Rapid prototyping, popularly known as three-dimensional, or 3D, printing, is not as new as some would think. 3D printing was, for example, key in the parts localisation and validation process during the development of the sixth-generation Isuzu KB bakkie, launched in South Africa last year, says General Motors South Africa (GMSA).

GMSA engineers have been working with the technology since 2007, when the company acquired a 3D printing machine to develop new prototype parts.

GMSA assembles the Isuzu pickup at its Port Elizabeth plant, in the Eastern Cape.

“We have used this technology to grow prototype parts of a range of components, including plastic clips, mud guards, support brackets, air cleaner and air conditioner components, radiator shrouds, rear step components, electronic module housings, and the utility box for the extended cab variant,” says GMSA validation engineer Dave Doubell.

“In addition, we often use the machine to make our own special tools and functional components to support our testing equipment, which we use on a daily basis in the engineering workshop.”

3D printing begins with a virtual design which is created on modelling or Computer Aided Design software.

A stereo lithography file format is then fed into the 3D printer, which translates the virtual design into a physical prototype part, building it layer-by-layer using a thermoplastic material called ABS plastic.

GMSA vehicle engineering manager Jessel Vencencie and his team use the technology extensively as it saves time and cuts development costs.

“Through this technology we are able to make functioning prototype parts, which are then used to give us an early indication of how the actual part will function when fitted to a vehicle,” he says.

“3D printing allows flexibility by speeding up the development process of parts as we fine-tune the design of a component for better form, fit and functionality.”

The thermoplastic parts produced by the process can endure exposure to heat, chemicals, humid or dry conditions, and mechanical stress.

“Development of the sixth-generation Isuzu did not stop when we launched the vehicle,” adds GM Africa engineering VP Wendle Roberts.

“We are constantly studying customer needs, feedback and warranty data to continuously develop and improve the capabilities of the KB.

“The beauty of rapid prototyping is that you can test components by installing three or four samples quickly without much cost. This allows us to try more options as we work to enhance the product.”