Delft University of Technology
DUT16 race car TU Delft
The DUT16 race car with 3D-printed parts
Photo Credit: 3D Hubs
Formula Student is an engineering competition for students held all over the world, where teams design, build, test and then race a small-scale formula style racing car. TU Delft’s Formula Student team have applied 3D printing techniques to enhance the production and performance of their cars.
The team have become one of the top teams on the circuit, winning multiple Formula Student races, including ones hosted at the Silverstone race track in 2014 and 2015. Chief Engineer, Jonas Holtermann leads the 75-strong team of engineers, making sure every part of the car achieves efficient motion. With just nine months to build a car from scratch, the Delft team have sought to integrate 3D printing into the production process, as well as using tools such as a lathe, mill and carbon fibre prepreg layups.
3D printing was first involved in the making of the DUT series of cars for the steering wheel. Their steering wheel was not only prototyped with 3D printing but the final design was also made in the same way. Since there are multiple drivers within the team, who all have their individual preferences and driving styles, the steering wheel is commonly the focus of much debate. The team usually deliberate on how the steering wheel should feel, grip and perform. FDM 3D printing has allowed TU Delft to produce a steering wheel in an affordable and fast way to go through many iterations without incurring large costs and delays.
Fused Deposition Modelling (FDM) is effective by extruding a reel of plastic through a heated nozzle which melts the plastic building layers which then cool and solidify.
Yet Holtermann highlights that the curvature and geometries of a steering wheel are an issue for Computer Numerically Controlled (CNC) mills which would need long passes around a part, take a long time and be expensive.
“A 3D printer doesn’t care as much about those (CNC) geometry limitations, this meant we could iterate and test, iterate and test without worrying about the cost or delays,” Holtermann said.
The process of creating the steering wheel began with a very rudimentary laser cut piece of wood, with clay stacked on top of it. This was then pressed with driving gloves on to create a rough outline and 3D scanned into modelling software. A steering wheel that didn’t require supports was wanted during the modelling process so iterations could be churned out as drivers tested them. Since the drivers were all gripping the wheel differently, the final production part had grip all over sides, suiting the wants of all three drivers.
“The steering wheel is in a narrow space and needs to be able to deal with lots of force, drivers need to be able to really dig into the shape and apply force around corners,” added Holtermann. “It being strong and having a good grip instils confidence in the drivers.”
3D printing has also enhanced a less visible part of the car, an integral bracket which connects the steering rod of the inner wheel to the front of the vehicle. Metal printing, a more familiar technology in the automotive industry, created the part in titanium using Direct Metal Laser Sintering (DMLS). Here, a mechanical arm spread a thin layer of fine titanium powder down onto the print-bed while a powerful carbon dioxide laser melts the powder and fuses the titanium together.
“The reason we used titanium 3D printing for the part was that it simply couldn’t be made in any other way, we needed very specific geometries for the loads that were being applied,” said Holtermann.
The Delft Formula Student team have pioneered 3D technology in the production of cars within the field and have so far reaped the rewards. With other teams likely to follow suit, Formula Student may become a hot bed of innovation and introduce the engineers to new concepts.