Quantification of the chip segmentation in metal machining: Application to machining the aeronautical aluminium alloy AA2024-T351 with cemented carbide tools WC-Co

The chip segmentation process has a significant effect on the cutting force fluctuation during machining which could affect tool vibration and tool wear. This paper deals with a quantitative analysis of the chip segmentation phenomenon in metal machining. The notion of intensity of the phenomenon has been introduced. Various parameters have been proposed for this purpose. These parameters are based on dimensional characteristics of the segmented chip and the strain distribution within the chip. A Finite Element based modelling has been developed to simulate the chip formation process in the case of machining aeronautical aluminium alloy AA2024-T351 with WC-Co based cutting tools. From the simulated chip morphologies, introduced chip segmentation parameters are assessed. The impact of the cutting speed and tool geometry on the chip segmentation intensity is clearly highlighted. The relevance of each parameter is discussed. Cutting force and contact length fluctuations with respect to the cutting speed variation when segmentation occurs are discussed and deeply analysed. A correlation between average cutting force reduction and segmentation intensity when the cutting speed increases as well as between chip formation process and cutting force oscillation has been established thanks to the introduced parameters, showing thus their usefulness.

► Chip morphology in metal machining is analysed.
► Various parameters are proposed to quantify the chip segmentation.
► The notion of intensity of the phenomenon has been introduced.
► Impact of the tool rake angle, cutting speed and feed on the segmentation is highlighted.
► A correlation between cutting force and segmentation parameters is established.