How Do Linear Slides Work And What Are They?

Linear guides, linear slides, or linear-motion bearings are all names for the same thing: a bearing that enables frictionless, one-axis motion. Parts of many types of machines, robotics, actuators, and sensors need to be able to move in a straight line along any of the three axes. Friction, the force exerted by two bodies moving in the opposite direction of motion, acts to oppose any free translational motion while in contact with another item. Frictional force is determined by the load applying on the contacting surface and the coefficient of friction attribute of the contacting surface.

The rolling element of linear bearings helps them glide effortlessly along a track or shaft. Bushes, track bearings, and several rail and carriage systems with varying profiles are just a few examples. The most widely used bearing is LME slide bearing (ลูกปืนสไลด์ LME, which is the term in Thai).

While “linear slide” is a more common name, “linear stage” is often reserved for more precise motorized positioners with bearings. “translation stage” and “linear translation stage” are synonyms for “linear stage,” while “translation slide” is rarely heard of.

Linear Slide Components

• Include a base that can be mounted to a machine or other surface and is typically stationary. The linear bearing, motor, and screw, if present, for the slide are typically supported by the base.
• The carriage mounts to the slidable part of the linear bearing or driver and moves along with it. A spindle, machine subassembly, or other component requiring linear motion is supported by the carriage. Typically, the carriage will be built of steel, aluminum, or cast iron.
• The LME slide bearing may either be included into the slide assembly’s base (as with a dovetail or box way slide) or installed as a separate component.
• A linear slide’s accurate and repeatable motion is made possible by the employment of ball screws and lead screws. In most cases, the screw will be fastened to the base, where it will be supported by a rotating bearing assembly, and the screw nut will be fastened to the carriage. The nut and carriage travel along the screw as it is turned (by hand or by machine).
• The linear motors allow for the carriage to be placed in precise locations. High acceleration and speed are also within the capabilities of linear motors.
• A gas or liquid pressurized piston is used in pneumatic or hydraulic cylinders to establish linear carriage positioning.