O objetivo do presente trabalho é analisar a influência de alguns parâmetros de usinagem na qualidade geométrica e superficial da peça. O brochamento é uma operação de usinagem antiga, a qual se desenvolveu com a indústria automobilística, mas que atualmente pode ser encontrada em diversos segmentos industriais. O processo consiste em uma remoção progressiva do material pela ação de uma ferramenta de corte multi-arestas. Este processo é capaz de, em um único ciclo, realizar as operações de desbaste e acabamento da peça em virtude da combinação de uma geometria adequada da ferramenta, tornando esta uma importante característica deste processo. Para o trabalho em questão, foi analisado um processo brochamento de acabamento na usinagem de blocos fabricados em ferro fundido. Este material foi escolhido por estar bastante presente na indústria de transformação devido à boa usinabilidade. Os resultados foram obtidos em medições com aparelhos eletrônicos e através de análise estatística foi avaliado o grau de interferência dos fatores para as características estudadas. Os resultados mostraram que os fatores e suas combinações interferem de forma diferente para cada característica analisada. Na maioria das situações analisadas, os fatores que individualmente apresentam significância para determinada característica, quando combinados entre si também podem interferir no resultado, este fato fica evidenciado com a análise dos resultados obtidos com as ferramentas diamantadas. / The objective of the present paperwork is to analyze the influence of some machining parameters on the geometrical and surface qualities of the work piece. The broaching is an old machining operation, which was developed with the automobile industry, but which nowadays can be found in diverse industrial segments. The process consists on a progressive removal of the material by a multi-edge cutting tool. This process is able of, in a single cycle, do the operations of the part\'s looping and finishing because of a peculiar geometrical configuration of the tool, what is an important characteristic of this process. For the paperwork on proposal, it was analyzed a process broaching of finishing in the machining of blocks made of cast iron. This material was chosen for being very present in the transformation industry due to its machinability. The results were obtained on measurements with electronic devices, and through statistical analysis it was analyzed the degree of interference of the factors to the studied characteristics. The results showed which the factors and its combinations interfere on a different way for each analyzed characteristic. In the most of the analyzed situations, the factors which individually present significance for determined characteristic, when combined among themselves, can interfere in the result too. This fact becomes evident with the analysis of the obtained results with the diamonded tools.

O objetivo do presente trabalho é analisar a influência de alguns parâmetros de usinagem na qualidade geométrica e superficial da peça. O brochamento é uma operação de usinagem antiga, a qual se desenvolveu com a indústria automobilística, mas que atualmente pode ser encontrada em diversos segmentos industriais. O processo consiste em uma remoção progressiva do material pela ação de uma ferramenta de corte multi-arestas. Este processo é capaz de, em um único ciclo, realizar as operações de desbaste e acabamento da peça em virtude da combinação de uma geometria adequada da ferramenta, tornando esta uma importante característica deste processo. Para o trabalho em questão, foi analisado um processo brochamento de acabamento na usinagem de blocos fabricados em ferro fundido. Este material foi escolhido por estar bastante presente na indústria de transformação devido à boa usinabilidade. Os resultados foram obtidos em medições com aparelhos eletrônicos e através de análise estatística foi avaliado o grau de interferência dos fatores para as características estudadas. Os resultados mostraram que os fatores e suas combinações interferem de forma diferente para cada característica analisada. Na maioria das situações analisadas, os fatores que individualmente apresentam significância para determinada característica, quando combinados entre si também podem interferir no resultado, este fato fica evidenciado com a análise dos resultados obtidos com as ferramentas diamantadas. / The objective of the present paperwork is to analyze the influence of some machining parameters on the geometrical and surface qualities of the work piece. The broaching is an old machining operation, which was developed with the automobile industry, but which nowadays can be found in diverse industrial segments. The process consists on a progressive removal of the material by a multi-edge cutting tool. This process is able of, in a single cycle, do the operations of the part\'s looping and finishing because of a peculiar geometrical configuration of the tool, what is an important characteristic of this process. For the paperwork on proposal, it was analyzed a process broaching of finishing in the machining of blocks made of cast iron. This material was chosen for being very present in the transformation industry due to its machinability. The results were obtained on measurements with electronic devices, and through statistical analysis it was analyzed the degree of interference of the factors to the studied characteristics. The results showed which the factors and its combinations interfere on a different way for each analyzed characteristic. In the most of the analyzed situations, the factors which individually present significance for determined characteristic, when combined among themselves, can interfere in the result too. This fact becomes evident with the analysis of the obtained results with the diamonded tools.

Les travaux présentés dans cette thèse visent à améliorer la compréhension des phénomènes physiques induits lors d'une opération de brochage. L'objectif final est le développement d'une méthode robuste pour la conception de broches en carbure de tungstène. Pour cela, un état de l'art détaillant les pratiques technologiques ainsi que les analyses scientifiques de ce procédé est réalisé. Une étude élémentaire de la coupe d' Udimet 720 est mise en œuvre avec des conditions expérimentales testées sur un vaste domaine de manière à définir leur influence sur l'évolution des sollicitations d'usinage, de l'usure de l'outil et de la qualité de la matière produite. Une méthodologie de conception adaptée au brochage d'alvéoles pied de sapin par des broches en carbure de tungstène est développée. En s'appuyant sur des modèles empiriques dérivés des campagnes expérimentales et sur un logiciel interne, cet usinage peut être simulé. L'exploitation des résultats permet d'estimer la durée de vie du jeu de broches, de vérifier son dimensionnement et de calculer sa rentabilité. La nouvelle méthode est appliquée sur deux cas industriels : le premier proche des contraintes de production et le second débridé afin d'exprimer le potentiel maximal de cette technologie. Au final, les gains réalisables sur le coût par pièce en développant le brochage avec des outils en carbure de tungstène sont estimés entre 60 et 80 % / The work presented in this thesis aims to improve the understanding of the physical phenomena induced by a broaching operation. The end goal is the development a robust method for designing tungsten carbide broaches. For this purpose, a state of the art detailing the technological practices as well as the scientific analyses of this process is realized. An elementary study of the Udimet 720 cut is carried out with experimental conditions varied over a wide range in order to define their influence on the evolution of the machining stresses, the wear of the tool and the quality of the material produced. A design methodology adapted to the broaching of fir tree slots by tungsten carbide broaches is developed. Based on empirical models derived from experimental campaigns and an internal software, this machining can be simulated. The exploitation of the results makes it possible to estimate the lifetime of the broaches, to verify its dimensioning and to calculate its profitability. The new method is carried out on two industrial cases: the first close to the production constraints and the second unbridled in order to express the maximum potential of this technology. In the end, the achievable gains on the cost per piece by developing the broaching with tungsten carbide tools are estimated between 60 and 80 %.

Bearbetningsprocesser är en viktig del av tillverkningsindustrin. Dessa företag måste kontinuerligt förbättra sina processer och göra dem mer effektiva, minska de ekologiska fotavtrycken och driftskostnaderna. Syftet med denna rapport är att förbättra en rund brotschningsprocess för ett bilföretag. Brotschverktyget är tillverkat av solid HSS och belagt med TiN, som dras genom ett hål i arbetsstycket. På grund av att flera skärkanter fungerar samtidigt är skärkraften hög. Med skärverktygets lågavlastningsvinkel spelar smörjmedlet en kritisk roll i brotschningsprocessen. Arbetet studerar olika skärvätskor i ett laboratorium, genom att simulera påverkan av skärvätskor i en brotschningsprocess med tappningsoperationer under liknande förhållanden. Momentvärdena och beteendet av processen har studerats för de olika smörjmedlen. Studien visade att smörjmedlet har en stor påverkan på vridmoment och spånbildningen. Relationen mellan smörjviskositet och smörjningsförmåga studerades. Dessutom undersöktes sambandet mellan spånbildning och vridmomentbeteende, vilket visar vikten av spånens utrymningskapacitet. Processen har utförts genom att använda olika typer smörjmedel för att undersöka deras påverkan på skärkrafterna och hur de utvecklades under hela processen. Resultaten och den efterföljande analysen har visat att viskositeten har stort inflytande i processen. Viskositeten är omvänt proportionell mot vätskans kapacitet för att komma åt vissa kritiska områden, vilket ökar friktionskrafterna och genereringen av långa spån. Både spånstorleken och smörjmedlets förmåga att utrymma har starka influenser på processen. / Machining processes are an important part of the manufacturing industry. Companies within the manufacturing industry are required to continuously improve their processes and make them more efficient, to reduce the ecological impact and operational costs. The aim of this thesis is to be able to improve a circular broaching process for an automotive company. The broaching tool is made from solid High-Speed Steel and TiN coated, which is pulled through a hole in the workpiece. Due to multiple cutting edges acting simultaneously, the cutting force is high. With a low relief angle of the cutting tool and low cutting speed, the lubricant plays a critical role in the broaching process. The thesis studies different cutting fluids in a laboratory, by simulating the impact of cutting fluids in a broaching process with tapping operations under similar conditions. The torques values and the behaviour of it during the process have been recorded for different lubricants. The lubricants were found to have a strong influence in the torque required and the chip formation. The relation between lubricant viscosity and lubrication performance was studied. In addition, the relation between chip formation and torque behaviour was explored, showing the importance of chip evacuation capacity. The process has been carried out by using different lubricants to examine the required cutting forces and how they evolved throughout the process. The results and the consecutive analysis have shown an influence of the viscosity in the process. The viscosity is inversely proportional to the capacity of the fluid to access certain critical areas, increasing the friction forces and the generation of long chips. Both the chip size and the ability of the lubricant to evacuate have strong influences on the process.

Counselor educators are responsible for training counselors-in-training (CITs), equipping them with knowledge and skills to best serve racially diverse clients (CACREP, 2015). CITs may demonstrate multicultural competence by broaching race, or inviting clients to consider the extent to which race contributes to one's presenting problem (Day-Vines et al., 2017). Practicum and Internship experiences offer counselor educators the opportunity to prepare CITs to broach race through group supervision. Thus, this interpretative phenomenological analysis aimed to explore experiences of Black counselor educators in CACREP-accredited counseling programs, as their voices have historically been overlooked in scholarship (Haskins and Singh, 2015). Five GETs were revealed including: (a) Degree of Multiculturalism in Counseling Program, (b) Regular Conversations of Race, (c) Defining Broaching, (d) Centering Clients' Culture, and (e) Feeling Tension with Students as well as three divergent experiences. Overall, these findings highlight the ways in which Black counselor educators navigate the task of supporting CITs with the broaching intervention. This study illuminates what counselor education programs, counselor educators, and CACREP can do to improve what is currently being done about broaching preparation in counselor education. / Doctor of Philosophy / Counselor educators are responsible for training counselors-in-training (CITs), equipping them with knowledge and skills to best serve racially diverse clients (CACREP, 2015). CITs may demonstrate multicultural competence by broaching race, or inviting clients to consider the extent to which race contributes to one's presenting problem (Day-Vines et al., 2017). Practicum and Internship experiences offer counselor educators the opportunity to prepare CITs to broach race through group supervision. Thus, this qualitative study aimed to explore experiences of Black counselor educators in CACREP-accredited counseling programs, as their voices have historically been overlooked in scholarship (Haskins and Singh, 2015). Five GETs were revealed including: (a) Degree of Multiculturalism in Counseling Program, (b) Regular Conversations of Race, (c) Defining Broaching, (d) Centering Clients' Culture, and (e) Feeling Tension with Students as well as three divergent experiences. Overall, these findings highlight the ways in which Black counselor educators navigate the task of supporting CITs with the broaching intervention. This study illuminates what counselor education programs, counselor educators, and the accrediting body for counselor education programs can do to improve what is currently being done about broaching preparation in counselor education.

In this dissertation, the extended Melnikov's method has been applied to several nonlinear ship dynamics models, which are related to the new generation of stability criteria in the International Maritime Organization (IMO). The advantage of this extended Melnikov's method is it overcomes the limitation of small damping that is intrinsic to the implementation of the standard Melnikov's method. The extended Melnikv's method is first applied to two published roll motion models. One is a simple roll model with nonlinear damping and cubic restoring moment. The other is a model with a biased restoring moment. Numerical simulations are investigated for both models. The effectiveness and accuracy of the extended Melnikov's method is demonstrated. Then this method is used to predict more accurately the threshold of global surf-riding for a ship operating in steep following seas. A reference ITTC ship is used here by way of example and the result is compared to that obtained from previously published standard analysis as well as numerical simulations. Because the primary drawback of the extended Melnikov's method is the inability to arrive at a closed form equation, a 'best fit'approximation is given for the extended Melnikov numerically predicted result. The extended Melnikov's method for slowly varying system is applied to a roll-heave-sway coupled ship model. The Melnikov's functions are calculated based on a fishing boat model. And the results are compared with those from standard Melnikov's method. This work is a preliminary research on the application of Melnikov's method to multi-degree-of-freedom ship dynamics. In the last part of the dissertation, the method of manufactured solution is applied to systems with chaotic behavior. The purpose is to identify points with potential numerical discrepancies, and to improve computational efficiency. The numerical discrepancies may be due to the selection of error tolerances, precisions, etc. Two classical chaotic models and two ship capsize models are examined. The current approach overlaps entrainment in chaotic control theory. Here entrainment means two dynamical systems have the same period, phase and amplitude. The convergent region from control theory is used to give a rough guideline on identifying numerical discrepancies for the classical chaotic models. The effectiveness of this method in improving computational efficiency is demonstrated for the ship capsize models. / Ph. D.

Le procédé de brochage est aujourd’hui, et depuis plus de cinquante ans, le procédé le plus utilisé par les motoristes aéronautiques pour usiner les alvéoles pied de sapin des disques de turbine. Les travaux présentés dans cette thèse visent à améliorer la compréhension du procédé de brochage dans le but d’améliorer la performance de ce procédé. Ils sont décomposés en quatre étapes, une étude sur la coupe de l’Udimet 720®, la modélisation des broches pied de sapin et des efforts de coupe, une étude expérimentale du brochage des alvéoles pied de sapin et finalement une proposition de surveillance de ce procédé. Une étude de la coupe en brochage de l’Udimet 720® est réalisée pour pallier le manque d’études actuel sur ce superalliage et développer des lois de coupe pour la simulation des efforts. La simulation permet d’associer à chaque partie discrétisée de chaque dent de la broche des efforts spécifiques en fonction des différents paramètres d’usinage. Les essais de brochage d’alvéole pied de sapin instrumentés ont servi à vérifier la pertinence de la simulation et à proposer, à partir de cette dernière, des choix de conception visant à améliorer la performance du procédé. La surveillance en usinage propose une stratégie visant à détecter différentes anomalies d’usinage pour limiter le risque de rebut de pièces à fortes valeurs ajoutées. / From more than fifty years ago, the broaching process is what the aeronautic engine manufacturers use the most to machine turbine disc fir-tree slots. The aim of this thesis is to improve the understanding of the broaching process in order to optimize the efficiency of this process. This study is divided into four steps: a study of Udimet 720® machinability, the modelization of fir-tree slot broaches and of cutting forces, an experimental study of fir-tree slots broaching and finally, a proposed method of process monitoring. A study of Udimet 720® machinability is made to fill the lack of current studies about this superalloy and to develop cutting forces model for the modelization of the broaching process. Modelization allows the association of specific forces to each discretized broach tooth according to various machining parameters. Fir tree slots broaching trials were used to check the accuracy of modelization and to suggest, according to the latter, conception choices aiming at improving the efficiency of the process. Process monitoring, in the broaching field, offers a strategy which purpose is to detect various machining disturbances and to limit the risk of rejected parts with high added value.

With the advancement of sensor technology and data processing capacities, various types of high volume data are available for process monitoring and prognostics in manufacturing systems. In a broaching process, a multi-toothed broaching tool removes material from the workpiece by sequential engagement and disengagement of multiple cutting edges. The quality of the final part, including the geometric integrity and surface finish, is highly dependent upon the broaching tool condition. Though there has been a considerable amount of research on tool condition monitoring and prognostics for various machining processes, the broaching process is unique in the following aspects: 1) a broaching process involves multiple cutting edges, which jointly contribute to the final part quality; 2) the resharpening and any other process adjustments to the tool can only be performed with the whole broaching tool or at least a whole segment of the tool replaced. The overarching goal of this research is to explore how engineering knowledge can be used to improve process monitoring and prognostics for a complex manufacturing process like broaching. This dissertation addresses the needs for developing new monitoring and prognostics approaches based on various types of data. Specifically, the research effort focuses on 1) the use of in-situ force profile data for real-time process monitoring and fault diagnosis, 2) degradation characterization for broaching processes on an individual component level based on image processing; and 3) system-level degradation modeling and remaining useful life prediction for broaching processes based on multiple images. / Ph. D. / Big data have been providing both opportunities and challenges for product quality assurance and improvement in modern manufacturing systems. In aerospace industry, broaching processes are one of the most important manufacturing processes as they are used to produce the turbine discs in the jet engine. Nonconforming turbine disc quality, either in terms of compromised surface finish or geometry accuracy, will lead to malfunction or even catastrophic failures in the aircraft engines. One of the major sources that lead to nonconforming product quality is excessive tool wear accumulation and other abrupt malfunctions of the broaching tools. In broaching processes, multiple cutting edges are sequentially pushed or pulled through the workpiece, and each cutting edge is responsible to shape the workpiece into a specific intermediate shaped contour. Therefore, a broaching process can be regarded as a multistage manufacturing process with variation propagating through the multiple cutting edges. The overarching goal of this dissertation is to explore how process knowledge can be used to improve process monitoring and prognostics for a complex manufacturing process like broaching. This dissertation focuses on the quality assurance and improvement for broaching processes which includes: 1) timely abrupt process fault detection; 2) tool performance degradation quantification; and 3) remaining tool life prediction, which contributes to both methodological development and practical applications in advanced sensing analytics in manufacturing systems.