The 3D Revolution

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Scania Press Release / September 15, 2015

In the 1940s, Scania design engineers relied on drawing boards to design the company’s products. Today, cutting-edge 3D printing technology is allowing their modern counterparts to quickly and simply test prototypes and new solutions.

Behind the glass in something that looks a little like a pizza oven, a receptacle is sweeping back and forth over a flat surface distributing thin layers of fine-grained plastic powder. As each new layer is deposited, a laser passes over the powder bed, seemingly cutting tracks in the material.

We’re in a basement at Scania’s Research and Development division, where two large “printers” are working at capacity to supply the company’s diverse range of research development projects with three-dimensional models and prototypes. The technique is called additive manufacturing and it’s the industrial equivalent of the 3D printers that are now starting to appear in consumer electronics stores.

Back in the 1940s, things were done very differently. In those days, the engineers working in Scania’s engineering department would stand bent over their drawing boards, which were the most important tools within product development. As a Scania newsreel from the 1940s put it, “You can safely say that there is no detail in a Scania Vabis product that is left to chance. It is thought through, even experienced, on the drawing board.”

New opportunities for “experiencing the product” were created by the computer revolution of the 1980s. Design engineers were able to use CAD programs as a tool for producing drawings, developing products and designing in a three-dimensional space.

CAD programs are still central to Scania’s operations and have been greatly refined since the 1980s. However, the design engineers now have a valuable complement to the computer: three-dimensional printouts.

The basic technology for additive manufacturing has been available for almost 20 years, but now the method is really beginning to take off. Scania is increasingly using the new 3D technology to print out parts and components, and in some cases models of entire engines or cab components in plastic.

Niklas Lind, is Head of the mechanical workshop at Scania. “The fact that it’s now easier than before to produce prototypes that you can pick up, twist and feel is a huge advantage,” he says. “We then use the models for things like function testing and wind tunnel testing, as well as for test mounting of new components in existing parts. And sometimes we have a purely visual focus – we need to see how a component feels and looks.”

The next technological leap after plastic modelling is printing out in metal and eventually making real parts made of metal.

“We’ve already produced a number of print outs in aluminium and stainless steel,” Lind says. “But we can’t yet print out large parts, and these parts can’t really replace the real parts. But the metal models are nonetheless a step towards being able to print out real components. Three-dimensional printing in metal is going to be happening more and more often.”

Printouts take up to 40 hours

Scania uses the Selective Laser Sintering (SLS) method of additive manufacturing. The technique involves using specialised software to build up a CAD model in layers 0.12 mm to 0.15 mm thick.

A batch of parts, in which several prototypes are printed out at the same time, is 500 mm high and takes between 30 and 40 hours to complete.

The steps in the process:

1. Specialised software builds up a CAD model in layers 0.12 mm to 0.15 mm thick.

2. Fine-grained powder is distributed on a platform inside the printer.

3. After every layer is deposited a laser beam passes over the powder bed. Where the laser touches it, the powder “sinters” (fuses) together.

4. When a layer is completed, the platform holding the fused-together part is lowered 0.12 mm to 0.15 mm and a re-coater travels above the surface distributing a new layer of plastic powder. The process continues until the final fused layer is completed.

5. Once the printout is completed, the prototypes must be left to slowly cool. The completed batch is then lifted out of the machine for further cooling.

6. Once complete, the individual finished prototypes are removed from the surrounding unfused material. The prototypes are cleaned, then blasted, rinsed in water and, in the case of large models, glued together.

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