With the accelerating emergence of electromobility and hybrid technology, the components machined by German firm Stöferle Automotive GmbH are becoming more and more complex, while dimensional accuracy and surface finish requirements are steadily increasing. As a result, the Laupheim-based company started looking for high-quality horizontal machining centres on which to produce mild steel hybrid car components in diameters ranging from 240 to 320 mm with fits between H6 and H7.

After evaluating numerous machines, Stöferle decided to invest in two second-generation HF 5500 five-axis machining centres from Heller. The machines (at the time installed ahead of their official launch) are now part of a production line operating three shifts, seven days a week, producing annually up to 350,000 components. In addition, Stöferle has bought two H 2000 four-axis models from Heller’s fourth generation H-series.

Joint managing director Erich Stöferle says: “We perform real endurance tests on Heller machines lasting years. We run them to the maximum, operating at a small percentage below the performance limits specified by the manufacturer. If the maximum weight of a milling cutter is specified as 16 kg, for example, we go up to 15.5 kg. We use a 160 mm diameter milling cutter at 15,000 rpm, which may not be a problem in single part manufacture, but we produce continuously over three shifts.”

He adds: “Another aspect of the tests is that the two HF 5500s are part of a manufacturing line comprising five or six machines. As annual production quantity has been set at 350,000 pieces, a high level of reliability is crucial. Our tests show that Heller’s aim of delivering machines capable of high productivity and precision day in day out has again been implemented in the new-generation HF-series.”
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