The ‘Metal Head’: From leaving school to pioneering in 3D printing – part II

Cooling channels (orange) inside molds, credits: Tooling Siegfried Hofmann / Concept Laser*

Frank Herzog – a.k.a. the ‘Metal Head’ – was still in elementary school in Bamberg, Bavaria (Germany) when he fell in love with metals and a few years later he left high school early to pursue his passion. This is part II of the story behind Concept Laser, here you can read part I.

Translated from German, original article: GE Reports Germany

Frank Herzog decides to ‘compromise’ and joins a prototype shop in the neighbourhood, that belongs to Kerstin’s uncle Robert Hofmann. This decision changed his life. It was in the middle of the 1990s, and the machine in the factory was one of the first stereolithography machines in Germany to ‘print’ 3D models of successive resin layers and harden them under UV light. “I told Robert: ‘oh wow, if we could do the same thing with metal, that would be really cool’,” Herzog tells. Robert liked the idea, and suggested he should think about it. “So I pulled the proverbial pencil and a piece of paper and tried it,” says Herzog.

Produce components made of metal

In many 3D printers and other AM devices, complex components ‘grow’ directly from computer data by fusing layers of raw material together. Herzog believed that by exchanging the UV light in the stereolithography systems with a laser beam, he would be able to produce components made of metals.

“If we could do the same thing with metal, that would be really cool.”

He submitted this idea as a master thesis in Coburg and built a small prototype. He used a laser he had found at school and made print samples from a stainless steel powder, which is applied in the coating of surfaces. The results were, however, not particularly encouraging. On the outside, the components looked really nice, but on the inside they were porous and tended to coalesce when cooled.

Steel box with perfect density

After numerous attempts to produce a dense component, one evening Frank discussed the matter with Kerstin, explaining he had made quite a lot of progress but now seemed to be stuck. Luckily, Kerstin saw a solution. She had acquired a state-of-the-art solid state laser for her master project. This emitted a continuous low-frequency light beam and was thus potentially suitable for the pressure of stainless steel parts with a uniform structure.

Herzog borrowed the laser, installed it in his 3D printing system, and connected software for motion control to it. To meet his deadline, he even spent the night sleeping next to the machine. “The production of the component lasted several hours and I had to be prepared for the occasion that the machine would get stuck at 2:30 am – which then actually happened,” Herzog tells. After many nights, he had produced a 1 x 1 cm thick ten-layer rectangular steel box with perfect density. “When we cut the component, I knew we had made it,” says Herzog.

Today, Concept Lasers Mlab cusing is able to manufacture artificial hip joints and surgical tools. Photo credits: Fraunhofer IWU / Concept Laser

Founding Concept Laser

The hard work paid off: Herzog not only received his diploma, but also an investment of 2 million euros from Kerstin’s father and uncle for further developing and marketing the design. There was a catch though: they had to make it within two years, because the two brothers would then need the money invested for other projects.

In 2000, Frank and Kerstin founded Concept Laser in a small area in Roberts factory and began the construction of their first machine. In the following year, they were able to present the first laser-driven 3D printer for metals at Euromold in Frankfurt.

*Opening image: Cooling channels (orange) inside molds for injection molding were among the first applications for Herzog’s 3D printers. “They pumped coolant through these channels, which could not be milled. This allowed the molds to be cooled down up to thirty percent faster,” says Daniel Hund, Marketing Director at Concept Laser. Picture credits: Tooling Siegfried Hofmann / Concept Laser

The third and final part of this story will appear here in week 29.

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