Major progress in external reaming of turned parts

The mass production of precise turned workpieces on multi-spindle automated lathes is subject to its own rules. In a hotly contested market, it is necessary to take every tiny opportunity for cost reduction, as Oberrindal-based WE Schultz, a customer of cutting tool specialist Mapal, can testify.

“As a true mass producer of comparably simple parts, we have to be able to compete in terms of price and quality with competitors from Asia here in Switzerland,” says Alexander Jaksch, deputy head of the turning shop.

A key lever in this ideology is the support of external partners such as cutting tool suppliers.
“Ultimately, the tools for a machine tool are as important as the tyres on a car,” states Jaksch.

The potential available here has been demonstrated to decision-makers at WE Schultz by a custom tool developed and subsequently optimised by Mapal.

“This project was about a part that seemed rather simple on the surface, a sleeve turned from solid with a diameter of almost 15 mm and a length of 10 mm,” says Emil Hugentobler, machine fitter at the Oberrindal plant. However, there are two crucial sticking points: a narrow diameter tolerance of 14.7 mm +12/-2 µm, and exceptionally low surface roughness of only Rz = 6 µm.

“In this situation we became aware of Mapal’s external reamers, particularly a custom tool for external reaming,” recalls Alexander Hildt,head of manufacturing. This external reamer is equipped with three guide pads and an adjustable indexable insert. The key advantage of the solution is that the outer dimensions of the workpiece are represented by the inner dimensions of the tool. Therefore, machine-related influencing factors such as increased play in the machine kinematics or the bearing of the spindle or chuckbecome practically irrelevant.
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