Abstract: A multi-objective optimization problem has been solved in order to search an optimal process environment consisting of optimal parametric combination to achieve desired quality indicators related to bead geometry of submerged arc weld of mild steel. The selected quality indicators were bead height, penetration depth, bead width and percentage dilution. Among aforesaid four quality indicators; penetration depth and percentage dilution are assumed to be the most important compared to the other quality features. However, penetration depth and percentage dilution may or may not be of equal importance; but they are expected to be highly correlated. Different requirements for different quality indicators highly depend on the area of application and the functional requirements of the welded joint. For example, in case of welding, wider bead (bead width) is not advisable to avoid excess weld metal consumption; whereas, in case of weld cladding, large bead width is generally recommended. In the present communication, the relative importance of different quality indicators of bead geometry has been estimated and their influence on the process environment resulting the optimal bead geometry has been investigated. Taguchi method followed by grey relational analysis has been adapted to evaluate the optimal process condition achieving multiple requirements of the desired weld quality. Sensitivity analysis has been carried out to check the casesensitiveness of relative importance (priority weights) of different bead geometry parameters imposing predominant effect on the optimal parametric combination.

Abstract: Weld cladding is a process of depositing a thick layer of a corrosion resistance material over carbon steel plate to improve corrosion resistance properties. The main problem faced in cladding is the selection of optimum combination of process parameters for achieving the required weld deposit area. This paper highlights the effects of various input process parameters on weld deposit area in stainless steel cladding of low carbon structural steel plates using gas metal arc welding. The experiments were conducted based on central composite rotatable design with full replications technique and mathematical model was developed using multiple regression method. The developed mathematical model has been checked for its adequacy and significance. This mathematical model is very useful for predicting the weld deposit area.

Abstract: In recent years, hardfacing processes have developed rapidly and are now applied in numerous industries. The biggest difference between welding a joint and hardfacing is dilution. The composition and properties of hardfacing are strongly influenced by the dilution obtained. Control of dilution is very important in hardfacing, where low dilution is typically desirable. This is obtained by proper selection of process parameters such as welding current, open circuit voltage, travel speed, nozzle-to-work distance, shielding gas, gas flow rate, and welding position. This paper presents about an experimental study carried out to analyze the effect of various parameters of plasma transferred arc welding in tungsten carbide hardfacing of 316L stainless steel plates on bead geometry. The experiments were conducted based on five-factor five level central composite rotatable design. Mathematical model were developed to predict bead width, height of reinforcement, depth of penetration and percentage of dilution. The developed mathematical models have been checked for their adequacy and significance. These mathematical models are very useful for optimizing the process parameters. The effects of process parameters on bead geometry have been presented in graphical form, which helps in selecting welding process parameters to achieve the desired bead geometry quickly.

Abstract: A prominent problem in manufacturing automation is the accurate and reliable presentation of small parts, in a single specified configuration called desired orientation, to a work cell. This is often referred to as the \"part feeding\" problem. Currently, handling of sector asymmetric shaped parts is done either manually or by using expensive robot and vision systems, which cumulatively increase the production cost. In the present work the brake liner, a typical sector shaped asymmetric component is considered to develop a part feeding system. The proposed low cost part feeder system uses sensor less mechanical devices or barriers such as slot, wiper blade and balcony and edge riser, to eliminate or reorient the arbitrary orientation into a desired orientation which facilitates stacking. A complete set of such mechanical devices is called trap. It was observed that there are eight possible orientations for brake liners. Among these, highest probabilities occurring orientations (when falling from hopper) were identified. Four different configurations of trap were designed and fabricated to get the desired orientation at the outlet of the feeder. Markov model was developed for each trap to find its efficiency. With these traps, the initial part feeding efficiency of 38% was improved to 64%. This percentage can be further improved by re-passing the eliminated parts from the trap. Stacking module was developed for stacking the parts with desired orientation. A theoretical model called constant acceleration model was developed to estimate the part feeding velocity which should match with the actual production rate of the industry. This model was validated by conducting experiments. E-mail: udhaya_mech@yahoo.com

Abstract: Robot parallel manipulators have high stiffness, rigidity and accuracy, which cannot be provided by conventional serial robot manipulators. Workspace is one of the useful measures for the evaluation of a robot. Simulation and workspace analysis is focused, two 3 DOF parallel manipulator (PM) units are taken as example. The PMs are modeled and simulated using 'ADAMS'. The concept involved is based on the transformation of motion from a screw joint to a spherical joint through a connecting link. This paper work has been planned to model the Parallel Manipulators (PM) using screw joints for very accurate positioning. Workspace analysis has been done for the determination of work volume of the PMs. The position of the spherical joints connected to the moving platform and the circumferential points of the moving platform are considered for finding the workspace. After the simulation, the position of the joints of the moving platform is noted with respect to simulation time and these points are given as input to the 'MATLAB' for getting the work envelope. Then 'AUTOCAD' is used for determining the work volume. The obtained values are compared with analytical approach by using PappusGuldinus Theorem. The analysis has been dealt by considering the geometrical parameters like, link length and radius of the moving platform. From the results it is found that the radius of moving platform and the link length influences the work envelope.

Abstract: In this paper, flank wear in drilling has been predicted using soft computing techniques. A wide range of experiments have been conducted varying the spindle speed, drill diameter, and feed-rate, using mild steel as the work-piece and the high speed steel (HSS) as the drill material. Back propagation neural network and a hybrid neural ant colony optimized neural network are used in this paper for the flank wear prediction. The result shows that the neuro ant colony optimized hybrid model gives better and faster prediction than the back propagation neural model.

Abstract: The present study highlights a multi-objective optimization problem by applying Weighted Principal Component Analysis (WPCA) coupled with Taguchi method through a case study in cylindrical grinding of Mild steel AISI 1040. The study aimed at evaluating the best process environment which could simultaneously satisfy multiple requirements of surface quality. In view of the fact, that traditional Taguchi method cannot solve a multi-objective optimization problem; to overcome this limitation, WPCA has been coupled with Taguchi method. Furthermore to follow the basic assumption of Taguchi method i.e. quality attributes should be uncorrelated or independent; which is not always satisfied in practical situation. To overcome this shortcoming the study applied Weighted Principal Component analysis (WPCA) to eliminate response correlation and to evaluate independent or uncorrelated quality indices called Principal Components which were aggregated to compute overall quality index denoted as Multi-Response Performance Index (MPI). A combined Quality Loss (CQL) was then estimated which was optimized (minimized) finally. The study combined WPCA and Taguchi method for predicting optimal setting. Optimal result was verified through confirmatory test. This indicates application feasibility of the aforesaid methodology proposed for multiresponse optimization and off-line control of correlated multiple surface quality characteristics in cylindrical grinding.

Abstract: The generation of intensive heat during grinding not only accelerates wheel wear but also impairs the machined surface by inducing tensile residual stresses, micro-cracks and thermal damage. The application of conventional cutting fluids does not help to remove these problems effectively, particularly under heavy cutting conditions. Moreover, conventional cooling methods produce environmental pollution, and health hazards. One of the possible and potential techniques to overcome such problems is the application of cryogenic cooling where liquid nitrogen is used as a coolant The present work investigates the effects of cryogenic cooling using liquid nitrogen on chip feature, surface hardness, roughness, and wheel wear in grinding mild steel and stainless steel. The reduction of temperature at the cutting zone is found to produce favorable chip formation and relatively more surface roughness, but improves the wheel life and reduces surface burning. Furthermore, the technique is environmentally friendly.

Abstract: The effect of cutting speed, feed rate and depth of cut on cutting force, surface roughness and tool wear are investigated in this study. For this purpose 316SS is machined with dry cutting conditions by all Gear lathe with commercial grade of tungsten carbide (DCMT 11T304 TN200) inserts having a nose radius of 0.6mm. Metal removing process is carried out for three different cutting speeds, feed rates and depth of cuts. The effect of cutting speeds, feed rates, and depth of cut on surface roughness, cutting forces and tool wear of the tungsten carbide (WC) insets was experimented and analyzed by using analysis of variance (ANOVA) technique. Optimal cutting parameters for each performance measure were obtained; also the relationship between the parameters and the performance measures were determined using multiple linear regressions.

Abstract: Diffusion bonding is a solid state welding technique that has been developed in the past few decades and permits the production of high quality joints with little or no need for post-weld machining. Although diffusion bonding of material such as copper, titanium and various steels can be relatively straight forward, aluminum alloys are generally difficult to join because of their stable and tenacious oxide films, which inhibit the formation of metal to metal contact and interfacial diffusion. Acetone is used to remove the surface oxide films. Oxide films will inevitably form on the surfaces of aluminum alloys when they are exposed to the atmosphere. In this paper we presented an experimental work was carried out by using various parameters of diffusion bonding (Al 6061 / SiCp) like as temperature, pressure and time in hydraulic press. The optimization of bounding operation based on the Taguchi method with multiple performance characteristics is performed the orthogonal array, multi-response, signal-to-noise ratio and analysis of variance are employed to study the performance characteristics in bonding operations. The optimization helps in selecting the suitable values of variables, are such as temperature, pressure, and time.

Abstract: This investigation was primarily aimed to examine the probable causes of sudden failure of one of the rear shield chock for longwall face in a colliery. The rear shield was made of micro alloyed steel and a through thickness fracture was observed in the 63 mm rear shield plate. Preliminary visual examination, nondestructive evaluation including dye-penetrant and magnetic particle testing, evaluation of mechanical properties, detailed optical and scanning electron microscopic analysis were the necessary supplements to this investigation. Finally, a study on residual stress measurement and effect of pulsating load on structural integrity was carried out. The outcome of the investigation infers that improper welding caused adverse metallurgical and stress conditions leading to sudden failure of the rear shield plate.

Abstract: A 3-d planar Solid Oxide Fuel Cell (SOFC) model has been developed to simulate the effect of 'change in constitutive materials of anode' on the overall performance of the fuel cell. The model couples electrochemical kinetics with multi-dimensional gas dynamics and multi-component transport of species. The present model is made in commercially-available computational fluid dynamics (CFD) software, Fluent and able to predict conventional I-V curves (polarization curve) in addition to details of internal processes, such as flow field distribution, species concentrations, potential and current distributions throughout the cell. The simulation sets are performed with and without the interfacial resistance effect in case study_l. Optimized cell without interfacial resistance shows increase in oxygen and hydrogen utilization respectively from 23.28% to 75.8% and 39.69% to 98.83%. On the other hand, the series ran with interfacial resistance shows decrease in the air and fuel utilization with the increase in interfacial resistance. Case study_2 dealt with the effect of the materials on the overall performance of the cell. Modeling in this part is made by taking the ionic part as the limiting condition for the electrical conductivity in the matrix. The MAT (i.e. the novel anode) showed better overall efficiency in the cell than that of Ni-YSZ anode under similar conditions.

Abstract: Micro WEDM is a versatile technique for machining electrically conductive materials to make components for micro system technologies. This paper presents an attempt to develop an appropriate machining strategy for machining of titanium alloy using zinc coated copper wire of 70 microns diameter. Voltage, capacitance, feed, wire tension and wire speed were taken as input parameters. Surface finish is considered as the measure of process performance. Design of experiments was done using Taguchi LI 6 orthogonal array. Optimization was done using taguchi signal to noise ratio technique. The results obtained from the experiments were analyzed using analysis of variance to find the significance of each input factor on the surface quality. Feed Forward Back Propagation Artificial Neural Network model was developed and trained.

Abstract: Hydro mechanical deep drawing combines the features of conventional deep drawing and hydro forming. In this process, the punch deforms the blank to its final shape by moving against a controlled pressurized fluid. Hydro mechanical deep drawing offers several advantages over conventional deep drawing like higher drawability, uniform strain distribution, better surface finish and improved dimensional accuracy. The objective of this work was to experimentally study the hydro mechanical deep drawing process as a means of shaping Inconel 625, a nickel-based super alloy sheets. In hydro mechanical deep drawing one side surface of the sheet metal is supported with pressurized fluid to assist forming. The effect of applying a varying pressure to the surface of Inconel 625 sheet was evaluated. In hydro mechanical deep drawing process it is necessary that an optimum fluid pressure-punch travel path is to be maintained in order to achieve maximum forming depth. The optimum fluid pressure-punch travel path is to be traced in the working zone between the rupture and wrinkle zones. A user interface to control fluid pressure-punch travel path was developed using commercial software LabVIEW. The punch travel was coupled with the liner variable transducer which in turn sends signal to the LabVIEW with the help of data acquisition card. According to the signal the fluid pressure was controlled between the wrinkle and rupture zones. Experiments were conducted by varying the process parameters such as blank thickness and blank diameter. The results obtained from the experimental work are useful to get optimum combination of parameters to obtain maximum forming depth.

Abstract: Acoustic Emission is one of the most efficient methods to monitor the grinding process which is the crux of the manufacturing process. This AE monitoring online helps improve the grinding process. This paper proposes a new approach to identify the optimum operating working conditions of the grinding wheel to obtain the best surface finish and also to determine when the grinding wheel has to undergo wheel dressing, which will help to avoid grinding being carried out by the loaded wheel. This avoids damage and a poor surface finish, thereby saving the time and money spent on a single unit. The experiments were carried out by varying different parameters such as cross feed, depth of cut, and grinding speed, while the optimum grinding conditions for obtaining the best surface finish for Inconel 625 and Monel 400 were determined using the Fuzzy C-means clustering approach as well as automating the time when the grinding wheel has to undergo the wheel dressing. An Acoustic Emission online monitoring system is proposed which monitors the entire grinding process based on the AE data acquired on line which is the input for Fuzzy C-means clustering approach. It is autonomous in nature thereby reducing human intervention and human error.

Abstract: This paper presents an integration of feature recognition and process planning using Virtual Reality Modeling Language (VRML) and Petri nets. The geometric information of the part is translated into manufacturing information through VRML. A Java program in Netbeans environment is used to recognize the features, where geometric information of the part is extracted from VRML file. By using this data, a PNML file format output is obtained which is given as input to the Petri net generation software P3. The resulting output file gives the number of machinable features present in the part in the form of places and transitions. The modeling and cost estimation technique for process plan is based on a new Petri net model. The Process Planning net (PP-net) represents manufacturing knowledge in the form of precedence constraints and incorporates the cost of machining operations in each operation transition. Using this model, the process plan for the example part is developed by considering the manufacturing costs (caused by the machine, setup and tool changing) and the pure operation cost. The method proceeds in the cost calculation by attaching a specific data structure to each PP-net transition which describes the associated machine, setup and the tool for the operation modeled by the transition. After the model is created, it is analyzed for minimum cost and minimum time of processing the part.