The highest precision is achieved through the optimal interaction of machine, tool and machining process. Japanese-Swiss company Big Kaiser therefore relies on the combination of hard turning and grinding on a Super Precision T51 SP MSY machine when manufacturing its high-precision tool holders in Rümlang near Zurich.

The list of machine manufacturers that produce high-precision hard turning machines is not long. One of the most prominent companies in this field was machine manufacturer Hardinge, which developed the Super Precision series. This series is now part of the portfolio of Kellenberger Switzerland AG.

Thanks to their rigidity and stability, the CNC high-precision lathes in the Super Precision series are suitable for hard turning as well as for combined hard turning and grinding operations in the production of complex workpieces in a single set-up. Measurement reports certify that the T series has a continuous machine accuracy of 3 µm, workpiece roundness of 0.25 µm (T42) and 0.70 µm (T65), a repeat accuracy (on all axes) of 0.76 µm, and an achievable surface finish of better than Ra 0.15 µm or Rz1.

“Of all the machine manufacturers we approached, only Hardinge guaranteed us process reliability,” says Big Kaiser’s head of supply chain Marcel Stettler. “That was courageous and ultimately convinced us.”

The new T51 SP MSY was ordered in December 2018 and delivered in summer 2019. A robot handling system for fully automated production was subsequently installed in October 2020.

For the combined turning/milling and grinding operations required for the complete machining of HSK tool holders, the T51 SP MSY machine features a grinding unit with driven tools developed for Big Kaiser, which has an inclined position. This inclined position is of decisive importance for the finish grinding of taper and shoulder features.

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