The TRUMPF Group ranks among the leading manufacturing companies worldwide. In the field of industrial lasers and laser systems, the company is the technological leader in the world market. With about 71 subsidiaries and branch offices, the Group is represented in almost every European country, in North and South America as well as in Asia. As the world’s leading provider of laser manufacturing technology, TRUMPF is the one-stop shop for all auto manufacturers and suppliers seeking cost-efficient, high-speed, top-quality solutions for their production requirements: starting with laser systems and extending through beam sources, beam guidance, optics and numerical control, to all inclusive service and support.
The laser is a universal tool for the production of automotive components. These applications are using the laser for laser cutting, laser welding, laser marking, laser structuring, laser cleaning, 3D-Printing… etc..
Laser processing in automotive production
Laser welding is around in automotive production for quite some years now and some applications even could be called a standard. In the meantime the laser processes have been developed further as well as significantly refined. Moreover accompanied pre- and after welding procedures have evolved. Below is an example of the production process in the production of automotive components.
For example an established Powertrain production line layout is set up as follows:
The first step is the machining of the individual parts, usually high precision processes like turning, milling or even grinding but also stamping for carriers. Hardening steps can be arranged after or before laser joining. For the latter it is necessary to weaken the intended welding area again. In any case the resulting parts have to fulfill the requirements towards the intended usage within the transmission assembly, most notably to transfer high torques for the calculated lifetime.
Therefore the materials used are in many cases difficult to weld but at the same time this is what made the laser technology the method of choice. Due to many process variables, e.g. laser power, spot diameter and positioning of the beam-caustic and the generally high energy density but yet low energy deposition, and it is possible to create a welding process which achieves unparallel results compared to alternative joining methods. That includes the possibility of welding demanding steel grades as well as achieving minimum assembly displacements while additionally realizing high welding feedrates.
With these advantages the weld processing step, actually consisting of two steps, can be entered: laser cleaning and laser welding. Residue from the pre machining steps have to be removed in a way which meets the demands of the laser process, meaning a top notch cleanliness for pore and crack free welding results. Furthermore laser cleaning even improves the high process stability typically seen in laser welding regarding weld depth variations, normally well below 0.3 mm, and a good uniformity of the shape of the seam over the entire circumference.
Camera based measuring systems attached to the laser optics and therefore observing the welding area directly are gaining a lot of importance. They are supportive in eliminating remaining tolerances coming from the work pieces, fixtures and positioners and thus increase the weld quality even further by ensuring the most precise positioning of the laser spot relative to the weld joint. Next generation sensor systems are going to feature a technique to measure the absolute weld depth at any point within the welding distance while processing the parts. This will not only speed up the overall cycle time. Moreover it is going to reduce the cost of destructive materials testing, the common quality assurance approach, and enable a seamless documentation on every joined assembly.
After laser processing the assemblies are handled over to post processing like brushing and measuring finally going to the final assembly lines.
Remote laser welding
Remote welding with today’s high brightness fiber delivered lasers has gained global acceptance in the automotive sector the last few years due to cost pressures, productivity and flexibility requirements. High volume production components such as doors, side panels, seat frames or parts common to several models, can be remote laser welded with 1 robot and realize production rates equal to that achieved with up to 10 resistance spot welding robots.
The future trend in steels used for engine and transmission components is going to be all driven by downsizing approaches.
In transmissions applied steel grades will not only be chosen by sheer geometry and therefore lightweight design possibilities but also by increasing initial torques which are featured within hybrid-drivetrains or electric engine coupled transmissions.
Traceability with laser marking
The end result of the laser marking process has always been a marked part. With a laser marking system you get a uniquely identified part and a total traceability in a file containing each part´s specific production and quality assurance information.