Hiwin HG Series Linear Rails

Characteristics of Linear Guides

Linear guide rail, also known as line rail, slide rail, linear guide rail, or linear slide rail, is used for linear reciprocating motion.

The design of the linear guide aims to have a larger contact area between the guide rail and the slider, improve the load-bearing capacity of the linear guide rail, widely spread the force, and expand the load-bearing area. To achieve this, there are various shapes of grooves for linear guides, with two representative ones being Gothic (pointed arch), which is an extension of a semicircle; Another type is circular arc shape, which can also serve the same purpose. Regardless of the structural form, the goal is only one, to strive for more rolling steel ball radius to contact the guide rail. This is a key factor determining the performance of linear guides.

The function of linear guide rail

The function of a linear guide rail is to support and guide moving parts, perform reciprocating linear motion in a given direction, have a higher rated load, and can also bear a certain torque, enabling high-precision linear motion under high load conditions.

Accuracy and lifespan of linear guides

Rolling steel balls are used between the guide rail and the slider of the linear guide rail. When the linear guide rail reciprocates, the steel balls circulate in the groove of the slider, distributing the wear of the slider to each steel ball, thereby extending the service life of the linear guide rail.

To eliminate the gap between the slider and the guide rail, preloading can improve the stability of the linear guide rail system. Preloading is the installation of oversized steel balls between the guide rail and slider. The diameter tolerance of the steel ball is ± 20 microns, with increments of 0.5 microns. The steel balls are sorted and installed on the guide rail separately. The size of the preload depends on the force acting on the steel ball. If the force acting on the steel ball is too large, the steel ball will withstand the preload for too long, resulting in an increase in the resistance of the slider movement. There is a balancing issue here; In order to improve the sensitivity of the system and reduce motion resistance, it is necessary to reduce the preload accordingly. However, in order to improve motion accuracy and accuracy retention, sufficient preload negative numbers are required, which are contradictory aspects.  

The working time of the linear guide is too long, and the steel ball begins to wear out, causing the preload acting on the steel ball to weaken, resulting in a decrease in the accuracy of the machine tool's working parts. If you want to maintain the initial accuracy, you need to replace the slider or even the guide rail.

HG Series,Linear Rails