Linear Actuators

Linear actuators are pre-assembled motion devices consisting of a drive mechanism, a housing, and in some cases, a linear guide. They come in a wide variety of configurations to suit almost any application – for example, belt driven and rack and pinion versions provide long lengths and high speeds, while screw driven rod type actuators supply high thrust forces.

As more designers and engineers are looking for ways to reduce time-to-market, improve reliability, and standardize machine components, manufacturers are making it easier to size and specify linear actuators. And they’re offering a wider range of fully “plug-and-play” actuators, with integrated motors, drives, and controls.

In this Motion Control Classroom, you’ll learn about the many variations of electromechanical linear actuators, get tips for sizing and selection, and see examples of where different actuator types are used.

Danielle Collins

Editor, Design World

Linear Actuator Classroom Sponsored by:

Linear Actuator Basics

Types  •  Applications  •  Make-vs-Buy

What are the main types of linear actuators?

Roller screw actuators: Design and applications

Linear actuators: The make vs. buy decision

Linear actuators come in myriad configurations to suit almost any application, environment or industry. They’re primarily categorized by their drive mechanism; then manufacturers use other features such as the type of guide and housing to further differentiate them.

Belt driven actuators for a wide range of applications

Electromechanical actuators come in many varieties, with common drive mechanisms being lead screws, ball screws, and roller screws. When a designer or user wants to transition from hydraulics or pneumatics to electromechanical motion, roller screw actuators are usually the best choice. 

With the range of linear actuators on the market, it’s becoming easier for machine builders and end users to find a standard or “customized standard” product that meets even the most unique application requirements. But there are still times when it makes sense to design and build an actuator in-house.

Belt driven actuators are the workhorses of the electromechanical world, offering longer stroke lengths and faster speed capabilities than screw driven designs, with less inertia and better resistance to contamination than rack and pinion drives.

FEATURED RESOURCESElectromechanical actuators

Electric Cylinder Offers Precise, Rapid Positioning

Suitable for single linear movements in every mounting position, the EPCS features a smooth running ball screw for rapid yet precise positioning. A cost-effective solution, this electric cylinder fits applications like positioning, clamping, distribution, sorting, ejection and more.

Ball Screw and Toothed Belt Axes

Compact and cost-effective, our ball screw axis ELGS-BS and toothed belt axis ELGS-TB offer precise, resilient recirculating ball bearing guides for the slide, as well as a powerful ball screw drive. Units include stainless steel cover strips and our unique “one-size-down” assembly system for easy mounting.

Rotary Drive For Swivel Tasks

Our rotary drive ERMS is ideal for simple swivel tasks. It includes a rotary plate with sturdy, precise and backlash-free ball bearings to absorb transverse loads and torques, and is available in two sizes, each with an angle of 90 and 180 degrees.

Linear Actuator Sizing and Selection

Sizing Criteria  •  Velocity  •  Torque

How to calculate motor drive torque for ball screws

How to calculate velocity from triangular and trapezoidal move profiles

When sizing a motor, one of the most important factors is the required torque. In general, motor torque-speed curves outline two primary areas of permissible torque: continuous and intermittent. 

How to calculate motor drive torque for belt and pulley systems

Don’t overlook these factors when choosing a linear system

When designing and sizing a linear motion system, one of the first steps is to determine what type of move profile the application requires, since this determines how to calculate velocity and acceleration.

Belt driven linear systems are common in applications that require long travel and high speed, such as gantry robots and material handling and transport. 

When sizing a linear system, the first application parameters that come to mind are probably travel, load, and speed.

High-speed linear actuators: What qualifies them as high speed?

Like many terms used in the linear motion industry, such as “heavy duty,” “miniature,” and “corrosion-resistant,” to name a few, there is no industry standard that specifies what constitutes a “high-speed” linear actuator.

Linear actuators: Pneumatic or electric?

Electrons or air molecules? That’s not a question you hear very often, but it’s one that engineers and designers wrestle with when developing a new machine or process. That’s because a wide range of linear actuators, especially rod-type versions, are available either electrically driven or pneumatically driven. 

Electric actuators displace other motion options — including manual designs: A Motion Trends report

Today, electric actuators are easier than ever to specify and install. Value-add services from component suppliers as well as application-specific actuator product lines (especially for battery-powered designs in mobile equipment and consumer use) eliminate many integration tasks for OEMs and end users. 

Realize Your Vision for Intelligent Automation

For nearly 100 years, Festo has provided industry leadership, superior products and global support. From servo motors to process valves, our portfolio includes over 33,000 electric, pneumatic and process automation products engineered to the highest industry standards.

In 2018, we acquired Fabco-Air Inc. and have since worked closely with this Florida-based company to produce high-quality inch-dimension actuators. Through these joint efforts, we’ve released new standard products—all while integrating the same high quality that is synonymous with the Festo name.