Fifty years ago, cars were made of steel. End of story. The little bit of wood, leather, rubber and glass for the interior and electrics accounted for only a small fraction of the overall weight. Nowadays, steel makes up just a little more than half the weight of most cars; the rest is a mix of aluminum alloys, plastics and fiber-reinforced composites such as CFRP. And even steel has long since become more versatile: more and more special alloys are finding their way into lightweight vehicles.
The automotive industry, aircraft construction and other sectors are all asking the question: how can we join all these different materials together – or split them apart? And second, how does this growing bundle of processes fit into a lean, modern factory?
There’s no shortage of answers: companies can opt for the simplest of processes, the most specialized, the most precise, the most flexible. And more and more of these answers contain the word “laser”.
Separating
The high thermal conductivity and reflectivity of aluminum make it necessary to cut more slowly and with higher energy input than for steel. For this reason, using lasers to cut aluminum was, for many years, seldom a profitable option. However, the wavelengths and beam quality of modern solid- state lasers have made possible highly productive industrial cutting applications, such as the deburring of die castings.
Joining – same materials
When processing aluminum, laser- based methods also had to rely on filler materials. Currently there are two strategies to avoid using a third component in the process. One way is to use composite materials which incorporate the filler material as a coating, for example. The other is to influence the cooling behavior by manipulating the molten material with an oscillating beam.
Joining – different materials
Aluminum and steel cannot be welded by conventional means. Using laser technology, however, makes it possible to create a solid lap joint. The laser fuses the steel in the focus of the beam, and the molten material heats up the aluminum beneath it. When it hardens, the steel forms a bond with the aluminum that is similar to brazing.
