Laser welding of gearwheels

From dual-clutch transmission to the classic differential:  modern transmission technology is a pivotal research sector in the automotive industry. With new materials and altered geometries designers optimise the functionality of the different gearwheels. Furthermore, these wheels are required in ever larger quantities owing to the fact that the number of speed-gears in many passenger cars is on the increase. The innovations that promote the effectiveness of the production processes being applied include, laser welding.

With their ELC series of machines, the specialists at EMAG have developed integrated solutions for the application of processes with high output rates. The company’s in-depth  knowledge of the production processes used for many transmission components, has added to its competency.

A first glance at a typical transmission component makes it plain where the challenges lie: even a small wheel with integrated synchronous gear represents a relatively complex design. To manufacture it efficiently and at the highest precision calls for the two different parts to be produced separately and subsequently joined in a joining+welding process. It is at this point in modern transmission manufacture that laser welding comes into its own”, explains Dr. Andreas Mootz, Managing Director of EMAG Automation. “The process allows you to concentrate a carefully dosed amount of the energy emitted by the laser beam on the welding point, minimising possible warping, whilst still achieving high welding speeds,” he added.

Furthermore, the welding process from EMAG uses solid-state lasers. Whereas a classic carbon dioxide laser will achieve an efficiency factor of just about 8%, the EMAG can rely on an efficiency factor of about 20% with their technology. In other words, the power used to achieve the same optical performance is noticeably less, with energy costs in the production department massively reduced.

Stationary welding device scores heavily

Similarly effective within the total process is the integration of different production sequences on the ELC system. For starters, the work spindle uses the pick-up principle to load itself. The components involved are then clamped and pressed together in the joining press. The clamping technology used  ensures the highly accurate positioning of the components, providing ideal conditions for the welding process. The design of the stationary optic ensures great operating safety and optimal stability of both machine and welding process.  Dependent on workpiece or material, the components can be induction-preheated prior to the welding process and brushed after it – and whatever is required, the process is completed in a single setup. The complete joining+welding process for a gearwheel takes just 12 seconds. This ensures that the components for a differential are thus finish-welded within no more than 40 seconds.

Advances in light-weight construction

The differential housing as an example clearly shows the possibilities the laser welding technology opens up in the general development of vehicle production. For some time now, automotive companies have  been  replacing  the  screw-type connection between differential housing and crown gear with a welding seam. The result: the cost of materials reduces and the weight of the assembly falls by about 1.2 kg. “When looking at the advances made in light-weight construction in the automotive industry, these kind of savingsAccesorios para el running