EXPERIMENTAL STUDY ON WEAR OF MIXED CERAMIC TOOL AND CORRELATION ANALYSIS BETWEEN SURFACE ROUGHNESS AND CUTTING TOOL RADIAL VIBRATIONS DURING HARD TURNING OF AISI 52100 STEEL

Wear investigation has been conducted on mixed ceramic cutting tool (70% Al2O3 + 30% TiC) when machining hardened AISI 52100 steel (66 HRC). Experimental planning method has been used to assess the relationship between radial cutting vibrations and surface roughness as a function of the machining conditions. First, wear results show that when the cutting speed is increased 3.78 times, tool life drops of 8.75 times. When increasing the feed rate by a factor of 2.75 tool life decreases by a factor of 1.4. Then, the effect of cutting parameters (speed, feed and depth) on one hand surface roughness (R alpha) and in the other hand radial tool vibrations has been determined using the multiple regression models with a coefficient of determination R-2 equal to respectively 95.5% and 89.3%. With regards to surface roughness, ANOVA analyses reveal that feed rate contributes of about 84% in the surface roughness. Meanwhile, looking at the vibration phenomena, the cutting speed has the most significant effect on the values of radial tool vibrations comparing to depth and feed rate effect. Finally the correlation between surface roughness and tool radial vibrations has been analyzed through the linear and nonlinear correlation coefficients. The values of Pearson and Spearman coefficient were respectively low 0.465 and 0.554 showing that above 1000 rpm of cutting speed, the machining system is no more stable generating a great effect of cutting vibrations.