Elbflorace is the registered club representing the TU Dresden University in the Formula Student competition. The Formula Student is an international design competition in which the teams of individual universities develop and construct a new racing car each year and race against each other at different events over the particular year. This year also, the Elbflorace racing car is electrically driven and many parts were 3D printed with the German RepRap x400. A great deal of experimentation was carried out in order to gain an edge in the competition. “Most of our activities therefore involve screwing parts and making things. 3D printing is obviously very useful to us since we can adapt components very flexibly to different requirements and manufacture parts that wouldn't otherwise be possible,” says Armin Bakkal, the person responsible for sensors.
“We made a definite decision in favor of 3D printing to enable us to respond with unlimited creative freedom and flexibility. Armin Bakkal compares the work to prototype construction: “We normally implement rapid prototyping when constructing our racing car. 3D printing is ideal for this because it is fast, cheap and flexible. The print quality and the achievable tolerances fully meet the requirements of 3D printed parts for a Formula Student racing car.” For example, this includes brackets for sensors, housings for PCBs, dials on the dashboard and much more..
Brake disk temperature sensor[/caption] The changeover to 3D printing brought many benefits. The sensor brackets previously required a mechanical solution every time. This proved to be very expensive, complicated and inflexible. It was also a major limiting factor in the possible number of sensors and their use since every drill hole in a supporting component weakens its strength. The high-tech parts from the 3D printer, on the other hand, can be mounted very simply and at virtually any position, as well as being really fast to manufacture. Mr Bakkal is delighted: “Without the 3D printer, the measurement of suspension travel in the way we have implemented it using rotation potentiometers would probably not be possible at all. Just imagine what it would have cost to cut a part like this from a block of aluminum!” The housings for the sensor boards are another interesting example. The Elbflorace team moved here from anodized metal housings to carbon fiber laminated boxes right through to the clever shrinking in a lot of shrinkable tubing. The current 3D printed housings on the other hand not only required less effort to manufacture. According to Mr Bakkal, they are also the “most functional, durable and easiest to maintain housings of all.”
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Even if the many sponsoring projects meant that no specific cost savings could be calculated, the club is delighted with the amount of time that could be saved through the use of 3D printing. Before they used the 3D printer, they first had to build a mold for the CFK housings, apply the fibers and then cure it in a vacuum in the autoclave. This took at least two full working days to complete per box. With 3D printing, however, the CAD model already available is used. The file for this is sent to the 3D printer which produces it in a few hours. The part is then ready for use. TU Dresden primarily uses Carbon20 material with the German RepRap x400 3D printer as this is excellently suited in terms of its technical properties. This has a high flex modulus of 6.2 GPa, very low stretch at breaking point of around 8 – 10% and can be finished for a perfect fit with little distortion. The finished parts are therefore very rugged and robust. After 3D printing came to the attention of the Elbflorace Team, they decided that a professional partner with the appropriate know-how was definitely and urgently needed. They chose German RepRap as partners due to their overall offering of product, material and know-how. “We were impressed by the possibilities. Through the limited capacity and quality available to us, the need for a professional printing partner soon became clear to us. We were therefore even more pleased to gain German RepRap as an innovative partner who supported us with such high quality printing results,” Armin Bakkal explains.
Florian Bautz, CEO of German RepRap GmbH, sums up: “In this particular application of the Elbflorace Team at TU Dresden, you can see very well how 3D printing can also produce a great result for end products. You can clearly see here the benefits of manufacturing with our 3D printers. There is firstly the obligatory time and cost saving, however, the use of the 3D printing offers the team far greater design freedom and the possibility to experiment and ultimately be winners of the competition.”