Manufacturing’s digital data, fed into a special 3D laser printer, literally can turn an engineering concept into a large, fully stressed metal part.
Porsche is taking advantage of 3D printing, or “additive manufacturing,” to quickly plug electric vehicle components into its vehicle-development programs. The automaker is working to make not only its vehicles, but also its build processes, agile and fast. But as usual, quicker comes at a cost.
Engineers at Porsche’s Weissach Development Center in Germany recently built a light-alloy, electric-drive housing using a laser-fusion 3D-printing process. This technology holds promise for Porsche’s special and small-series production and motorsports efforts.
“This proves that additive manufacturing, with all of its advantages, is also suitable for larger and heavily stressed components in electric sports cars,” Falk Heilfort, the project manager, said in a statement.
But importantly, this type of “printer” costs between $100,000 and $5 million. So, unless one of the growing number of contract-printer vendors is used, the return on investment will depend on throughput. Parts can be printed in aluminum, steel, nickel, copper, bronze, titanium, silver or even alloy mixes.
“It’s called laser metal powder-bed fusion,” explained Terry Wohlers, president of consulting firm Wohlers Associates in Fort Collins, Colo. “And in relatively low quantities, it can be an effective way to produce parts. But it’s not Jeep doing the Grand Cherokee in the hundreds of thousands. You’d be casting and machining those metal parts.”
Ideas move from a CATIA digital sketch to a more highly detailed engineering drawing that can be loaded directly into the printer for production, eliminating the normal toolmaking step.
Thermal- and load-analysis programs optimize the design for quietness, mass and strength. The component also will be modeled so that it uses fewer parts and fasteners and is smaller and less expensive than a traditional part that is cast, milled, pressed, drilled or turned.
In Porsche’s case, the housing is 40 percent lighter than a cast part and, once integrated, provides a 10 percent lighter motor-gearbox unit.
“Our goal was to develop an electric drive with the potential for additive manufacturing, at the same time integrating as many functions and parts as possible in the drive housing, saving weight and optimizing the structure,” Heilfort said.
The design data, analyzed by engineers and even artificial intelligence, is converted into a job file. Then it is fed to the five-axis head in the printer.
The digital model is broken into data slices. The head’s nozzle sprays out metal powder in layers 0.02 mm to 0.1 mm thick. The nozzle is paired with a laser that heats that layer of alloy powder, melting its particles together, under a cloud of argon shield gas. And the process repeats. The part’s walls are built up with successive layers also fused together by the laser’s blast.
With the earlier printer, the housing required several days and two processes, but Porsche’s experts have upgraded hardware and say they can now do the housing as a single unit in one process. Given that, they estimate print time could be slashed by 90 percent. So, no matter how you slice it, that is much faster.