Analytical modeling of the uncut chip geometry to predict cutting forces in orthogonal centric turn-milling operations

Abstract Turn-milling operations are machining processes that couple the rotational movement of the workpiece while conventional milling is carried out. This technology is an interesting alternative for machining large work diameters or massive eccentric parts as in the large format or aeronautic industries. Adding a rotational movement to the workpiece presents several advantages, but it is difficult to set the cutting parameters in the optimum operation window. The literature describes some approaches to predict the cutting forces based on the uncut chip geometry however, the effect of the cutting parameters is not well understood. This research presents a new approach to predict the instantaneous uncut chip geometry in orthogonal centric turn-milling operations based on the boundary lines of the uncut geometry. The accurate prediction of this geometry is fundamental to understanding the process mechanics, the cutting force and the machining temperature predictions. The presented models are able to predict the uncut chip geometry in large and small depth of cut regimens and were used to predict the cutting forces in several scenarios. The force predictions were validated with experimental data, demonstrating a good correlation with experimental data and overall error of around 15%. The findings presented in this research therefore could provide theoretical foundation for efficient machining strategies in the orthogonal centric turn-milling operations.