3D printing is one of the most progressive technologies. In cooperation with MCAE Systems and Misan we have been able to use it in two different ways.
For the first time, we chose plastic printing on the carbon discs. Normally it would be necessary to have cores milled on a CNC machine from special and very expensive foam, but we managed to circumvent this process and, together with MCAE System, come up with an easier solution to print it out. The great advantage of 3D printing is the possibility of a variable structure of the part. The center of the core has a full structure due to load transfer, the rest of the component is a honeycomb hexagonal structure.
Another major benefit and simplification of the production process was the printing of mold parts. The first models were formed and the final mold was casted from aluminum.
A duct for air intake to the engine cooler was also made of the printed plastic. This has saved us a lot of work because the carbon fiber duct used in the past required a mold to be produced, and then lamination of the duct itself. A great advantage is also the choice of different types of plastic. A special Ultem was used on the cores of the disc, while the ABS plastic was used to the duct.
For the second time, we chose laser sintering on paddles, commonly called a 3D metal print. Because the sintering method is suitable for components that can not be manufactured using conventional technology, it has been decided to design the part using topological optimization of the shape. For this purpose, the paddle region was set so that the paddle did not collide with other components on thecar in all states. Subsequently, the position was selected against the steering wheel so that the driver could easily reach the paddles during the formula handling. The maximum force that one can develop when such a paddle is pressed has been measured experimentally with all our drivers. The proposed model has been converted to Hyperworks. In accordance with the paddle attachment in the formula, the boundary conditions required for the optimization loop were defined. Subsequently, topological optimization was performed using the OptiStruct solution.
Optimization took place under two conditions
• The total stress generated during the load should not exceed 100 MPa
• Minimum weight condition
The ideal shape of the component was found after 46 iterations. During each iteration, the optimization program removed the material in the least stressed places. Subsequent to each iteration, FEM computed the component load and the loop was repeated again. The final shape was converted into a CAD environment and then sent to production. The finalt lever weighs 11g, which is a small difference compared to the plastic variant, while using sintering it was possible to design rigid paddles and with sufficient strength, which was proven in testing and races where the formula has already passed a total of 500km.