Stuttgart, Germany - Mercedes-Benz has begun making 3D printed spare parts out of metal. The first item, a thermostat cover for older truck and Unimog engines, has passed quality assurance testing and is now available to order.

The company has been 3D printing plastic parts for a year now; the process is well suited to small batches or even individual orders for hard to get out-of-production parts. If the software is on file, those parts can be produced without any set-up costs - other than a few mouse clicks.

Now that process has gone a step further with 3D metal printing. Aluminium parts from the 3D printer are as strong as the diecast originals, with even better metal purity and thermal resistance. They’re actually harder and more wear-resistant in some instances, so they’re specially suited as replacement parts for engine peripherals and cooling system components that are subject to thermal shock, especially complex shapes that are difficult to cast without inclusions.

Intricate shapes

While the obvious application for 3D metal printing is for reproducing discontinued parts, it may even wind up being the most accurate and cost-effective way to make smaller batches of parts for classic cars or very intricately shaped aluminium parts such as intake manifolds or oil pumps for racing engines, which are currently made by machining them out of solid blocks of metal - the most time-consuming, most labour-intensive and costliest way of making anything.

Availability of spare parts, especially for older trucks and vans, is always an issue - every day they are off the road costs their owners money. 3D printing opens entirely possibilities for providing spare parts, long after production has ceased.

In the future, 3D metal printing could allow decentralised, much faster, local production, right there in the workshop. Which means no transport costs, no delays and almost instant availability at any Mercedes-Benz workshop that has its own printer.

Imagine this conversation:

Workshop Manager: “I’m sorry, sir, your 1967 Unimog needs a new left-side ufflicator widget.”

Customer: “And how long is it going to take to get one?”

Workshop Manager: “Oh, a couple of hours to print, and another hour to install - could you come back this afternoon?”

Impossible? Not any more.

The new thermostat cover in the picture is just one example of cost-effective production of high quality spare and special parts, usually made of die-cast aluminium alloy. This component, used on older commercial Mercedes-Benz and Unimog engines that have been out of production for about 15 years, is ordered only in very small numbers - too few to justify re-starting production - but this shows that, specialised or discontinued parts can be ordered and delivered anywhere in the world on request.

3D metal printing is a little different from the Selective Laser Sintering used in plastic printing. In a process called Selective Laser Melting, powdered aluminium/silicon material is applied in individual layers and melted by an energy source - usually one or more lasers. When one layer is completed, a new layer of powder is applied automatically and the process is repeated, until the entire component has been built up.

IOL Motoring