Tech Tips - Selecting Pneumatic Linear Slides for Automation Projects

sponsored by: slide selection Selecting a linear slide involves several basic factors, including: • What Force is required — determines air cylinder bore size • Load Capacity required — determines size and bearing type of the slide guide mechanism • Stroke required — total linear distance traveled • Operating Speed — cycles per minute and/or inches per second By utilizing the slide manufacturer’s Engineering Data provided for each model series, much engineering time can be saved. Data in this article will be expressed in US Customary units of pounds and inches. Force By using the formula Force = PSI x Area (power factor), the linear slide’s cylinder bore is determined. Note that many slide models have a different power factor for the extend and retract stroke (factor considers area lost by the piston rod). If the application involves pressing, such as an assembly operation, consider the possibility that more force may eventually be required than initially expected. A preventative solution is to size to a larger bore and regulating it to a lower supply pressure. This pressure can then be increased when required, to increase the slide’s output force. Another method of increasing slide’s output without sizing to a model with a larger bore is to utilize a tandem cylinder or Multi-Power® option. (Multi-Power® is a registered trademark of Fabco-Air, Inc.) Lifting applications require that the slide have at least twice the output force as the weight to be lifted. Underpowered slides that “just barely lift” the load will operate poorly, with a slow, jerky, and un-controlled motion. Finally, many applications require very little force, and bore size is often mistakenly ignored. Select a slide with a bore size that provides a sufficient volume of air to operate with a smooth, controlled motion. Avoid excessively large bores that waste air needlessly, and thereby waste energy. 3