01
How bore changes cylinder force
Theoretical extension force is pressure multiplied by the full piston area. Retraction force is lower on a single-rod cylinder because the rod occupies part of the pressurized area. Real available force is lower again after friction, seal drag, pressure losses, load angle, and the desired operating margin are considered.
A bore should be selected from the required force at the cylinder's minimum available pressure, not from the compressor setpoint or a nominal catalog pressure alone.
02
Why the smallest workable bore is not always the best choice
A cylinder sized too close to the theoretical requirement can stall as supply pressure fluctuates or friction changes. Oversizing, however, increases compressed-air demand, valve and tubing flow requirements, impact energy, and often the physical envelope.
- Use a documented load or force margin appropriate to the machine and failure consequence.
- Check both extension and retraction where the rod-side force matters.
- Recheck valve flow, tube size, cushioning, and mounting loads after changing bore.
03
Bore does not prove interchangeability
Two cylinders with the same bore and stroke can still differ in mounting dimensions, overall length, port thread, rod-end thread, sensor groove, cushioning, allowable side load, and working-pressure range. ISO 15552 aligns selected dimensions for its stated cylinder family; it does not make every catalog cylinder universally interchangeable.
Selection checklist
What to verify before selection
- 01
Required push and pull force
- 02
Minimum pressure at the cylinder inlet
- 03
Load direction and friction
- 04
Duty cycle and target speed
- 05
Mounting and envelope limits
- 06
Valve, tube, and exhaust flow capacity
Application caution
Common mistakes
- Using compressor pressure instead of pressure available at the actuator
- Applying full piston area to retraction force
- Choosing bore without checking air consumption and stopping energy
FAQ