Bonding plastic parts for Polaris pool cleanerAccording to Tim Herlehy, Vice President of Manufacturing for the Vista, California company, Polaris was experiencing gear jam-ups, due to loose- fitting bearings. "When the bearings were press-fit into the turbine wheel, they just weren't consistently tight enough," says Herlehy. "Ultrasonic welding with the SureWeld 20 causes the materials to become one. Now the bearing doesn't move within the assembly, so the jamming problem has been eliminated."

Sonobond Ultrasonics, headquartered in West Chester, PA, designed a custom welding horn and fixtures specifically for Polaris's application. The custom SureWeld equipment achieved superior results not only by eliminating the slippage problem, but also by perfectly aligning the welded parts. In addition, the SureWeld 20 allows for easy set-up and quick operation. Polaris is experiencing an average weld time of 0.3 - 0.4 seconds.

Ultrasonic technology utilizes vibrational energy which is transmitted to the interface of the plastic parts being joined. This causes the plastic material to soften in a fraction of a second. When the material resolidifies, the bond is made. With a rugged welding press and a heavy-duty 1000-3000-watt power supply, "Sonobond's SureWeld units provide superior control and repeatable accuracy for joining the rigid plastics used in the Polaris products," says Janet Devine, president of Sonobond Ultrasonics.

With the success of ultrasonics in the assembly of the turbine wheel, Polaris is also looking to ultrasonics to speed up production of other components as well. They are now testing a new protopype developed by Sonobond to produce the wheel and pulley assembly. Explains Herlehy, "Using adhesives to join the wheel to the pulley is labor intensive and time consuming. The glue is slow to dry and the process must be done by hand. Converting to ultrasonic assembly will reduce costs and production time."