Liebherr-Verzahntechnik GmbH has established targets for the new series of gear skiving machines: With the LK 180 / 280, a gear skiving machine is launched on the market that enables chamfering during the machining process. “With this machine, you can also produce internal gears with a defined chamfer”, explains Dr. Oliver Winkel, Head of Applied Technology at Liebherr-Verzahntechnik GmbH. “This is a world first.” The advantages are obvious: The 90 degree positioned chamfering device does not influence the cycle time and delivers deburred and chamfered workpieces – an absolute advantage for any customer.

“For us as gear specialists, it was important to be able to offer our customers new additional functions”, proclaims Oliver Winkel. “Our tool changer can accommodate up to twelve tools for different operations.” Gear skiving tools for roughing and finishing, drilling, and turning tools allow machining in a single workpiece clamping fixture. This is of particular interest with position-orientated gears, explains Thomas Breith, Head of Product Management. “Beyond mass production, we can very clearly see a trend towards the integration of various work steps. The aim here is to reduce the set-up times of associated or adjacent machines, as well as the influence on workers.”

If re-clamping is dispensed with, many operations become faster and more reliable. Holes can be drilled, for example, exactly at the position of the gear without the need for a reference point marking or renewed measurement. Particularly on ring gears for planetary gear sets, the reference journal (or reference hole) can be precision turned to match the gear so that one step of the operation can be dispensed with. “The quality and accuracy of our gears are increasing because they always relate to the reference surfaces”, adds Oliver Winkel.

Quality is also the main argument for tool measurement in the machine. “The gear skiving machine was developed with a view to the highest precision in all aspects”, emphasises Winkel. By performing tool measurement in a clamped state in the spindle, a higher process reliability and constant quality are achieved. External tool pre-settings are dispensed with and also the multiple administration of tool data becomes superfluous. This helps to avoid faults and eliminates inefficient procedures.

“Our larger LK 500 gear skiving machine was received very well by the market”, reports Thomas Breith. “We are extending the portfolio downwards with the new machine because many parts can also be machined on a smaller model. At the same time, we offer a package with additional options such as tool changing system, multi-machining functions, tool measurement and chamfering during the machining process, that doesn’t exist anywhere else and we can promise great interest in it. This small machine leaves almost nothing to be desired and is also of interest to customers who have so far not discovered the benefits of gear skiving for themselves.”

Liebherr-Verzahntechnik GmbH offers the new gear skiving machine generation variably with various table and head variations – in the trusted modular system. The new series is set to cover the maximum workpiece diameters of 80, 180 and 280 in future and will be extended gradually.

The process of gear skiving depends heavily on the tool. “Successful skiving depends on many details and we know our setting screws”, reports Arroum Haider, Team Leader of Tool Sales at the Ettlingen factory. “Instead of taking an empirical approach during configuration, we prefer our calculation models that are becoming more and more accurate.” A deep knowledge of the kinematics of skiving is required, particularly at the limits of operation. “This process is not forgiving of inaccuracies or even faults. On the contrary: It punishes incredibly, and severely.” Customers have discovered the procedure for themselves and welcome the design and manufacture of skiving tools from a single source.