Analysis of chip morphology and surface topography in modulation assisted machining

Abstract

Modulation assisted machining (MAM), superimposing a controlled tool modulation in the feed direction of conventional machining process, can change the chip morphology and the surface topography of machined components, and finally affect the functional performances of the components. This paper is dedicated to gaining a better understanding of the chip and surface formation processes in MAM. Geometrical analysis of the tool path in face turning configuration with MAM is performed, revealing how discrete chips are generated and presenting the effects of modulation conditions on chip morphology and undeformed chip thickness. Based on the chip formation analysis, an analytical model for prediction of surface topography is developed, which takes into account tool geometries, cutting conditions, modulation conditions and the effects of plastic side flow. By using the proposed model, the influences of modulation conditions on surface topographies are shown qualitatively by laser microscope, and are analyzed quantitatively through a set of three-dimensional (3D) surface amplitude parameters. Finally, a series of turning experiments is carried out to verify the prediction of surface topography. Errors between the measured results and the predicted results are within 20% for most conditions, and the underlying sources of these errors are analyzed. This paper can serve as a theoretical basis for the further controlling of chip morphology and surface topography.