Analytical Modelling and Experimental Investigation of Rake Contact and Friction Behaviour in Metal Cutting (Turning) for Aluminium

The friction due to the contact between the work piece and the tool is one of the key subjects in machining research. It is well known that cutting involves three deformation zones. The primary shear zone, i.e. the shear plane, is responsible for the chip formation whereas in the secondary shear zone on the rake face the work piece and tool are in a complex state of contact. The third region, on the other hand is responsible for the Ploughing and flank contact. Although there are numerous models proposed involving, analytical with thin and thick shear zone approaches, semi analytical and Numerical methods. Two important inputs for these models are the material model parameters and the friction coefficient between the tool and the work piece material. By considering literature surveys, the friction behavior in metal cutting operations is analyzed using a thermo mechanical cutting process model that represents the contact on the rake face by sticking and sliding regions. The relationship between the sliding and the overall, i.e. apparent, friction coefficients are analyzed quantitatively. The sliding friction coefficient is identified for different work piece–tool couples using cutting tests. In addition, the effect of the total, sticking and sliding contact lengths on the cutting mechanics is investigated. The effects of cutting conditions on the friction coefficients and contact lengths are analysed. The cutting tool materials are Uncoated Carbide and Coated Carbide tools, and the Work piece material is aluminium which is being machined at cutting speed ranging from 600 m/min to 1200 m/min with a depth of cut 2mm. By considering the experimental results for the analysis of Rake Angle and friction behavior in metal cutting (Turning), the parameters are optimized by using the Taguchi method. For this an appropriate orthogonal array has been selected as per number of factors and their levels to perform minimum experimentations.