Understanding ISO standards in pneumatics

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1. What is an ISO cylinder?

ISO cylinder is a standard for pneumatic actuators developed by the International Organization for Standardization (ISO). This standard ensures that pneumatic actuators meet uniform standards in terms of mounting dimensions, bore diameter, and stroke length. 

Therefore, different manufacturers, brands, and models are easily interchangeable as long as they meet the same ISO cylinders.

Pneumatic Cylinder Standard

* If you have any questions about ISO standards for pneumatic cylinders, please contact VPC Pneumatic.

2. What are the types of ISO cylinders?

① ISO 15552 - Standard Cylinder

 ISO 15552:2018 - Pneumatic fluid power — Cylinders with detachable mountings, 1 000 kPa (10 bar) series, bores from 32 mm to 320 mm — Basic, mounting and accessories dimensions.

(From: https://www.iso.org/standard/66921.html)

Key Features:

• High Interchangeability: Alternative to ISO 6431 and German Standard VDMA 24562.

• Standard adjustable air cushioning for smooth end-of-stroke control.

• Built-in magnet in the cylinder piston for position sensing.

• Available in various robust constructions, including profiled and tie-rod styles.

• A wide range of cylinder accessories is available.

DNC Series ISO 6431 Standard Pneumatic Cylinder

SI Series Mickey Mouse Tube Pneumatic Cylinder

CP96 Series ISO15552 Standard Cylinder

② ISO 6432 - Mini/Round Cylinder

 ISO 6432:2015 Pneumatic fluid power — Single rod cylinders, 1 000 kPa (10 bar) series, bores from 8 mm to 25 mm — Basic and mounting dimensions.

(From: https://www.iso.org/standard/64054.html)

Key Features:

• Small size and compact structure, ideal for space-constrained applications.

• Built-in elastic cushion for cushioning, not adjustable.

• Available in stainless steel.

• Flexible mounting via threads on the front cover or mounting accessories on the rear.

DSNU Series Stainless Steel Mini Cylinder

MAL Series Mini Cylinder

③ ISO 21287 - Compact Cylinder

ISO 21287:2018 - Pneumatic fluid power — Compact cylinders, 1 000 kPa (10 bar) series, with bores from 20 mm to 200 mm — Basic, mounting and accessory dimensions.

Key Features:

• With the same bore and stroke, its overall length is 40% to 50% shorter than an ISO 15552 cylinder.

• It features a built-in elastic cushion.

• It can be mounted on the top, bottom, or side of the cylinder, eliminating the need for additional mounting brackets.

• Its output force is equivalent to that of a standard cylinder of the same bore, ensuring sufficient thrust even in confined spaces.

C(D)Q2 Double Acting Single Rod Compact Cylinder

ADVU AEVU Series Compact Cylinder

ADN Series ISO 21287 Compact Cylinder

ISO15552 VS ISO6431 VS ISO6432 VS ISO21287

3. How to choose ISO standard cylinder?

① Determine application requirements: Identify required thrust, pull, speed, operating environment, etc.

② Select the appropriate ISO standard:

• New project design: Prioritize the most universal ISO 15552 standard.

• Equipment repair/replacement: Confirm the ISO standard to which the existing cylinder complies. (ISO 15552 can directly replace older ISO 6431 cylinders.)

• Specific market/customer requirements: For example, exports to North America may require NFPA standards.

③ Select cylinder type: Based on space and load requirements, choose between standard (ISO 15552), compact (ISO 21287), or miniature (ISO 6432).

④ Determine specific parameters: Bore, stroke, mounting method (flange, foot, trunnion, etc.), cushioning type, and rod end attachments.

4. Why are ISO standards important for pneumatic cylinders?

• Interchangeability: Cylinders from different brands can be directly interchanged as long as they adhere to the same ISO standards.

• Simplified Design and Procurement: Engineers can design based on standard dimensions, eliminating the need to reserve space for specific brands. Procurement personnel can also find qualified suppliers worldwide.

• Simplified Maintenance and Reduced Costs: During equipment maintenance, engineers can quickly find replacement parts simply by selecting parts based on ISO standards. For overpriced products, alternatives can be found to reduce production costs.

• Quality Assurance: ISO standards not only specify dimensions but also cover pressure ratings, cushioning methods, stroke accuracy, and other factors, ensuring a baseline for product quality.

5. Non-standard cylinders and applications

Rodless cylinders, rotary cylinders, and guided cylinders often have their own manufacturer standards rather than unified international standards. In special operating conditions (such as high temperature, explosion-proof, and food-grade), cylinders with special materials and seals are required.

CY1 Series Magnetically Coupled Rodless Cylinder

MSQ Series Rotary Table Rack & Pinion Cylinder

MGPM Series Compact Guided Pneumatic Cylinder

Our cylinders are manufactured in strict accordance with ISO standards, ensuring complete interchangeability and compatibility with other brands. We can also customize them to your specifications. Contact VPC Pneumatic's technical team to find the right product for you!