Machining Parameters Optimization of Developed Yttria Stabilized Zirconia Toughened Alumina Ceramic Inserts While Machining AISI 4340 Steel

An attempt has been made to investigate the machinability of zirconia toughened alumina (ZTA) inserts while turning AISI 4340 steel. The insert was prepared by powder metallurgy process route and the machining experiments were performed based on Response Surface Methodology (RSM) design called Central Composite Design (CCD). The mathematical model of flank wear, cutting force and surface roughness have been developed using second order regression analysis. The adequacy of model has been carried out based on Analysis of variance (ANOVA) techniques. It can be concluded that cutting speed and feed rate are the two most influential factor for flank wear and cutting force prediction. For surface roughness determination, the cutting speed & depth of cut both have significant contribution. Key parameters effect on each response has also been presented in graphical contours for choosing the operating parameter preciously. 83% desirability level has been achieved using this optimized condition. Keywords—Analysis of variance (ANOVA), Central Composite Design (CCD), Response Surface Methodology (RSM), Zirconia Toughened Alumina (ZTA). HE last two decades, manufacturing professionals and researchers have uncovered the significance and importance of the quantitative prediction of efficient machining parameters of non-conventional cutting tools. The economical performance of metal cutting operation, a predictive model has to be ascertained for any work tool combination between the input independent parameters and output variables. As the newer materials are gradually replacing the conventional cutting tool materials making machining operation smoother, it is essentially required to optimize the input parameters, such as feed rate, cutting speed, depth of cut, tool angle for improvement of output variables, such as tool life, cutting forces, surface roughness etc. Cutting Nilrudra Mandal, B Mondal are with the Centre for Advanced Materials Processing, CSIR-Central Mechanical Engineering Research Institute, Durgapur, 713209, India. (Corresponding author: phone: 91-343-6510255; fax: 91-343-2546745; e-mail: [email protected] B Doloi is an Associate Professor, Dept of Production Engineering, Jadavpur University, Kolkata, 700032, India force is one of these output variables that may have either direct or indirect effect on the performance of other variables such as tool wear rate, surface finish and machining cost. Before cutting operation, the operating conditions like power requirement, working materials, feed and depth of cut are to be selected. The cutting parameter influence on cutting forces and surface roughness in finish hard turning of MDN 250 steel using coated ceramic tool was studied [1]. Effect of three different forces i.e. feed force; thrust force and cutting force were investigated using RSM. The same approach was also used for investigating the effect of process parameters on force ratio and the relationship between force ratio and flank wear was also established while turning EN 24 using HSS tool [2]. RSM was also used by Noordin et al. [3] for modeling the cutting force and surface roughness when turning AISI 1045 steel with coated carbide tool. The contribution of feed parameter was found to be maximum for surface roughness and cutting force modeling. Some researchers also attempted [4] –[5] to analyze the effects of depth of cut and machining time on machinability aspects like machining force, power, surface roughness, cutting force and tool wear during machining of high chromium steel with ceramic inserts. Davim and Figueira [6] had evaluated the performance of conventional & wiper ceramic tools in terms of cutting forces, surface roughness and tool wear for hard turning AISI D2 steel. It was reported that, while machining, the wiper ceramic performed better in respect to surface roughness and tool wear whereas the conventional ceramic exhibited less machining force and power. An assay was made to establish a relation between tangential cutting force and flank wear while turning tool steel with different types of inserts like HSS, uncoated WC, coated TiAlN etc [7]. The same relationship between tool flank wear area and component of forces in single point turning had also been established by Sikdar and Chen [8]. Machining force evaluation was also done [9] when turning hardened AISI 4340 steel using coated carbide inserts. Investigators also reported that cutting force decreased slightly with the increase in work hardness. An experimental investigation about the effect of cutting forces on grey cast iron was carried out using silicon nitride based ceramic tool [10]. This tool also exhibited good performance at high cutting speed machining in respect to tool wear, temperature, surface finish of the work-piece. Cutting force prediction model was Nilrudra Mandal, B Doloi, B Mondal Machining Parameters Optimization of Alumina Ceramic Inserts While Machining AISI 4340 Steel T