The National Fluid Power Association (NFPA) and International Organization for Standardization (ISO) were set up to help alleviate these complexities for machine builders and end users. NFPA is used primarily in North American markets to cover inch products, whereas ISO encompasses the global metric market. The interchangeability that NFPA and ISO standards provide, bring consistency to machine design, simplify maintenance and reduce overall downtime.
NFPA and ISO standards define a variety of features such as mounting styles and overall dimensions, allowing pneumatic cylinders to be interchangeable across different manufacturers.
ISO 21287 applies to compact cylinders or short stroke cylinders. Using short pistons and end-caps, they are considerably shorter for the same working stroke than typical pneumatic cylinders. ISO compact cylinders are an excellent choice in applications where space is at a premium. However, this comes with the trade-off: they will not be as robust as other standard cylinders and generally should not be exposed to side loadings.
ISO 15552 profile cylinders are one of the most popular cylinder types in industry. The standard outlines key dimensions for manufacturers to follow. It provides basic dimensions for the cylinder, along with bore sizes: in this case from 32mm to 320mm. There are given dimensions for the mounting interface and attachable accessories as well as nominal/recommended stroke lengths.
Additionally, there is detail on the types of mounting options (i.e. trunnion mount), accessories (i.e. clevis bracket) and cushioning method. Due to the extended distance between the nose bearing and piston, this design is generally robust and capable of running with some side loading. With more space available in the front end-cap, there are many options for scraper, seal and bearing variants providing options to cope with different demands or running characteristics.