Absolute zero-backlash, maximum rigidity, best synchronism run properties and the large hollow shaft for the tool drive result in a highly torsionally stiff and thus, highly precise gearbox solution in the upper turret. In this way, it is now possible to position it steplessly with high precision and to machine workpieces interpolating in several axes. This was not possible with Hirth gearing and hydraulic clamping. Both components are completely eliminated in the new lathe - the solution with Galaxie^® allows the new INDEX ABC to machine a significantly wider range of components.

The innovative Galaxie^® high-performance gearbox ideally meets the requirements of precision machine builders like INDEX. The key characteristic – dynamic individual teeth instead of a rigid gear, full-surface contact during tooth meshing instead of a much smaller line contact, and the bearing design with segmented outer ring – make it factors better than cycloidal gearboxes and other gearbox technologies in all important technical parameters. The very high stiffness is constant even under alternating loads at zero cross without reducing the maximum torques. In addition, disadvantages such as mechanical abrasion and wear are almost negligible with Galaxie^® gearboxes due to the hydrodynamic lubrication – in contrast to involute and cycloidal gearboxes.

The main challenges were the repeatability of the tool positioning and the rigidity of the overall system. After trials with various Galaxie^® gearboxes, the use of the Galaxie^® GS 190 from the new accuracy line with optimized, integrated bearing concept finally led to the goal. The integrated bearing led to the best possible rest values, an important acceptance criterion. Here WITTENSTEIN benefits from the close cooperation with INDEX: it was possible to successfully adapt the rest measurements, as handled by the machine manufacturer, in the WITTENSTEIN test lab. As a result, WITTENSTEIN is now in a position to measure valid rest values of the gearboxes and also transfer them in the digital twin.

The new turret technology offers end customers improved cycle times and higher productivity. The gearbox enables infinitely variable and highly precise positioning of the upper turret - with ultimate improvements in the functionality of the CNC lathe. It is now possible to realize an interpolated Y-axis, which enables the ABC turret to perform off-center drilling and surface milling, as well as a center height adjustment of the cutting edges. This ensures more precise machining of small drillings. On the other hand, the chip pattern can be improved by the height correction.

Many new additional functions
Another advantage results from the now possible use of double tool holders. With the same turret size and number of slots, this increases the tool capacity from seven to 14 fixed or driven tools. This plus can be used for sister tools or a larger machining spectrum. Another station is permanently occupied by the synchronous spindle for backworking. All these additional functions significantly increase the range of parts that can be machined on the new INDEX ABC. Due to the gearbox ratio and the function-related high efficiency of the Galaxie^® gearbox, INDEX was able to increase the energy efficiency of the lathe. The use of the Galaxie^® gearbox opens the door to a completely hydraulics-free machine in the future.
 

With the Galaxie^® gearbox, another chapter has now been added. The high-performance gearbox enabled significant improvements such as the continuously variable turret, its Y-functionality, the height adjustment and the switch to multiple holders. As a result, this small, extremely fast CNC lathe meets current market trends towards smaller quantities and more complex geometries. The excellent price-performance ratio – to which the Galaxie^® technology makes a significant contribution – will also make the INDEX ABC usable in the future for parts that previously required a more expensive machine.