Harald Feuerherm's inventions optimized extrusion blow molding
By Karen Hanna
The raft of technologies that Feuerherm GmbH offers to optimize the blow molding process bear long names, shortened to acronyms: PWDS, SFDR and WDLS.
But Benjamin Lopez recounted a different word an employee in the industry used to describe them: Magic.
At the Annual Blow Molding Conference in September, Lopez, an SPE Blow Molding Division board member, lauded the magician behind Feuerherm’s Partial Wall Thickness Distribution, Static Flexible Deformable Ring and Wall Thickness Position Control (WandDickenLagenSteuerung) technologies — Harald Feuerherm — as the winner of the 2025 Lifetime Achievement Award.
“There’s a little bit of magic at the end of all these, all the innovations,” said Lopez, a technical manager at Bekum.
In a presentation introducing Harald, his grandson, Max Feuerherm, recounted the experiences that led to the 1977 founding of the Troisdorf, Germany, company that bears the family’s name.
According to Max, who’s now managing director of the family business, Harald graduated from school in the 1950s, but had little money to pursue higher education full time. Instead, he trained as a machine fitter, eventually going on to engineering school.
An accomplished runner, he could have competed for a spot on the Olympic team for the 1964 Tokyo Games. However, according to remarks provided by Max, he committed to a different path.
“Not out of a lack of desire, but because he knew that a sporting dream would delay his studies. This decision was difficult, but it shaped his further path: focus, discipline and the conviction to choose the right thing, even if it is difficult,” Max said.
Through the 1960s, Harald developed a number of innovations to help optimize the blow molding process.
“Harald is not the guy smoking in the back; he is the working guy in front,” Max said.
In 1973, he landed at Mauser Maschinentechnik in Bruehl, Germany, where Max said, “he encountered a problem: the uneven wall thickness distribution of plastic drums.”
“So, he spent evenings at his desk: 100 hours of work, 13 sheets of paper, three inventions — a new accumulator head, the later PWDS and the SFDR technology.”
In 1975, Harald submitted his inventions to Mauser; the following year, the company released the inventions back to him.
In 1977, Harald and his wife, Gisela, founded the Ingenieurbüro H. Feuerherm and Handel Gisela Feuerherm companies based on Harald’s ideas.
With more than 2,000 PWDS and SFDR units now in use all over the world, Harald’s ideas have cast a spell across the last half-century.
According to Max, the PWDS replaces the solid die tool in a standard blow molding process, while the SFDR replaces the solid core or solid mandrel.
Each has a flexible ring made out of a special steel alloy, which can be dynamically or statically ovalized.
“What Harald did is connecting two actuators to the flexible ring of the PWDS so that for the parison forming process, he can have a dynamic influence on the parison for every wall thickness profile point,” Max said.
Harald, who delivered a brief statement thanking the Blow Molding Division for his recognition, retired in 2019 at the age of 79, with dozens of patents to his name, “and started his golf career since then,” Max said.
From its roots, with Harald at first tinkering in the cellar, family-owned Feuerherm has come a long way, with a new facility that opened in 2014.
Max beamed with admiration throughout his presentation.
“Personally,” he said. “I am extremely proud of having Harald as my grandfather, and I am very thankful that his lifetime achievements are honored this way.”
This article appears in the fall 2025 issue of The Journal of Blow Molding.
© 2025, Society of Plastics Engineers Blow Molding Division
About the Author
Karen Hanna
Senior Staff Reporter
Senior Staff Reporter Karen Hanna covers injection molding, molds and tooling, processors, workforce and other topics, and writes features including In Other Words and Problem Solved for Plastics Machinery & Manufacturing, Plastics Recycling and The Journal of Blow Molding. She has more than 15 years of experience in daily and magazine journalism.