“No longer available” – for collectors of rare classic cars, the unavailability of spare parts can quickly lead to problems. In the worst case scenario, the car may even just stop. Porsche Classic, the division of Porsche dedicated to classic vehicles, has come up with a solution to this problem. Namely, producing extremely rare parts that specialists only need in small quantities using 3D printers. Production happens through using the 3D printing process. Thus the company meets the requirements in terms of absolute fidelity to the original specifications – both from a technical and a visual perspective.
The Porsche Classic range currently includes some 52,000 parts
If a certain spare part is no longer in stock or stock is dwindling, specialists use the original tools to reproduce it. For larger quantities, production may require the use of new tools. However, ensuring the supply of limited spare parts sometimes poses a major challenge, even for the experts. Producing small batches using new tools would be largely inefficient. Before embarking on a project to produce a particular component, Porsche Classic always evaluates various manufacturing processes.
As the quality of “additive” manufacturing processes continues to improve with generally decreasing costs, this form of manufacturing presents an economic alternative for the production of small quantities. Say, for example, the release lever for the clutch on the Porsche 959 is no longer available. This component is from grey cast iron and it has to be of very high quality. But it is in very low demand. Not least because there are only 292 of these super sports cars. The only manufacturing process worth considering would be selective laser melting.
To manufacture the release lever, a layer of powdery tool steel less than 0.1 millimetres thick is applied to a processing plate in a computerised process. In an inert atmosphere, a high-energy light beam then melts the powder in the desired locations to create a steel layer. Thus, layer by layer goes the production of the complete three-dimensional component. Both the pressure test with a load of almost three tonnes and the subsequent tomographic examination for internal faults were passed by the printed release lever with flying colours. The practical tests with the lever installed in a test vehicle and extensive driving tests confirm the impeccable quality and function of the component.
Due to the consistently positive results to date, Porsche is currently manufacturing eight other parts using 3D printing
The parts in question are steel and alloy parts produced using the selective laser melting process. And production of plastic components is with an SLS printer. SLS stands for selective laser sintering. The material heats up to just below the melting point. The remaining energy goes through a laser to fuse the plastic powder at a precise point. All parts are subject to the quality requirements of the original production period as a minimum, though they usually meet higher standards. Tests ensure the accuracy in terms of size and fit. Depending on the area of application, plastic parts of various materials as in the original must be resistant to oils, fuels, acids and light.
Porsche Classic is currently testing whether 3D printing is suitable for the production of a further 20 components. The benefits: Three-dimensional design data or a 3D scan of the component is a sufficient basis to commence production. Production of the components can happen on demand, thereby eliminating tool and storage costs.
— Porsche (@Porsche) February 5, 2018