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Pneumatic Cylinder: How It Works, What Types There Are, and How to Choose the Right One
siłownik cpp prema z ustawnikiem pozycyjnym

Pneumatic Cylinder – How It Works, Types, and How to Choose the Right One

A pneumatic cylinder is one of the key components of industrial automation systems. It converts the energy of compressed air into linear or rotary motion and is used wherever something has to be moved, clamped, locked or precisely positioned. From simple assembly stations to complex production lines – without pneumatic cylinders, modern industry practically would not exist.

If you want to quickly select a cylinder for your application, you can approach the task in three steps:

  1. Define the type of motion and the required stroke.

  2. Determine the required force at the specified operating pressure.

  3. Choose the cylinder type (ISO, compact, mini, rodless, clamping, for harsh operating conditions) from the CPP PREMA range.

You can find an overview of all series in the category:
Pneumatic cylinders – CPP PREMA online store

Siłowniki pneumatyczne CPP PREMA – ISO 6432, ISO15552, CNOMO FORTIS

What is a pneumatic cylinder and how does it work?

A pneumatic cylinder is an actuator in which compressed air acts on a piston inside a cylinder, causing the piston rod or a carriage (in rodless cylinders) to move. In most cases it generates linear motion, but in the case of rotary (oscillating) cylinders it can also produce rotary motion within a defined angle range.

Construction of a pneumatic cylinder

A typical pneumatic cylinder consists of:

  • a body / tube (profiled or round),

  • front and rear end caps,

  • a piston with seals,

  • a piston rod with guidance,

  • end-of-stroke cushioning elements (mechanical or pneumatic),

  • pneumatic ports,

  • mounting accessories (feet, clevises, flanges, joints).

Compressed air is supplied to one of the cylinder chambers. The increase in pressure causes the piston to move, transferring motion to the piston rod. When the supply valve is switched over, air is directed to the opposite chamber and the movement occurs in the opposite direction.

When designing and documenting such systems, consistent notation on diagrams is extremely helpful. That’s why we have prepared a practical cheat sheet in PDF format:
pneumatic graphic symbols by CPP PREMA
– you can print it out and use it as a constant point of reference when creating documentation.

Single-acting and double-acting pneumatic cylinder

  • Single-acting cylinder – compressed air acts in one direction only, while the return stroke is provided by a spring. This solution is suitable for simple clamping, locking and positioning applications.

  • Double-acting cylinder – air is supplied alternately to the front and rear chambers. Force is generated in both directions, which allows full control of the motion. This is the standard solution in industrial automation.

Pneumatic, hydraulic or electric cylinder?

In practice, designers often compare three technologies:

  • Pneumatic – fast, clean and cost-effective for medium forces, ideal for serial applications and production environments.

  • Hydraulic – very high forces and high power density, but with a more complex system (oil, tightness, filtration).

  • Electric – precise positioning and high controllability, but with higher purchase costs and greater sensitivity to overloads.

The differences between pneumatic and electric cylinders are described in more detail in the article:
What type of linear actuators to choose: pneumatic or electric? 
If you are comparing pneumatic drives with hydraulic ones, it is worth reading:
A universal guide to the world of power hydraulics

budowa siłownika pneumatycznego – przekrój tłoka z tłoczyskiem i uszczelnieniami

Types of pneumatic cylinders in the CPP PREMA range

The CPP PREMA portfolio covers the full spectrum of cylinders – from compact mini actuators to heavy-duty designs for extremely harsh operating conditions. You can find all series grouped together in the category

ISO 15552 / ISO 6431 cylinders – including the SSI series


ISO 15552 / ISO 6431 cylinders are an industrial standard. They ensure full dimensional interchangeability with solutions from other manufacturers that comply with the same norms.

Key characteristics:

  • a wide range of bore sizes (e.g. D32–D320),

  • a very large variety of stroke lengths,

  • a wide selection of mountings and accessories,

  • high mechanical strength.

Within the CPP PREMA range, the SSI series stands out in particular – pin-mounted ISO cylinders with an additional scraper, designed for heavy-duty operating conditions. This series is covered by an extended warranty of up to 36 months, which significantly reduces the risk of downtime and maintenance costs.

Selected series and categories:

Practical tips for selecting ISO cylinders can be found in the article:
How to quickly choose a pneumatic cylinder? Proven methods from machine designers

ISO 6432 round mini cylinders

ISO 6432 round mini cylinders D12–D25 are compact actuators with low weight and small overall dimensions. They are ideal wherever space is limited and motion has to be fast and repeatable.

Typical applications:

  • packaging machines,

  • laboratory equipment,

  • lightweight manipulators,

  • solutions for medical and pharmaceutical applications.

You can find more details in the category:
ISO 6432 round mini cylinders D12–D25
The applications of mini cylinders in “clean” environments are well complemented by the article:
Pneumatics in the medical and pharmaceutical industry

ISO 21287 compact cylinders

ISO 21287 compact cylinders are designed to minimise overall length while maintaining the required force. They are a solution for applications where every millimetre of space matters.

Key advantages:

  • very short overall length,

  • possibility of installation in tight machine spaces,

  • compliance with ISO 21287, which facilitates upgrades and replacements.

You can find compact cylinders in the main category:
Compact cylinders D16–D100 ISO 21287

Cylinders for harsh operating conditions

CPP PREMA offers a dedicated line of cylinders for operation in environments that are:

  • heavily dust-laden,

  • humid,

  • contaminated with chips, swarf or sawdust,

  • exposed to vibration and impact.

Design features of such cylinders:

  • additional scrapers on the piston rod,

  • reinforced guiding,

  • seals resistant to contamination,

  • bodies prepared for operation in heavy-duty conditions.

Check the details:
Cylinders for harsh operating conditions D32–D320 ISO15552 / ISO6431
Their typical use is described, among others, in the articles:

Rodless cylinders

Rodless cylinders provide long strokes without a protruding piston rod. The piston moves inside the profile, and the motion is transferred to an external carriage.

Applications:

  • linear transport of workpieces,

  • movement of tables and heads,

  • axes in pick-and-place systems and robots,

  • applications requiring long strokes with limited space.

You can find the full range here:
Rodless cylinders
3D models are also available for designers:
Rodless pneumatic cylinders – 3D models

Clamping cylinders

Clamping cylinders, usually single-acting with a return spring, are ideal for:

  • welding tables,

  • assembly fixtures,

  • vises and clamps,

  • test stations.

They are available in the category:
Clamping cylinders D16–D100
and with dedicated accessories:
Accessories for clamping cylinders D16–D100

CNOMO cylinders – SCN series with extended warranty

The CNOMO standard is often found in older production lines and installations where a specific cylinder geometry is required. Using new CNOMO cylinders makes it possible to modernise the system without modifying the machine’s mechanical design.

CPP PREMA offers pin-mounted CNOMO cylinders D32–D200 of the SCN series, covered by an extended 36-month warranty – just like ISO SSI cylinders. This is a strong argument when planning upgrades and optimising service costs.

Product category:
Pin-mounted CNOMO cylinders D32–D200
3D models of CNOMO and ISO cylinders are available collectively on the page:
Pneumatic rod cylinders – 3D models

Przegląd typów siłowników pneumatycznych CPP PREMA – ISO15552, CNOMO, ISO 6432,

How to choose a pneumatic cylinder for a specific application?

Selecting a cylinder is a combination of several decisions: the type of motion, the required force, the operating environment and the mounting method. Below is a practical step-by-step approach.

1. Define the motion and stroke

Start by answering a few questions:

  • What type of motion is needed – linear or rotary?

  • What stroke length is required – short, medium or very long (over 1000 mm)?

  • Should the motion serve only for clamping, or for a full travel of the workpiece?

Example choices:

  • linear motion, standard strokes → ISO cylinders (e.g. SSI),

  • no space for cylinder length → ISO 21287 compact cylinders,

  • very long stroke, limited space for the piston rod → rodless cylinders,

  • clamping and locking of the workpiece → clamping cylinders.

2. Calculate the required force

The theoretical force F generated by a cylinder depends on:

  • the operating pressure p,

  • the effective piston area A.

In practice you need to:

  • take into account pressure losses in the system,

  • include a safety margin for the force (typically 20–30%),

  • remember that the pushing force is higher than the pulling force (because of the piston rod).

The most convenient way is to use the online tool:
Cylinder force calculator
A detailed step-by-step explanation can be found in the article:
How to calculate the force of an ISO pneumatic cylinder

3. Define the operating environment

Next, assess the surrounding conditions:

  • level of dust and contamination,

  • humidity and presence of aggressive media,

  • temperature range,

  • vibration, shock, outdoor operation.

For clean production halls, standard ISO or compact cylinders are sufficient. In harsh conditions it is worth choosing designs with additional scrapers and reinforced guiding right from the start:

Cylinders for harsh operating conditions D32–D320 ISO15552 / ISO6431
For the entire installation, the following article is useful:
Comprehensive guide to pneumatic installations: from design to maintenance

4. Select mountings, accessories and sensors

A complete drive system is not only the cylinder itself, but also:

  • mounting feet, clevises, flanges and joints,

  • piston rod ends and compensating connectors,

  • piston position sensors and sensor brackets,

  • flow control valves and silencers,

  • proper preparation of compressed air.

Accessories for ISO cylinders can be found in the categories:

5. Use standards and interchangeability

Thanks to the following standards:

  • ISO 15552 / ISO 6431,

  • ISO 6432,

  • ISO 21287,

  • CNOMO,

CPP PREMA cylinders can be used as replacements for many solutions from other manufacturers. This is particularly important when upgrading older production lines. An additional advantage is the extended 36-month warranty on ISO SSI and CNOMO SCN cylinders, which helps reduce the total cost of ownership (TCO) of the drive system.

Applications of pneumatic cylinders – examples from industry

Power generation and district heating

Pneumatic cylinders are used in:

  • drives for dampers and gates,

  • flow control systems for various media,

  • automation systems in boiler houses and combined heat and power plants.

More practical examples can be found in the article:
The role of pneumatic cylinders in modern power generation industry

Production automation and assembly lines

In automation systems, cylinders are used for:

  • transferring workpieces between stations,

  • clamping and positioning components,

  • operating rotary tables, conveyors and feeders,

  • axis movements in simple manipulators.

The impact of properly selected cylinders on efficiency is described in the article:
The impact of pneumatic cylinders on efficiency in production automation

Medical, pharmaceutical and food industries

In these industries, the key factors are:

  • cleanliness of the medium,

  • repeatability of motion,

  • compact dimensions of the actuators,

  • the possibility of using materials resistant to cleaning and disinfecting agents.

Applications are described, among others, in:

Mining, rail and heavy industry

In heavy-duty conditions, pneumatic cylinders with additional scrapers and reinforced guiding are used in:

  • loading flaps and chutes,

  • locking and braking systems,

  • safety and protection systems.

In such applications, resistance to contamination and reliability are crucial, which is why it is worth choosing cylinders from the SSI and CNOMO SCN series, available with an extended warranty in ATEX versions.

The most common mistakes when selecting and operating pneumatic cylinders

Insufficient force margin

Selecting a cylinder with almost no safety margin usually results in:

  • unstable operation,

  • movement stopping when resistance increases,

  • faster wear of mechanical components.

The solution:

Ignoring the operating conditions

Using a standard cylinder in extremely harsh conditions results in:

  • faster wear of seals,

  • air leakage,

  • increased failure rate.

In heavy-duty applications, it is worth choosing designs with additional scrapers and reinforced guiding right from the start, for example:
cylinders for harsh operating conditions D32–D320 ISO15552 / ISO6431

Lack of proper compressed air preparation

Poor compressed air preparation means:

  • condensate in the system,

  • solid contaminants,

  • insufficient lubrication (where it is required).

As a result, cylinders wear out faster, their tightness decreases and the system becomes less predictable.

This can be improved by:

Neglected maintenance and lack of inspections


Although a pneumatic cylinder is a durable component, it is not completely maintenance-free. Lack of inspections can lead to:

  • loss of tightness,

  • reduced force and speed,

  • increased friction,

  • unplanned downtime.

In the article
Maintenance and servicing of pneumatic cylinders
you will find specific guidelines on how to plan inspections and what to check. Combining good service practices with the extended 36-month warranty on key series (ISO SSI, CNOMO SCN) makes it possible to significantly extend the trouble-free operating time of the system.

Engineering tools: calculators, 3D models and knowledge base

CPP PREMA supports design engineers and technologists with a range of online tools and downloadable materials that make it easier to design pneumatic systems and prepare technical documentation:

FAQ – the most frequently asked questions about pneumatic cylinders

What is a pneumatic cylinder? It is an actuating element in which compressed air causes the movement of a piston and rod or a carriage, generating linear or rotary motion. It is used for moving, clamping and positioning components in automation systems.

How does a pneumatic cylinder work step by step? Compressed air is supplied to one of the cylinder chambers. The pressure acts on the piston, which moves inside the barrel and transfers the motion to the piston rod. The direction of movement changes after switching the valve and supplying air to the opposite chamber.

What are the basic types of pneumatic cylinders? The most important ones include: ISO 15552 / 6431 cylinders (including the SSI series), compact ISO 21287 cylinders, ISO 6432 mini cylinders, CNOMO (SCN) cylinders, rodless cylinders, clamping cylinders and cylinders for harsh operating conditions.

How to choose a pneumatic cylinder for the required force? You need to know the required force, operating pressure and take into account pressure losses in the system. Then, using a calculator, you select the cylinder bore with an appropriate safety margin (usually 20–30%). This is supported by the cylinder force calculator and the article How to calculate the force of an ISO pneumatic cylinder.

What operating pressure is typical for pneumatic cylinders? In many industrial installations, an operating pressure of around 6 bar is used. Exact permissible pressure ranges are always given in the data sheets and product descriptions.

What is the difference between pneumatic, hydraulic and electric cylinders? Pneumatic cylinders are fast, simple and cost-effective for medium forces. Hydraulic cylinders make it possible to generate very high forces but require an oil system. Electric cylinders allow precise positioning, but they are more expensive and more sensitive to overloads.

What warranty do CPP PREMA cylinders have? As standard, CPP PREMA cylinders are covered by a long manufacturer’s warranty, and selected series – ISO SSI and CNOMO SCN cylinders – have an extended 36-month warranty period, which is one of the longest in this product class.

How to take care of a pneumatic cylinder so that it lasts longer? The key is proper compressed air preparation (filtration, pressure regulation, lubrication), correct selection of the cylinder for the operating conditions and regular inspections. Detailed recommendations can be found in the article Maintenance and servicing of pneumatic cylinders.

Summary – what will be your next step?

A pneumatic cylinder is the “muscle” of many automation systems. The correct choice of cylinder type, bore size, stroke, mounting method and proper compressed air preparation determines the reliability of the entire installation.

At CPP PREMA you will find:

  • a full range of ISO, compact, mini, CNOMO, rodless and clamping cylinders,

  • ISO SSI and CNOMO SCN series with an extended 36-month warranty,

  • accessories, mountings, sensors and complete compressed air preparation systems,

  • engineering tools – calculators, 3D models and an extensive knowledge base.

If you want to move from theory to practice:

  • browse the range: Pneumatic cylinders – CPP PREMA online store

  • start by calculating the required force in the cylinder calculator

  • and for more complex projects, contact the technical and sales team directly via Contact – CPP PREMA.

On this basis, you can now confidently select a pneumatic cylinder for your application – with full manufacturer support and a long, reliable warranty.