Revival of a legend: Reverse engineering a Münch Mammut with 3D printing

The Münch 4 TTS (also known as the Münch Mammut is one of the most sought-after motorbikes in the motorcycle scene.

At the end of the 1960s, the designer and motorbike enthusiast Friedel Münch became self-employed and founded his own workshop, where he built a limited number of Münch motorcycles. The most famous of these is the Münch 4 TTS with an engine capacity of 1200 cm³. Friedel Münch specialised in the use of air-cooled, four-cylinder engines and manufactured every motorbike using his own drawings. Overall, the company produced merely 500 motorcycles over a period of 10 years. Another feature that became particularly well known was the use of Elektron (a magnesium alloy) light metal casting on the rear wheel and the front brake. At the time, this was an unusual method of construction.

Today, the Münch Mammut has reached a real cult status. Due to the small quantities produced and the uniqueness of the engine, there are hardly any genuine originals left in good working condition. However, in the motorbiking world, that doesn’t stop people from pursuing their dream of owning this iconic piece of machinery.

Markus Pohl, a metalworker from Straubing, Germany, has decided to make his lifelong dream a reality and build his own Münch Mammut. An ambitious project.

Luckily, the trained engineer was able to buy an original Münch 4, but it was not ready to drive. As original spare parts are also a rare commodity these days, Pohl started searching for an alternative solution. Finally, by using latest technology, a breakthrough was made. Markus Pohl dismantled the motorbike into its individual parts, in order to digitize them via 3D scanning technology. The generated datasets were further processed on the computer to create the corresponding casting molds.

In order to recreate the cast components and make them true to the original, the Bavarian engineer turned to voxeljet in Friedberg, near Augsburg. The company is one of the leading manufacturers of industrial 3D printing systems, and operates one of the largest on-demand service centres producing sand molds for metal casting in Friedberg.  Markus Pohl submitted his data sets to voxeljet to allow 3D printing of dimensionally accurate sand molds without any need for tooling.

“The great advantage of 3D printing is that you can produce sand molds quickly and without the use of tools,” explains Markus Pohl. “This meant I had the molds ready for casting within just a few days, instead of having to wait six to eight weeks.”

The building process for sand molds using additive manufacturing is fully automated. In the 3D printing system, the so-called recoater applies a 300 µm thin layer of silica sand onto a building platform. A high-performance print head then moves over the platform and glues the sand together using a Furan resin, whereever the component is to be created. The building platform then lowers by one layerthickness, and a new layer of sand is applied. This process is repeated until the component has been fully constructed. After removing any excess sand, the mold is ready for casting and can be integrated seamlessly into standard sand casting processes thanks to the usage of common casting materials.

To create the metal components, Pohl turned to the foundry Gugg in Straubing. A foundry specialised in various alloys, including aluminium, which was used to produce the parts for Pohl's Mammut.  “For small series, or as in this case, producing an individual part, the conventional method of pattern making is simply not feasible. 3D printing offers an ideal alternative for producing custom-fit parts quickly and economically,” the Münch fan added.

Markus Pohl was able to assemble the entire Münch in just one year. And he is already planning his next project: In 1972, the famous artist Luigi Colani designed a new edition of the legendary motorbike in collaboration with Friedel Münch. Now Markus Pohl also wants to recreate this model in his workshop in Saulburg.