Actuators are getting a makeover with new materials, smoother performance, and greater energy efficiency. They may look the same, and they may do essentially the same tasks they’ve done for decades, but below the surface, these tools are going through a metamorphosis. For one, electric actuators are running ahead of hydraulics and pneumatics in the efficiency race.
Hydraulic and pneumatic actuators are working to keep up by attacking efficiency with reduced leakage and friction. Servo technology is offering greater control, and actuator manufacturers are competing on overall support for their equipment and for their customers’ wider needs of selection, maintenance, and repair.
New materials for the old body
New types of materials are being used in actuator construction. The goals are, as always, cost savings, reduced weight, and increased performance. Companies are producing improved bearing materials for reduced friction and better operating performance. “A lot of the new materials include different types of polymers for bushes, bearings, and cylinders,” Mike Guelker, product manager of actuators, air supply and accessories at Festo, told Design News. “A lot of our cylinders are customized with new materials to meet a particular need. It’s application-specific, or specific for an industry.”
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Pneumatic cylinders used in pick-and-place application for bottle filling.
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Guelker notes that a lot of Festo’s application-specific products are made with new materials or variations of materials to support high-temperature environments or for actuators exposed to chemicals or moisture. “You have to use corrosion-resistant materials to reduce or prevent contamination,” he said. “We also create custom actuators for specific industries such as food processing, where you have to make sure the product meets current regulations and is built to perform in that environment.”
Cost savings can also drive changes in materials. “Sometimes we introduce new materials when we can cut costs without sacrificing the life or performance of the actuator,” said Guelker. “New materials might also improve performance or provide a lighter weight.”
Electrification and integrated sensors
Many actuator manufacturers are switching to electric servo drives and moving away from hydraulics or pneumatics. “You get better control with a servo, and it’s easier to follow an exact path, easier than with fluid power,” Nathan Davis, product manager for screws and system products at Bosch Rexroth, told us. “With electric actuators, you can just push a button to change the profile. That’s a big reason for electrification.”
Davis notes that electrification also delivers energy savings. “Customers want to reduce energy usage, and electrical actuators are more efficient. You get more control with less energy consumption,” he said. Another advantage is the cleanliness. “In the food and packaging industries, they don’t want dripping oil,” said Davis. “Electric actuators also offer noise reduction, since pneumatics and hydraulics are noisy.”
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Davis sees mechatronics in the future of cylinders, pointing to integrated sensors and electronics as part of the package. “Our customers want a way to predict when a cylinder may fail or when it may need maintenance,” he said. “You take a mechatronics approach so you can see if the actuator slips outside of a certain envelope. Sensors can detect a problem or monitor the end-of-life of an actuator.”
One recent trend that is impacting actuators is the automation of the manufacturing process. “You try to keep costs down so you can offer an actuator at reasonable price. So logically, you look at the production process to improve efficiency,” said Festo's Guelker. “In the past five years, we’ve seen a transition from manual production processes to semi-automated production, and on to fully automated processes where there is no human hand touching the cylinder. With automation, you improve the cost, the quality, and the reliability.”