Everything You Need to Know about How to Choose a Linear Actuator

How to Choose a Linear Actuator

Linear actuators are used in everything from industrial and agricultural machinery, robotics, cutting tools to everyday apparatus to control movements within a machine. Unlike electric motors that use a circular motion, linear actuators create straight motion. Linear actuators are powered by electricity, pressurized fluid, air, or manually.

Without actuators, industry would come to a standstill. That’s because actuators keep things moving—from automated production plants to values that pump fuel and fluids through machinery. Deciding which actuator is right for you depends on what you’re using it for and what works best for your work environment.

Difference Between Linear Actuators and Rotary Actuators

Actuators incorporate motors, cylinders, and other devices to produce rotation or linear movement. Rack and pinion systems, roller screws, and other types of power transmission components connect the motors or cylinders to their moving loads.

Motion and power source differentiate actuators. There are two main types of actuators: linear and rotary.

  • Linear actuators move objects along a straight line, typically in a back-and-forth motion. Movement of linear objects is described as distance. Linear actuators are used in everything from computers to industrial equipment. Regardless of where they’re used, the function is the same: to move something a precise distance.
  • Rotary actuators rotate objects so they can move at any angle. They can rotate continuously, incrementally, or a set amount—90 degrees, for example. The movement is measured in degrees.

In some cases, linear actuators begin with a rotary motor, but the rotation is converted to linear motion through a power screw or other device. Electric linear actuators developed by engineers at Washington-based Creative Motion Control use roller screws to transform rotary motion into linear movement. Roller screws have at least two times the load capacity of ball screws.

Both linear and rotary actuators often are used to operate control valves—a power-operated device used to regulate or manipulate the flow of fluids, such as gas, oil, water, and steam. The actuator delivers a signal to the control valve that opens or closes it and helps it regulate flow. A gate valve is a common linear control valve, and a butterfly valve is a common rotary valve.

How to Choose a Linear Actuator

Determining motion and force is key in selecting between a linear or rotary actuator. If you need a device to perform a tugging or circular motion, choose a rotary actuator. If you need a pushing motion, select a linear actuator. For now, let’s take a look at how to choose a linear actuator.

There are three main types of linear actuators:

  • Electric
  • Hydraulic
  • Pneumatic

Linear actuator products are used in many industries, including:

Each actuator type is essential to specific applications. However, recent advances in technology and manufacturing have allowed the devices to be interchangeable in some situations. Linear motion manufacturer Creative Motion Control has developed innovative new electric linear actuators to handle a wide range of applications.

Because of their flexibility, precision, and ease of use, electric linear actuators are a top choice for most linear project needs. However, each type of linear actuator has its benefits and drawbacks. It’s important to weigh each linear actuator’s functions, benefits, and disadvantages before deciding on the right actuator for your project.

Electric linear actuators

Electric linear actuators convert rotary motion into linear motion. These devices are designed to have fewer working parts than other actuators, which reduces maintenance and improves ease of use. Electric linear devices provide the highest precision control of any actuator.

Electric linear actuators work by using an electric motor to generate a high-speed motion slowed by a gearbox. This increases the torque that turns the lead screw. The lead screw prompts the linear motion of the drive nut.

Electric linear actuators are highly adaptable for almost any purpose. Key benefits include:

  • Highest precision-control of any actuator
  • Available in many sizes for superior project flexibility
  • Allow for multiple actuators to accurately move in sync
  • Provide instant feedback
  • Easy to reprogram
  • Offer complete control of motion, with custom speeds and stroke lengths
  • Make less noise than other actuators
  • Don’t leak fluid, so they’re safe for the environment
  • Can be modified for greater control over velocity, torque, position, and force

Electric linear actuators are highly flexible, but they can cost more than other linear actuators. However, over the life of the device, electric linear actuators actually prove to be less expensive than fuel-powered actuators because of their energy efficiency. In addition, because electric models are environmentally friendly, you save on costly cleanups from actuators that leak toxic chemicals.

Many industries use these high-performance electric linear actuators for:

  • Valve and damper control for the power industry
  • Valve regulation in car engines
  • Bearing pressing systems in manufacturing
  • Synchronized bottle filling in the food industry
  • Edge guide systems in the paper and sheet metal industry for web control
  • Plastic industry tensioning
  • Auto assembly line parts movement
  • AC and DC motors

Hydraulic linear actuators

These actuators are powered by oil or another form of pressurized hydraulic fluid. Using a piston-cylinder configuration, liquid from a pump moves the piston in the cylinder. As the liquid is pressurized, the piston moves inside the cylinder to create a linear force.

Hydraulic linear actuators are most commonly used for high force. Heavy-duty machinery like construction equipment often relies on the force produced by these actuators. Hydraulic actuators also are used on car transport carriers that require a great amount of pressure to raise and lower vehicles.

Benefits of hydraulic linear actuators include:

  • Produce extremely high force—the most force of any actuator
  • Hold force and torque constant without needing to pump more pressure
  • Produce very high speeds
  • Tolerate harsh conditions and heavy shock loads
  • Last long with proper maintenance

Drawbacks include:

  • Prone to leak fluids, which leads to a loss in efficiency
  • Need a specialized sensor to monitor actuator data
  • Allow only manual adjustments, which jeopardizes precision
  • Can be extremely noisy
  • Demand high maintenance

Pneumatic Linear Actuators

Pneumatic linear actuators function similarly to hydraulic models. However, pneumatic actuators use air rather than fluid to drive movement. A piston-cylinder system compresses the air to create a linear force.

Pneumatic linear actuators are composed of a piston inside a hollow cylinder, making it a very simple system. A compressor moves the piston, which builds pressure and creates linear force. These actuators are commonly used for sensors, air compressors, switches, pumps, mining, nail guns, and medical equipment.

Benefits include:

  • Simple system at a low cost
  • Resist overheating and can withstand wet and moist work environments
  • Resistant to explosion and shock
  • High force and speed

Disadvantages include:

  • Require a compressor to run constantly to maintain air pressure
  • Must be custom-sized for specific jobs, which adds to the cost and complexity of the system
  • Can experience damage if air becomes contaminated from fluids
  • Achieving position accuracy is difficult
  • Require high maintenance

Other Considerations in Choosing a Linear Actuator

When considering how to choose a linear actuator, it’s important to take your work environment into account. You don’t want to use an electric linear actuator in a damp environment, and placing an extremely loud hydraulic actuator in a small space could blow your staffs’ eardrums out.

Important factors in how to choose a linear actuator include:

  • Operating conditions: It’s important to choose the proper actuator to suit the operating environment. If the space doesn’t have an electric supply or experiences extreme temperatures, you should consider a hydraulic or pneumatic actuator. However, if you have access to electricity, choosing an electric linear actuator is almost always the best option.
  • Environmental issues: Unlike hydraulic and pneumatic actuators, electric linear actuators don’t use hazardous oils or fluids. This eliminates the risk of leaks that contaminate the environment. They also are more than 90% energy efficient.
  • Space constraints: Determine how much space is available for your system. Electric linear actuators typically take up less floor space than other actuators because they are self-contained and don’t require external supporting equipment.

Need Help with How to Choose a Linear Actuator? Call Creative Motion Control

Regardless of which device you choose, linear actuators are an essential part of manufacturing and day-to-day life. These devices allow industries to transform manual functions into efficient and precise automated ones. To make sure you’re choosing the right actuator for your company, count on Creative Motion Control, a leading manufacturer of American-made linear motion control products.

Since 2002, Creative Motion Control has developed and delivered innovative motion control technologies. The company’s team of engineers and scientists has designed the future of high-force electromechanical linear motion. Its products deliver unmatched performance with higher load capacity, longer life, and improved efficiency.

Creative Motion Control has the expertise and the products to help you select the best linear actuators on the market. Located in Woodinville, Washington, Creative Motion Control sells and delivers actuators, roller screws, and grooved roller bearings across the country. Contact Creative Motion Control at 866-497-7202 to discuss your needs or request a quote.

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