Rainer Armbruster has a different definition of slowing down in retirement than most people.
The longtime employee of Foboha Inc. in Germany fashioned a career in mold making that earned himself a spot in the class of 2024 for the Plastics Hall of Fame. Armbruster, specifically, made a name for himself as the inventor of cube molds, which allows for higher productivity and advanced production techniques compared with standard injection molds.
While he has now technically retired from the company, he continues on as a consultant for the firm while still putting in 30 or so hours a week. That's down from the 70-80 hours he used to work up until about five years ago.
Armbruster's employment journey began in 1966 when he began an apprenticeship in metal stamping, making molds for Dual GmbH in 1974 in Hornberg, Germany, and he eventually landed at mold maker Foboha in 1977 in Haslach im Kinzigtal, Germany.
"I was employee No. 5," he recalled. "I like to work in the small family business. ... That was the reason I moved to here. ... It was a small company, a family-owned company. There you can do everything, the whole process, to produce a mold," Armbruster recalled. "It was much more interesting for me to do this."
Armbruster remembers he was not an expert mold maker when he joined the company, but he learned the trade over time from owner Werner Bodmer, who started the company in 1973.
"I don't have the skills of injection molding at this time, but I learned it from him," he said. "He saw I learned very quickly."
It was not long before Armbruster and the company agreed he would go back to school full time to bring back more skills and knowledge to the company, a move that allowed Foboha to improve processes and embrace automation at the time. He finished studies in this master school in 1982.
Many mold making projects have passed through the doors of Foboha over the years, but one particular request helped change the course of not only the company but also Armbruster's career.
A customer seeking a way to produce complicated parts without sacrificing cycle time asked Armbruster whether he had any ideas to improve production. The idea came to him immediately: the cube mold, which rotates to allow different functions to take place simultaneously. A part could be molded using one face while other parts already made could be removed without slowing down production time, for example.
While he is recognized as the inventor of the cube mold, Armbruster is surprised all these years later about the technological advancements the concept has allowed in the world of injection molding over time.
Once Armbruster landed at Foboha, now a unit of Barnes Group Inc., he never had any desire to leave. And that was 46 years ago. He found a professional home, and he knew it.
"He's a genius. He is a genius as an inventor, a pioneer, but also from a human being. He loves what he does. He loves his profession. But he also loves the complete company and the employees. And he always helps to get better, each of us. It's not only from the professional side, but it's also from the human being side. It's great to work with Rainer," said Eveline Geppert, head of global marketing communications with Barnes.
Mold making and plastics has always been an exciting field for Armbruster. Foboha's success over time validates his decision, he said: "There was always a need for more molds and better molds, and the demand on plastic components in each kind of industry [continued to grow]."
The chance to improve every day and come up with new ideas for new applications for plastics keeps his interest to this day. "It makes the job interesting in a way to create something for the future," he said.
Armbruster decided to remain a consultant to Foboha even after his retirement, seeing the opportunity as a way to transfer a career's worth of knowledge over time. All of those mold making details can't be explained in a day, but the ability to continue to be involved in projects allows him to teach other employees what he knows on an ongoing basis.
"I want to transfer my knowledge of what I have. You cannot do this from one day to the other day. You can do this from job to job, when customers send us new inquiries. I can bring my knowledge in, and I want to transfer my knowledge to the people," he said.
Armbruster's current consulting contract runs until September 2025, the self-professed workaholic said. "Then we will see."
Asked about his future, Armbruster points to his children and grandchildren and said he expects to spend more time with them.
"Armbruster has repeatedly proven his incredible technical creativity and courage to bring even the most complex mold concepts into production. Armbruster's extraordinary talent and commitment to his innovations now enable the plastics industry to manufacture complex, multipiece injection molded components in fewer steps and in less space on the shop floor," the hall said.