Simplified electric motion with combined pneumatics
01 April 2021
Many machine builders think that they need to choose between electric automation and pneumatic drives. Some claim that electric actuation is cheaper, easier to work with and more energy efficient. Others feel pneumatic technology is far more rugged, simpler and has a higher power density. But is this ‘one or the other’ approach always helpful in meeting the needs of the application?
In this article, Warren Harvard, Product Marketing Manager at Festo, argues the case for a more application-led approach to linear motion, including hybrid solutions which can incorporate the simplicity of pneumatics with the benefits of electric automation.
Each industrial application has its specific requirements with regard to technical criteria, such as speed, acceleration, load capacity and force required, cycle time, holding duration, power-to-weight ratio, accuracy, control behaviour, torsional rigidity, efficiency, and robustness. Both pneumatic and electric technologies have specific advantages and disadvantages, but energy efficiency wholly depends on the task at hand.
Let’s take some simple examples. Testing and measurements reveal that, for a simple motion task, an electric drive can be efficient. For a pressing or clamping operation, the level of process force and the duration of the operation decide which technology is more efficient. However, if the application requires a holding force, pneumatics is clearly at an advantage, especially for tasks that require large holding forces for extended periods. Electric drives would require constant electricity consumption to generate the holding force in the same applications.
The following rules of thumb can be applied: the shorter the stroke length, the greater the end position force, and the longer the holding duration, the more efficient pneumatic technology is. In contrast, the greater the stroke length, the lower the end position force, and the shorter the holding duration, the more efficient electric drive technology is.
Read the full article in the April issue of DPA
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