Round VS Square Linear Guide

Round VS Square Linear Guide: How to Choose?

In modern mechanical design and automation systems, linear guides are key components for achieving precise motion and positioning. According to different application requirements, linear guides can be divided into many types, of which circular linear guides and square linear guides are the two most common types. Choosing the right type of guide is essential to improving the performance, accuracy and reliability of the equipment. 

1. Round Guides

Circular guides are used to roll or slide on the optical axis through linear bearings to complete linear motion. Circular guides are not suitable for high-speed operation; when the speed is slightly higher, the operation is not smooth enough and the noise is very loud; if the linear bearing used is a closed-end type, the support of the optical axis can only be supported in two sections, which limits the stroke. The stroke cannot be too long, and too long a stroke will cause the optical axis to produce deflection deformation.

2. Square Linear Guides

Square guides are not suitable for high-speed operation; they are noisy at slightly higher speeds; they have high requirements for the accuracy of the installation datum surface, which makes processing and installation time-consuming and labor-intensive; they also have high requirements for the application environment, and stable environmental conditions are required to ensure stable installation datum accuracy.
Square guides can well meet high-load applications that require high rigidity. For example, the maximum load of a 25mm square guide can reach 20kN, and when running parallel between the bearing guide and the guide, it can achieve a high accuracy of 3~10mm/m.
Square linear guides are usually rectangular or square in design, with a large contact surface, and are usually used in conjunction with sliders to provide linear motion.

Round VS Square Linear Guide
Round VS Square Linear Guide

3. How to Choose to Use Square Linear Guides or Round Guides?

The competition between round guides and square guides is mainly in several major factors such as load, accuracy, rigidity, and finish.
Usually, in order to achieve optimal performance, the components must be modified to improve performance or match in the desired space. When compared with the load rating, square linear guides are more compact than round ball bushing bearings. Thus, if the geometry supports the user's system requirements, the user will have a fairly optimized housing. However, if a modification is required, it is easier to do this on a round rail system. Round shafting can be configured in many ways to facilitate end fixation of the shaft and use as a structural member in large-size assemblies, as well as central and radial through bores, flats and diameters of the axle box. Pillow blocks make the bearings easy to install and allow for some modification.
In some applications, flatness can be another major factor to consider. Although there may be slight differences between components and applications, and industry-related flatness data is often lacking, ball bushing bearings tend to run very smoothly, and the difference between square linear guides and round guides can usually be felt by hand. Round rails may be more advantageous. Also, due to their simple round geometry, seals on round bushings tend to be more reliable and produce less drag. Square rail wipers must conform to the ball tracks in the rails to achieve a durable seal.

Summary

Of course, how to choose to consider the actual application requirements, choose the one that suits you, is the best solution. Whether to choose square linear guides or round guides requires a detailed analysis of the specific situation, and it is not necessary to use square rail bearings in linear guide pairs or even bearing pairs. Round rails are commonly used in various applications such as sorting and placing modules in industrial automation systems and DNA samplers.

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