Rinco Ultrasonics has demonstrated that servo-driven ultrasonic welding systems deliver significant energy savings compared with standard pneumatic systems. In a recent commercial application with a leading European automotive manufacturer, Rinco showed that its eMotion 20-kHz servo-driven ultrasonic welder delivers 87% energy savings over pneumatic systems in the production of an automotive assembly.
Rinco’s work is believed to be the first effort to quantify the energy benefits of servo-driven ultrasonic welders. Many of the benefits of ultrasonic welding technology, such as fast cycle times, low cost of investment, repeatability, and a high level of process control, are common knowledge in the industry. However, recent advances in drive technology have improved capabilities and even significantly reduced the energy consumed, according to Rinco.
"We expected the electrically driven ultrasonic welding machine to perform better in terms of energy consumption, but we didn't expect such a big difference," said Jürgen Baumert, head of R&D at Rinco Ultrasonics. Servo-driven ultrasonic presses have become well known for a high level of control and precision. However, the reduced energy savings along with finished part strength and aesthetic improvements often are not fully appreciated, said the company.
The automotive assembly required the use of ultrasonic assembly equipment to bond components of dissimilar materials — PA-12 to PC/ABS. Because of the materials’ incompatibility, a true weld could not be achieved, and a mechanical forming process had to be used to assemble the parts. Simon Hug, who leads Rinco’s Ultrasonic Competence Center in Romanshorn, Switzerland, conducted the study. He compared the energy cost and bond performance of a servo-driven system with a pneumatic drive using high-cost compressed air. For an apples-to-apples comparison, Rinco used two machines with identical frequency, power, and stroke specifications; only the drives differed.
The results of the study showed a faster cycle time, improved finished part strength, and the aforementioned energy savings as well as aesthetic improvements using the servo-driven system. Rinco also reports that the eMotion welder’s unique ability to manipulate melt velocity enabled better and stronger bonds.
Rinco continues to examine the benefits resulting from servo motion-control technology in the ultrasonic welding process. While servo-drive technology is not the answer to every application in ultrasonics, it shows promise for customers focused on cutting energy consumption and improving assembly quality in plastic part assembly.