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1
Blom, Ricky J. "Production and evaluation of rapid tooling for electric discharge machining using electroforming and spray metal deposition techniques." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16014/1/Ricky_Blom_Thesis.pdf.
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To survive in today's manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have
seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods.
The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes.
Electroforming is one method of producing electrodes for EDM. The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture.
The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings.
The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture. The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes.
The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable.
It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.
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Blom, Ricky J. "Production and Evaluation of Rapid Tooling for Electric Discharge Machining using Electroforming and Spray Metal Deposition Techniques." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16014/.
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To survive in today's manufacturing environments companies must push the standards of accuracy and speed to the highest levels possible. Electro Discharge Machining (EDM) has been used for over 50 years and recent developments have seen the use of EDM become much more viable. The goal of this research is to produce and evaluate electrodes produced by different manufacturing methods. The use of electroforming and spray-metal deposition has only recently become viable methods of producing usable rapid tooling components. The speed and accuracy as well as the cost of manufacture play a vital role in the tool and mould manufacturing process. Electroforming and spray-metal deposition offer an alternate option to traditional machining of electrodes. Electroforming is one method of producing electrodes for EDM. The fact that electroforming can be used to produce multiple electrodes simultaneously gives it the advantage of saving on costs when multiple electrodes are needed. Spray-metal deposition offers another alternative that is much cheaper and relatively faster to manufacture. The used of these non-traditional manufacturing methods in this research are compared to the performance of traditional solid electrodes in terms of machining time, material removal rate, tool wear rates and surface roughness at several standard machining settings. The results of this research are presented in this thesis along with conclusions and comments on the performance of the different methods of electrode manufacture. The major findings of the research include the solid electrodes performed better than the electroformed electrodes in Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) at all machine settings. However it was found that the production cost of the solid electrodes was six times that of the electroformed electrodes. The production of spray metal electrodes was unsuccessful. The electrode shell walls were not an even thickness and the backing material broke through the shell making them unusable. It is concluded that with further refinements and research, electroforming and spray metal processes will become an extremely competitive method in electrode manufacture and other rapid tooling processes.
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Shieh, Marvin Bryan. "Face-up chemical mechanical polishing : kinematics and material removal rate." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36701.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.<br>Includes bibliographical references (leaf 27).<br>A working prototype face-up CMP tool has successfully been completed. Experiments conducted on the face-up CMP machine qualitatively correspond with the theoretical polishing model. Discrepancies in data from the theoretical model could potentially be caused by non-uniform loading of the polishing pad and uneven distribution of slurry over the pad due to the edge effects on fluid flow. Despite the discrepancies, experimental data suggest that the theoretical model used to describe blanket wafer polishing by the face-up CMP tool is at least partially valid.<br>by Marvin Bryan Shieh.<br>S.B.
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Ersvik, Erik, and Roj Khalid. "Milling in hardened steel - a study of tool wear in conventional- and dynamic milling." Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-255646.
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Milling is a commonly used machining process where a rotating cutter removes material from the workpiece. In recent years, attention has been turned towards so called dynamic milling methods which differ from the conventional way of milling. Dynamic milling normally uses, as opposed to the conventional way, more of the axial cutting edge, smaller radial depth of cut, significantly higher cutting speed and feed per tooth. The method has demonstrated potential to save both time and money under specific circumstances, for manufacturing companies.This thesis was conducted at ISCAR Sverige AB in Uppsala, Sweden. ISCAR Metalworking is a full service supplier of carbide cutting tools. The objective is to establish if there are benefits with dynamic milling methods with regard to material removal rate and lifetime of the tool by experimentally investigating and comparing tool wear that occur with conventional- and dynamic milling methods in hardened steels. Tools used were ISCAR’s MULTI-MASTER end mills, MM A and MM B, and the hardened steels were Hardox 600 and Dievar. Analysis was performed by using a USB-microscope, scanning electron microscope (SEM) and a Wyko-profilometer. The results of this study show that dynamic milling parameters can give several benefits regarding tool life and material removal rate. When machining in Hardox 600 and Dievar, both end mills were able to achieve a higher material removal rate and lifetime with dynamic parameters compared to more conventional ones. MM A outperformed MM B in Dievar, but the results were reversed in Hardox, MM B performed better. Results from the profilometry analysis showed that in Dievar, the dynamic parameters generated a smoother surface while the surface results from Hardox were more equivocal. The main conclusion was that milling with dynamic parameters is generally more advantageous and should be utilised, if possible.
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Kurdi, Mohammad H. "Robust multicriteria optimization of surface location error and material removal rate in high-speed milling under uncertainty." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011626.
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Kulkarni, Milind Sudhakar. "Tribochemical investigation of microelectronic materials." Thesis, [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1831.
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Konda, Ramesh. "Predicting Machining Rate in Non-Traditional Machining using Decision Tree Inductive Learning." NSUWorks, 2010. http://nsuworks.nova.edu/gscis_etd/199.
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Wire Electrical Discharge Machining (WEDM) is a nontraditional machining process used for machining intricate shapes in high strength and temperature resistive (HSTR) materials. WEDM provides high accuracy, repeatability, and a better surface finish; however the tradeoff is a very slow machining rate. Due to the slow machining rate in WEDM, machining tasks take many hours depending on the complexity of the job. Because of this, users of WEDM try to predict machining rate beforehand so that input parameter values can be pre-programmed to achieve automated machining. However, partial success with traditional methodologies such as thermal modeling, artificial neural networks, mathematical, statistical, and empirical models left this problem still open for further research and exploration of alternative methods. Also, earlier efforts in applying the decision tree rule induction algorithms for predicting the machining rate in WEDM had limitations such as use of coarse grained method of discretizing the target and exploration of only C4.5 as the learning algorithm.
The goal of this dissertation was to address the limitations reported in literature in using decision tree rule induction algorithms for WEDM. In this study, the three decision tree inductive algorithms C5.0, CART and CHAID have been applied for predicting material removal rate when the target was discretized into varied number of classes (two, three, four, and five classes) by three discretization methods. There were a total of 36 distinct combinations when learning algorithms, discretization methods, and number of classes in the target are combined. All of these 36 models have been developed and evaluated based on the prediction accuracy. From this research, a total of 21 models found to be suitable for WEDM that have prediction accuracy ranging from 71.43% through 100%. The models indentified in the current study not only achieved better prediction accuracy compared to previous studies, but also allows the users to have much better control over WEDM than what was previously possible. Application of inductive learning and development of suitable predictive models for WEDM by incorporating varied number of classes in the target, different learning algorithms, and different discretization methods have been the major contribution of this research.
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Llanto, Jennifer M. "Optimisation of process parameters in abrasive waterjet contour cutting of AISI 304L." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2502.
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This research work presents an optimisation of abrasive waterjet contour cutting process parameters with the objectives of maximising material removal rate, whilst minimising taper angle and surface roughness. This thesis contains an in-depth review of the systems behind abrasive waterjet machining and recent progress trends regarding its applications. The impacts of input parameters are investigated including traverse speed, waterjet pressure and abrasive mass flow rate against selected responses in abrasive waterjet contour cutting of austenitic stainless steel 304L. Experimental data is utilised to generate regression models in predicting responses, where the results are statistically evaluated to assess the percentage contribution of each parameter in the performance of contour cutting. Techniques, such as Taguchi and Response Surface Methodology, are employed to perform a single and multi-objective optimisation. Abrasive waterjets demonstrate similar responses in cutting curvature and straight line profiles during contour cutting. The study reveals that an increasing level of waterjet pressure and abrasive mass flow rate results in lower surface roughness, lower kerf taper angle and higher rate of material removal. Similarly, a lower rate of traverse speed achieves minimum surface roughness and kerf taper angle, whereas increasing its rate attains the maximum value of material removal rate.
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Guichard, Bastien. "Contribution à la définition d'un processus de polissage robotisé. Application aux pièces aéronautiques en acier à haute résistance." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22619.
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Dans le cas des pièces aéronautiques de grandes dimensions et de formes complexes nécessitant un bon état de surface, les opérations de polissage sont la plupart du temps réalisées manuellement par des opérateurs spécialisés. Ces opérations étant longues, pénibles et coûteuses, il paraît pertinent de s’intéresser à leur automatisation. Dans ces travaux de thèse, nous nous intéressons à la mise en place d’un processus de polissage robotisé pour un train d'atterrissage en acier à haute résistance. La définition du processus robotisé passe par la définition des outils adéquats (taille de grain, forme et souplesse), des conditions de polissage (effort, vitesse de coupe, vitesse d’avance, angle de dépinçage et recouvrement) et le réglage des paramètres de la commande en effort en fonction du matériau à polir et de la spécification de rugosité visée. Un modèle d’enlèvement de matière est ensuite proposé afin de maîtriser le défaut d’état de surface généré pour des outils « disques ». Une campagne expérimentale permet enfin de valider la mise en œuvre du robot et du processus de polissage sur une pièce spécifique, notamment en ce qui concerne la chaîne numérique<br>In the case of aircraft large parts and complex shapes requiring a good finish state, polishing operations are mostly performed manually by specialized operators. These operations are long, painful and expensive, it seems relevant to be interested in their automation. In the thesis work, we focus on the development of a robotic polishing process for high strength steel landing gear. The definition of the robotic process involves the definition of appropriate tools (grain size, shape and flexibility), polishing conditions (force, cutting speed, feed rate, inclination angle and overlap) and adjustment of parameters the force control based on the material to be polished and the specification roughness. A material removal model is then proposed to control the surface state generated for discs tools. Finally, an experimental campaign validates the implementation of the robot and the polishing process on a specific part, in particular as regards the numerical chain
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Natale, Lorenzo. "Optimization of liquid flow rate distribution in etching modules through numerical simulationsand experiments." Thesis, KTH, Skolan för kemivetenskap (CHE), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-212556.
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The purpose of this study was to simulate the liquid flow rate distribution in the etching modules and find the optimal setup in order to achieve a distribution as homogenous as possible. The commercial software Matlab 2015a has been employed for all the numerical simulations. The optimization has been carried out varying several parameters, i.e. spray cross sections of the nozzles, the oscillation parameters, the rotating angle of the nozzles within etching module 1 and the nozzle arrangement inside the modules. Furthermore, the optimization has been carried out separately along the two directions of the modules. The results achieved computationally have been validated via experimental procedures. During this study a specific experimental setup has been developed in order to be able to compare experimental and computational results. The validation process has shown that the computational method matches the experimental results to a good extent. The experimental liquid distribution in etching module 2 widely matches the simulations to a quantitative extent, while the one in etching module 1 provides the same qualitative but different quantitative results.
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Bonilla, Hernández Ana Esther. "Analysis and direct optimization of cutting tool utilization in CAM." Licentiate thesis, Högskolan Väst, Forskningsmiljön produktionsteknik(PTW), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-8672.
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The search for increased productivity and cost reduction in machining can be interpreted as the desire to increase the material removal rate, MRR, and maximize the cutting tool utilization. The CNC process is complex and involves numerous limitations and parameters, ranging from tolerances to machinability. A well-managed preparation process creates the foundations for achieving a reduction in manufacturing errors and machining time. Along the preparation process of the NC-program, two different studies have been conducted and are presented in this thesis. One study examined the CAM programming preparation process from the Lean perspective. The other study includes an evaluation of how the cutting tools are used in terms of MRR and tool utilization. The material removal rate is defined as the product of three variables, namely the cutting speed, the feed and the depth of cut, which all constitute the cutting data. Tool life is the amount of time that a cutting tool can be used and is mainly dependent on the same variables. Two different combinations of cutting data might provide the same MRR, however the tool life will be different. Thereby the difficulty is to select the cutting data to maximize both MRR and cutting tool utilization. A model for the analysis and efficient selection of cutting data for maximal MRR and maximal tool utilization has been developed and is presented. The presented model shortens the time dedicated to the optimized cutting data selection and the needed iterations along the program development.
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Holmberg, Jonas. "Surface integrity on post processed alloy 718 after nonconventional machining." Licentiate thesis, Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-12191.
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There is a strong industrial driving force to find alternative production technologies in order to make the production of aero engine components of superalloys even more efficient than it is today. Introducing new and nonconventional machining technologies allows taking a giant leap to increase the material removal rate and thereby drastically increase the productivity. However, the end result is to meet the requirements set for today's machined surfaces.The present work has been dedicated to improving the knowledge of how the non-conventional machining methods Abrasive Water Jet Machining, AWJM, Laser Beam Machining, LBM, and Electrical Discharge Machining, EDM, affect the surface integrity. The aim has been to understand how the surface integrity could be altered to an acceptable level. The results of this work have shown that both EDM and AWJM are two possible candidates but EDM is the better alternative; mainly due to the method's ability to machine complex geometries. It has further been shown that both methods require post processing in order to clean the surface and to improve the topography and for the case of EDM ageneration of compressive residual stresses are also needed.Three cold working post processes have been evaluated in order to attain this: shot peening, grit blasting and high pressure water jet cleaning, HPWJC. There sults showed that a combination of two post processes is required in order to reach the specified level of surface integrity in terms of cleaning and generating compressive residual stresses and low surface roughness. The method of high pressure water jet cleaning was the most effective method for removing the EDM wire residuals, and shot peening generated the highest compressive residual stresses as well as improved the surface topography.To summarise: the most promising production flow alternative using nonconventional machining would be EDM followed by post processing using HPWJC and shot peening.
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Dragan, Rodić. "Optimizacija procesa elektroerozivne obrade savremenih inženjerskih materijala." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2019. https://www.cris.uns.ac.rs/record.jsf?recordId=110508&source=NDLTD&language=en.
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Predmet istraživanja ove disertacije predstavlja unapređenje, modelovanje i optimizacija procesa elektroerozivne obrade (EDM) savremenih inženjerskih materijala. Prvo su predstavljene dve inovativne metode: EDM u dielektrikumu sa pomešanim prahom i EDM sa pomoćnom elektrodom, a zatim i njihova kombinacija. Za generisanje matematičkih modela primenjene su metodologija odzivne površine i alati veštačke inteligencije. U nastavku su postavljeni optimizacioni procesi određivanja ulaznih parametara sa jednom i više funkcija cilja koji su rešeni primenom klasičnih metoda optimizacije. U završnom osvrtu sprovedena je verifikacija dobijenih modela i optimalnih ulaznih parametara elektroerozivne obrade.<br>The subject of the research of this dissertation is the improvement, modeling and optimization of the electrical discharge machining (EDM) of advanced engineering materials. First, two innovation methods are presented: EDM in powder mixed dielectric fluid and EDM with assisted electrode and that their combination. The method of response surface and artificial intelligence tools were applied to generate mathematical models. The optimization problems of determining the input parameters with single and multiple target functions are solved by the application of classical optimization methods. Finally, verification of the obtained models and optimal input parameters of electrical discharge machining was carried out.
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Hendriko, ? "Advanced virtual simulation for optimal cutting parameters control in five axis milling." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22464/document.
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La thèse concerne l’usinage à 5 axes de formes complexes. Le but est d’estimer le plus précisément possible les efforts induits par la coupe pour ajuster la vitesse d’avance et gagner en performance. Pour cela, il est nécessaire d’estimer les engagements radial et axial de la fraise à chaque instant. Ce calcul est rendu particulièrement complexe à cause de la forme de la pièce, de la forme du brut et de la complexité de la géométrie de l’outil. Les méthodes usuelles par Zbuffer sont particulièrement couteuses en temps de calcul. Dans ces travaux nous proposons une méthode de calcul rapide à partir d’une modélisation du contact dans toutes les situations envisageables. Différentes simulations et expérimentations ont permis de valider la précision expérimentalement<br>This study presents a simple method to define the Cutter Workpiece Engagement (CWE) during sculptured surface machining in five-axis milling. The instantaneous CWE was defined by determining two engagement points, lowermost engagement (LE)-point and uppermost engagement (UE)-point. LE-point was calculated using a method called grazing method. Meanwhile the UE-point was calculated using a combination of discretization and analytical method. During rough milling and semi-finish milling, the workpiece surface was represented by vertical vector. The method called Toroidal–boundary was employed to obtain the UE-point when it was located on cutting tool at toroidal side. On the other hand, the method called Cylindrical-boundary was used to calculate the UE-point for flat-end cutter and cylindrical side of toroidal cutter. For a free-form workpiece surface, a hybrid method, which is a combination of analytical method and discrete method, was used. All the CWE models proposed in this study were verified and the results proved that the proposed method were accurate. The efficiency of the proposed model in generating CWE was also compared with Z-mapping method. The result confirmed that the proposed model was more efficient in term of computational time. The CWE model was also applied for supporting the method to predict cutting forces. The test results showed that the predicted cutting force has a good agreement with the cutting force generated from the experimental work
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Guiot, Anthony. "Modélisation et simulation du procédé de prépolissage automatique sur centre d'usinage 5 axes." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-01044984.
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La réalisation de formes complexes comme les moules ou les prothèses médicales nécessite l'utilisation d'opérations de super finition pour obtenir de faibles défauts géométriques, pouvant aller jusqu'au poli-miroir. Ces opérations de pré-polissage et de polissage sont encore régulièrement réalisées manuellement. En effet, malgré des avantages en termes de répétabilité, de productivité et de qualité géométrique, les méthodes de polissage automatique sont peu utilisées car elles nécessitent une mise au point importante. Les travaux de recherche présentés participent à la maîtrise du procédé de polissage automatique tout en contrôlant la qualité géométrique des pièces. Pour parvenir à cette maîtrise, un outil de simulation de l'enlèvement de matière est mis en place. Cet outil permet de simuler l'enlèvement de matière au cours d'une opération de prépolissage réalisée sur centre d'usinage 5 axes. Il se base sur un modèle du contact obtenu entre l'outil de pré-polissage et la pièce, ainsi que sur un modèle du pouvoir abrasif intégrant l'usure et l'encrassement du disque. Cette simulation permet de vérifier la régularité de l'abrasion sur une surface et d'identifier les zones pouvant faire apparaitre des défauts macro-géométriques importants. Une méthode est également proposée pour compenser les variations du pouvoir abrasif au cours du temps. La compensation s'effectue en optimisant les consignes de vitesse d'avance et/ou de fréquence de broche le long de la trajectoire. Cette méthode de pilotage permet d'obtenir un taux d'enlèvement de matière plus constant et ainsi de réduire les défauts géométriques générés pendant une opération de prépolissage.
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SINGH, MANOJ KUMAR. "MATHEMATICAL MODELING OF MRR FOR ELECTRICAL DISCHARGE MACHINING." Thesis, 2012. http://dspace.dtu.ac.in:8080/jspui/handle/repository/15710.
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The right selection of manufacturing parameters is one of the most important aspects in the electrical discharge machining operation as these conditions has important effect on material removal rate (MRR). In this work the experiments are conducted on the machining of EN 31 die steel with graphite electrode in electrical discharge machining (EDM). The EDM oil commercial grade has been used as dielectric fluid. The effect of various EDM parameters such as discharge current, Ton and Toff has been investigated to yield the response in terms of MRR. In this work mathematical models have been developed for relating the MRR with machining parameters like discharge current, Ton, and Toff. The optimum value has been determined with the help of main effect plot and Annova table. With the help of MINITAB 15 software mathematical modeling has been done. The optimum value for MRR has been determined.
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Ahmed, N., M. Rafaqat, S. Pervaiz, et al. "Controlling the material removal and roughness of Inconel 718 in laser machining." 2019. http://hdl.handle.net/10454/17198.
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No<br>Nickel alloys including Inconel 718 are considered as challenging materials for machining. Laser beam machining could be a promising choice to deal with such materials for simple to complex machining features. The machining accuracy is mainly dependent on the rate of material removal per laser scan. Because of the involvement of many laser parameters and complexity of the machining mechanism it is not always simple to achieve machining with desired accuracy. Actual machining depth extremely varies from very low to aggressively high values with reference to the designed depth. Thus, a research is needed to be carried out to control the process parameters to get actual material removal rate (MRRact) equals to the theoretical material removal rate (MRRth) with minimum surface roughness (SR) of the machined surfaces. In this study, five important laser parameters have been used to investigate their effects on MRR and SR. Statistical analysis are performed to identify the significant parameters with their strength of effects. Mathematical models have been developed and validated to predict the machining responses. Optimal set of laser parameters have also been proposed and confirmed to achieve the actual MRR close to the designed MRR (MRR% = 100.1%) with minimum surface roughness (Ra = 2.67 µm).<br>The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding this work through research group number RG-1440-026.
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Ahmed, N., M. Rafaqat, S. Pervaiz, et al. "Controlling the material removal and roughness of Inconel 718 in laser machining." 2001. http://hdl.handle.net/10454/17198.
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No<br>Nickel alloys including Inconel 718 are considered as challenging materials for machining. Laser beam machining could be a promising choice to deal with such materials for simple to complex machining features. The machining accuracy is mainly dependent on the rate of material removal per laser scan. Because of the involvement of many laser parameters and complexity of the machining mechanism it is not always simple to achieve machining with desired accuracy. Actual machining depth extremely varies from very low to aggressively high values with reference to the designed depth. Thus, a research is needed to be carried out to control the process parameters to get actual material removal rate (MRRact) equals to the theoretical material removal rate (MRRth) with minimum surface roughness (SR) of the machined surfaces. In this study, five important laser parameters have been used to investigate their effects on MRR and SR. Statistical analysis are performed to identify the significant parameters with their strength of effects. Mathematical models have been developed and validated to predict the machining responses. Optimal set of laser parameters have also been proposed and confirmed to achieve the actual MRR close to the designed MRR (MRR% = 100.1%) with minimum surface roughness (Ra = 2.67 µm).<br>The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding this work through research group number RG-1440-026.
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Chian, Yu-Feng, and 錢玉峰. "The Study of the Relationship between the Material Removal Ratio (MRR) and the Machining Depth in EDM." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/64487045080393222651.
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碩士<br>國立臺灣大學<br>機械工程學研究所<br>89<br>This thesis focuses on the relationship between the material removal ratio (MRR) and the machining depth in EDM. The goal of this study is to explore the way how the MRR changes with the machining depth and, by analysis of experimental data, to understand the factors that cause the change. Besides, the effects caused by the discharge area and various machining parameters are to be revealed as well.
According to the experimental results, the MRR, with the increase of the machining depth, increases first and then decreases. The increase of the MRR is attributed to the enlargement of the impact force acted on the workpiece; on the other hand, the decrease of the MRR is attributed to the increase of the ratio of abnormal discharges caused by the failure of evacuating the gap debris under a certain depth.
In view of the discharge area, because of the better resistance to the increase of abnormal discharge, the larger the discharge area , the deeper the depth within which the MRR keep increasing; also, the decrease of the MRR becomes slighter.
The effects of various machining parameters are concluded below. When working with shorter pulse durations, the decrease of the MRR will become moderate because of the slight increase of abnormal discharges. In the beginning of machining process, the adoption of shorter pause durations will help to increase the MRR. Nevertheless, when the machining proceeded further, although the adoption of longer pause durations reduces the occurrence of abnormal discharges, it decreases the discharge frequency in the same time. Consequently, the variation of pause durations doesn’t cause obvious effects. The MRR increases with the peak current; however, no matter how large the peak current is adopted, the MRR will change with the machining depth as mentioned above. For the material close to the surface of the workpiece, the adoption of smaller servo gaps increases the MRR, but it makes the ratio of abnormal discharges rise earlier; therefore, the MRR begins decreasing in the shallower depth.
Key words: EDM, MRR, machining depth, discharge area, machining parameters
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Chang, Clack, and 張躍馨. "EDM Gap Control based on Material-Removal-Rate." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/06367245805871628508.
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Lai, Cheng-Yu, and 賴承佑. "Studies to Improve the Material Removal Rate in Ultrasonic Osteotomy." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/26512457197697018069.
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碩士<br>國立臺灣大學<br>機械工程學研究所<br>99<br>The aim of this research is to increase the material removal rate (MRR) in ultrasonic osteotomy. According to the basic cutting theory, MRR can be increased by decreasing the specific cutting energy or by increasing the cutting power.
For the same work material, the specific cutting energy is mainly affected by the geometrical shape of the cutting tip, including the number of the teeth and the geometrical shape of the teeth. The Taguchi method was used to find the better geometrical shape of the cutting tip compared with the tips in clinical usage now. The highest MRR was found in this experiment for the 5 teeth cutting tip with 0∘rake angle、15 ∘inclination angle and 40∘chamfer angle of each tooth.
Three stainless steel cutting tips with different coefficients of friction were used in the experiment to increase cutting power, and thus MRR. They are uncoated, TiN-coated and DLC-coated, the coefficients of friction are about 0.5, 0.4 and 0.1 respectively. Under the mode of 50 the MRRs for the uncoated tip, TiN-coated tip, and DLC-coated tip are 0.149 mm3/s, 0.153 mm3/s and 0.165 mm3/s. Less power was consumed in overcoming the friction between the tip and side wall of the groove for the lower coefficient of friction cutting tip. This leads to a larger power left for cutting under the same power provided by the hand-piece. As a result MRR is higher.
In base of the experimental results above, a DLC-coated 5 teeth cutting tip with 0∘ rake angle、15∘inclination angle and 40∘chamfer angle of each tooth was proposed. The MRR of this cutting tip was expected to reach 0.49 mm3/s, which was 3.8 times larger than the tip in clinical usage now.
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Sowers, Jason Michael. "Examination of the Material Removal Rate in Lapping Polycrystalline Diamond Compacts." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-9917.
Full textAbstract:
This study examines the lapping machining process used during the manufacturing of polycrystalline diamond compacts (PDCs). More specifically, it is aimed at improving the productivity of the process by developing a better understanding of the parameters that affect the material removal rate (MRR) and MRR uniformity of lapped PDC samples.
Experiments that focused on several controllable lapping parameters were performed to determine to what extent they affected the process. It was determined that the MRR can be modeled with the Preston equation under certain ranges of pressure and speed. It was also found that using a hard and rigid sample holder produces higher MRRs than soft and flexible sample holders. The results have also shown that MRRs in excess of 300 micrometers per hour can be achieved while using 10 grams of diamond abrasive per PDC per hour of lapping. The productivity of the lapping process can also be improved by placing the maximum allowed PDC samples in a concentric circle on the edge of the sample holder. The MRR uniformity between samples lapped on the same sample holder was found to be dependent on the sample holder material.
This thesis is composed of six chapters. The first chapter introduces the need for PDC's as extreme cutting tools, the manufacturing process of PDC's, and the lapping process. The second chapter discusses the motivation behind this research and the primary objectives that were established. The third chapter details the materials and the experimental procedure, and the fourth chapter presents the results. The fifth chapter discusses the results, and the sixth chapter presents conclusions and information on possible future work.
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Lan, Tian-Syung, and 藍天雄. "An Approach of Optimization of Material Removal Rate for CNC Machining." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/02732365026149211870.
Full textAbstract:
博士<br>大同大學<br>機械工程研究所<br>91<br>Optimizing the machining operation of an individual cutting tool as well as the machining project has become important for the modern computer numerical controlled (CNC) machining industry. In this study, the mathematical models to achieve the optimum material removal rate (MRR) control of a cutting tool, a machining project, and multiple machining quantities are established under constrained and unconstrained time periods. This paper not only applies MRR into the objective functions dynamically, but also implements Calculus of Variations to resolve the cutting rate control problems comprehensively.
Additionally, the dynamic solutions, the optimality of the solutions, as well as the completeness of the solutions for the control of MRR are proposed and the decision criteria for selecting the optimal solutions are recommended. Moreover, the sensitivity analyses for decision variables in the optimum solutions are fully discussed. To demonstrate the advantages of this study, the versatility of this study is furthermore exemplified through a numerical illustration from the real-world industry with computerized programs. It is shown that the theoretical and simulated results are in good agreement. With this study, the manufacturing planning, machining profit/cost estimating, and even the contract negotiation can be then further approached.
The dynamic approaches of single-tool MRR control and the analyses of surface roughness for the machined parts from the numerical case are experimentally performed on an ECOCA PC-3807 CNC lathe with VERDURE PA-100 controller connected to an IBM PC 586 microprocessor. The machined work-pieces are found to reach well surface roughness for finish turning. Therefore, the adaptability and applicability of the dynamic machining model are furthermore guaranteed. The dynamic MRR optimization for multi-operation and multi-tool CNC machining process can then be extended through this study.
The dynamic MRR control is the goal to optimize machining operations in the CNC machining systems. This study definitely explores a very promising solution of controlling the machining rate to not only dynamically arrange the MRR, but also comprehensively schedule the production period of machining quantities for the existent machining industry with profound insight.
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Wang, Sheng-Min, and 王聖閔. "Investigation of Material Removal Rate Increase during Polishing of Single-Crystal Silicon Carbide." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/99904940827920379598.
Full textAbstract:
碩士<br>國立勤益科技大學<br>機械工程系<br>102<br>The application field of single-crystal silicon carbide (SiC) as a next-generation compound semiconductor is expanding because of its significant advantages of high power, high frequency, low coefficient of thermal expansion, and high thermal conductivity. Currently, only can achieve full planarization key technology is chemical mechanical polishing(CMP), very important issue is how to get high material removal rate and ultra-smooth surface.
In this study, we based on theory of brittle materials grinding single grain grinding mechanism, using single grain grinding mechanism to remove surface scratches and subsurface damage, then using grinding generated crack depth value to prediction the amount of mechanical polishing removed, finally construct mechanical polishing (rough polishing) and chemical mechanical polishing (finish polishing) standard process. Furthermore, the use a novel arrangement of diamond disk, which were radially arranged in a cluster arrangement with 3–4 grits per cluster. The surface characteristics of the polishing pads, as well as the surface roughness, surface damage, and removal rate of silicon carbide polished with these pads and diamond disks were investigated and compared with the corresponding attributes shown by a conventional diamond disk. Improve the material removal rate of chemical mechanical polishing for silicon carbide were made 0wt%, 1wt% and 5wt% polyurethane nano diamond polishing pad, at the same time dressing and polishing in the recycling slurry process. Experimental results showed that the novel diamond disk resulted in a dressing rate around two times higher and a removal rate about 13% higher than those obtained using the conventional diamond disk. In addition, SiC polishing tests revealed that the nano diamond polishing pads provided better surface roughness without any damage, as well as about 1.5 times higher removal rate than that provided by the polyurethane polishing pad.
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Wu, Sheng-Hao, and 吳聲澔. "Predicting Wafer Material Removal Rate for Semiconductor Chemical Mechanical Polishing using Machine Learning." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/8332vc.
Full textAbstract:
碩士<br>國立交通大學<br>工業工程與管理系所<br>107<br>Predicting wafer material removal rate (MRR) is an important step in semiconductor manufacturing for total quality control (TQC). With the progress of virtual metrology (VM) and machine learning (ML), the processing parameters obtained from manufacturing machine can be analyzed and build prediction models to predict and improve manufacturing quality. In this thesis, we conduct our experiments with the 2016 PHM Data Challenge competition dataset. The goal of the competition is to predict the wafer MRRs of chemical mechanical polishing (CMP) by processing parameters that collected by VM. In our experiments, we construct ensemble model to achieve better prediction performance and compare our prediction performance with the first prize on 2016 PHM Data Challenge competition. Moreover, we build scoring models with few parameters for practical applications. The experimental results indicate that either the ensemble model or the scoring models outperform pervious researches.
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Wang, Hsueh-Ming Steve. "Analysis of the effect of process parameters on material removal rate in ultrasonic machining /." Diss., 1998. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9914251.
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Po-ChenLai and 賴柏辰. "A Study on Maximum Material Removal Rate under the Constraint of Flatness in Milling." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/24437755705596343652.
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碩士<br>國立成功大學<br>機械工程學系碩博士班<br>101<br>Milling can achieve complex geometry and high surface quality part. Therefore, milling is widely utilized in precision manufacturing industry. However, milling induces residual stress and deformation, resulting in poor quality parts, such as the flatness of plate. In this article, systematic method of experiment design is used to analyze the influence of flatness on plate and to establish a model of flatness in milling. The model is used to find maximum material removal rate under the constraint of flatness. First, we utilize the cutting coefficients and convolution milling force model to find the milling parameters under the limit of vacuum chuck and spindle. Then, we use response surface methodology and combination of orthogonal array (L9) and Box-Behnken design in order to analyze milling parameter of flatness and obtain an accurate model of flatness with efficient number of experiments. Also, the flatness model considers process variation due to the fact that it is more efficient for industry. The result of experiment showed that high speed, low feed per tooth and low depth of cut constitute the key parameters for better flatness. Finally, we use the derived flatness model incorporating process variation effect to find the optimal process parameters to achieve the maximum material removal rate under the constraint of flatness.
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Tsai, Che-Cheng, and 蔡哲誠. "Investigation of Material Removal Rate for C-face Single-Crystal Silicon Carbide during Polishing Process." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/09371187968633127391.
Full textAbstract:
碩士<br>國立勤益科技大學<br>機械工程系<br>103<br>The application field of silicon carbide (SiC) as a next-generation compound semiconductor is expanding because of its significant advantages: high power, high frequency, low coefficient of thermal expansion, and high thermal conductivity. Many researchers have investigated SiC polishing for the manufacturing of semiconductor substrates using SiC. However, because SiC is a chemically and mechanically stable material, these researchers have faced difficulties due to its very low polishing rate (95–540 nm/h). Therefore, methods are required for increasing the material removal rate of SiC.
The aim of this study was to investigate the increase in removal rate during the polishing of single-crystal SiC subjected to simultaneous polishing and dressing by using a new diamond slurry for mechanical polishing and a novel catalyst etching mechanical polishing (CEMP). The diamond is heated at different temperature in a furnace to allow for diamond oxidation to occur, which results in improved diamond surface roughness. The surface characteristics of the new diamond slurry and CEMP, as well as the surface roughness, surface damage, and removal rate of the SiC polished with this slurry, were investigated and compared with the corresponding attributes displayed by a conventional diamond slurry. Experimental results reveal that new diamond slurry can produce 4-5 times the material removal rate compared to commercial diamond slurry. Consequently, a mechanical polishing time reduction by over half is expected. Experimental results showed that the removal rate of SiC with CEMP approximately 3 times higher than that provided by the chemical mechanical polishing (CMP). The surface roughness polished by CEMP is about 1.37 Å which close to commercial standard value (1 Å). In addition a diamond conditioner manufactured using polymer-bonded diamond grits, known as polyepoxide diamond disks containing 600, 1200 and 3000 diamond grits. PDDs are made by reverse casting of the substrate. Instead of using a flat substrate as the backing for the attachment of diamond grits, the substrate is made after diamond grits are leveled on a mold. PDDs diamond disk is designed and manufactured to markedly improve the leveling of diamond tips, reducing the amount of diamond grit. It is found that pad cut rate of new diamond disk is 2.5 times higher than that of conventional diamond disk.
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SRIVASTAVA, VIDHAN. "OPTIMIZATION OF MATERIAL REMOVAL RATE IN DRILLING CARBON NANOTUBE EPOXY COMPOSITE SPECIMEN BY TAGUCHI METHOD." Thesis, 2017. http://dspace.dtu.ac.in:8080/jspui/handle/repository/16031.
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This project introduces the application of Taguchi optimization methodology in
optimizing the drilling parameters for machining pristine and functionalized multi walled
carbon nanotube epoxy composite material to obtain maximum material removal rate.
The drilling parameters which are chosen to be evaluated in this study are the diameter of
dill bit, cutting speed and feed rate. While, the response factor to be measured is the
material removal rate of the composite material. An orthogonal array was set up and
signal-to-noise (S/N) ratio was employed to find the optimal levels of drilling parameters
for achieving maximum material removal rate (MRR). MINITAB 18 software was used
to find out signal-to-noise (S/N) ratio and mean. The combination of optimal drilling
parameters for both pristine and functionalized multi walled carbon nanotube epoxy
composite has been obtained at speed 440 rpm, feed 0.03 mm/rev and drill bit diameter
12 mm. In this study, Analysis of variance (ANOVA) revealed that speed is the dominant
parameter followed by feed and diameter of drill bit for pristine multi walled carbon
nanotube epoxy composite while feed is the dominant factor followed by diameter of drill
bit and speed for functionalized multi walled carbon nanotube epoxy composite.
Keywords: carbon nanotubes, dispersion, functionalization, drilling, Taguchi.
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Wu, P. L., and 吳佩霖. "A Study on the Milling Condition for Maximum Material Removal Rate under Constrant of Workpiece Temperature." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/89416311210395233375.
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碩士<br>國立成功大學<br>機械工程學系<br>88<br>The heat generated during metal cutting process will degrade the dimensional accuracy and surface integrity including residual stresses, micro-structural changes and cracks etc. First, the work temperature beneath the surface in an end milling process is analyzed with the moving heat source theory and the results are verified with experiments. In order to investigate the influences of the tools geometry and cutting conditions on the temperature on work surface, the cutting simulation software “AdvantEdge” in combination with Taguchi method is used to identify the significant parameters that affect the surface temperature of AL7075-T6. Further investigation shows how to maximize the metal removal rate under the constrained of maximum surface temperature.
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Huang, Pay-Yau, and 黃培堯. "Theoretical and Experimental Study on the Material Removal Rate and Polishing Temperature Rise of Precision Polishing Processes." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/98277306740768622509.
Full textAbstract:
博士<br>國立中正大學<br>機械系<br>93<br>Due to the demand for high precision and high performance, the requirements for surfaces of mechanical and electronical components are becoming stricter. Precision polishing is a finishing process that makes the roughness and planarity of a surface reach a certain admissible range. This method is widely used for surfaces of metal, ceramic, glass or wafer. The operation parameters and consumables’ characteristics can significantly affect the polishing results. Therefore, the understanding of the relationship between the operation parameters and polishing results is the key to improve the precision polishing processes.
Chemical Mechanical Polishing is a highly effective technique for planarizing wafer surfaces. Consequently, considerable research has been conducted into its associated material removal mechanisms and polishing temperature rise. The present study proposes an improved micro-contact model that considers the effects of abrasive particles between the polishing interfaces. Comparisons with experimental data and underlying physics provided by this approach demonstrate that our approach can investigate the effects of consumables in addition to the operation parameters of CMP and look into the physical insight of the interfacial phenomena not elucidated by previous approaches. The extensions of this approach to endpoint detection technology and Post-CMP cleaning process are also discussed. Furthermore, the developed model have also been modified to investigate the metal polishing process to study the relationship amount the operation parameters, material removal rate and polishing temperature.
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Lai, Ming-Yuan, and 賴明源. "Optimization and Implementation of Dynamic Material Removal Rate Control for a Turning Tool on a CNC Lathe." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/81041350801808953337.
Full textAbstract:
碩士<br>大同大學<br>機械工程研究所<br>90<br>Optimizing the machining profit or cost of an individual cutting tool has become important for computer numerical controlled (CNC) machining industry. The mathematical models to achieve the optimal material removal rate (MRR) control of a cutting tool during machining are established in this study. This paper not only applies MRR into the objective functions mathematically, but also implements Calculus of Variations to resolve the cutting rate control problems comprehensively. In addition, the dynamic solutions for the control of MRR are proposed and the decision criteria for selecting the optimal solutions are recommended.The versatility of this study is furthermore exemplified through a numerical illustration from the real-world industry with BORLAND C++ BUILDER. It is shown that the theoretical and simulated results are in good agreement. With this study, the manufacturing planning, machining profit/cost estimating, and even the contract negotiation can be then further approached. Furthermore, the implementation of dynamic MRR control and the analysis of surface roughness for the numerical case are experimentally performed on an ECOCA PC-3807 CNC lathe with VERDURE PA-100 controller. The machined parts are found to reach well surface roughness for finish turning. Therefore, the adaptability and applicability of the dynamic machining model are furthermore guaranteed. This study definitely provides an efficient tool of controlling the machining rate for production engineers in today’s manufacturing with profound insight.
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Khandey, Umesh. "Optimization of Surface Roughness, Material Removal Rate and cutting Tool Flank Wear in Turning Using Extended Taguchi Approach." Thesis, 2009. http://ethesis.nitrkl.ac.in/1378/1/Optimization_of_Surface_Roughness%2C_Material_Removal_Rate_and_Cutting_Tool_Flank_Wear_In_Turning_Using_Extended_Taguchi_Approach.pdf.
Full textAbstract:
Quality and productivity play significant role in today’s manufacturing market.From customers’ viewpoint quality is very important because the extent of quality of the procured item (or product) influences the degree of satisfaction of the consumers during usage of the procured goods. Therefore, every manufacturing or production unit should concern about the quality of the product. Apart from
quality, there exists another criterion, called productivity which is directly related to the profit level and also goodwill of the organization. Every manufacturing
industry aims at producing a large number of products within relatively lesser time. But it is felt that reduction in manufacturing time may cause severe quality
loss. In order to embrace these two conflicting criteria it is necessary to check quality level of the item either on-line or off-line. The purpose is to check whether
quality lies within desired tolerance level which can be accepted by the customers. Quality of a product can be described by various quality attributes. The attributes may be quantitative or qualitative. In on-line quality control controller and related equipments are provided with the job under operation and continuously the quality is being monitored. If quality falls down the expected
level the controller supplies a feedback in order to reset the process environment. In off-line quality control the method is either to check the quality of few products from a batch or lot (acceptance sampling) or to evaluate the best process environment capable of producing desired quality product. This invites optimization problem which seeks identification of the best process condition or
parametric combination for the said manufacturing process. If the problem is related to a single quality attribute then it is called single objective (or response)
optimization. If more than one attribute comes into consideration it is very difficult to select the optimal setting which can achieve all quality requirements
simultaneously. Otherwise optimizing one quality feature may lead severe quality loss to other quality characteristics which may not be accepted by the customers.
In order to tackle such a multi-objective optimization problem, the present study applied extended Taguchi method through a case study in straight turning of mild
viii steel bar using HSS tool. The study aimed at evaluating the best process environment which could simultaneously satisfy requirements of both quality and
as well as productivity with special emphasis on reduction of cutting tool flank wear. Because reduction in flank wear ensures increase in tool life. The predicted
optimal setting ensured minimization of surface roughness, height of flank wear of the cutting tool and maximization of MRR (Material Removal Rate). In view of the fact, that traditional Taguchi method cannot solve a multi-objective
optimization problem; to overcome this limitation grey relational theory has been coupled with Taguchi method. Furthermore to follow the basic assumption of Taguchi method i.e. quality attributes should be uncorrelated or independent. But is practical case it may not be so. To overcome this shortcoming the study applied Principal Component analysis (PCA) to eliminate response correlation
that exists between the responses and to evaluate independent or uncorrelated quality indices called Principal Components. Finally the study combined PCA,
grey analysis, utility concept and Taguchi method for predicting the optimal setting. Optimal result was verified through confirmatory test. This indicates
application feasibility of the aforesaid techniques for correlated multi-response optimization and off-line quality control in turning operation.