The 10 most-common Mistakes Made When Sizing Pneumatic Rodless Actuators

Here are some tips for getting the most out of the next rodless actuator you purchase. Edited by Stephen J. Mraz Rodless cylinders both support loads and supply guidance, eliminating the need for other load-bearing elements and reducing costs, size, and design time. Given these advantages, why do designers often overlook rodless actuators? Maybe they don't know enough about them and can't spec them properly. The following common mistakes made when sizing rodless actuators will help engineers get the best actuator. #1: Overestimating available air pressure A pneumatic actuator needs the proper amount of air pressure to perform up to specs. Engineers must know how much air pressure is actually available. So check your air pressure with a gage to get an accurate reading and build in safe engineering practices. For example, a plant may supply air at 100 psi, but pressure can vary from site to site in the factory as much as 10% due to variable demand cycles. This means actual available air pressure is only 90 psi. A 5 to 10% fluctuation in air pressure is quite common and can make a big difference in selecting the proper cylinder for an application. It is always best to factor in a 10% pressure loss factor from the gage air-pressure reading. #2: Incorrectly determining the working stroke and overall length Part of the actuator stroke cannot be used due to interference of internal components and the room needed to go to the end of stroke. This is normally referred to as the actuator's "dead length" and is determined by the manufacturer. It should be indicated on the dimensional information for each actuator. To properly determine the actuator's overall length (OAL), you must know the distance of travel (working stroke), then add the given dead length at each end of