Ultra-light Rims for Fuel-Saving Prototypes

HEIDENHAIN supports college team

With its IDRAkronos, Team H2politO of the Turin Polytechnic University built the most beautiful prototypes for this year’s Shell European Eco-Marathon and drove up to the victory podium in the category of hydrogen fuel cells. The rims for the prototypes were created with support from HEIDENHAIN.  

This year’s Shell European Eco-Marathon—the so-called fuel-saving Formula One—took place in London from June 30 to July 3, 2016. Here prototypes and UrbanConcept vehicles with various types of motors line up to start. The winner is the vehicle that does eight rounds on the race track within the permitted maximum time with the lowest consumption of fuel or alternative energy. Among the prototypes with hydrogen fuel cells, the IDRAkronos from the polytechnic institute’s H2politO team was the most economical. In addition, it won the design award.  

HEIDENHAIN, with its special know-how, supported the development, design, and production of the rims for the IDRAkronos. The new rims weigh the same as those on its predecessor vehicle, but have greater rigidity and less strain in the ground-contact area. That improves the vehicle’s performance during the race. The material used was Ergal, the aluminum alloy with the highest strength values. The machine process started with 23 kg workpiece blanks to produce light rims weighing only 1160 grams (2.56 lb) each. Here the emphasis was on reducing as far as possible the residual stress and strain in the material. These faults can occur during milling and diminish the performance of the finished part.

The rims were machined on a specially optimized 5-axis machining center with a HEIDENHAIN TNC control. Among the features responsible for these excellent results on the NC control side were the PLANE SPATIAL function for tilting the working plane, KinematicsOpt for automatic calibration of the rotary axes, and Cycle 32 “TOLERANCE.” The machining center was ideal for the high-precision operation thanks to Closed Loop position measurement through linear and angle encoders.