Pneumatic actuators, often called air cylinders, are an inexpensive and easy-to-use design choice for many industrial applications that require linear motion. While the technology has been around in nearly its current form for more than half a century, there are some interesting trends and design advances that engineers should be aware of.
Air cylinders have vastly improved sealing technology from models of a generation ago. Both piston seals and rod wiper seals have a new range of different materials - and the extended lifetime that they provide are real game chagers, said Mike Guelker, product manager for pneumatic actuators and air supply products, Festo Corp.
“The different types of operating environments in which these seals can function extend the range of applications,” he said. “This has really opened up new application opportunities with pneumatic actuators. New seal materials can operate in higher and lower temperatures than has been the case in the past.”
Guelker said his engineers are seeing reductions in leakage, which reduces the cost of operating pneumatic actuators.
Above, pneumatic actuators operate this assembly system for locking clip on connector housings. At right, air cylinders help in the production of sealing
New permanent lubrications have extended the life of non-repairable cylinders, according to Jerry Scherzinger, product marketing manager for Bimba Manufacturing. He said that this was, in part, responsible for doubling the life of his company’s OL cylinder line.
Other changes that design engineers will find include predictive maintenance technology for cylinder life, increased use of servo-pneumatic controls, improved corrosion resistance and various air cushioning technology (including self-adjusting styles).
Phil O’Neil, product manager, Aventics, said that cushioning technology can make a big difference to users.
“We’d visit applications such as sawmills, where they were using big, heavy, steel NFPA cylinders that were just beating themselves to death,” he said.
Pneumatic actuators are used in myriad industries, but there seems to be growth ahead particularly in food, packaging and medical.
“The medical industry has the largest growth potential due to our aging population fed by the baby boomer age bracket,” said Scherzinger. “The continual drive toward automation in the medical industry will provide solid growth for the pneumatics industry.”
“There have been a lot of advances in Europe and the U.S. regarding food safety and following different guidelines and standards. Companies are adapting to these food safety regulations and standards. That means new products and applications for pneumatic actuators,” said Guelker.
Another change being seen involves the changing nature between manufacturing and distribution locations. As a case in point, Aventics uses what O’Neil calls a ‘kit approach’ for their Lexington, Ky., manufacturing location, given its distance from headquarters in Germany.
“Here in the U.S., we optimize our manufacturing, so we use pre-assembled head caps and pistons, so we can manufacture and deliver cylinders very quickly out of our Lexington facility…all we have to do is cut the stock materials to length, assemble them and test them,” O’Neil said. “What we’re finding is rather than the traditional stocking distributor delivering standard components off the shelf, now we’re able to deliver custom stroke or custom assembly cylinders, cylinders with rod accessories, flow controls, mounts, switches out of the factory to customer specifications in a couple of days—where that would have taken a week or two if someone had to engineer them manually, as we did eight or 10 years ago.”
Top, air cylinders help automate printing on packaging material. Above, a line of compact pneumatic actuators form part of an assembly machine for telephone displays.