Orientador: João Eduardo Guarnetti dos Santos / Banca: Jair Rosas da Silva / Banca: Luis Gonzaga Campos Porto / Resumo: O setor da cana-de-açúcar sempre foi muito bem visto no Brasil; nos séculos XVI e XVII com a grande aceitação do açúcar no mercado europeu e alto valor financeiro agregado ao produto, houve uma grande expansão do setor no nordeste brasileiro devido à adaptação da plantação ao clima e à grande presença do trabalho escravo africano no cultivo. Na década de 70 do século XX houve um salto do setor sucroenergético com a produção do etanol como fonte alternativa de energia e à fabricação do carro a álcool em um período de altas do petróleo no mercado mundial. Junto com a rápida evolução do setor sucroenergético, vieram também os problemas ecológicos e sociais. Grandes corporações subsidiadas pelo Governo Federal no Projeto Próacool, recebiam as verbas e benefícios para uma produção mais eficiente e limpa. Com todos esses problemas, no final da década de 80 do século XX, o setor entrou em desaceleração. No início do século XXI o setor vive uma oportunidade histórica, pois com o fim anunciado das reservas de petróleo e as catástrofes devido às mudanças climáticas causadas pelo homem, hoje o etanol brasileiro é visto pelo mundo como uma fonte alternativa e sustentável; sem contar com o alto valor do açúcar pelo mercado europeu como nos séculos XVI e XVII. Mas o setor não é só alegria, pois luta contra os problemas de vivência dos tratos dos trabalhadores do setor, que se assemelha muito ao trabalho escravo sofrido pelos africanos no período áureo do açúcar. Apesar de o governo fiscalizar e criar novas leis, como a NR 31 (Norma Regulamentadora - Segurança e Saúde no trabalho na agricultura, pecuária silvicultura, exploração florestal e aquicultura); os trabalhadores do setor sucroenergético tem tido pouca atenção dos profissionais que desenvolvem produtos para este setor. Tudo que se é exigido... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The sector of cane sugas has always been well regarded in Brazil, in the sixteenth and seventheenth centuries with great acceptance in the European market for sugar and high value added to the product, there was a great expansion of the sector in northeastern Brazil due to adaptation plantation climate and large presence of African slave labor in cultivation. In the 70s of the twentieth century there was a jump of the sugarcane industry with the production of ethanol as an alternative energy source and manufacture the car with alcohol in period of high oil on the world market. Along with the rapid development of the sugarcane industry, came also the ecological and social problems. Large corporations subsidized by the Federal Government in Proálcool Project, received the money and benefits for a cleaner and more efficient production. With all these problems in the late 80s of the twentieth century, the industry went into deceleration. At the beginning of the XXI century industry is experiencing a historic opportunity, because with the announced end of oil reserves and disasters due to climate change caused by humans, today Brazilian ethanol is seen by the world as an alternative and sustainable source, not counting the high amount of sugar in the European market as the sixteenth and seventeenth centuries. But the industry is not only joy, for combating the problems of living the treatment of workers in the sector, which closely resembles slave labor suffered by Africans in the heyday of sugar. Althrough the government oversee and create new laws, as the NR 31 (Norm - Safety and Health at Work in agriculture, forestry livestock, forestry and aquaculture); workers in the sugarcane industry has had little attention from professionals who develope products for this sector. All that is required is adapted from another industry... (Complete abstract click electronic access below) / Mestre

As empresas não mais podem pensar em desenvolvimento econômico sem a paralela preservação do meio-ambiente e do benefício mútuo da sociedade. É importante que as condições econômicas e sociais sejam melhoradas ao longo do tempo, sem exceder a capacidade de suporte do planeta. As indústrias podem contribuir para melhorar esse cenário aplicando uma gestão sustentável de manufatura, uma vez que estes são um dos principais agentes causadores de impactos. No entanto, para que consigam aprimorar a sustentabilidade de seus processos, é indispensável, antes de tudo, conhecer o seu real desempenho. O presente trabalho tem como objetivo principal desenvolver um método estruturado e simples para a avaliação de desempenho em sustentabilidade de processos de manufatura, permitindo a construção de relatórios de sustentabilidade mais precisos, periódicos e que venham a apoiar o processo de tomada de decisão gerencial. Embora modelos para a avaliação de desempenho em sustentabilidade tenham sido apresentados nos últimos anos, como o guia GRI, estes ainda carecem de critérios e regras para realizar análises mais precisas e integradas. O método proposto pode ser aplicado em dois processos de manufatura distintos, comprovando a sua eficácia e robustez. Ele é usado para analisar e comparar o desempenho em sustentabilidade de dois processos de usinagem, Retificação e Torneamento de Metais Endurecidos. Esses processos concorrem entre si em algumas faixas de atuação, tornando difícil a decisão sobre qual dos dois processos é o ideal para a produção de determinadas peças. Por meio do trabalho, foi possível comprovar a superioridade do processo de retificação em termos de ganhos econômicos, com a contrapartida de pior desempenho ambiental / Companies can no longer consider economical development without the parallel preservation of the environment and mutual benefit of the society. It is important that the economic and social conditions are improved over time, without exceeding the planet carrying capacity. Industries can contribute to improve this scenario by using cleaner and more efficient technologies, since they are one of the main sources of impacts. However, for them to improve their processes sustainability, it is essential to use an assessment tool which is able to evaluate their performance properly. The main goal of this work is to provide a structured and simple method for assessing sustainability performance of manufacturing processes, allowing the construction of more accurate and frequent sustainability reports, that may support the managerial decision making process. Although sustainability performance assessment models have been presented in recent years, as the GRI, there are still a lack of criteria and rules for carrying out more accurate and integrated assessments. The proposed method was able to be applied in two different manufacturing processes assessments, proving its effectiveness and robustness. It was used to analyze and compare the sustainability performance of two machining processes, grinding and hard turning. These processes compete with each other on some applications, making it difficult to decide which of the two processes is ideal for the production of certain parts. Through the study, it is demonstrated the grinding process superiority in terms of economic gains, at the cost of a higher environmental burden

O propósito deste trabalho é estudar as forças de corte envolvidas no processo de fresamento de bordas de chapas utilizadas para a fabricação de tubos de aço com costura e como estas variam em função dos parâmetros de corte utilizados. O objetivo é correlacionar estas forças à qualidade do acabamento superficial das bordas usinadas, uma vez que esta é fundamental para a qualidade final da solda do tubo. Para isso, foi construído um dinamômetro de mesa para medição das forças, e os dados foram analisados através do Método da Regressão Linear Múltipla. Os resultados obtidos demonstraram que, tanto para a força de corte quanto para a rugosidade da superfície usinada, o parâmetro que mais influencia é o avanço por dente, seguido pela largura de corte, sendo que o que menos influencia é a velocidade de avanço. Estes resultados foram comprovados com êxito no processo industrial foco deste estudo através da medição da corrente elétrica dos motores dos eixos-árvore e da vibração dos mesmos. / This work aims to study the cutting forces involved in the edge milling process for welded pipes manufacturing and how these forces vary due to the cutting parameters. The objective is to create a relationship between these forces and the surface roughness of the machined edges, once it\'s fundamental to the pipe weld quality. To do this, it was designed and manufactured a dynamometer, and the data was analyzed statistically by the Linear Multiple Regression Method. The results show that for the cutting forces as well as the surface roughness, the most significant parameter is the feed per tooth, followed by the cutting width and the feed speed. These results were successfully proven on the industrial process that is the focus of this study, through the spindle motors electric current and its vibration.

O planejamento de processos é uma atividade essencial nas diversas etapas do ciclo de manufatura, em particular nas indústrias que produzem peças através de processos de usinagem. O uso de sistemas CAPP tem implicado em uma evolução nos sistemas de planejamento. A determinação da máquina, da ferramenta e das condições operacionais adequadas visando a otimização das diversas operações é fundamental para o sucesso do processo produtivo e da empresa, podendo ser melhorado pelo uso do CAPP. Estudam-se, assim, os fatores que influenciam esse tipo de processo, propondo-se um modelo de sistema protótipo para o seu planejamento, de forma a se ter no final uma especificação teórica da profundidade de corte, do avanço e da velocidade de corte, considerando aspectos como a usinabilidade do material da peça, os tempos de fabricação secundários e auxiliares, e a própria logística aplicada ao fluxo de peças no chão-de-fábrica através da definição quanto à máquina empregada ser ou não gargalo além de considerações sobre a disponibilidade de carga-máquina. Procurou-se elaborar um critério de otimização que considere não apenas o intervalo de máxima eficiência como proposto por vários autores, mas discuta a aplicação de seus limites e as restrições do sistema máquina-ferramenta-peça. Além do planejamento teórico o sistema possui um módulo de ensaios práticos visando refinar os valores teóricos da velocidade de corte adotada para garantir a sua perfeita aplicação com a máquina e a ferramenta adotados. A proposta do sistema é semi-generativa, unindo soluções algorítmicas e baseadas em conhecimento, com uma interface simples e amigável ao usuário. / Process planning is an essential activity in the several stages of the manufacturing cycle, particularly in industries which produce parts by means of machining processes. The use of CAPP systems has implied in a planning systems evolution. The determination of machine, tooling and suitable operational conditions looking at the optimization of the several operations is fundamental to the success of the productive process and of the enterprise, and can be improved by use of CAPP systems. It was studied the factors which influence this kind of process and it was proposed a prototype system model for this planning and for obtaining a theoretical specification of the depth of cut, feed and cutting speed, taking into consideration aspects like machinability of the part material, secondary and auxiliary manufacturing times, and the logistics applied to the flow of parts at the shop-floor through the definition of the used machine to be or not a production neck beyond considerations on the availability of machine capacity. It was proposed an optimization criterion which considers not only the maximum efficiency interval as quoted by many authors but also discuss the application of its limits and the restrictions of the system machine-tool-part. Besides the theoretical planning the system has a practical testing module intended to refine the theoretical values of the adopted cutting speed to guarantee its application to the defined machine and tooling. The system approach is semi-generative, with algorithmic and knowledge based solutions, with a simple and user-friendly interface.

Burnishing is a chipless finishing process used to improve surface integrity by severe plastic deformation (SPD) of surface asperities. As surface integrity in large measure defines the functional performance and fatigue life of aerospace alloys, burnishing is thus a means of increasing the fatigue life of critical components, such as turbine and compressor blades in gas turbine engines. Therefore, the primary objective of this dissertation is to characterize the burnishing-induced surface integrity of Ti-6Al-4V alloy in terms of the implemented processing parameters. As the impact of cooling mechanisms on surface integrity from SPD processing is largely unexplored, a particular emphasis was placed upon evaluating the influence of cryogenic cooling with liquid nitrogen in comparison to more conventional methodologies. Analysis of numerical and experimental results reveals that burnishing facilitates grain refinement via continuous dynamic recrystallization. Application of LN2 during SPD processing of Ti-6Al-4V alloy suppresses the growth of new grains, leading to the formation of near-surface nanostructures which exhibit increased microhardness and compressive residual stress fields. This is particularly true in cryogenic multipass burnishing, where successive tool passes utilizing lower working pressures generate thermally stable work hardened surface layers, uniform nano-level surface finishes, and significantly deeper layers of compressive residual stresses.

Four main aspects are studied and explored throughout this dissertation: (1) On-Package Multipolar antenna system design for integration with commercial wireless sensor nodes for machine-to-machine communication applications; (2) Development of a novel MMIC packaging process and subsequent antenna integration for chip-to-chip communication applications, (3) Design and characterization of additively manufactured lumped passive elements for integration with MMIC and hybrid circuits, (4) Design and characterization of antennas for on- and off-metal radio frequency identification (RFID) applications. This work presents the design of different 3-D printed tripolar antenna systems operating at 2.4 GHz. The antennas are designed for integration with commercial wireless nodes with the purpose of mitigating multipath and depolarization channel effects that might be present in many machine-to-machine (M2M) deployments. The antennas are fabricated utilizing an additive manufacturing (AM) approach that combines fused deposition modeling (FDM) of ABS plastic for dielectric parts and micro-dispensing of silver paste Du-Pont CB028 for conductive layers as the majority of the devices presented in this work. Over the air testing demonstrates a 1% channel improvement of up to 14 dB, achieved in a highly-reflective, Rayleigh-like fading environment by implementing selection diversity between three mutually orthogonal monopoles. This improvement leads to better bit error rate (BER) performance (as is also shown). Additionally, RSSI measurements show significant improvement when the prototype antenna system is integrated with commercial wireless sensor hardware. Implications of tripolar antenna integration on M2M systems include reduction in energy use, longer communication link distances, and/or greater link reliability. In order to incorporate the proposed multipolar selection diversity technique into short range wireless chip-to-chip communications, a novel and versatile 3D printed on-chip integration approach using laser machining is subsequently demonstrated for microwave and mm-wave systems in a process herein referred to as Laser Enhanced or Laser Assisted Direct Print Additive Manufacturing (LE-DPAM). The integration process extends interconnects laterally from a MMIC to a chip carrier. Picosecond laser machining is applied and characterized to enhance the 3D printing quality. Specifically, the width of micro-dispensed printed traces is accurately controlled within micrometer range (e.g. laser cuts ~12 μm wide), additionally, 150 μm probe pads are cut in order to facilitate RF measurement. The S-parameters of a distributed amplifier integrated into the package are simulated and measured from 2 to 30 GHz. It is seen how the overall performance is significantly better than a traditional wirebonded QFN package and previously reported AM MMIC interconnections. The attenuation of the microstrip line including interconnects is only 0.2 dB/mm at 20 GHz and return loss with the package is less than 10 dB throughout the operating frequency band A 17 GHz package integrated linearly polarized patch antenna, fabricated with a multi-layer and multi-material LE-DPAM process is then introduced for vertical interconnection with a MMIC die. Performance is successfully measured and characterized achieving a return loss greater than 19 dB at the desired design frequency. Good agreement between simulated and measured radiation patterns is also obtained with a peak gain of 4.2 dBi. Another section of this work utilizes LE-DPAM to fabricate lumped capacitors and inductors for coplanar waveguide (CPW) circuits, especially useful for filtering and matching network implementation. Laser machining is used to achieve ~12 µm slots on printed conductors, producing aspect ratios greater than 2:1, as well as to fabricate vertical interconnects or vias that allow for the fabrication of the multilayer inductors. Inductances in the range of 0.4-3 nH are achieved, with a maximum quality factor of 21, self-resonance frequencies up to 88 GHz, and an inductance per unit of area of 5.3 nH/mm2. Interdigital capacitors in the range of 0.05-0.5 pF are fabricated, having a maximum quality factor of 750 and self-resonances up to 120 GHz. All the components are made on the center line of a CPW that is 836 µm wide. The results show that LE-DPAM enables the fabrication of compact passive circuits that can be easily interconnected with MMIC dies, which at the same time, can be manufactured as part of a larger component. This enables the fabrication of structural electronics that are functional into the mm-wave frequency range. A final aspect of this work goes through antenna designs for specific RFID (radio frequency identification) applications. RFID tag design is generally focused specifically on either off-metal or on-metal configurations. In this work passive 2D and 3D RFID tags are presented which perform similarly in both configurations. The presented tags operate in the ISM RFID UHF bands that cover 864-868 MHz and 902-928 MHz. A matching loop consisting of two parallel stubs to ground is used for impedance matching to a passive integrated circuit, which has -18 dBm sensitivity. A planar 2D tag with a footprint of 13126.5 mm2 is first introduced, showing a simulated gain of approximately 3 dBi and a measured read range of 10 m (for 31 dBm transmit power from the reader) in both on-metal and off-metal conditions. The tag is miniaturized into a 3D geometry with a footprint of 2524.25 mm2 (520% reduction) and achieves the same broadside simulated on-metal gain. The antennas are fabricated using a DPAM process, and a meshed ground configuration is explored in order to accomplish a 50% conductive paste reduction without disrupting the performance. The proposed tags are compared with commercially available tags as well as previously published tags in terms of read range and size. The tags in this work present an improvement in terms of read range, gain, and area with respect to previous designs covering the ISM RFID UHF bands. Moreover, the performance of these tags is maintained in on- and off-metal conditions, achieving comparable performance and a reduction in volume of 11482% with respect to the best tag reported.

I denna rapport beskrivs en undersökning och jämförelse av två olika sorters segjärn. Detvå materialen som har studerats har varit det segjärnet som används i Parker Hannifinsnuvarande hydraulikmotorer och ett nytt segjärn, vars mekaniska egenskaper har påståttsvara mer fördelaktiga. Målet med arbetet var att få fram en tillförlitlig jämförelse av de olikamaterialen och avgöra om det fanns ett tydligt underlag för att inleda processen av ett byteav material i vissa komponenter i Parker Hannifins produkter.Det utfördes jämförelser mellan de olika materialens mekaniska egenskaper baserade delspå information som redan fanns om materialen och dels på data insamlad vid tester medskärande bearbetning. Förslitning på verktygen vid fräsning studerades tillsammans medskärkraften med olika sorters skärdata. Restspänningar efter ingreppen i de båda materialenmättes med en röntgendiffraktometer.Resultaten gav inga signifikanta indikationer på att ett materialbyte skulle innebära en lägreproduktionskostnad, dock visade analyser att det nya materialet tål att bearbetas fortare ändet traditionella segjärnet och att fler undersökningar bör göras. Efter att ha analyseratmekaniska egenskaper så som hållfasthet, hårdhet, hårdhetsspridning och styvhet kundeslutsatser dras. Det visade sig att det nya segjärnet hade högre hållfasthet och jämnarehårdhet, men det hade även lägre styvhet. Styvheten i materialet är en viktig faktor dåläckage kan uppstå i hydraulikmotorer om materialen inte har tillräckligt hög styvhet.Mätningarna av skärkraften hos de båda materialen tydde på att det kunde uppstå högrestandardavvikelse, eller variationer av skärkraften vid fräsning av det traditionella segjärnet.Eftersom dessa variationer endast visade sig ett fåtal gånger går det inte att entydigtkonstatera att det nya materialet har mer fördelaktiga bearbetningsegenskaper. För att draen sådan slutsats hade det krävts ytterligare analyser på fler detaljer. / This report describes a study and comparison of two different types of ductile iron. Thetwo materials that have been studied have been the ductile iron used in Parker Hannifin'scurrent hydraulic motors and a new ductile iron, whose mechanical properties are said tobe more advantageous. The goal of this study was to obtain a reliable comparison of thedifferent materials and determine if there were clear grounds for initiating the process of achange of material in certain components of Parker Hannifin’s products.Comparisons between the mechanical properties of the materials were based partly oninformation that was already available and partly on data collected through machining trails.The wear on the tools after milling was studied along with the cutting force from variouskinds of cutting data. Residual stresses after the operation in both materials were measuredby an X-ray diffractometer.The results yielded no significant indication that a change of material would result in lowerproduction cost, however, analyses showed that the new material can withstand beingprocessed faster than the traditional ductile iron and that more studies should beconducted. After analyzing the mechanical properties, such as strength, hardness, hardnessvariation and stiffness, conclusions could be drawn. It turned out that the new ductile ironhad higher strength and more uniform hardness, but it also had lower stiffness. Thestiffness of the material is an important factor because if the materials do not havesufficient rigidity, leakage can occur in hydraulic motors. Measurements of the cutting forceof the two materials indicated that there could be a higher standard deviation, orfluctuation of the cutting force during milling of the traditional ductile iron. Since thesevariations only appeared a few times, it is difficult to conclude that the new ductile ironwould be more advantageous when it comes to machining. To be able to draw that kind ofconclusion would require more collected data.

L'aéroacoustique est une filière de l'acoustique qui étudie la génération de bruit par un mouvement fluidique turbulent ou par les forces aérodynamiques qui interagissent avec les surfaces. Ce secteur en pleine croissance a attiré des intérêts récents en raison de l'évolution de la transportation aérienne, terrestre et spatiale. Alors que les tests sur un objet réel sont possibles, leur implantation est généralement compliquée et les résultats sont facilement corrompus par le bruit ambiant. Par conséquent, les tests plus strictement contrôlés au laboratoire utilisant les modèles de dimensions réduites sont préférables. Toutefois, lorsque les dimensions sont réduites par un facteur de M, l'amplitude et la bande passante des ondes acoustiques correspondantes se multiplient respectivement par 10logM en décibels et par M. Les microphones avec une bande passante de plusieurs centaines de kHz et une plage dynamique couvrant de 40Pa à 4 kPa sont ainsi nécessaires pour les mesures aéroacoustiques. Les microphones MEMS ont été étudiés depuis plus de vingt ans, et plus récemment, l'industrie des semiconducteurs se concentre de plus en plus sur ce domaine. Par rapport à tous les autres principes de fonctionnement, grâce à la miniaturisation, les microphones de type piézorésistif peuvent atteindre une bande passante plus élevée et ils sont ainsi bien adaptés pour les mesures aéroacoustiques. Dans cette thèse, deux microphones MEMS de type piézorésistif à base de silicium polycristallin (poly-Si) latéralement cristallisé par l'induction métallique (MILC) sont conçus et fabriqués en utilisant respectivement les techniques de microfabrication de surface et de volume. Ces microphones sont calibrés à l'aide d'une source d'onde de choc (N-wave) générée par une étincelle électrique. Pour l'échantillon fabriqué par le micro-usinage de surface, la sensibilité statique mesurée est de 0.4 μV/V/Pa, la sensibilité dynamique est de 0.033 μV/V/Pa et la plage fréquentielle commence à 100 kHz avec une fréquence du premier mode de résonance à 400 kHz. Pour l'échantillon fabriqué par le micro-usinage de volume, la sensibilité statique mesurée est de 0.28 μV/V/Pa, la sensibilité dynamique est de 0.33 μV/V/Pa et la plage fréquentielle commence à 6 kHz avec une fréquence du premier mode de résonance à 715 kHz.

Over the past few years, manufacturing companies have had to deal with an increasing demand for feature-rich products at low costs. The pressures exerted on their existing manufacturing processes have lead manufacturers to investigate internet-based solutions, in order to cope with growing competition. Today, the availability of powerful and low cost 3D tools, along with web-based technologies, provides interesting opportunities to the manufacturing community, with solutions directly implementable at the core of their businesses and organizations. The wooden sign is custom i.e. each sign is completely different from each other. Mass Customization is a paradigm that produces custom products in masses. A wooden sign is custom in nature, and each sign must be completely different from another. Although process planning for mass customized products is same, the tool path required to CNC machine the custom feature varies from part to part. If the tool path is created manually the economics of mass production are challenged. The only viable option is to generate the tool path automatically; furthermore, any time savings in the tool path lead to better profit margins. This thesis presents the automatic web-based tool path planning method for machining sculptured wooden sign on 3 axis Computer Numerical Controlling (CNC) Machines using optimal and cost-effective milling cutters. The web-based tool path planning strategy is integrate with web-based CAD system to automatically generate tool paths for the CAD model using optimal cutter within desired tolerances. The tool path planning method is divided into two parts: foot print (path along which cutter moves) and cutter positioning. The tool path foot print is developed during design stage from the CAD model based on the type of surface to be machined. The foot print varies from part to part which facilitates the mass customization of wooden sign. After designing foot print, the foot print is discretized into points and the gouge-free cutter position at each of these points is found using "Dropping Method". The Dropping Method where cutter is dropped over the work piece surface, and the highest depth at which cutter can go without gouging the surface is calculated. This is repeated for all the position along the foot print. This tool path planning strategy is developed for ball nose, flat-end and radiused end milling cutter for machining wooden sign. The tool path generated using this method is optimized for machining time, tool path generation time and final surface finish. The bucketing technique is developed to optimize tool path generation time, by isolating the triangles which has possibility of intersection at particular position. The bucketing Technique reduced the tool path computation by 75 %, and made tool path generation faster. The optimal cutter selection algorithm is developed which selects best cutter for machining the surface based on the scallop height and volume removal results. The radiused end milling cutter results in highest volume removal which results in lower machining time compared to ball nose end milling cutters, but the scallop heights is higher. However, the scallop height in the radiused end milling cutter is higher only in few regions which reduces the final surface finish. For a sign, it was found around the boundary of logo, outline of lettering, interface of border and background. Thus, in order to achieve higher surface finish and lower machining time, a separate tool path is developed using "Pencil Milling Technique" which will remove the scallops from the regions that was inaccessible by radiused end mills. This tool path with the smaller cutter will move around the boundary of logo and lettering, and clean-up all the scallops left on the surface. The designed tool path for all the three cutters were tested on maple wood and verified against the actual Computer Aided Design model for scallop height and surface finish. The numerical testing of tool path was carried out on a Custom Simulator, ToolSim and was later confirmed by actually machining on a 3 axis CNC machine. The same sign was machined with variety of milling cutters and the best cutter was selected based on the minimum scallop and maximum volume removal. The results of the experimental verification show the method to be accurate for machining sculptured sign. The average scallop height in a machined using 1/8 th inch radiused end milling cuter and using Pencil tool path on the machined surface is found to be 0.03989 mm (1.5708 thou).

Germanium is a brittle semi-metal, used for lenses and windows in Thermal Imaging Systems since it transmits infrared energy in the 2 &micro / m - 12 &micro / m wavelength range at peak. In this thesis study, polycrystalline diamond is used as cutting tool material to machine germanium. Diamond is the hardest, most abrasion-resistant material and polycrystalline diamond is produced by compacting small diamond particles under high pressure and temperature conditions, which results more homogeneous, improved strength and a durable material. However, slightly reduced hardness is obtained when compared with natural diamond. Different from finish cutting, rough cutting, performed before finishing, is used to remove most of the work-piece material. During rough cutting, surface roughness is still an important concern, since it affects the finishing operations. Roughness of the surface of product is affected by a number of factors such as cutting speed, depth of cut, feed rate as cutting parameters, and also rake angle as tool geometry parameter. In the thesis, the optimum cutting and tool geometry parameters are investigated by experimental studies for rough cutting of germanium with polycrystalline diamond tools. Single Point Diamond Turning Machine is used for rough cutting, and the roughness values of the optical surfaces are measured by White Light Interferometer. Experiments are designed by making use of &ldquo / Full Factorial&rdquo / and &ldquo / Box-Behnken&rdquo / design methods at different levels considering cutting parameters as cutting speed, depth of cut, feed rate and tool geometry parameter as rake angle.