Experimental and numerical investigation of the uncut chip thickness reduction in Ti6Al4V orthogonal cutting

The downsizing of traditional cutting ("macro-cutting") to micro-cutting introduces changes in the cutting process. The uncut chip thickness decreases and the cutting edge radius of the tool cannot be neglected anymore. The minimum chip thickness phenomenon takes importance, as well as ploughing. The size effect appears and the influence of the microstructure grows. Determining the value of the uncut chip thickness is a major concern to produce high quality parts. This paper focuses on the determination of that value experimentally with a setup providing strictly orthogonal cutting configuration and a one-time machining of the surface, as well as numerically with a finite element model by only changing the value of the uncut chip thickness. Specificities of micro-cutting are highlighted experimentally and numerically. The cutting refusal is observed in both cases and the minimum chip thickness is estimated (at minimum 25 % of the cutting edge radius) with a good correlation.