How this calculator works
Pressure difference times loaded piston area gives theoretical force. This estimate reduces that force by an entered friction fraction. Double-acting retraction uses the annulus left after subtracting rod area. A single-acting cylinder also subtracts its spring force during extension; the spring value applies at the selected stroke position. Seal friction, exhaust backpressure, acceleration and side loading vary in service, so this is a static estimate.
Formula
A = pi D^2/4; Ar = pi(D^2 - d^2)/4. Extension F = delta p A(1 - f) - Fspring. Double-acting retraction F = delta p Ar(1 - f).
Worked example
At 600000 Pa, a 0.05 m bore and 0.02 m rod with 10% friction give extension 1060.287521 N and retraction 890.6415173 N. Without friction, extension is 1178.097245 N.
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Frequently asked questions
Is supply pressure the pressure difference?
Only when the opposite chamber exhausts at the chosen reference pressure. Backpressure reduces the actual force.
Why is retraction weaker?
The rod occupies part of the piston face, leaving less pressure-loaded area.
Does single-acting return use compressed air?
This model assumes spring return and reports only the powered extension force. Actual return force depends on spring compression and friction.