Applied Mechanics and Materials Vols. 813-814

Abstract: Surface integrity estimation is used to enhance the functional behavior of the machined component. Enhancement of surface integrity in a turning operation by one of the reliable factor is micro hardness. Micro hardness measurement used to measure the degree of work hardening, sub surface alteration, functional attribute and analyzes the difference between machining affected zone and bulk material. The objective of this present work is an effort to review some of the importance of micro hardness measurement done in turning operation. In conclusion a summary of the importance of micro hardness measurement is outlined.

Abstract: In the present work, an attempt has been made to analyze the factors influencing tool wear while milling Al/Al₂O₃/Gr particulate composites. Materials used for the present investigation are Al 6061-aluminium alloy reinforced with alumina (Al₂O₃) of size 45 microns and graphite (Gr) of an average size 60 microns, which are produced by stir casting route. Central composite design (CCD) was employed in developing the tool wear model in relation to machining parameters such as feed rate, cutting speed, depth of cut and weight fraction of Alumina. From the Analysis of variance (ANOVA), it is found that feed is the dominant parameter for tool wear whereas weight fraction of alumina shows minimal effect on tool wear compared to other parameters. From the Scanning Electron Microscope (SEM), the Al₂O₃ and Gr particles get adhered to the tool surface owing to the high pressure generated at the tool-workpiece interface.

Abstract: In metal cutting surface finish is a crucial output parameter in determining the quality of the product. Good surface finish not only assures quality, but also reduces manufacturing cost. Surface finish is an important parameter in terms of tolerances, it reduces assembly time and avoids the need for secondary operation, thus reduces operation time and leads to overall cost reduction. It is very important to select optimum parameters in metal operations. Traditionally, the experience of the operator plays a major role in the selection of optimum metal cutting conditions. However, attaining optimum values each time by even a skilled operator is difficult. The non-linear nature of the machining process has compelled engineers to search for more effective methods to attain optimization. The main aim of the present work is to build a model to solve real world optimization problems in manufacturing processes.The selection of optimal cutting parameters are speed, feed and depth of cut. are important for all machining process. Experiments have been designed using Taguchi technique, dry and single pass turning of AISI No. 1042 (EN-41B) steel with cermet insert tool performed on PSG A141 lathe. By using signal to noise (S/N) ratio and Analysis of variance (ANOVA) are performed to find the optimum level and percentage of contribution of each parameter. A mathematical model is developed using regression analysis for surface roughness and the model is validated.Moreover, the proposed algorithm, namely GA and PSO were utilized to optimize the output parameter R_a in terms of cutting speed, feed and depth of cut by using MATLAB.

Abstract: Hard turning is recent upcoming technology through which surface quality of machined components can be enhanced while comparing with the traditional grinding method. Since the absence of metal cutting fluids during this process, numerous harmful effects on shop floor operators and possible negative impacts on environment can be eliminated. Normally some of the vital machinability aspects such as surface integrity of machined parts has been influenced by magnitude of cutting temperature which evolved in metal cutting interface. Therefore in this experimental investigation, the influence of various process control parameters on tool-chip interface temperature was evaluated during hard turning of AISI D3 tool steel in dry condition. The machining trials were conducted as per the L₉ Taguchi DOE approach and subsequent experimental data were analysed with the use of Design-Expert® V7 statistical software. This experiment results revealed that feed rate is having predominant influence in determining the magnitude of cutting temperature followed by depth of cut and cutting speed whereas the influence of cutting tool nose radius is insignificant.

Abstract: In this present work, influence of cutting parameters on feed force is studied and optimized using Taguchi approach. AISI 1018 steel alloy is selected and machined using tungsten carbide tool. Eighty-One specimens were thus turned and cutting force was measured using lathe tool dynamometer. L₂₇ orthogonal array in Taguchi approach selected for optimization. From ANOVA, the results showed that out of the parameters selected feed rate has major effect on feed force. In addition, the combination of cutting speed and feed rate has major effect on feed force

Abstract: Ti–6Al–4V is widely used in the aerospace, automobile, and biomedical fields, but is a difficult to machine material. Electrical discharge machining (EDM) is regarded as one of the most effective approaches to machining Ti–6Al–4V alloy, since it is a noncontact electro-thermal machining method, and it is independent from the mechanical properties of the processed material. In electro discharge machining (EDM), dielectric plays an important role during machining operation. The machining characteristics are greatly influenced by the nature of dielectric used during EDM machining. In present paper silicon powder suspended kerosene as dielectric is used to explore the influence of these dielectrics on the performance criteria such as material removal rate (MRR), tool wear rate (TWR) and surface roughness (Ra) during machining of titanium alloy (Ti-6Al-4V). Peak current, pulse on time, pulse off time and concentration of powders added into dielectric fluid of EDM were chosen as process parameters to study the PMEDM performance in terms of MRR, TWR and Ra. The experiments were carried out in planning mode on a specially designed experimental set up developed in laboratory. Response surface methodology, employing a face-centered central composite design scheme has been used to plan and analyze the experiments.

Abstract: Proper selection of manufacturing conditions is one of the most important aspects in the die sinking Electrical Discharge Machining (EDM) process, as these conditions determine important characteristics such as Material Removal Rate and Surface Roughness.In this work, mathematical models have been developed for relating the Material Removal Rate (MRR) and Surface Roughness (Ra), to machining parameters like tool rotational speed (S), discharge current (C), pulse-on time (T) and flushing pressure (P). The experiment plan adopts the centered central composite design unblocked (CCD). The separable influence of individual machining parameters and the interaction between these parameters are also investigated by using analysis of variance (ANOVA). This study highlights that the proposed mathematical models have proven to fit and predict values of performance characteristics close to those readings recorded experimentally with a 95% confidence interval. Results show that are the two significant factors affecting MRR (discharge current and flushing pressure). The discharge current, flushing pressure and electrode rotation have statistical significance on the Ra.

Abstract: This paper is to evaluate the cutting force and surface roughness in turning of Glass fiber reinforced plastics (E-glass fiber) using coated carbide insert. The comparison of the results with uncoated carbide inserts. The carbide insert is coated by multilayer chemical vapour deposition process, the coating elements are TiN/Al2O3/TiCN. The experiment is carried out in the conventional lathe machine under dry condition by varying the three cutting parameter such as speed, feed and depth of cut. The cutting force is measured using a lathe tool dynamometer and surface roughness are measured by using surf tester.The result of the experiment shows the effect of machining parameter on cutting force and surface roughness. The results have confirmed that the coated carbide insert has better results than uncoated and tool life is increased.

Abstract: The carbon fibre reinforced composites are one such class of materials finding widespread application owing to their superior mechanical and chemical properties. The addition of fillers has further increased their application spectrum. The present paper focuses on the multiple performances analysis in machining characteristics of drilling carbon fibre reinforced Composites produced through compression moulding route. Experiments are conducted on a radial drilling machine using L₁₆orthogonal array. Drilling test is carried out using coated HSS drill of 6 and 10 mm diameter. The effect of drill diameter, wt % of fly ash,spindle speed and the feed rate has been investigated on the thrust force and delamination. After conducting experiment, mathematical models have been developed to fit the output responses using Response surface methodology and drilling parameters have been optimized using Desirability based approach. This methodology deals with the development of modelling equations for each response.The relative significance of the various parameters has been found using ANOVA.

Abstract: This paper presents an experimental study on the diametrical overcut and taper obtained during the machining of micro holes by electro-discharge machining (EDM). Many trials were taken by machining a 2.0 mm electrolytic copper rod to 0.50 mm under various conditions to analyse the effect of process parameters by wire electric discharge grinding process (WEDG). The optimum process parameters were determined by Taguchi’s method. Then a set of electrodes were produced with the determined optimum process parameters and were used to machine micro holes on Ti-6Al-4V alloy. The diameters of the holes were measured and the effects of various parameters were analysed for the variation in taper and diametrical overcut. The experimental results were analysed using analysis of variance approach.