How to Decide Between Hydraulic and Pneumatic Actuation for Your Project

Fluid power can be complex. There are a lot of variables to consider when deciding what type fluid will be best to power your project. Should you choose hydraulic actuation that uses an oil-type fluid or pneumatic actuation that uses compressed air?

Here is a quick guide for picking the right kind of actuation for your project.

What is available?

Many industrial facilities use compressed air in multiple ways, so pneumatic actuators may be the obvious practical choice.

Mobile or stationary?

Pneumatic actuators are “tethered” to their air source. Hydraulic systems can be self-contained, so mobility is unrestricted. Think construction equipment.

How much power do you need?

A hydraulic cylinder can generate up to 25 times the force of a comparable size pneumatic cylinder. Because hydraulic fluid cannot be compressed, these actuators can exert tremendous force to not only lift and move very heavy loads but reliably hold them in place almost indefinitely. Compressed air can sometimes lose pressure. That said, for many applications, the lower pressure exerted by pneumatic actuation is just fine.

How strict are the working conditions?

Hydraulic systems leak. That can contaminate and damage the system’s own internal and external components, not to mention the general working environment and the products being manufactured. For food, beverage, medical device, and semiconductor applications, that won’t do. Pneumatic cylinders are clean and involve no hazardous chemicals. They also function better in very high or low temperatures.

How much space is available?

Although pneumatic actuation requires a nearby source of compressed air, the cylinders themselves can be very small. That can be a big advantage when it comes to facility design. Hydraulic systems are cumbersome because there are so many bulky components — fluid reservoirs, motors, pumps and so on.

Is noise a consideration?

Hydraulics are noisy. You can dress them up with noise-reduction measures, but they’re still noisy. Depending on the location of your project, that may not matter.

How precise are the movements you need to actuate?

Every actuator moves a load. Linear actuators move loads forward and/or backward in a straight line. For some applications, these movements must unfailingly meet extremely tight tolerances. A pneumatic linear cylinder can consistently meet repeatability tolerances within .001 inches and accuracy tolerances within 0.1 inches.

Beyond Picking the Right Fluid Power: Which Actuator?

Choosing between hydraulic and pneumatic actuation is just the first step. Now, you have to decide which specific type of cylinder you want to use. Depending on the complexity of your project, you may well want more than one type of cylinder. This part of your decision-making process can be much more complicated because there are so many variables and configuration options.

Fear not, though. At W.C. Branham, we love a good puzzle, so give us a call. We can help you sort through your options — especially if you’ve chosen pneumatic actuation — to find just the right components for your project.