Wiring Harness News Sep-Oct 2022 - Page 39


Understanding PowerWheel ® for EV Cable Terminations

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The torsional technology allows for welding of larger size welds , bus bars , 3D terminals , more geometrical shapes , out of reach joining areas and applications where gentle vibration is required . This has expanded the ultrasonic application spectrum significantly . Many joining applications that were previously impossible with conventional longitudinal welding are now possible .
Benefits of PowerWheel ® Welding Technology
Welds can be produced up to 30 % narrower and higher compared to those produced by a linear system . This can often result in considerable savings in both material and space required to position the assembly . A further benefit is that thicker terminal connections can be welded with great strength . The welding takes place in a swaying and rolling motion directly above the weld area . As a result , the maximum amplitude is always in the center of the welding area and the energy is directed and focused within the welding zone . With direct force at the welding interface and smaller amplitude in the nugget transition area , the welder can drive more energy for a larger cable because the damage to the wire strands is minimal , if at all . Due to the torsional movement of the sonotrode , there is practically no load on the surroundings of the welding zone due to the ultrasound . The torsional process is therefore particularly suitable for sensitive applications where vibrations outside the welding zone could cause damage . The slow rate of vibration propagation along the cable ’ s axis makes PowerWheel ® more desirable for shorter cables . Often there is a concern for short cables being welded on both sides
as the second weld vibration may weaken the first weld . Studies were conducted in 2011 for 50 mm ² cables of 180 mm using PowerWheel ® . The results showed that no difference could be found on the weld strength of both ends of cable . In addition , the mechanical strength was about 30 % higher than those done with the traditional longitudinal process .
Telsonic ’ s PowerWheel ® standardized sonotrodes are optimized for copper and aluminum wires , meet the requirements of OEM ’ s and harness makers , as well as the USCAR 38 standard ( performance specification for ultrasonically welded cable terminations ). As with conventional ultrasonic welding , the PowerWheel ® system can also be used to weld nonferrous metals .
PowerWheel ® Welding Advantages at a Glance :
• Maximum output of up to 8 kN with 14.4 kW
• For large cable diameters , large terminals / tubular cable lugs
• Welding of up to 160 mm 2 cop per / 200 mm2 aluminum wiring
• Up to 30 % narrower welds
• Significantly improved wire compacting
• Excellent welding strengths
• Adjustable weld directions for universal feed
• Excellent accessibility to weld zone
Necessary Equipment
Like conventional ultrasonic welding , ultrasonic torsional welders have a generator , converter and sonotrode . In contrast to conventional systems , however , the sonotrode does not oscillate longitudinally but torsionally ,
which is how stress on the parts is reduced . At the same time , an ultrasonic output of up to 14.4 kW can be passed through the sonotrode . Consequently , the electrical vibrations formed by a generator in torsional processes are relayed into a PZT vibration transformer to be converted
into mechanical vibrations through a piezoelectric effect . Converting linear generated vibrations into torsional movement is done by assembling the acoustic components in the SO- NIQTWIST ® vibration head in a particular order .
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