The car of the future should still be fast, comfortable, safe and able to go the distance. The car of the future should have very low CO2 emissions. But how?
The K node is a tiny thing. Nothing more than a wee imprint in a car body component. Yet this imprint acts as a shock and anchoring mechanism for another component in the joining process. A welding robot draws a laser weld seam a few millimeters long from one edge to the other and then jumps to the next node point. That is all there is to it. This means the K node is a typical laser-driven innovation for the automobile on its road to the future, even though it‘s invisible and maybe even uninteresting to car buyers. Yet innovations such as the K node are leading to far-reaching rethinking of the way future cars are designed.
The rules of the game in the era of combustion
The regulations for the coming decade are clear: Anyone burning a liter of gasoline produces 2,320 grams of carbon dioxide and with combustion 8.9 kilowatts of power are released. Those are the rules of chemistry. Fleets of cars that are built on combustion as a power unit may not currently emit more than 133 grams of CO2 per kilometer. Otherwise, manufacturers risk being subjected to severe fines
Those are the laws of important sales markets such as the European Union, Japan and China. Others will follow. That much is also clear. Ultimately, fuel prices will continue to rise over the long term. This is dictated by the laws of supply and demand in a market that obviously deals in non-renewable resources like oil.
The belief that the age of powerful combustion engines will come to an end at some point is firmly anchored in the minds of the consumers. Cars should be more fuel-efficient and release fewer emissions – legislators and customer purchasing decisions couldn‘t be making this clearer. However, the car should change as little as possible in the process. By their purchasing decisions, customers are also emphatically driving home the point that they want to continue to drive fast, go far and be safe on the road. They just want to get rid of the exhaust emissions.
The automotive future starts here
How is this possible? This question brings us back to the K node – a small example of how laser-oriented designs are changing automobile design and manufacturing. What automotive engineers can best influence is how much energy they must use to move a car, how much of that remains leftover for the on-board systems and how much energy disappears into the air as heat. Many solutions in this process will have little or nothing to do with laser technology, others will have a lot to do with it.
The laser plays a particularly important role in terms of moving mass. In this case, this inconspicuous little K node helps make a characteristic feature of the classic self-supporting car body disappear: flange connections. If you can subtract flange connections from the equation, you reduce weight and materials considerably.
In addition, components could be placed closer to one another in many areas because it is usually only the flange collar that marks the distance between parts. In the next step, the weight of an entire assembly could be reduced because the K nodes incorporate a form closure and are welded edge to edge. These characteristics combined with the high quality of laser seams stabilize the design, allowing for a reduction in material strength and weight in some areas.
Another “laser-supported” trend in car body design and construction that’s part of the drive to reduce vehicle weight is the quest for lighter weight workpieces. High quality and highly resistant steels are creating an opportunity that the industry is already pursuing. The laser is helping industry to make the thermoforming process chain more flexible and yet also more cost-efficient. When laser machines replace mechanical punching presses set up before the kiln and after the forming station, tooling times, tool costs and production damage like micro cracks will be eliminated from production.
Another very recent concept in car body design and construction is being adopted for certain bearing structure elements or assemblies that have been traditionally steel. Instead, light metal alloys are being used for these components. The components produced in the die casting process are as resilient as their steel counterparts, but they are some 20 to almost 50 percent lighter. Additionally, the cast parts can be designed such that, under certain circumstances, one component can replace an entire steel assembly comprising five, six or seven parts produced separately and subsequently welded on.
In this case, too, highly flexible laser machines that operate contact- and tool-free eliminate limitations in the production flow caused by the need for additional mechanical cutting of cast parts. The same intention of replacing heavy components with lighter ones and designing leaner parts or eliminating them altogether, if possible, is also emerging in the design and building of the power train. Laser welding is increasingly replacing flange constructions on extremely stressed joints. Its ability to deep weld and join very different materials that are normally not weldable is very welcome here.
The road to e-mobility
But let’s look much farther into the future toward the electric car. Imagine that the car now no longer emits CO2 gases; however, it has to store the 540 kilowatt hours of power that was previously produced by a full 60-liter gasoline or diesel tank in the appropriate energy accumulator – without modifying the car’s design. A lithium ion battery that stores this quantity of energy would weigh about four and a half tons.
Though there is great potential in battery development, the car would nevertheless have to be modified to accommodate the new energy accumulator by slimming down on a massive scale. This would require far fewer pounds than the classic self-supporting steel body could afford to give up. In fact, it is now becoming apparent that hybrid cars will need different car bodies to accommodate electric drives that their “green-aware” owners want to be more than an auxiliary engine for city driving.
The body of future, more fuel efficient and mass-production-friendly electric and hybrid cars will probably return to the roots of car body construction: a supporting skeleton covered with an outer shell. Only the car body of the future will combine lightweight metal profiles with modern composites. The laser will also play a key part in that process. The know-how and process chains are already evolving in the most varying industries.
Engineers are increasingly experimenting with designs assembled from profile constructions that are laser-cut, then 3D-formed and laser-welded. This knowledge can be combined with the experiences of automotive design engineers when it comes to concepts such as incorporating space frame construction into the mass market cost effectively. At the same time, current research is devising laser processes to produce future carbon fiber components rapidly, flexibly, and above all, efficiently. lassen.
The laser and the car have enjoyed an association that has been and continues to be mutually beneficial. The laser industry continues to exist in this form and scope because the laser has been such a key tool in so many different automobile applications in the last 20 years. And the farther we look into the future, the closer the relationship between laser technology and the automobile appears to be.
The car: reinvented
What would be good examples? The automated welding of lightweight materials like aluminum? The welding of thin films for fuel cells or batteries for future electric cars? High performance micro processors that are manufactured using lasergenerated, extremely short-wave UV light ? Optical networks that sooner or later will replace a majority of parts in the electrical on-board power supply?
Then there are still the large-area OLEDs as lighting elements, glass panes and solar cells that both save and produce on-board power: A mass production-friendly process is currently emerging that coats glass with the aid of the laser. Or how about a powerful, compact electric engine with coils made of superconductors? There, too, laser light applies the functional layer. None of this is science fiction. These are developments of today that are paving the way toward an energy-saving, emission-free future for the automobile.
The next two or three decades will probably be the most exciting in the history of the automobile. The industry is already beginning to reinvent the car. Many changes will be visible on the exterior. However, most will never be seen. Laser light will make many of these changes cost efficient for the first time – and for a growing number of them, laser light will make it possible at all.
TRUMPF Laser GmbH + Co. KG
Dr. Rüdiger Brockmann
This article was first published in fall 2010.