Porsche 3D-Prints EV Parts That Are 10% Lighter & Twice As Strong
January 31st, 2021 by Jennifer Sensiba
Last month, we missed a really cool story that’s still worth covering. Porsche is using 3D printing to create EV drivetrain components that are lighter, stronger, and easier to work with. All of these things improve emissions from manufacture to driving the vehicle around.
“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.
Porsche isn’t using consumer 3D printers, though. The company has much better printing tools that can use metal for a raw material, allowing for much higher strength than you’d get at home with an Ender 3 or Prusa. From the images, though, it appears that the process is very similar. For example, they have to use “supports” when printing, which makes the straight up-down vertical lines below the actual part. After printing is done, the small attachment points between the part and the supports and the part are detached and smoothed to make the final part.
The end result is a drive unit housing that is 10% lighter than it would be with cast parts. There are special shapes they’re able to make with 3D printing that make it double the strength cast parts would have been, meaning it’s both stronger and lighter. When you consider that automakers do insane things like not include a spare tire just to get a slightly better EPA or WLTP ratings, saving 40% of the shell’s weight and 10% of the drive unit’s total weight is a big deal.
“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 Heilfort.
Another advantage of building parts this way is that they don’t need to go from design to tooling to production. They can go straight to the final shape in one printing process if they design it right and include appropriate supports. The company was also able to introduce nature-inspired lattice structures within and around the unit, which allows for an increase in strength without just making the whole thing thicker. That’s how they can get better strength without making the casing heavier.
This didn’t happen all in one step, though, as this was a learning exercise for the automaker. The first designs had to happen in three pieces, and there were mistakes made along the way. After learning from what they did, the team was able to make the whole housing in one print, which not only saves time, but makes everything stronger.
3D printing also gave the company several other advantages. First, the honeycomb structure (apparently not as easy to do with casting) reduces the vibrations and flexing in the outer case during use. This improves the acoustics of the whole drive unit. It also made the unit more compact and easier to build, eliminating 40 steps in the assembly process, saving 20 minutes to build each one. It also allowed them to build a heat exchanger into the housing, which helps create more cooling overhead for performance.
While the company doesn’t currently plan to build mass production cars with 3D-printed parts, this process lends itself well to small production runs and racing applications. For mass market cars, it will also benefit the company with the ability to use 3D printing in the development and testing phase, allowing for more rapid development and better overall end products that eventually roll off the assembly lines.
Another thing the company said this could help with is producing obscure spare parts, including for older vehicles that are long out of production. It also might allow small runs of customization parts that most customers won’t want, but a few would.
All in all, this method gives the company flexibility, and that’s a valuable thing for a big company to gain.
Making A Big Company Act A Little More Like A Small Organization, & Vice Versa
Big companies like the Volkswagen Group, with its huge organizational structures and global footprints, have to act like a well-oiled machine. Changes are considered very carefully, and they also happen very slowly in most cases. If they don’t, small mistakes amplified a million times all over the world could bring a big company down. This is why large car companies were generally a lot more hesitant to get into EVs than a new player like Tesla was.
Still, making mistakes can be good for innovation, but took Tesla to the edge of ruin on several occasions, like the Model 3 production ramp. Elon Musk told a Twitter user that the company was about a month short of bankruptcy during the worst of that ordeal, which lasted from 2017 to 2019.
A technology like high quality metal 3D printing allows the divisions of big companies to be a little more agile, despite the company’s size. Being able to experiment with new things and take little risks isn’t as big a deal when the company has to only risk that a 3D print might not turn out. When using more traditional methods, you’d have to risk that expensive tooling and custom fabrication doesn’t work out, which introduces more risk that the company might just as well want to avoid at the cost of innovation.
This doesn’t give a big company the full flexibility that a smaller organization probably has, but it brings them just a little closer.
The reverse is also true.
For small companies and even unpaid teams of volunteers on the internet, 3D printing has been a game changer. Being able to do the protoyping work that can happen with 3D printing and get designs to the testing phase without huge expenses, the little guys can do things that only larger companies with ample funding were once able to do.
Here’s one noteworthy example from the unpaid volunteers I mentioned:
Like it or not, 3D printing isn’t changing all manufacturing, but it’s certainly making all kinds of marks on the world.
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