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Linear guides — profiled and round (spline)

Welcome to this installment of MC² on linear guide and slide systems!

Recall that these linear-motion supports take the form of guide rails, slides, and ways … and include profile rails, linear bearings, guide wheels, slides, and plain-bearing systems that bear load while employing either sliding or rolling to allow translational motion. Typical designs pair rail or shaft with mating carriages or runner blocks.

You’ll find some resources on linear guides and slides to help design engineers choose from the vast array of these linear systems … and satisfy requirements for loading, stroke, speed, accuracy, and design life.

Also check out our library on preloading considerations and market-specific topics … including machine-tool applications and semiconductor manufacturing (where rolling linear guides abound); advanced medical applications (where square rails are common); and simpler machine axes (where forgiving slide designs maintain build ruggedness).

Lisa Eitel

Senior Editor, Design World

Linear Guides — Profiled and Round (Spline) Classroom Sponsored by:


Specify • Trends • Measure • Performance

Specifying and sizing linear rails for motion systems

Why use integrated position measuring with linear guides?

What are the differences between plain and rolling linear guides?

Trends: Consumer health-monitoring devices

The best approach to specifying and sizing linear rails is to define the most critical parameters of the application first; narrow the choices based on these requirements; and then apply critical variables to make the final linear-rail selection.

Linear guides provide accurate, high-capacity travel for a wide variety of machine types and processes. In the most demanding applications, linear position feedback is often needed in order to ensure the tool, gripper, or workpiece follows an exact path or reaches a precise

Growth of consumer health-monitoring devices is prompting new uses of linear-motion designs. Just consider two prototypes shown at the recent CES 2018 by THK America Inc. (with THK Co. Ltd.) that demonstrate new uses for linear slides and guides.

A linear guide (or linear bearing) is a mechanical element that allows relative motion between two surfaces, with one surface supporting the other, and minimum friction between the two. There are two basic types of linear guides: plain and rolling element. 

Linear Motion Video

Learn how to apply the most important equations for sizing, selecting, and comparing linear bearings.

Round shaft or profiled rail? How to choose

Choosing the wrong linear motion system can be a costly mistake, resulting in design or structural changes, poor machine performance, or oversized components with higher costs.

Hiwin Linear Guideways

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Topics in Linear Splines

What are ball splines and rotary ball splines?

When should you use a ball spline?

Ball spline preload: How, why, and when it’s applied

Ball splines are often lumped into the category of recirculating linear bearing guides (aka linear bushings), but they offer functionality beyond that of traditional linear bushings. Standard ball splines provide both linear motion and torque transmission

A ball spline is a type of rolling bearing linear guide, similar to a round shaft and bushing assembly, but with a critical distinction in its operation. The shaft of a ball spline is much like a linear guide shaft, except that the spline shaft has grooves along its length.

Like other linear motion components where rolling elements ride in raceways, ball splines can be supplied with preload. In the case of a ball spline, the main purpose of preload is to reduce angular backlash — clearance in the rotational direction — when torque is applied.

Bearing and Linear Motion Technology That Reduces Our Environmental Impact

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Design World’s MC² video on linear guide and slide systems

Welcome to this installment of Design World’s MC² (motion control classroom) on linear guide and slide systems. Linear-motion systems work in all kinds of applications, from industrial drawers to Cartesian robots

Common applications for linear rails

Linear rails are the backbone of many industrial applications, providing low-friction guidance and high stiffness for loads that can range from just a few grams to thousands of kilograms.

Their range of sizes, accuracy classes, and preloads make linear rails suitable for virtually any performance requirement.


Technical Focus • Tips • Linear Bushings • Geometry

Tips for selecting and applying telescoping linear bearings

How raceway geometry affects profiled rail guide performance

Technical summary: What is linear motion design engineering?

How do self-aligning linear bushings work?

Linear bushings ride on a hardened, round shaft to provide linear guidance with low friction.

Profiled rail bearings are ideal for applications that require long stroke lengths in a fixed footprint.

Technologies including linear motors, linear actuators, and linear rolling guides.

The two most common raceway geometries are referred to as circular arc and Gothic arch


IKO: Maintenance Free Linear Guides

Hiwin: Miniature Linear Guideways

With 50 years of experience, IKO specializes in quality needle bearings, linear motion rolling guides, precision positioning tables and machine components. At IKO, we offer our patented C-Lube technology in many of our products. This built-in lubrication system remains maintenance-free for 20,000km, and more. Our products are highly regarded in the worldwide marketplace, and we strive to live up to the inspiration for IKO’s name: Innovation. Know How. Originality.

HIWIN is the world leader in motion control and system technology, providing high quality and reliable standard and custom components and complete motion control solutions with precision quality, at competitive prices. With an extensive inventory in Chicago, our products are widely used in industrial equipment, lab equipment, semi-conductor and more.