Performance prediction models for turning with rounded corner plane faced lathe tools. I. Theoretical development

In this paper the need for reliable quantitative machining performance information for efficient and effective use of machining operations is discussed, as are the recent developments of predictive models for forces and power in practical machining operations based on the 'unified mechanics of cutting approach'. This investigation is aimed:at extending this mechanics of cutting approach to turning with rounded corner plane faced lathe tools. Three predictive models for the forces, power and chip flow angle based on the 'unified mechanics of cutting approach' have been developed while the surface roughness models have been based on the feed marks generated on the machined surface allowing for the precise tool corner profile. The first force model is based on the modified mechanics of:cutting analyses for single edge tools while the two alternative models are based on the generalised mechanics of cutting analyses for single edge and multi-edge form tools for the turning cut as a whole. The predictive force models incorporate the effects of the major tool geometrical variables including the corner radius, the cutting conditions as well as the effect of TiN coating. This first paper will outline the development of the models while the proposed models will be numerically tested and experimentally verified qualitatively and quantitatively in the subsequent parts of this investigation.