Discussion on how to control the accuracy of line and rail

The line rails of each manufacturer shall be marked with the accuracy grade, using one letter of the accuracy name, including ordinary grade (N), advanced grade (H), precision grade (P), super precision (SP) and top precision (UP). Accuracy is a comprehensive concept, which generally consists of the traveling straight-line error of the slider datum surface on the side of the rail datum.

Width: it is the key to determine the load. Width generally includes: 15, 20, 25 (23), 30 (28), 35 (35), 45, 55 (53), 65 (63). Some brands are only 45, and there are micro wire rails with specifications of 3, 5, 7, 9, 12 and 15. There are two rows of slide rail mounting holes for 15, and there are 12 kinds of micro rails.

Length: total length=effective stroke+slider length+slider spacing (>2 sliders) * number of sliders+safe stroke at both ends. If protective covers are designed to be added, the compression length of protective covers at both ends needs to be calculated. Generally, the whole rail of the line rail is 4m, and some are ＞ 4m. If the length exceeds the existing length, butt joint processing is required. The distance between the mounting holes on the rail is fixed. When determining the rail length, pay attention to the position. Length error: generally, ± 1mm to 2mm below 2000 and ± 2mm to 3mm between 2000 and 4000 by default. If accuracy is required, error value shall be indicated or drawings shall be provided when ordering.

Sliding block type and quantity: there are two common sliding blocks, flange and square. Flange height is low, slider width is wide, and mounting hole is through threaded hole. The square height is high, the slider is narrow, and the mounting hole is a blind threaded hole. The two types of sliding blocks are respectively short, standard and extended. The main difference is that the metal length of the slider and the mounting hole are different. The short type has 2 mounting holes.