Using trend-setting hybrid technology, the Imperia GP Roadster from Belgium combines pure driving fun with a clear conscience courtesy of a hybrid engine with 350 HP and outstanding torque that helps the Imperia achieve the driving values of a super sports car. It only takes four seconds to accelerate from 0 to 100 km/h, and that’s only the beginning: The roadster also boasts sensationally low levels of CO2 emissions at 50 grams per kilometre.
The firm behind this technical innovation is Lüttich-based Green Propulsion, which has already brought several hybrid vehicle concepts to series readiness. To support marketing activities around the new roadster, the three company founders Yves Toussaint, Nicolas Naniot and Bernard Loly resurrected the Belgian automobile brand Imperia, which produced a vehicle with a fuel-electric motor as early as 1907.
Resurrection of a Legend
The new Imperia GP Roadster fuses the branding of a legend with entirely new technology. It derives its power from a 1.6 litre turbo gasoline engine with 200 HP, and an electric motor with an output of 150 HP. It also features an in-house developed gear unit with 4×2 gears. The production of the gear unit required some creativity, given the lack of large-series products available from suppliers’ shelves. To this end the Imperia developers turned to French foundry Sicta, which specialises in the production of aluminium die casting prototypes. 3D printing was the solution proposed for manufacturing the required sand moulds, specifically the large scale voxeljet process.
voxeljet Services is one of Europe’s largest service providers for the on-demand production of plastic models and sand moulds for metal casting. More than ten 3D high-performance printers, including large format printers, which can generate moulds the size of a sports car, guarantee the rapid and efficient implementation of customer orders. A monthly print capacity of over 200,000 litres ensures short lead times even during times of high demand.
According to voxeljet CEO Dr. Ingo Ederer: “The 3D printing of sand moulds for a prototype gear unit is one of those classic voxeljet tasks. These projects are always about producing small batch sizes quickly, efficiently and at a high quality. That is precisely the type of product for which our technology is considered the first choice.”
Rapid and Efficient: 3D Printing of Sand Moulds
In contrast to the conventional manufacture of moulds, in which the production of model plates or core boxes alone can take several weeks, the sand moulds for the gearbox were printed on voxeljet’s VX1000 high-performance 3D printer in just a few days. The moulds are created without cumbersome and expensive mould set-ups, and are produced in a fully automated process purely based on CAD data using the layer building method, which consists of the repeated application of 300 micrometer thick quartz sand layers that are selectively glued together with a binder using the print head of the system.
The voxeljet print technology offers another advantage by using fine quartz sand. Compared with hand-made sand moulds, these finished cast parts feature a significantly smoother surface quality. “The past few years have seen veritable quantum leaps with respect to printing quality as well as printing speed. The high-performance print heads of the new machines achieve excellent resolutions and printing speeds that are five times higher than even just a few years ago,” said Dr. Ederer.
In addition to time aspects, there are also cost saving considerations that favour the use of layer building technologies. When examined with respect to total costs, up to a certain batch size 3D printing is significantly cheaper than conventional methods due to the lack of tool costs. The smaller the batch size, the greater the cost advantage offered by voxeljet’s technology.
Imperia and the Sicta foundry were very impressed with the performance of the voxeljet service centre and the quality of the printed sand moulds. And the Imperia gearbox was delivered just three weeks after receiving the order.