Prototype for small-series production: electric drive housing from a 3D printer
Porsche has produced its first complete housing for an electric drive using 3D printing. The engine-gearbox unit produced using the additive laser fusion process passed all the quality and stress tests without any problems.
Engineers in the Advanced Development department were able to carry out several development steps at once with the prototype. The additively manufactured alloy housing is more lightweight than a conventionally cast part, and reduces the overall weight of the drive by approximately ten percent. Thanks to special structures that have only become possible due to 3D printing, the stiffness in highly stressed areas has nevertheless been doubled. Another advantage of additive manufacturing is the fact that numerous functions and parts can be integrated. This considerably reduces assembly work and directly benefits part quality.
“This proves that additive manufacturing with all its advantages is also suitable for larger and highly-stressed components in electric sports cars,” says Falk Heilfort, Project Manager in the Powertrain Advance Development department at the Porsche Development Centre in Weissach. It is conceivable that the optimised electric drive could be used in a limited-edition super sports car, for example.
3D printing opens up new possibilities in development as well as in the production of low-volume components. "Our goal was to build an electric drive using the potential of additive manufacturing. With the aim of structurally integrating as many functions and components as possible into the drive housing, saving weight and optimizing the structure," says Falk Heilfort.
3D printing opens up new opportunities in development and manufacture of low-volume parts. “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 optimising the structure,” says Falk Heilfort.
The drive housing was manufactured from high-purity metal powder using the laser metal fusion process (LMF). Here, a laser beam heats and melts the powder surface corresponding to the part contour.
Optimisation of the electric drive started with the design integration of components such as bearings, heat exchangers and oil supply. This was followed by the computer-calculated definition of loads and interfaces. Determination of the load paths then took place on this basis. The next step in the virtual development method was optimisation of the load paths by integrating the so-called lattice structures.
The weight of the housing parts was reduced by approximately 40 percent due to the integration of functions and optimisation of the topology. This represents a weight savings of around ten percent for the entire drive due to the lightweight construction. The stiffness was increased significantly at the same time. Despite a continuous wall thickness of only 1.5 millimetres, the stiffness between the electric motor and the gearbox was increased by 100 percent due to the lattice structures. The honeycomb structure reduces the oscillations of the thin housing walls and thus considerably improves the acoustics of the drive as a whole.
Further information: https://newsroom.porsche.com