12 October 2020
DSM and Lightyear aim to design solar roofs for all types of electric vehicles
"How strong are 3D printed parts?"
That’s the question most engineers ask when they consider 3D printing. After all, it’s crucial to know what’s possible with the tools at your disposal. It was also this question that engineers from Ultimaker, Covestro, and the Royal Dutch Navy came together to find out. But not in a conventional way...
The conventional way to measure a material’s strength is by using a tensile testing machine. A small sample is printed and put under a large force until it snaps. The force projected on the part divided by the surface of the center intersection at the time of breaking will express its strength.
While these numbers mean a lot to engineers, sometimes “seeing is believing”. To really render an image in the minds of people on how strong 3D printed parts can be, Covestro, the Dutch Royal Navy, and Ultimaker started a unique collaboration to lift something seriously heavy.
But what would work? Gym weights? A motorbike? A car? Perhaps a large jeep? And then the Dutch Royal Navy asked:
''Why not an armored vehicle?''
It takes less time to 3D print a solid, 2-kilogram link than producing it with traditional methods. However, the number of iterations necessary to validate the right geometry meant that time was still a factor. That’s why the design was optimized before printing using computer simulations.
Covestro digitally applied the forces on the design using software that knows the exact physical properties of their carbon fiber nylon material. By running simulations, we were able to identify where the design needed to be adjusted and where material could be removed. This created an optimized design which could lift more weight, while needing less material, resulting in a faster production time with less cost.
Before we were able to lift our heavy vehicle, we needed to verify the printed part’s calculated strength physically. Two designs were generated for two sizes. The first was a 1-kilogram link which we estimated could withstand 12 tonnes. The second weighing roughly 2 kilograms was estimated to be able to withstand 38 tonnes. The Royal Dutch Navy has an on-site industrial tensile tester which is able to project up to 343 kilonewtons of force on an object. Both the initial and optimized versions were tested for the large and small version.
The optimized design was able to withstand a higher force, while weighing a third less. The difference between the tested results and the simulated numbers was also extremely close, being only 1% off on average. This made this workflow accurate and profitable in time-to-market and increased performance.
A technical data sheet will tell you a material’s strength in abstract numbers. But when you see what can be achieved with strong and optimized 3D printed parts, it’s easier to understand the possibilities of additive technology and get inspired for new and exciting applications.