Single Acting vs. Double Acting Pneumatic Cylinder: Which is Better?

Valves and cylinders (actuators) play an important role in medium to large-scale industries today. These actuators are available in a number of configurations to serve various application requirements, with two of the most common actuator types being single-acting and double-acting. While they both serve a common purpose (converting compressed air to linear motion), they differ greatly in other ways.

Now, you may be asking yourself: Which one is better? To answer this, we will need to explore each of these, weighing their pros and cons, and talking about their key features in this article.

What are single-acting pneumatic cylinders?

As the name suggests, single-acting cylinders exert the force in one direction only. The compressed air moves the piston in one direction, and this motion can be used to perform the desired operation, like lifting. In most cases, the piston comes back to its original position with the help of a mechanical spring. Some cylinders also use gravity or an external spring to bring the piston to its original position, although this setting is not very common.

Single-acting cylinders come in different configurations based on the mechanical spring position:

Push setting: In this design, the air thrust is used to pull the piston, and then the spring pushes it back to its original position.

Pull setting: In this setting, the air thrust is used to push the piston, and then the spring pulls it back to its original position.

One of the key advantages of a single-setting cylinder is that it returns to its base position automatically in case of pressure or power loss.

Pros and Cons

Let's weigh the pros and cons of single-acting cylinders.

Pros:

• Simple design

• Comes with a lower upfront cost

• Easier to maintain due to only one moving part

• Energy efficient, as it uses half the air compared to double-acting cylinders

• Compact size, ideal for applications with space constraints

Cons:

• Reduced stroke length

• Lower thrust due to the opposing mechanical spring

• As the spring wears down, the piston strokes do not remain consistent

• Not as precise as the double-acting cylinders

While these cylinders offer a cost-effective option, they do not offer the same level of precision and control compared to other types.

What are double-acting pneumatic cylinders?

Double-acting cylinders utilize the compressed air to exert a bidirectional force on the piston. This makes them a more versatile option compared to a single-acting cylinder in numerous industrial automation tasks.

Double-acting pneumatic cylinders are crucial in modern industrial and manufacturing systems, due to their versatility. Their ability to provide precise, bidirectional motion, a durable structure, and consistent performance makes them suitable for various applications.

Whether your application requires pushing or pulling materials or holding something in place, double-acting cylinders can do the job for you.

Pros and Cons

Like any other great actuator, double-acting cylinder have their fair share of benefits and drawbacks.

Pros

• Precise and controlled bidirectional force

• Robust built

• Ability to control the bore size

• Have a higher chance of being compliant with ISO

• More suitable for high-cycle applications

Cons

• Uses 2x compressed air compared to single-acting cylinders

• Comes with a higher upfront cost

• Not as energy efficient as a single-acting cylinder due to high air consumption.

Double-acting cylinders are a robust and versatile option for applications requiring continuous thrust; however, they come at a higher price and may not be as energy efficient as the single-acting cylinder.

Single Acting vs. Double Acting Pneumatic Cylinder: Which one is better?

So, which one is better? Single-acting or double-acting? Let's compare them so see which one wins:

If you need an actuator for light-duty applications with unidirectional force requirements, a single-acting cylinder is a winner. And, if you need continuous and bidirectional force for your application, then a double-acting cylinder is a winner. 

There is not one winner in all the situations, so your budget and application needs will decide which one you should pick.

Factors to consider before choosing:

Don't just choose an actuator based on your gut feeling. Consider the following factors before finalizing your purchase:

Speed and force requirements

Consider the speed, force and accuracy requirements for your applications before choosing the right actuator. Single-acting cylinders are not known for extensive force or speed, so if your application requires considerable force and speed, then choose double-acting cylinders. 

Working conditions

If your working environment has consistent exposure to weather and tough elements, then go for double-acting cylinders. They are robust in nature and need minimal maintenance compared to single-acting cylinders.

Actuator usage

Does your application require 24/7 usage of an actuator? If yes, then choose a double-acting actuator. Single-acting cylinders use a spring or any outside force to return to their original position; that's why they wear out easily.

Cost (upfront and running)

Consider the overall ownership cost of the actuator, not just the upfront cost. Single-acting cylinders come at a lower upfront cost, but they require frequent maintenance and replacement, making them costlier in the long run. For regular, demanding applications, choose double-acting cylinders.

Do your homework, ask yourself the right questions before you finalize your purchase.

Conclusion

So, if you ask us, which one is better? We will say both. It just depends on your application and how much you are willing to spend. Consider factors like maintenance requirements, overall ownership costs, precision and control to choose the most suitable option.