Electro-Mechanical vs. Hydraulic & Pneumatic Actuators
Precision linear actuators are often a better choice than hydraulic or pneumatic alternatives with advantages of simpler and smaller installation, easier control, lower energy costs, higher accuracy, less maintenance, less noise, and a cleaner, healthier environment.
Electrical Actuators vs. Hydraulic and Pneumatic Cylinders | |||
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Electrical Linear Actuators | Hydraulic Cylinders | Pneumatic Cylinders | |
Installation | All electric operation requires simple wiring. | Requires expensive plumbing, filtering, pumps, etc. | Requires expensive plumbing, filtering, pumps, etc. |
Accuracy | Very repeatable (to ± 0,013 mm) and rigid, multi-stop capabilities. | Requires expensive position sensing and precise electrohydraulic valving to implement, has tendency to creep. | Difficult to achieve.Requires expensive position sensing and precise valving to implement, has tendency to creep. |
Control | Directly compatible with standard programmable controls allowing easy automatic operation of complex motion sequences. | Requires electronic/fluid interfaces and exotic valve designs. Hysteresis, dead zone, supply pressure and temperature changes complicate control. | Inherently non-linear, compressible power source severely complicates servo control. |
Speed | Smooth, variable speed with from 0 to 2 m/s with controlled acceleration. | Difficult to control accurately. Varies with temperature and wear. Stick slip can be a problem. | More susceptible to stick slip and varying load. Well-suited for light high speed applications. |
Reliability | Repeatable, reproducible performance during the entire product life. Very little maintenance required. | Very contamination sensitive. Require regular maintenance. Seals are prone to leak. Reliable with diligent maintenance. | Very contamination sensitive. Air sources require proper filtration. Good reliability, but usually many system components are involved. |
Power | Up to 40 000 N | Virtually unlimited force. Most powerful. | Up to 25 000 N. Typically used below 6000 N. |
Life expectancy | Up to millions of cycles at rated load. Easy to predict. | Dependent on design and seal wear, usually good. | Dependent on design and seal wear, usually good. |
Environment | Standard models rated for -30 to +70 °C. Inherently clean and energy efficient. | Temperature extremes can be a major problem. Seals are prone to leak. Waste disposal is increasingly problematic. | Temperature extremes can be a major problem. Seals prone to leak. Air-borne oil can be a problem. |
Load holding | Acme screw units are selflocking if power fails. Fail-safe brakes available for ball screw and roller screw models. | Complex back-up safety devices must be used. | Complex back-up safety devices must be used. |
Cost | Moderate initial cost, very low operating cost. | Components often cost less, but installation and maintenance are increased. Hydraulic power unit cost is high if not pre-existing. | Components often cost less, but installation and maintenance are increased. |