For industrial use, 3D printable metals using SLS include steel, titanium, aluminium and copper. Once formed from the powder, the end result “is almost as strong as the base material”, says Martin Hillebrecht, head of the competence centre for lightweight design at EDAG. “It is weldable and fatigue capable.” He also foresees the possibility of fibre-reinforced plastic components being produced.
Applied to an entire car, additive manufacturing could be used to create a modern take on spaceframe construction, taking its cues from nature. The delicate-looking but rigid framework of the Light Cocoon echoes the web-like skeleton of a leaf, and the side members visible beneath the fabric skin resemble the inner structure of a bird’s bone.
Fabric skin? The Light Cocoon is clad in a specially developed high-strength, all-weather fabric developed by outdoor clothing and equipment manufacturer Jack Wolfskin. ‘Light’ is a play on words, because the concept not only weighs much less than a car made from steel or aluminium but the skin can also be lit from the inside by LEDs. This virtual paint means the owner can change the colour of the car at will by tapping a touchscreen or smartphone app.
A fabric covering seems delicate and prone to damage by bumps or vandals, but EDAG reckons it’s no more sensitive than a convertible roof or a painted steel or aluminium skin and is repairable with new sections. The fabric is washable and the show car has a washing instructions label like any piece of clothing.
It’s flexible, too – so flexible that it can allow the structure of the car to change shape beneath it. An adjustable spoiler can be increased in size without revealing any gaps, the skin stretching to accommodate the change. This concept could be easily applied to changing the car’s shape, giving owners the option of altering a car’s style and colour at will.
The idea seems fantastic, but EDAG says it is founded in reality and it’s just a matter of time before laser additive manufacturing literally grows to fit the role. Components are already made for the aerospace industry this way today, although the size of components is limited. “Machines have increased from 350mm to 650mm in just two years,” explains Hillebrecht, and the trend continues. EDAG believes larger interior parts, such as instrument panels, could become a reality in five years’ time and complete cars could be made this way 20 years from now.
One drawback is the time taken by the printing process, but in the next 10 years, Hillebrecht continues, “we expect the process speed to increase by 100”. The potential cost saving for car makers adopting such technology, were it to become a large-scale reality, could be substantial.
In setting up conventional production facilities to produce a new car today, manufacturers must invest millions in tooling. This takes the form of expensive steel moulds for pressing body panels and machine tools. Using this process, pressing body panels would become a thing of the past, as would the moulds used to press them. And as for machining, “one laser additive system machine can replace 17 milling machines”, says Hillebrecht.
The same machine could produce any shape and style of body without retooling, the only change being the CAD file downloaded to it. It is expected that the first whole-body applications would come from smaller-volume manufacturers “where tooling investment is a major decision”.
Additive manufacturing would enable complete body structures to be produced from a single process, with other components being made individually. Other challenges will include overcoming NVH (noise, vibration and harshness, including wind noise), but Hillebrecht says the same rules apply in relation to isolating occupant space from noise and vibration as they do with other materials. EDAG says there has been considerable interest from vehicle manufacturers in the concept, which also featured at the Inside 3D Printing conference in Berlin this month.
“It seemed like every car maker was represented at the conference,” Hillebrecht concludes. “I believe that industrial applications follow the consumer market, so this is not just hype. It is an industrial revolution.”
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