New machine concept for manufacturing of worm shafts

Erwin Junker Maschinenfabrik is awarded the special prize from the Ministry of the Environment for the JUMAT grinding machine. The grinding machine can be used to produce worm shafts with a highly productive and energy-efficient method in mass production.

The special award of the Jury for this year's Baden-Württemberg Environment Technology Prize goes to Erwin Junker Maschinenfabrik GmbH, based in Nordrach, for the new JUMAT machine concept. Hidden behind the name JUMAT is a highly productive, energy-efficient process for mass production of worm shafts, completed in just one machine.The worm shafts produced are used in various gearboxes and drives. Their applications are broad, ranging from electrically driven systems for cars such as steering & brake systems, seat-, mirror-, and hatch- movements; general mechanical engineering, to drives used in hospital beds or camper vans. Some applications are so widespread that the manufacturers produce several million of these worm shafts per year.

In concrete terms, around 40 percent of energy and material resources can be saved in the JUMAT manufacturing process

In goes a blank, out comes a worm shaft

The new procedure replaces the manufacturing process whereby the individual worm shaft has to pass through three machines (milling, rolling or whirling, followed by smoothing or finishing and finally deburring), along with the corresponding time and effort required for handling. The worm shaft is ground from solid material out of the blank, which already has a basic geometry and two bearing seats, without even once opening the machine door. The blank is fed into the fully automated process via a loading system and undergoes two grinding processes, pre-grinding and finished-grinding. The work piece is then moved to the machine internal deburring station, so that a finished worm shaft comes out at the end. Significant innovations to bring this about include a newly developed tool geometry and an optimized pre-grinding process, which takes over the principal cutting capacity and works at very high feed rates.

However, the values have proved to be realistic. The first customer applications that we were able to support in 2021 have in some cases significantly exceeded our forecasts

Savings in many ways

"Erwin Junker Maschinenfabrik GmbH has developed not only a new grinding process, but also a comprehensively new approach, which achieves improvements and savings in many ways. That is what motivated the jury to award the special prize to the JUMAT," says Environment Minister Thekla Walker. In concrete terms, around 40 percent of energy and material resources can be saved applying the JUMAT manufacturing process. In production, extremely long tool lives go hand in hand with reduced space requirements, cycle times shortened by at least 50 percent and energy consumption reduced by around 25 percent – whereas the production processes and their effects can vary significantly. "We were rather conservative in our calculations. However, the values have proved to be realistic. The first customer applications that we were able to support in 2021 have in some cases significantly exceeded our forecasts, ”says Joachim Himmelsbach, Managing Director of Erwin Junker Maschinenfabrik GmbH.The new machine model has been available since early 2021.

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