Linear guide rail, also known as line rail, slide rail, linear guide rail, or linear slide rail, is used in situations of linear reciprocating motion and can bear a certain amount of torque, achieving high-precision linear motion under high loads. The function of linear guide rail movement is to support and guide moving components to perform reciprocating linear motion in a given direction. Linear guide rails have been increasingly widely used in industries such as CNC machine tools, CNC machining centers, precision electronic machinery, and automation equipment. So, how to choose a linear guide rail? How to install a linear guide rail?

Linear guide selection

Usually, the selection of linear guides must be based on usage conditions, load capacity, and expected lifespan. The so-called usage conditions mainly refer to factors such as the type of equipment used, accuracy requirements, rigidity requirements, load mode, stroke, operating speed, frequency of use, and usage environment. Select the appropriate product series according to the conditions.

1. Type selection

At present, there are many manufacturers of linear guide rails in the market, and each manufacturer has different model names and types. Zhongda PMI has a relatively complete range of linear guide rail types, which can basically cover all market demands. Its main types include self aligning full steel ball heavy-duty (MSA), self aligning full steel ball low assembly (MSB), all stainless steel micro compact (MSC), full roller heavy-duty (MSR), and silent steel ball (column) heavy-duty (SME/R).

Precision selection

The accuracy of linear guides includes:

1) Walking parallelism (dynamic accuracy). This includes the walking parallelism of the sliding block C surface (upper surface) relative to the sliding rail A surface (bottom surface), and the walking parallelism of the sliding block D surface (slide side reference plane) relative to the sliding rail B surface (slide side reference plane).

2) Geometric dimension accuracy. This includes the allowable size error of height H, the paired mutual error of height H (△ H), the allowable size error of width W2, and the paired mutual error of width W2 (△ W2).

Determination of preloading level

The magnitude of preload determines the rigidity of the guide rail and can eliminate the radial clearance of the slider. Experiments have shown that the effect of preload can increase the rigidity of the linear guide rail by 2.8 times when it is not preloaded. PMI linear guide preloading Elo rating system is divided into four grades: light preloading (FC), medium preloading (FO), heavy preloading (F1), and overweight preloading (F2). The correct selection of the pre pressure of the linear guide rail has a significant impact on the rigidity of the equipment.

Installation of linear guide rail

Installation examples for machinery with vibration and impact effects and requiring high rigidity and precision

(1) Be sure to remove burrs, scratches, and dirt from the installation surface of the machinery before installation

Note: As the LM rolling guide rail is coated with anti rust oil, please wipe it clean with cleaning oil before installation. After removing the rust preventive oil, the reference surface is prone to rust. It is recommended to apply lubricating oil with low viscosity for the main shaft.

2) After gently placing the LM track on the base, partially lock the assembly bolts to make the LM track lightly against the installation surface. (The horizontal reference plane of the base should be aligned with the marked side of the LM track.)

Note: Please use clean assembly bolts to secure the LM rolling guide rail. At the same time, when inserting the assembly bolts into the installation holes of the LM track, it is necessary to confirm in advance whether the bolt holes match. If the holes do not match and the bolts are forcibly screwed in, it will reduce accuracy

(3) Tighten the stop screws of the LM track in sequence to make the track close to the horizontal mounting surface.

(4) Use a torque wrench to tighten the assembly bolts to the specified torque.

Note: The tightening sequence of LM rail assembly bolts is to tighten sequentially from the central position to the end of the shaft, in order to achieve stable accuracy.

(5) The remaining LM tracks are also installed using the same method until all installations are completed.

(6) Drive the hole cover into the assembly bolt hole until it is in the same plane as the top of the LM rail.

Installation of LM slider,

(1) Gently place the workbench on the LM slider without fully locking the mounting bolts.

(2) Contact the reference side of the LM slider with the reference surface of the workbench side through the stop screw to position the workbench.

(3) Fully lock the assembly bolts on the reference and driven sides to complete the installation.