Lakhdar Boulanouar

Mathematical modeling for turning on AISI 420 stainless steel using surface response methodology

In this study, an attempt has been made to statistically model the relationship between cutting parameters (speed, feed rate and depth of cut), cutting force components (Fx, Fy and Fz) and workpiece absolute surface roughness (Ra). The machining case of a martensitic stainless steel (AISI 420) is considered in a common turning process by means of a chemical vapor deposition–coated carbide tool. A full-factorial design (43) is adopted in order to analyze obtained experimental results via both analysis of variance and response surface methodology techniques. The optimum cutting conditions are achieved using mutually response surface methodology and desirability function approaches while the model adequacy is checked from residual values. The results indicated that the depth of cut is the dominant factor affecting (Fx: 86%, Fy: 58% and Fz: 81%), whereas feed rate is found to be the utmost factor influencing surface roughness behavior (Ra: 81%). In addition, a good agreement between the predicted and measured cutting force components and surface roughness was observed. The results are also validated experimentally by determining errors (Fx: 6.51%, Fy: 4.36%, Fz: 3.59% and Ra: 5.12%). Finally, the ranges for optimal cutting conditions are projected for serial industrial production.

RMS-based optimisation of surface roughness when turning AISI 420 stainless steel

The aim of this investigation is to determine the correlation between the cutting conditions such as cutting speed, feed rate, and depth of cut; and surface roughness parameters (Ra, Rq, Rt, Rp, and R3z). The case of turning operation of martensitic stainless steel AISI 420 using CVD coated carbide tool is studied. Full factorial design (43) was adopted. Statistical analysis ANOVA and response surface methodology (RSM) was used to develop quadratic regression models and to determine optimum cutting conditions. It was found that the feed rate (f) is the highest factor influenced the surface roughness parameters when compared with speed and depth of cut. Moreover, a good agreement was observed between the predicted and the experimental surface roughness criteria. The use of lower cutting speed, lower feed rate, and lower depth of cut ensures minimum surface roughness variations.

Tool Life Evaluation of Cutting Materials in Turning of X20Cr13 Stainless Steel

The aim of this experimental study is to evaluate the tool life of each cutting material used in dry turning of X20Cr13 steel. The tests of straight turning were carried out using the following cutting materials: CVD coated carbide (GC2015) and PVD coated carbide (GC1015). Experimental results enable us to study the influence of machining time on flank wear VB of these cutting materials and to determine their lifespan for this cutting regime (depth of cut ap = 0.2 mm, feed rate f = 0.08 mm/rev and cutting speed Vc = 280 m/min). It arise that CVD coated carbide (insert GC2015) is more resistant to wear than cutting materials. Its tool life is 65 min and consequently, it is the most powerful.