Hainbuch, Hänel team to perfect prototype Mando G211 mandrel


Hard work and first-class teamwork between the gear factory Hänel and Hainbuch have paid off. The new mandrel Mando G211 for gear manufacturers, suitable for gear hobbing, gear cutting, and gear grinding, is now available as a standard mandrel from stock and can be used optimally on gear-cutting machines. This project was not only a success for Hainbuch, but also for Hänel. This enabled optimization of manufacturing processes, reduced set-up time, and improved gear quality because the mandrel guarantees stable clamping and dampens vibrations.

When a new product, in this case the Mando G211 mandrel, specifically for the production of gears, is to be launched on the market, it must be tested thoroughly under real conditions. Hainbuch was looking for a reliable partner for testing this prototype — one who was open-minded about new things, placed great value on precision, and ran manufacturing processes on a high level. Hainbuch approached the gear manufacturer Hänel GmbH & Co. KG from Bad Friedrichshall, Germany, explained the situation, and was well accepted.

Production manager Jürgen Renner said, “We have already had positive experiences with Hainbuch clamping devices. For us, the whole thing has sounded promising from the very beginning. We saw potential for improvements in our manufacturing and processes. That’s why we agreed. I must add, that our management is very open to such partnerships. If this results in rewarding optimization and keeps investments manageable, nothing stands in the way of such a project.”

Hänel initially received two prototypes of the Mando G211 mandrel in sizes zero and two. The mandrels were tested on the Richardon R 400 manual loading machine and on the Gleason-Pfauter GP 200 hobbing machine with automatic loading to see if they would be compatible and work properly.

Renner said, “For our employees, this new clamping system was very strange. For 20 years, they worked with a clamping system from the machine manufacturer without radial clamping, which worked fine so far. For the first attempts, we had to make some adjustments to the machine. In addition, we did not reach our zero line on the Gleasen-Pfauter machine because the mandrel was too tall. As a result, adjustments to the machine and loading system were required. It also turned out that the mandrel had to be technically slightly optimized. What followed were a few conversations and phone calls with Thomas Steiger, product manager, and Hannes Ludwig, the responsible designer, both at Hainbuch. We have diligently tested and passed on all the information needed to further optimize the mandrel. All design changes were implemented by Hainbuch. Subsequently, the revised second prototypes were made available. After a lengthy field trial and a few minor adjustments to the machine, the stiff and slender mandrel could, thanks to the use of Hänel, go into series production and be produced for stock.“

At Hänel, the batch sizes are between 30 and 1,000 pieces. Customers are buying their gears because of the precision. As a rule, these are hardened and ground gears in a very high quality. For this reason, the most important requirement for Renner was to save a single manufacturing step on this new mandrel, namely the rework.

“With the current clamping system, we did not manage to achieve a good concentricity. The workpiece was pressed axially downwards. Now, it is clamped with the mandrel from the inside, radially outwards. Thus, we have a higher stability within the clamping. This eliminates the reworking of certain components. For some of our orders, the old clamping system was good, because the concentricity was not so important. But basically, I must say, the better the concentricity, the easier it works later. With a normal hardened gear, the bore still needs to be reworked, but all the workpieces that are fully geared can now be reduced to one operation,” Renner said.

In addition, Hänel was hoping to speed up set-up by the use of the new mandrel. That is possible now. Hänel can summarize smaller orders if the components are similar. With the Mando G211 mandrel, only the segmented clamping bushing and not the entire clamping system have to be changed.

Andreas Hoffmann, head of toolmaking, said, “Thanks to better stability, we can drive partially higher feed rates. Even the tool wear is reduced because we have less vibration.“

Hänel now has six Mando G211 mandrels — the two prototypes and four standard mandrels in sizes zero to four.

“All new components have been manufactured with the mandrel ever since,” Hoffman said. “Even with older components, we try to change over to the mandrel clamping, because the segmented clamping bushings from Hainbuch can be delivered within one day. That’s a huge advantage for us.”

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