Rapid prototyping of aerodynamics research models

Rapid prototyping techniques are ideally suited to the manufacture of aerodynamics research models as these items usually consist of highly complex 3 Dimensional (3D) forms. The fabrication of complex curvatures on traditional Computer Numerical Control (CNC) machines often requires the production of additional tooling supports to allow for full machining of all surfaces. Such a necessity often results in extra cost and fabrication time, as well as a potential loss in accuracy due to any repositioning required to allow machining of internal and external features. It is often necessary to divide the model into additional sections to allow for the machining of internal features which can cause issues with mismatching of adjacent surfaces. The inclusion of small or complex internal features and hollow sections may be problematic if not impossible. In contrast, many rapid prototyping techniques eliminate most of these manufacturing issues due to the additive nature of modern 3D printing processes. Popular techniques for the rapid prototyping of polymers include Selective Laser Sintering (SLS), Fused Deposition Modeling (FDM) and stereolithography. The basic technique reduces a 3D object into a series of thin 2D slices. The 2D slices are then "printed" vertically in succession to produce the final 3D item The "slicing" technique is readily compatible with the formation of complex 3D curvatures as well as internal and hollow features. In addition, any required tooling supports are produced simultaneously with the desired item, which greatly reduces processing time and loss of accuracy due to part repositioning. The necessity to produce a model from multiple sections to allow access for machining of internal features can in many cases be reduced significantly. The characteristics intrinsic to many modern 3D printing techniques are greatly beneficial for the production of complex wind tunnel models made from polymer. The current work describes the design process and features of a wind tunnel model used for research into a novel aerodynamic flow control technique. An additive manufacturing technique was chosen as the most suitable for the rapid, accurate and simplest fabrication process for the model.