Auto Filters Get Superior Seals with Servo Ultrasonic Welding
Automotive Tier 1 gets stronger welds and shorter cycle times in assembly of small transmission filters—results not possible with vibration welding.
The switch to ultrasonic welding from vibration welding in assembling small (3.5 × 5 in.) transmission filters helped global automotive Tier 1 supplier ITW Powertrain Components solve problems it had experienced with vibration welding—notably weld cycle time, particulates, flash, and the cost of tooling and machines.
The Chicago-based company opted to use the the iQ Servo Ultrasonic Welding System from Dukane. This was the first time a complete transmission filter assembly was ultrasonically welded by ITW Powertrain Components, according to Rich Stuber, project manager. Transmission filters require hermetic seals and are subject to burst tests to ensure leakproof performance.
Dukane says its patented Melt-Match and Round Energy Design is more forgiving of inaccuracies during molding and allows more plastic to be melted during the process, which results in stronger hermetic welds. In addition, Dukane says servo-controlled ultrasonic welding has been shown to produce consistent parts, reduce particulates and provide tighter process control. Dukane anticipates this capability will be a game changer as processors experience growing demand for electric and hybrid vehicles.
Tory Solheim, ITW Powertrain Components’ design engineer, explains that the Dukane system is used in welding a proprietary transmission filter for a major OEM. It entails first welding in the pleat pack, followed by welding the cover over the pleat pack. These units are molded in a 33% glass-filled nylon 66.
Servo-controlled ultrasonic welding has been shown to produce consistent parts, reduce particulates and provide tighter process control.
A Welding First
Stuber of ITW says use of the iQ Servo 15-kHz welding system allowed this filter to be successfully sealed with ultrasonics. “Historically, transmission filters have been assembled with vibration welding, thus creating particulate in the filters and long cycle times (18 sec/weld for vibration vs. 3-4 sec/weld for ultrasonic). Previously we could not achieve the seal requirements (14.5-psi burst test) with pneumatic welders and a standard energy director. Though use of the servo technology and round energy director, we were able to achieve the part criteria with a very reliable and wide process window and a reduced cycle time.”
Another key feature of the Dukane technology that proved particularly helpful in improving the welding process was Melt Detect. This enabled the company to weld more uniform seals across the part and increase the weld integrity. This feature is especially useful for applications where it is difficult to achieve the required amplitude to melt the parts.
Stuber and Solheim say the biggest advantage with the new technology is the ability to perform—in one unit—two different weld processes via a two-stage weld side by side, instead of having to use two large vibration welders. They see this system as ideal for transmission filters of this size and smaller, and also for other small-scale applications.
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