Community Research and Development Information Service - CORDIS

Clean and cost-effective Technology for highly precise and reliable components; Clean-Tech

In the machining sector, improved process know-how and newly-developed and sophisticated cutting materials are available. This means, that operations with a geometrically-defined cutting edge can be employed for the machining of highly-tempered and hardened steels. Especially against the background of stricter environmental legislation, hard machining with a geometrically-defined cutting edge presents an ecologically and economically interesting alternative to grinding. Apart from a higher process flexibility offered by non-shape-bound tools the energy consumption of hard turning for the same cutting power is lower than for grinding operations. The specific advantages offered by hard turning include superior environmental compatibility due to easily recycled machining scrap.
The goal of the project Clean-Tech, funded within the scope of Brite-EuRam by the EU, was to optimize the hard turning process for machining bearing and gear components, designed to withstand rolling stresses. In general, the project consists of two parts.
In the first part of the project, the means of production as machine tool and clamping device as well as cutting material and tool making were improved. Furthermore, cutting strategies and methods for compensation of thermally induced form errors were developed to meet the high demands of accuracy to size and shape.
In the second phase of the project the fatigue life of hard turned bearing rings and gear wheels were the focus of the investigations. The results attained indicate, that changes of the microstructure in the subsurface zone of the parts, caused by tool wear, have no negative impact on the rolling strength of the workpieces. Moreover, there is no negative influence of the typical turning surface structure on the lubrication oil film between the rolling partners. Therefore, the life endurance of hard turned parts under rolling load was comparable to ground parts.

Reported by

DaimlerChrysler AG
89013 Ulm
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