Selection Criteria for the Type of Automation

Criteria Pneumatic Hydraulic Hydropneumatic
Cost Lowest High Low
Clamping force Light - 2 to 3 kN max. Higher forces if no space constraints Medium and heavy - above 5 kN Medium and heavy -From 5 kN to 100 kN
Clamping clyinder size Bulky for even medium clamping force (Op.Pr. 5 bar) Compact (For SPM Op.Pr. 30 to 70 bar) Most Compact for heavy forces (Op.Pr. 150 to 200 bar)
Clamping stroke Wide range - from short to very long Wide range - from short to very long Short stroke - 50 mm max
Clamping speed Very fast Fast Fast
Impact while clamping Present Not present Not present
Reliability Low - as can be overpowered due to the compressibility of air Most safe - due to the check valve and incompressibilty of oil Safe - as factor of safety for force selection can be more
Sequencing Possible Possible Difficult
Piping & circuit Complicated Complicated Simple
Oil heating problem Not applicable Present Not present
Return stroke,
speed and power
Fast due to double acting cylinder, but with low power Fast, with power and positive due to double acting cylinder Slugish due to spring return clyinder
No. of clamping points No limit No limit Limited, 3 to 5 per intensifier
Other Applications Material handling, Valve actuation, Door movement Feed cylinders, Cutting, Hole punching, Deep drawing,
Earth moving equipment
Pressing, Assembly, Rivetting, Crimping, Cutting

* Hydropneumatic automation referred above is with hydropneumatic intensifier. Hydropneumatic pump is not considered.