GKN Sinter Metals in Bonn, Germany, has supplied seat specialist Keiper with sintered metal components that enable seats to recline since 2000. The parts, known as ‘wedges’, reached an impressive milestone recently when the one billionth part was produced, all made with zero defects.
In 1998, the first discussions were held with Keiper about replacing traditional metal components in its backrest adjustment system with sintered parts. “We have been producing products from powder metal at this site since 1934 so there was no problem in terms of process. However, Keiper’s high annual demand of 80 million ‘wedges’ gave us a real headache,” stated Matthias Voss, GKN Sinter Metals Plant manager.
The first volume production order was issued by the OEM in 2000. It comprised 100,000 units per week and manufacturing at Bonn started with one press and three employees, states GKN Sinter Metals. Due to the success of the part the orders were rapidly increased and the production capacity expanded to the current level of seven presses within just one year.
“If I had known at that time that my team and I were to produce 320,000 components each day, I would hardly have considered it possible. However, we have independently developed the various processes required and improved them continuously,” stated Blaise Akono, head of the GKN Sinter Metals production cell.
By 2001 the Bonn plant had delivered 25 million wedges to Keiper and within four years the deliveries were already at 300 million parts, all with zero defects. On several occasions over the years the customer has honoured the team in Bonn for its high quality standards.
Today, the manufacturing cell now operates in three shifts with a total of ten skilled workers. Manufacturing process include pressing, sintering, hardening, tempering, vibratory finishing, drying and hardness testing, while a complex camera system ensures a 100% quality inspection. A special feature is that the parts are produced in three different dimensions that cannot be visually distinguished. Therefore, the final step involves automatic sorting and packaging of the different variants.
“The quality assurance concept has been constantly refined,” added Matthias Voss, Plant Manager. “The hardness is checked by an eddy current system. Subsequently the parts are fed into the sorting unit in the correct position so that the cameras can check the dimensional accuracy and surface finish of the components. Defective parts are sorted out by the system and we have now reached one billion parts with zero defects.”
“Currently we have follow-up projects both in production and on the verge of starting volume production, including even some more complex components. Therefore we are very optimistic about the future, especially as the benefits of powder metal technology increasingly come into view of development engineers and production managers,” Voss added.