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Time is a precious resource, particularly in F1. Rapid prototyping procedures allow a finished mock-up to be obtained in a short amount of time, in order to make functional, fluid-aerodynamic, fitting and assembling tests. The Red Bull Racing Formula 1 aerodynamic department and CRP’s rapid prototyping department have been cooperating to evolve from rapid prototyping to rapid manufacturing.
(Published on May 2008 – JEC Magazine #40)
For instance, a 1:1 scale aerodynamic model has been produced for F1 wind tunnel testing (figure 1). F1 constructors have to face many challenges that include doing as many design iterations as possible, focusing on return on investment and staying within limited resources. Aerodynamics is a key parameter to win. Rapid prototyping helps engineers in this task.
Evolution of prototyping materials
A wind tunnel model has been developed over the past ten years to test as many iterations as possible. A bottleneck in the process was the model shop making parts, with its time-consuming, costly procedures. Stereolithography with clean resins was used for the first time for wind tunnel models eight years ago, but the parts were brittle and unstable as the available resins were too weak.
About six years ago, a ceramic-filled stereolithography was tested, showing higher mechanical properties, but still producing very fragile, heavy parts that were photo and humidity sensitive. Three years ago, metal-plated stereolithography yielded increased mechanical properties, but with very high weight. Selective Laser Sintering (SLS) with Windform™ materials developed by CRP Technology has been used for a few years. Using SLS, a part is made by consecutive overlapping of layers in a chamber, with an inert atmosphere and at constant temperature.
A roll deposits a layer of thin powder on a platform, on which a CO2 laser is pointed out for local sintering of the powders. Sintering means forming a coherent mass by heating. The latest improvement to this technology is the Windform XT material.
From rapid prototyping to rapid manufacturing
Launched in 2004, Windform XT was created for the high-performance SLS market, where carbon-fibre-filled materials do make the difference. It was the first such polymeric material ever launched on the SLS market and represents the ultimate technological goal, having been created expressly for laser sintering technology. This product is not only a new material, but also a great improvement in rapid prototyping, so CRP enabled SLS technology to make a big step forward, from rapid prototyping applications to rapid manufacturing. It is an opaque, black carbon/polyamide material with brilliant reflections (see example figure 2). WindForm™ XT is characterized by its stiffness and extremely high ultimate tensile strength, excellent surface finish, resistance to extreme wear and optimum reproduction of details.
Red Bull Racing is now using Windform materials extensively, for both the wind tunnel model and the racing car, but one of the key parts, the brake air intake, still poses some problems for rapid manufacturing processes. The part is located close to the wheel upright and cools the brake system in order to allow effective, continuous brake performance. A hightemperature material (still not available on the market) is now required for this part. However, the many "cold" parts made of Windform XT on the F1 car have no problem at all and can race all the Grand Prix weekend.