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Round vs. Square Rail Linear Guides

Which type of linear guide rail should be used - round or square?

Since the introduction of the square or profile linear guide rail in the 1970’s, the design engineer has been faced with the pivotal question: use a round linear guide or square?

While square linear guide rails initially cost many times more than round technology due to the extensive grinding requirements inherent in the design, the new linear guides manufacturing techniques and economies of scale have allowed square rails to compete effectively in a broader application space. Once subjugated to the realm of machine tools, profile rail linear guides can now be found in many of the same applications that were once only supported by round rail. However, the ball bushing linear guide remains popular due to some intrinsically unique and often advantageous characteristics that lend themselves to specific applications.

In order to apply the correct type of linear guide in a particular application, the design engineer must consider the advantages and capabilities of each. The cost of selecting the wrong linear guide technology can result in much additional design complexity, poor function and cost in the overall assembly. As a first cut it is useful to have a general understanding of the strengths and weaknesses of each type of linear guide product.

Profile rail linear guides are well suited to high load applications that require good stiffness and high accuracy. These linear guides achieve their performance through the precise grinding of the ball tracks in the rail, which have close conformity to the balls. The classic application for profile rail bearings is in the machine tool industry, where load capacity, stiffness and accuracy are paramount. Round rail linear guides offer several advantages of their own, including the ability to run smoothly when mounted to less-than-perfect surfaces.

What makes Thomson's linear guide rails superior?

Thomson offers a wide array of square and round linear guides and has been a leading innovator in this linear guide market since introducing the original round rail Ball Bushing® in the 1940s. Engineers are encouraged to look to Thomson for linear guides and linear guide rail solutions.

Profile Rail Linear Guide Systems

The Thomson Profile Rail assortment consists of the next generation Profile Rail 500 Series ball and roller linear guides, 400 Series, AccuMini, compact miniature MicroGuide®, and lightweight T-Series. It is a complete offering of rails and carriages in a broad range of styles, sizes and unique features produced to industry standard dimensions for easy retrofitting into existing applications or designing into new applications.

Square Profile Rail Guides

Round rail linear guides

Pre-assembled, ready to install stages providing low friction, smooth, accurate motion for a wide range of moment or normal loading configurations. Market applications include factory automation, medical, packaging, machine tool, semiconductor, printing, automotive assembly, aerospace and food processing. Slide tables are available as customizable RoundRail Linear Guides to multiaxis, turnkey systems complete with motors, drives, controls and electromechanical accessories.

Round rail linear guides
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