Mercedes 300 SL Cabrio by DOMINIK BARTSCH is licensed under CC 2.0


German car instrument restorer Classictacho GmbH repairs mechanical and electronic speedometers and gauges to high technical standards. When original parts are no longer usable or available, they hand craft parts that meet the required specifications. This was recently the case when restoring instrument panel backlights from the Mercedes 300 SL Roadster. To re-build these engineering master pieces, Materialise’s know-how in 3D Printing along with Classictacho bespoke manufacturing proved to come in handy


Reverse Engineering

The engineering team at Materialise started off by 3D scanning the original part. The scanned file served as dimensional input and formed the basis for re-engineering and design. The team took the opportunity to use the full potential of 3D Printing and optimized the design with regard to function integration and component reduction. With the use of heat resistant printing materials in mind, the metal components present in the original part could be left out, eliminating the need for assembly afterwards. 


A 3D Printed Spare Part

The new version of the backlight consists of a bottom section in laser sintered polyamide with a black finish and vacuum casted light points in transparent HMPU13. Separate inner tubes guide the light into the right direction, combining ambient light for water and oil temperature, fuel level, oil pressure and a cluster of pilot lights including the specially formed pilot light for high beam.



What challenged our engineers was the technical complexity of the part,” says Erik de Zeeuw, Senior Project Manager at Materialise. “Although all the lights are combined in one single part, there’s no light interference between the indicators and the background. It’s this kind of complexity, combined with the small amount of parts needed that made this project a typical success story for 3D Printing.” 

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