Modelling of single grit micro-cutting of Ti-6Al-4V and In-718 with experimental validation

Abstract

In the present study, a single-grit micro-cutting simulation model was developed for Ti-6Al-4V and In-718 work materials when ground with a single cBN grit on the grinding wheel hub. User-defined subroutines were implemented to integrate the phenomenon of dynamic recrystallization and strain gradient effect. Numerical simulations were performed using a pyramidal shaped and CT-scanned actual grit with varying grit orientations. The effect of process parameters and grit orientation on the mechanism of material removal, pile-up ratio, micro-cutting forces, specific micro-cutting energy, and chip morphology was analyzed for Ti-6Al-4V and In-718. The simulated results using CT-scanned grit agreed with experimental values. The average deviation of the pile-up ratio with varying micro-cutting velocity at maximum uncut chip thickness of 10 µm using CT-scanned grit for Ti-6Al-4V was 9.2 %, and for In-718 was 8.1 %. The comparison of the average effect of grit orientation on the peak magnitude of normal and tangential micro-cutting force obtained by numerical simulation at maximum uncut chip thickness of 10 µm and cutting velocity of 30 m/s using CT-scanned grit matched precisely with experimental values with an error of 3.2 % and 2.7 % for Ti-6Al-4V and 2.2 % and 3.8 % for In-718. The error of the simulated results for specific micro-cutting energy was 13.8 % for Ti-6Al-4V and 11.8 % for In-718. The developed modelling algorithm provides a valuable understanding for selecting effective grinding parameters for different alloys, provided the material constitutive parameters are given.