The machine concept, with its rigid, thermo-symmetrically designed main assemblies, the digital AC feed drives, and elaborate profile rail guides and ballscrews in all linear axes, provides a solid basis for the necessary reliable processes. In addition, various control and monitoring devices are integrated. In the standard version, this includes a vibration sensor on the spindle, via which the machining process can be monitored and optimized. Holger Quintus, Regional Sales Manager of the Starrag Group, explains: "The sensor includes an analysis software, which recognizes any tools with excessive imbalance as well as wear on the spindle bearings. This makes it possible to plan servicing in advance and prevent sudden failures. Because it also shows vibrations during machining, the process can be optimized with regard to higher quality and longer spindle life."

For Klaus Tollerian there are further important details: "The working space is designed so that the swarf falls freely into the centrally arranged chip conveyor. This prevents swarf accumulations forming in the working space, which would in turn jeopardize the process reliability." He also approved of the use of solid sheets instead of telescopic covers to optimally protect the functional elements from swarf and coolant. This permits higher accelerations and rapid traverse rates, since the sheets do not have to be carried along with the linear axes.

While other providers' machines were unable to combine all the benefits of the Heckert HEC 800 Athletic HV MT in one system (or only do so with costly extras), the total package with its compatibility to existing equipment, high performance, and cost advantage was crucial in making the decision, Klaus Tollerian argues. "In addition, with the machining area being about a third larger than on the CWK 630, we are now able to produce a far wider spectrum of parts. This suffices even for large impellers - our pump sizes now extend up to a nominal diameter of 400 - which push our cycle lathes to their limits."

The machine configuration selected with a horizontal / vertical milling head and an NC rotary table played a crucial role in the success. The HV-head has two working positions, horizontal and vertical, in which it can pivot even when the spindle is running, significantly reducing unproductive downtimes. If the respective end position is reached, the head is locked in a Hirth coupling. The positive fit thereby produced contributing to a high stability, which is especially important in turning. The additional decoupling of the drivetrain in turning mode directs any shocks in case of interrupted cuts to the housing, thus sustainably preventing damage to the spindle bearings. In addition, the tool-holder HSK-T100 is used for turning, which enables precise radial positioning. This ensures the familiar Heckert high accuracy also in turning.

The high-precision NC rotary table, which can handle up to two tons, fulfils another prerequisite for the internal machining of the large impellers with its output of 57 kW (at 100% duty), a speed of up to 500 rpm, and maximum torque of 2520 Nm. Holger Quintus also points out the automatic imbalance detection, which comes as standard in the HEC 800 Athletic: "An integrated program measures the imbalance and indicates the position and size of the necessary counterweights so the operator can quickly eliminate it."

Thanks to the overall kinematics of the Heckert HEC 800 Athletic HV MT, the Herborner Pumpentechnik machining team can now process many parts in a single clamping, where previously several were required. "We have cut the processing time by up to a third", says Klaus Tollerian enthusiastically. He is equally pleased to note that the existing programs of both machines in the Liebherr system can be used without modification, and all the previous components can also easily be processed on the HEC 800 Athletic HV MT.

In order to create the necessary conditions, they had a modified 630x630mm machine table installed instead of the usual 800 table. Another feature is the automatic loading hatch in the machine roof, through which outsized workpieces can be simply loaded. And the production manager mentions one more point in its favor: The tool magazine with 180 pockets, which can automatically handle tools up to a diameter of 340 mm and a length of up to 800 mm. "This capacity is sufficient for every task despite the enhanced range of applications. There is even enough room for backup tools. "In spite of its large capacity, the tool magazine requires a much smaller footprint than other solutions on the market, which is an important argument in confined conditions.