The driving power behind cable assembly

Following the recent launch of Telsonic’s Telso Terminal TT7 in the latter part of 2021, the system is more than living up to expectations, and already revolutionising ultrasonic metal welding applications in a number of areas. Key amongst these are applications within the fast-growing electromobility sector, where TT7 is addressing the increasing demand for the highest levels of quality and process control in cable assembly, terminal assembly, and battery production applications.

The flexibility and capability inherent within this latest generation system is clearly demonstrated through the diversity of the applications where the system has been adopted to date. Telso Terminal TT7 has been proven to be the optimum solution for a wide range of metal cable cross sections, configurations, and connector types as illustrated in this small selection of customer examples.

High power lock box terminals (SQ4) are manufactured from C15100 copper alloy and left free from plating around the weld area. In this particular application, cables with cross-sections of between 35 mm² and 50 mm² were required to have SQ4 terminals attached. The width of the weld area for the 50 mm² variant was increased from 13mm to 18mm, to allow a weld width of 15mm, and also accommodate a clamping width of 1.5mm on each side of the terminal when using a 15mm sonotrode.

The height of the connector, which was approximately 17mm, posed a particular challenge for sonotrode spacing when considering linear and conventional ultrasonic welding processes. Using these options, it is not physically possible to construct a linear sonotrode that can reach over the 17mm height and still efficiently achieve the required frequency of 20 kHz. The solution in this application came in the form of Telsonic’s PowerWheel torsional welding system.

Available as an integral part of the TT7 system, PowerWheel technology was able to achieve the termination height and produce a high-quality weld between both the 35 mm² and 50 mm² cable variants and the SQ4 terminal. The orientation of the sonotrode allows for not only sufficient clearance, but also the required weld energy to deliver a quality weld without affecting the finer strands in the transition area, or the connector itself thanks to the gentler vibrations.

PowerWheel also offers advantages when welding a larger cable in a smaller area. This was clearly demonstrated in the application where a ProEV cable, manufactured by Promark Electronics, a division of ECI, was joined to a silver-plated Rosenberger connector.

In instances such as this, the height of the weld nugget is greater than in a normal scenario. Since the amplitude in torsional welding is at its highest in the middle of the weld nugget, more energy can be applied to compensate for the greater height, whilst once again limiting the potential for damage to the strands within the transition area of the weld seam. Telsonic’s PowerWheel torsional welding system was the perfect solution for this application, achieving a good quality weld between the 35 mm² flexible ProEV cable and the 10mm wide connector.

In a further example of welding within a smaller space, a ProEV cable was joined to a Stäubli PerforMore compact two-pin connector, the combination being used for electric propulsion systems. This particular cable, with 95 mm² and 3,000 flexible, fine strands of 0.2 mm diameter, is used to terminate the Stäubli connector, with limited space for the required weld width. The available weld seam width of 18 mm, as opposed to 22 mm, once again brought with it the challenge of offering a welding solution in a smaller space, where the required weld seam compression must be achieved without damaging the finer strands in the weld seam transition area.

In each of the application examples here, quality control variables such as. the final height of the weld, the welding time, and the power were easily monitored and controlled in each cycle to ensure perfect results every time.

As can be seen in these examples, the Telso Terminal TT7, combined with the latest version of Telsonic’s proven PowerWheel welding technology, ensures maximum reliability and optimum process control for welding metal cable cross sections up to 200 mm². Additional benefits include the ability to change tools in under 5 minutes, thanks to the TT7’s new quick-change system. The Telso Terminal TT7 also features standardised interfaces for digital networking and ease of integration into production systems.