Whether it’s a futuristic concept or a face-lifted grille for a family sedan, being able to create a full-size, three-dimensional plastic replica of a new component speeds up the design process by reducing the time and money spent on clay modeling and hand-carving expensive prototype parts.
Designers and engineers at General Motors are able to see and touch their creations sooner and at lower cost because of the digital manufacturing set-up at the GM design centre.
Technicians use selective laser sintering and stereolithography to go from computer models to one-off parts for wind-tunnel testing in not much more time than it takes to print out a drawing - and if they then want to change something, they can quickly and easily make another one, so more shapes can tested in less time.
Aerodynamics engineers can put a production vehicle in the wind tunnel and quickly swap body parts such as bumpers, grilles, spoilers and mirrors between test runs to perfect the aerodynamic performance of a face-lift before a single metal part is made.
In fact, says GM, testing capacity has doubled in the past two years.
Aerodynamic development engineer Suzanne Cody explained: “Long before a full-size model or vehicle is built, rapid prototyping helps to improve the accuracy of the one-third scale models that are used for early aerodynamic testing.
“Air-flow through the engine compartment and underneath the car is critical to both cooling the engine and lowering drag.”
In the past, modelers would carve a rough approximation of the front structure and the engine from foam or wood to evaluate airflow through the engine bay. Now GM’s prototyping lab can generate a fully detailed model including the engine, transmission, brake lines, drive-shafts, exhaust system, suspension and other components under the car.
Cody said: “The air-flow measurements over the models is much closer to the full-size car, so fewer changes are needed in pre-production, when they are much more expensive. With the design of components such as cooling systems finalised earlier, fewer prototypes are needed and vehicles can go from concept to production more quickly.”