KEVOS® MAKEOS · Pneumatics
Pneumatic Cylinder Force and Bore Selection
What force does this air cylinder give, and is the bore large enough for the load?
Extend and retract forces of a double-acting pneumatic cylinder, the load ratio against a recommended limit, and the smallest bore that meets it.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Bore | mm | Cylinder bore. |
| Rod diameter | mm | Piston rod diameter. |
| Supply pressure (gauge) | bar | Minimum supply pressure at the valve. |
| Efficiency (seal friction) | % | Allowance for seal friction (about 85–95%). |
| Load force to move | N | Force needed to move the load (friction, weight, process force). |
| Maximum load ratio | % | Highest share of theoretical force to use; makers often recommend about 50–70% for dynamic motion and higher for slow clamping. |
Method and formulas
- Extend F = p × π D² ÷ 4 × η; retract F = p × π(D² − d²) ÷ 4 × η (p in N/mm² = bar ÷ 10).
- Load ratio = load ÷ theoretical extend force.
- Minimum bore = √(4 × load ÷ (π p × ratio)).
- Example: a 50 mm bore at 6 bar pushes 1,060.3 N; a 600 N load needs at least 42.649 mm bore.
Limitations
- Static force; acceleration, cushioning and air supply flow are not included.
- Side loads on the rod need guides.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Select a cylinder bore for a load
- Check an existing cylinder at a lower pressure
- Compare push and pull forces
Who it is for
- Automation engineers
- Maintenance engineers
- Machine builders
What you get
- Extend and retract forces
- Load ratio
- Smallest bore meeting the load ratio
Interpreting the result
- Choose the next standard bore (32, 40, 50, 63, 80, 100 mm…) above the minimum.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 3032–3041. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
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