Photos courtesy Porsche AG.
Own old cars, trucks or motorcycles long enough, and sooner or later a common problem arises: A needed part is no longer available. Porsche Classic has recently announced an innovative solution (for a select grouping of components, anyway), which raises the question: Can 3D printed parts eventually be the answer to owners’ and restorers’ prayers?
Three-dimensional printing, now part of a process commonly referred to as additive manufacturing, can trace its roots to the 1980s, but it would take until the early 21st century for the technology to jump from lab to industry. By 2010 or so, printers had become affordable and powerful enough to gain favor among low-volume manufacturers, where they were typically used for rapid prototyping of parts.
A support bracket from the Porsche 356 B and C, now created using selective laser melting.
Early 3D printers used plastic resins (usually cured by UV light) to create objects, limiting their potential uses. An intake manifold, for example, could be designed on a computer, printed in a shop, and then tested on a customer’s vehicle for fit, but the plastic material wasn’t initially capable of withstanding high temps and strong vibration. On the other hand, the plastic part could be used to produce a mold to create the final metal-cast part, streamlining the tradtional design and manufacturing process.
In more recent years, additive manufacturing has expanded to included a wider array of printable materials, including both stronger plastic and metal, leading to the rise of “desktop manufacturing.” Not only are automotive aftermarket parts now occasionally made in this manner, but hypercar manufacturer Koenigsegg and boutique manufacturer Local Motors have both adopted 3D printing as part of the manufacturing process. Even the aerospace industry has embraced the technology, using 3D printed parts in the Airbus A350 XWB and the Eurofighter Typhoon.
Plastic parts, such as this Porsche 959 filler cap seal, must meet standards for UV and chemical resistance.
Which brings us full circle to Porsche Classic, which announced earlier this month that 3D printing would be used to create parts for cars such as the uber-rare 959, of which only 292 examples were ever created. Prior to 3D printing’s maturation, duplicating an out-of-stock part sometimes required the re-creation of machine tools or dies, a costly proposition for a low-volume replacement part.
In contrast, Porsche describes the process of 3D printing a clutch release lever for the 959 in its press release:
To manufacture the release lever, a layer of powdery tool steel less than 0.1 millimeters thick is applied to a processing plate in a computerized process. In an inert atmosphere, a high-energy light beam then melts the powder in the desired locations to create a steel layer. Thus, the complete three-dimensional component is produced, layer by layer. Both the pressure test with a load of almost three tons and the subsequent tomographic examination for internal faults were passed by the printed release lever with flying colors. The practical tests with the lever installed in a test vehicle and extensive driving tests confirm the impeccable quality and function of the component.
Thanks to such positive results, Porsche Classic’s 52,000 item parts stock now includes nine parts manufactured via a 3D printing process. Steel or alloy parts are “built” using the selective laser melting process described above, while plastic parts are created using a Selective Laser Sintering (SLS) process, where the material is heated to just below its melting point prior to being deposited on the layer below. A laser is then used to fuse the plastic powder in the desired location, (eventually) creating the part desired. Like the original components, 3D printed plastic parts must meet the German automaker’s standards for strength, as well as UV light and chemical resistance.
Porsche 911 Speedster mirror foot. No longer “no longer available.”
Creating a 3D printed part begins with a three-dimensional scan of an original part, eliminating a potentially complex design step. Porsche Classic is currently evaluating an additional 20 components to determine whether 3D printing represents a viable alternative to more traditional production methods.
Though 3D printing continues to have limited applications today, advances in material science (and 3D printers themselves) may change this in the coming years. With an ever-increasing number of automakers adding “Classic” divisions (a list that now includes Porsche, Jaguar, Land Rover, FCA, Mercedes-Benz, Ferrari, BMW, and Lamborghini), is it possible that future collectors and restorers may never know the anguish of “no longer available?” Could a viable business model soon be made for a small, low-volume shop to scan, edit, and then print a new fender for a Studebaker, or a new engine block for a flathead Ford V-8?
Not tomorrow, most likely, but perhaps in the next decade or so. Perhaps this “future” thing won’t be so bad, after all.
AUTHOR: Kurt Ernst