with the change of speed, and the collision loss is large. It is easy to crawl at low speed/(1-60mm/min/), and then the positioning accuracy of moving parts is reduced. , so except for economical CNC machine tools, it is no longer used on other CNC machine tools. At present, most CNC machine tools use plastic-only guide rails, that is, a layer of plastic film soft tape composed of other chemical materials such as plastic is pasted on the conflicting surface of the moving guide rails.

3. The disadvantage of rolling guide rails is that they have small damping and are prone to overshoot or oscillation, have low stiffness, are difficult to manufacture, and are more sensitive to dirt and rail surface errors. The rolling guide rail is especially suitable for situations where the working parts of machine tools require uniform movement, active movement and high positioning accuracy.