Definition and determination of the minimum uncut chip thickness of microcutting

Uncut chip thickness is comparable to cutting edge radius in micromachining. If the uncut chip thickness is less than a critical value, there will be no chip formation. This critical value is termed as minimum uncut chip thickness (MUCT). Although minimum uncut chip thickness has been well defined in orthogonal cutting, it is often poorly understood in practical complex turning and milling processes. In this paper, a set of definitions of minimum uncut chip thickness for three-dimensional turning and milling processes are presented. This paper presents an analysis of the state-of-the-art research on minimum uncut chip thickness in precision micromachining. Numerical and experimental methods for determination of MUCT values and their effects on process mechanics and surface integrity in microcutting will be critically assessed in this paper. In addition, a detailed discussion on the characteristics of different methods to determine minimum uncut chip thickness and several unsolved problems are proposed for the future work.