http://localhost:8081/jspui/handle/123456789/121 2025-06-30T15:35:35Z http://localhost:8081/jspui/handle/123456789/17396 Title: PRIMARY AND SECONDARY PROCESSING OF METAL MATRIX COMPOSITES Authors: Singh, Sarbjit Abstract: The growing steel prices have significantly affected the manufacturing expenditure in automobile and house hold industries, thus making a strong case for substituting steels with materials having light weight and high strength to weight ratio. The aluminium and its alloys have outstanding properties like light weight, wear and corrosion resistance that make them suitable in numerous industrial applications. These materials being comprehensively used in automobile and aerospace industries have nearly touched their limit of practicality. Therefore, substantial investigations in the area of materials science and engineering have been focused towards the growth of newfangled materials. Among the newfangled materials, Metal Matrix Composites (MMCs) has numerous industrial as well as defense related applications. The superior properties of MMCs over the monolithic materials such as, high specific strength, improved wear and corrosion resistance, are source of attraction for industries and researchers. Solid, liquid and vapor state processing methods are used for the production of MMCs. Stir casting route has been prominently used as a production process technique but it faces technical challenges as well. The main research challenge is to get a uniform distribution of the reinforcement in the matrix with minimum porosity. The poor wettability of the abrasive reinforcement with the molten matrix is the major problem in the stir casting route. It causes weak interfacial bonding and deterioration of the mechanical properties. The presence of hard abrasive particles as reinforcement limits the machinability of MMCs and consequently they have limited applications. Both conventional and - unconventional machining processes have been used for machining of MMCs. The factors that affect the machinability of MMCs are work material, percentage of reinforcement, tool iv material, tool profile and cutting parameters like cutting speed and feed rate. These parameters also affect the drilling behavior of MMCs in terms of thrust force, torque, chip formation, surface roughness, and associated problems like built-up edge (BUE) formation, tool wear, burr formation, out of roundness etc. Unconventional machining processes like electric discharge machining (EDM), powder mixed-EDM, wire-EDM, abrasive water jet machining have also been employed for machining of MMCs. However, their material removal rate is significantly less as compared to the conventional machining processes. Therefore, there is an imminent need to explore the processing techniques for 4. MMCs in order to produce net-shape or near-net-shape products to avoid the problems associated with the machining of MMCs. Selected machining processes; particularly drilling is still required for joining and assembly of MMC products. Therefore, there is a necessity to investigate the process of processing and machining of MMCs in order to produce industrial components of good quality at reasonable price. The present experimental investigation is divided into two main sections, primary processing and secondary processing of metal matrix composites. The primary processing comprises of development of the 'stir-squeeze-quench' setup for the production of nearnet- shape of MMC components. The distribution of the SiC particles in the metallic matrix affects the variations in physical, mechanical and tribological properties of the developed metal matrix composites. Uniform distribution of the SiC particles along with appropriate wetting of SiC particles with matrix causes enhanced physical and mechanical properties such as, high density or minimum porosity, increased tensile strength, hardness and wear resistance. The secondary processing deals with the machining aspects of the developed materials. Drilling behavior of metal matrix composites has been experimentally V investigated using the solid carbide drill point geometries of different profiles (twist, parabolic and Jo-drill) as well as modified drill point geometry. The drilling performance has been evaluated in terms of cutting forces, surface finish, tool wear, burr formation and chip formation during the hole making of MMCs at different cutting conditions. Modifications in the drill point geometry and drilling process have been attempted to improve the quality characteristics. Exhaustive experimentation has been carried out to explore the drilling behavior of the developed MMCs. The drilling experimentation has been divided into three Phases. IPhase I explore the drilling behavior of inter drill point geometry (cutting profile of geometry) along with machine tool parameters. It has been found that the drill point geometry plays a significant role for the output quality characteristics such as; thrust force, torque, surface roughness, burr formation and tool wear. Modified drill point geometry has been designed and developed for burr free drilling in MMCs in the Phase 11 of experimentation. The intra drill point geometry investigation of the modified drill point geometry has been carried out using response surface methodology (RSM). An experimental setup named Abrasive Assisted Drilling (AAD) has been designed and developed in Phase Ill of experimentation for improvement in surface roughness. A significant improvement in the surface roughness of the drilled hole wall surface has been observed using the AAD process. Some of the prominent objectives of the present experimental investigation have been under: To develop a setup for near-net-shape manufacturing of MMCs products by stir casting having modified features of squeezing action, bottom pouring and water/oil quenching. vi • To characterize the developed Al-SiC composite by optical micrographs, hardness and mechanical strength tests to ascertain the feasibility and reproducibility of the material. Experimental investigation using design of experiments for understanding the wear behavior of the fabricated MMCs to determine the wear rate. These results can be used to establish the wear characteristics of the developed MMCs. Experimental investigation using design of experiments for understanding the drilling behavior of Al-SiC using different drill point geometries. Quantification of quality characteristics like Thrust force (TF) Torque (TQ) Surface Roughness (SR) Tool wear and Burr formation. • To develop and validate predictive models for the various output responses with help of statistical methods. • To optimize drilling process parameters for drilling of Al-SiC composites. The intra-drill point geometry investigation will be carried out for the optimized drill point geometry. • To conceptualize, design, development and optimize a modified drilling process for enhancing the quality characteristics (surface roughness) during drilling on MMCs. 2013-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/17329 Title: INVESTIGATIONS ON USE OF MICROWAVE ENERGY IN WORKSHOP WASTE TREATMENT Authors: Bist, Vaibhav Abstract: During manufacturing processes in workshops, a lot of material is wasted as scrap wasted in the form of metal chips, pieces, cutting fluids etc. The conventional techniques used for recycling of scrap are not efficient economically. 'l'hey require a lot of time for processing and cause pollution. Microwave processing of materials is a new technique for processing materials efficiently with lower power consumption, small processing time and lesser pollution. Microwaves have a characteristic property that when it interacts with material it may result in absorption, reflection or transmission. Microwave absorbed by the materials results in heating and due to heating the material above its melting point, the material gets melted. Metals can't be processed directly by microwave as they reflect most of the radiation. The conventional microwave heating technique is limited to he used only for those materials which can absorb microwave. Microwave hybrid heating is used to solve the purpose as the heating is done by microwave as well as the direct heating by the susceptor materials. The properties of the material processed by microwave hybrid heating are better than conventional methods and the time required for processing is smaller as compared to conventional processes. The process is safe and clean. Microwave hybrid heating is used for processing of metals because they reflect most of the radiation, so direct heating is not possible. The metal waste collected from workshop is processed with microwave and the product obtained is having desired mechanical and metallurgical properties. 2014-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/17328 Title: PERFORMANCE MODELING OF RMS IN MULTI-PRODUCT ENVIRONMENT Authors: Tefera, Tesfaye Abstract: The need for reconfigurable manufacturing systems is triggered by unforeseeable changes in the market, the increasing fi-equency of new products introductions, changes in the pails for existing products, large fluctuations in product demand and mix, changes in government regulations, and changes in the process technology. These changes are driven by the global aggressive economic competition, educated and demanding customers. To remain competent in this new manufacturing environment, companies must be able to respond quickly and cost effectively to changes. This dissertation focuses on the study of the effects of configuration on the performance of a manufacturing system in multi-product environment in terms of throughput, queue length, server utilization, capacity scalability, convertibility and floor area. Four configurations with the same number and type of machines but different in the arrangements and connection with the material handling equipment have been considered for selecting the optimum machining system configuration. 10 This study met these research aims through an extensive study of relevant literature and the implementation of discrete event Simulation (DES) modelling using MATLAB (SimEvents) to evaluate the performance measures. Some hypothetical assumptions were taken as input for starting the models The findings from this study were: Queue length is lower for configurations having higher configuration width and crossover connections afler every stage, server utilization increases with increasing configuration width and crossover connections, throughput is higher for configurations with higher width, scalability of a system is zero for configurations having a serial connection in any of the stages and if addition of machines is required at those stages, convertibility is higher when the number of routing connection is more, i.e. when width of configuration and crossover connections are higher, convertibility is enhanced when the minimum number of replicated machines (configuration width) at a particular stage is higher. the degree of convertibility increases when the increment of conversion is minimum. The main conclusions drawn from this study were that in the design of new systems, r companies need to be concerned on future products, i.e. products throughout the life of the systems in addition to the products that are manufactured today. Though RMSs initial costs are higher, when the life time cost of the system is considered, is lower than the conventional manufacturing systems. Therefore, the development and implementation of RMS's technology is vital for manufacturing companies to compete and grow their market share in the current manufacturing environment. This study recommends that RMS as a new manufacturing system paradigm needs a lot of work to achieve the benefits that the conventional manufacturing systems could not provide. Therefore, the model would develop and give a complete picture of the systems if machine level reconfiguration, part quality and system reliability are considered for future study. 2014-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/17326 Title: HORIZONTAL INTEGRATION IN SUPPLY CHAIN : A STRATEGIC APPROACH Authors: Patra, T. Devi Prasad Abstract: Over the years supply chain industry has emerged as a very profitable industry and it has become a very essential part of any manufacturing or service industry. It directly affects the profit and efficiency of a company and to operate the supply chain smoothly we need to have integration among the organizations in a supply chain either at the same stage of a supply chain or among organizations at different stages in supply chain and to achieve integration in supply chain is no mean thing, it requires thorough analysis of the companies and strategies. The decision makers face many challenges while going for the integration and this report 41 presents the reasons for horizontal integration, its necessities in supply chain and the challenges one face to achieve integration. It also presents how to approach strategically to achieve horizontal integration basically it gives one idea about how to approach for horizontal integration 2014-06-01T00:00:00Z