Entering the new technological era of the 21st century, "Made in China" has undergone a comprehensive upgrade, with improved quality and significantly enhanced capabilities. Linear guides are widely used in industrial machinery design, and the selection of the appropriate linear guide is a crucial consideration.
Below is a simple explanation of how to select a linear guide:
1. Determining the Linear Guide Width
The guide width is a key factor in determining the load capacity of the guide. Linear guide product widths generally include 15, 20, 25 (23), 30 (28), 35 (35), 45, 55 (53), and 65 (63) mm. Some brands only offer sizes up to 45 mm. There are also miniature linear guides with specifications of 3, 5, 7, 9, 12, and 15 mm. These models also have wide versions (the slide rail width is twice the standard type), and the 15 mm slide rail has two rows of mounting holes. There are a total of 12 types of miniature guides.
2. Determining the Linear Guide Length
Determine the total length of the guide. The total guide length = effective stroke + slider length + slider spacing (for more than two sliders) multiplied by the number of sliders + safety travel at both ends. If a protective cover is added to the design, the compressed length of the protective cover at both ends needs to be calculated. Generally, the standard length of a linear guide is 4 meters, and some may exceed 4 meters; this needs to be confirmed with the brand manufacturer. If the selected guide length exceeds the existing length, splicing is required. If splicing is necessary and the user wants to process the mounting holes on the machine beforehand, it is best to provide interface drawings. Also, please note that the spacing between the mounting holes on the guide is fixed. When determining the guide length, users should pay attention to the position. For example, a 15 mm guide, 600 mm long. If the supplier is not informed of the required end dimensions, the delivered product will generally have 10 mounting holes, with the distance from the end faces of the guide to the center of the nearest mounting hole being 30 mm each, but other dimensions are also possible. Different brands have slightly different regulations for end dimensions, but most default to equal lengths at both ends. Another point to note is the length tolerance of the guide. Generally, brands default to ±1~2 mm for lengths below 2000 mm, and ±2~3 mm for lengths between 2000 and 4000 mm. If the user requires higher precision, it is best to specify the tolerance value or provide drawings when ordering.
3. Determining the Slider Type and Quantity
There are two common types of sliders: flanged and square. Flanged sliders are shorter in height and wider, with through-threaded mounting holes. Square sliders are taller and narrower, with blind threaded mounting holes. Both types of sliders are available in short, standard, and extended versions. The main difference is the length of the metal part of the slider. The mounting holes also differ; generally, short sliders have two mounting holes. The recommended principle is: use the minimum number of sliders required to bear the load, and the maximum number that can be installed.
4. Determining the Accuracy Grade
Each manufacturer of linear guides specifies accuracy grades. These are generally indicated by the first letter of the accuracy name: Normal (N), High (H), Precision (P), Super Precision (SP), and Ultra Precision (UP). Accuracy is a comprehensive concept, generally determined by the linear travel error of the slider's reference surface relative to the guide rail's reference side, combined height error, lead side slider reference side width error, paired height error, and paired width error. For most industrial machinery, normal accuracy is sufficient; for higher accuracy requirements, choose H-grade; for CNC and other machine tools, choose P-grade. The latter two grades require stringent installation and conditions to achieve their performance.
Summary
In practical applications, proper selection can significantly improve equipment operating stability and service life, while effectively reducing maintenance costs and system failure risks. If you have any uncertainties during the selection process, please contact us. CSK technical personnel will recommend the linear guide that best meets your needs.