This research develops an analytical scientific approach for investigating the high precision surface generation and the quantitative analysis of the effects of direct factors in precision machining. The research focuses on 3D surface characterization with particular reference to the turning process and associated surface generation. The most important issue for this research is surface functionality which is becoming important in the current engineering industry. The surface functionality should match with the characterization parameters of the machined surface, which can be expressed in formula form as proposed in chapter 4. Modelling and simulation are extensively used in the research. The modelling approach integrates the cutting forces model, thermal mode% vibration model, tool wear model, machining system response model and surface topography model. All of those models are integrated as a whole model. The physical model with such as direct inputs is formed. The major inputs to the model are tooling geometry and the process variables. The outputs from the modelling approach are cutting force, surface texture parameters, dimensional errors, residual stress and material removal rate. MATLAB and Simulink are used as tools to implement the modelling and simulation. According to the simulation results, it is found that the feed rate has the most profound effect on in surface generation. The influence of the vibrations between the cutting tool and the workpiece on the surface roughness may be minimised by the small feed rate and large tool nose radius. Surface functionality simulation has been developed to model and simulate the surface generation in precision turning. The surface functionality simulation model covers the material and tool wear as well. It shows that chip formation is resulted from cutting forces. Cutting trials are conducted to validate the modelling and simulation developed. There are positive results that show the agreement between the simulation and experimental results. The analysis of the results of turning trials and simulations are conducted in order to find out the effects of process variables and tooling characteristics on surface texture and topography and machining instability. From the research, it can be concluded that the investigation on modelling and simulation of precision surfaces generation in precision turning is performed well against the research objectives as proposed. Recommendations for future work are to improve the model parameters identification, including comprehensive tool wear, chip formation and using Neural Networks modelling in the engineering surface construction system.

Abstract Prediction of chip-breaking in machining is an important task for automated manufacturing. There are chip-breaking limits in machining chip-breaking chart, which determine the chip-breaking range. This thesis presents a study of the effect of 3-D groove insert parameters on chip breaking chart. Based on the chip-breaking criteria, the critical feed rate is formulated through an analysis of up-curl chip formation for 3-D grooves. Also in order to predict chip-breaking limits, for protruded insert grooves in finish machining, analytical models are established. In the analytical models, minimum and maximum depth of cut are identified for using different chip breaking models. As well insert nose radius effects on chip thickness for small depth of cut are studied. In the end, the analytical critical feed rate model is extended to finish machining with 3-D chipbreaking grooves.

Carbon Fiber Reinforced Polymers (CFRP) are a class of advanced materials widely used in versatile applications including aerospace and automotive industries due to their exceptional physical and mechanical properties. Owing to the heterogenous nature of the composites, it is often a challenging task to machine them unlike metals. Drilling in particular, the most commonly used process for component assembly is critical especially in the aerospace sector which demands parts of highest quality and surface integrity. Conventionally, all composites are machined under dry conditions. While there are drawbacks related to dry drilling, for example, poor surface roughness, there is a need to develop processes which yield good quality parts. This thesis investigates the machining performance when drilling CFRP under cryogenic, MQL and hybrid (CryoMQL) modes and comparing with dry drilling in terms of the machining forces, delamination, diameter error and surface integrity assessment including surface roughness, hardness and sub-surface damage analysis. Additionally, the effect of varying the feed rate on the machining performance is examined. From the study, it is concluded that drilling using coolant/ lubricant outperforms dry drilling by producing better quality parts. Also, varying the feed rate proved to be advantageous over drilling at constant feed.

Submitted by PAULO ROBERTO GOMES ALVES null (pauloalves@grad.itapeva.unesp.br) on 2016-03-19T13:35:12Z No. of bitstreams: 1 ANÁLISE DO ACABAMENTO SUPERFICIAL E DA POTÊNCIA CONSUMIDA NA USINAGEM DE FRESAMENTO FRONTAL E CILÍNDRICO TANGENCIAL DA MADEIRA DE EUCALIPTO.pdf: 4159341 bytes, checksum: 1aece2dc81a26f1c87e9e4d59ff0dd54 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-03-22T13:52:55Z (GMT) No. of bitstreams: 1 alves_prg_dr_guara.pdf: 4159341 bytes, checksum: 1aece2dc81a26f1c87e9e4d59ff0dd54 (MD5) / Made available in DSpace on 2016-03-22T13:52:55Z (GMT). No. of bitstreams: 1 alves_prg_dr_guara.pdf: 4159341 bytes, checksum: 1aece2dc81a26f1c87e9e4d59ff0dd54 (MD5) Previous issue date: 2016-02-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A expansão tecnológica e de mercado da madeira e produtos derivados de madeira industrializada, fazem com que as pesquisas dos processos que envolvem esse material sejam cada vez mais necessárias. O fresamento é um processo de usinagem muito utilizado na indústria, quando se pretende obter um acabamento superficial de qualidade. O presente trabalho teve por objetivo avaliar o desempenho do processo de usinagem de madeiras das espécies de Corymbia citriodora e Eucalyptus saligna, realizado em centro de usinagem CNC, através da análise do acabamento superficial e da potência consumida em operações de fresamento frontal e cilíndrico tangencial. As madeiras foram usinadas de forma tangencial em movimentos concordante e discordante, com profundidade de corte (ap) de 1,0 mm; de forma frontal nas direções perpendicular e paralelo em relação às fibras com (ap) de 5,0 mm. Como condições de usinagem, empregaram-se quatro velocidades de corte (Vc) 5,9; 8,4; 10,9; 13,4 m/s, e quatro velocidades de avanço (Vf) 3,0; 5,0; 7,0 e 9,0 m/min. Utilizou-se para os ensaios uma fresa helicoidal de metal duro maciço com três dentes e diâmetro de 16,0 mm. Foram analisados os resultados de Rugosidade Média (Ra) obtidos através de rugosímetro e potência consumida captada por sensor de efeito Hall, e verificado a integridade das superfícies fresadas através de microscópio eletrônico de varredura (MEV). Os resultados foram analisados pelo software Minitab e tratados estatisticamente através da análise de variância ANOVA e teste de Tukey. Concluiu-se que as melhores qualidades superficiais registradas ocorreram para as menores velocidades de avanço, maiores velocidades de corte, no fresamento tangencial para o corte discordante, no fresamento frontal para o corte paralelo às fibras da madeira. Para a potência média consumida, o menor valor médio ocorreu para as maiores velocidades de corte e a espécie citriodora, obteve melhor qualidade superficial quando comparado com a espécie saligna. / The technological expansion and market wood and derived from wood products industrialized make research processes involving this material are increasing necessary. Milling is a machining process commonly used in the industry, when applying for a surface finish quality. This study was to evaluate the performance of wood machining process of species Corymbia citriodora and Eucalyptus saligna realized out in CNC machining center, through the analysis of surface finish and the power consumed in tangential front and cylindrical milling operations. The woods were used tangentially on down-milling and up-milling movements, cutting depth of 1.0 mm; the front in parallel and perpendicular directions in relation to the fibers with cutting depth of 5.0 mm. As machining conditions, we used four cutting speeds of 5.9, 8.4, 10.9 and 13.4 m/s, and four feed speeds 3 5, 7 and 9 m/min. It was used for testing a helical cutter solid tungsten carbide tool with three teeth and diameter of 16 mm. The results were analyzed Roughness Average (Ra) obtained from roughness and power consumed captured by Hall effect sensor and the integrity of the machined surfaces obtained by scanning electron microscope. These results were analyzed by Minitab software and statistically analyzed by ANOVA and Tukey test. It is concluded that the best recorded surface qualities were obtained for lower feed rates, higher cutting speeds, the tangential milling cutting for up-milling in front for cutting parallel to the wood fibers. For the average power consumed, the lowest average value occurred for higher cutting speeds and the species citriodora, obtained better surface quality when compared with the species saligna. / CAPES: 00.889.834/0001-08

Calcium treatment is an established operation in the production of steels. Most importantly, it serves to modify detrimental inclusions in the melt for improved castability and superior product properties. Due to calcium’s low melting point and high vapour pressure, its addition to liquid steel is challenging and yields are generally low. The current standard method for addition is cored wire feeding, in which a calcium-bearing compound is injected into the melt inside a sacrificial metal tube. The depth at which the compound is released has a pronounced impact on its yield and depends on the rate at which the wire is injected. A mathematical model is constructed to predict the time after which release occurs and thus estimate injection depth. It is based on one-dimensional heat transfer and respects phase change effects, i.e., solidification of melt on the cold wire surface and subsequent melting of the wire and compound. Equations are derived using the finite difference method and the model is solved numerically using an implicit method. The model is applied to two different steel grades – one austenitic (AISI 316L), one super-duplex (SAF 2507) – and predictions are tested for the former grade in a 75-ton industrial ladle furnace. Results indicate that a decreased feeding rate (<100 m/min) leads to better calcium yield. Positive effects were also observed with downward melt stirring and a good slag coverage. Improved yield can lead to savings in process and material cost. The results also provide insights into the cored wire feeding process which may be useful for future process development, both for calcium and other additions. / Kalciumbehandling är en etablerad process vid tillverkning av stål. Framförallt används den för modifieringen av skadliga inneslutningar i smältan för att förbättra gjutbarheten och produktegenskaper. På grund av kalciums låga smältpunkt och höga ångtryck är det svårt att tillsätta det till flytande stål och utbytet är i allmänhet låg. Den nuvarande standardmetoden för tillsats är inmatning av tråd, där ett kalciumhaltig ämne matas in i smältan inuti en metallhölje som smälter bort. Djupet på vilket ämnet frigörs påverkar utbytet och beror på hur snabbt tråden matas. En matematisk modell konstrueras för att beräkna den tid efter vilken frisättning sker. Den bygger på endimensionell värmeöverföring och tar hänsyn till fasförändringseffekter, dvs. stelning av smältan på den kalla trådytan och smältning av tråd och kalciumämne efteråt. Ekvationer härleds med hjälp av finita differensmetoden och modellen löses numeriskt med hjälp av en implicit metod. Modellen tillämpas på två olika stålsorter – en austenitisk (AISI 316L) och en superduplex (SAF 2507) – och förutsägelser testas för den förstnämnda sorten i en 75-tons industriell skänkugn. Resultaten visar att en minskad matningshastighet (< 100 m/min) leder till ett ökat kalciumutbyte. Positiva effekter observerades med nedåtgående smältomrörning och god slaggtäckning. Ett förbättrat utbyte kan leda till besparingar i fråga om process- och materialkostnader. Resultaten ger också insikter i processen för inmatning av tråd, vilket kan vara användbart för framtida processutveckling, både för kalcium och andra tillsatser.

In this study, universal motion command generator systems utilizing a Field Programmable Gate Array (FPGA) and an interface board for Robotics and Computer Numerical Control (CNC) applications have been developed. These command generation systems can be classified into two main groups as polynomial approximation and data compression based methods. In the former type of command generation methods, the command trajectory is firstly divided into segments according to the inflection points. Then, the segments are approximated using various polynomial techniques. The sequence originating from modeling error can be further included to the generated series. In the second type, higher-order differences of a given trajectory (i.e. position) are computed and the resulting data are compressed via lossless data compression techniques. Besides conventional approaches, a novel compression algorithm is also introduced in the study. This group of methods is capable of generating trajectory data at variable rates in forward and reverse directions. The generation of the commands is carried out according to the feed-rate (i.e. the speed along the trajectory) set by the external logic dynamically. These command generation techniques are implemented in MATLAB and then the best ones from each group are realized using FPGAs and their performances are assessed according to the resources used in the FPGA chip, the speed of command generation, and the memory size in Static Random Access Memory (SRAM) chip located on the development board.

Dans le processus de fabrication en fraisage à grande vitesse ‘FGV’, l’étude de la réaction de la machine au cours de l’usinage est une tâche très délicate et importante. En effet, l’identification du comportement de la machine nécessite la modélisation de la loi de mouvement des axes et de la trajectoire réelle aux niveaux des discontinuités. Le nombre important de discontinuités engendrent une instabilité de la vitesse de déplacement des axes, ce qui implique une augmentation du temps d’usinage et un non-respect de la vitesse d’avance programmée, se traduisant par des problèmes de productivité et une sous-estimation du coût de l’usinage pour l’industriel. L’objectif de cette thèse est de développer un outil informatique qui permet de calculer la vitesse d’avance et de faire une estimation précise du temps de cycle pour n’importe quelle trajectoire générée par un logiciel de FAO. Pour ce faire, nous avons déterminé un modèle qui permet d’identifier le comportement cinématique des axes d’un centre d’usinage en FGV pour toute forme de trajectoire. À partir de la modélisation de la variation de la vitesse d’avance, nous avons déterminé le temps réel selon les trajectoires et l’erreur imposée par le bureau des méthodes. Enfin, nous utilisons ces résultats pour mettre en place une méthodologie pour l’aide au choix du diamètre de l’outil et de la stratégie d’usinage. Afin de valider les modèles et les méthodologies développés, une étude expérimentale a été réalisée sur des applications didactiques et industrielles. / In the context of high speed milling ‘‘HSM’’, the feed rate does not always reach the programmed value during the machining process which implies an increase of machining time and non-compliance with the programmed feed rate. This phenomenon leads to productivity issues and an underestimation of the cost of machining for the industry.The aim of this study is to develop a computerised tool in order to automate the determination process of the evolution of the feed rate for an imposed error and the estimation of cycle time and production cost. To begin with,a modeling approach in order to evaluate feed rate during any type of discontinuity between linear and circular contours in different combination by taking into account the specific machining tolerances.is presented. Then, the cycle time will be estimated with a maximum error of 7% between the actual and the prediction cycle time. The proposed method permits to develop a methodology to determine the optimal diameter of the tool and the optimal strategy. Finally, an industrial application was carried out in order to validate models and to determine the influence of feed rate evolution on the cycle time.

Twin screw wet granulation has been proved as a feasible alternative for traditional batch granulation process due to its continuous processing feature; considered as a significant processing method especially in the pharmaceutical industry. This thesis will explore the processibility of twin screw wet granulation with various formulations. The first section of the thesis focused on examining the processibility of wet granulation in a twin screw while using various grades of hydroxypropyl methylcellulose (HPMC) as an extended-release excipient. The method to find the processibility was by modifying the liquid-to-solid ratio for each formulation. The process window was defined by examining the amount of granules that fall in a pre-determined acceptable size range. This part focused on three substitution types of HPMC (Type 2910, Type 2208, and Type 2906) that varied in molecular weights. It was found that only Type 2910 HPMC showed a shift in the process window (also known as granulation range) in relation to the molecular weight of the formulations. A higher demand for binder liquid was found for higher molecular weight Type 2910 HPMC in order to form granules with acceptable sizes. The second part of this thesis was focused on understanding the process variables that might influence the processibility of the HPMC formulations. This part examined the impact of feed rate on the granulation range of Type 2910 HPMC specifically was examined. Multiple feed rates were tested, and it was found that the granulation range for lower molecular weight Type 2910 HPMC was easier to shrink when higher feed rates were applied. A transition in the granule formation method from liquid-bridging to compaction with respect to the feed rate was found for low molecular weight HPMC, whereas the high molecular weight HPMC always formed granules through compaction at all feed rates due to strong water retainability. / Thesis / Master of Applied Science (MASc)

This study deals with technology of abrasive water jet material cutting and influence of cutting head feed rate on surface topography of cut walls with regards to roughness. Eight parameters were chosen based on the CSN EN ISO 4288 standard representing quality of surface after AWJ cutting. When AWJ cutting the chosen material – commercially pure ASTM B265 grade 2 titanium – feed rate was being changed and in order to obtain information about each parameter´s distribution in various depths of the cut, surface composition was evaluated. It was found out that feed rate has significant influence on surface and that the profile elements´ width grows when increasing the feed rate and cut depth. Furthermore, two selected feed rate results were compared to laser beam technology and conclusion for the selected material was made that AWJ cutting is more preferable due to final roughness and no heat affect on the material.