Several Common Guide Rails Used in CNC Milling Machine

CNC milling machine are metal cutting machine tools, which have high requirements for accuracy. The guide rail is one of the basic components of CNC milling machines and an important link of feed transmission system. It also determines the rigidity and accuracy of CNC milling machine. What are the common guide rails used in CNC milling machine and what are their advantages?

Hydrostatic guideway is also called hydraulic guide rail. Because the working surface of the guide rail is completely under pure liquid friction, the friction coefficient is very low during operation; The movement of the guide rails are not limited by load and speed, and the movement is uniform without crawling; Because the liquid has the function of absorbing vibration, the vibration resistance of the guide rail is good; Large bearing capacity and good rigidity; The friction heating and the temperature rise of the guide rail is low, but the structure of the hydrostatic guide rail is complex and the cost of a set of hydraulic system is higher than that of other guide rails; It is difficult to keep the oil film thickness constant, and hydrostatic guide rails are more common in large or heavy CNC milling machines.

Sliding guide rail, commonly known as box rail; It has the characteristics of simple structure, strong rigidity and high vibration resistance. It is widely used. Most of them use metal to plastic form. The plastic coated sliding guide rail has good friction, wear resistance, low speed, stable movement and good manufacturability.

Rolling guide rail is to place rolling elements such as balls, rollers or pins between the guide rail surfaces of CNC milling machine, so that the guide rail surfaces are rolling friction rather than sliding friction. Rrolling guide rails have higher sensitivity and small friction coefficient. Due to the small difference between dynamic and static friction coefficients, it moves evenly, especially when moving at low speed, it is not easy to crawl; The positioning accuracy is high, and the repeated positioning accuracy can reach 0.2 μ m； low traction, light movement, little wear, good accuracy retention and long service life; However, the rolling guide rail has poor vibration resistance, high protection requirements, complex structure, difficult manufacturing and high cost.