Table of Contents
How Pneumatic Cylinders Work
A pneumatic cylinder converts compressed air energy into linear mechanical force. When pressurized air enters the bore it acts on the piston face producing a push force. The retract force is lower because the rod occupies part of the piston area. Understanding these forces is essential for sizing cylinders in automation, clamping, and material handling applications where precise force control is required for reliable operation.
Actual output force depends on bore diameter, operating pressure, rod diameter, and mechanical efficiency. Friction between seals and cylinder wall reduces theoretical force by 5-20 percent depending on seal type, lubrication, speed, and cylinder age and overall condition of the pneumatic system components.
Force Formulas
Common Bore Sizes
| Bore (mm) | Rod (mm) | Push @6bar | Pull @6bar |
|---|---|---|---|
| 32 | 12 | 483 N | 415 N |
| 50 | 20 | 1178 N | 989 N |
| 80 | 25 | 3016 N | 2721 N |
| 100 | 25 | 4712 N | 4417 N |
Frequently Asked Questions
Why is pull force less than push?
The rod reduces effective piston area on the retract side creating an annular area smaller than the full bore area used during extension stroke. This is inherent to all single-rod double-acting cylinders.
What efficiency should I use?
Standard cylinders have 85-95% efficiency. Use 90% as default. Low-friction types with special seals can reach 95%. Very old or poorly maintained units may be 75-80%.
How to choose bore size?
Calculate required force, add 25-50% safety factor, select smallest bore meeting requirements at available pressure to minimize air consumption and system cost.