Les technologies de fabrication additive(FA) basées sur la technique de fusion laser sur lit de poudres, telles que les procédés de fusion sélective laser (Selective Laser Melting ‘SLM’) et de fusion par faisceau d'électrons (Electron Beam Melting ‘EBM’), ne cessent de se développer afin de produire des pièces fonctionnelles principalement dans les domaines aérospatial et médical. Le procédé de fabrication additive offre de nombreux avantages, tels que la liberté de conception, la réduction des étapes de fabrication, la réduction de la matière utilisée, et la réduction de l'empreinte carbone lors de la fabrication d'un composant. Néanmoins, les pièces obtenues nécessitent une opération d’usinage de finition afin de satisfaire les tolérances dimensionnelles et l’état de surface. / Additive Manufacturing (AM) techniques based on powder bed fusion like Selective Laser Melting(SLM) and Electron Beam Melting processes(EBM) are being developed to make fully functional parts mainly in aerospace and medical sectors. There are several advantages of using AM processes like design freedom, reduced process steps, minimal material usage and reduced carbon footprint while producing a component. Nevertheless, the parts are built with near net shape and then finish machined to meet the demands of surface quality and dimensional tolerance.

Recent technoligical advancement demands new robust micro-components made out of engineering materials. The prevalent methods of manufacturing at micro-nano level are established mostly for silicon structures. Therefore, there is interest to develop technologies for micro-fabrication of non silicon materials. This research studies microend-milling of 316L stainless steel. Machine tool requirement, tool modeling, cutting fluid evaluation, and effect of cutting parameters are investigated. A machine tool with high rigidity, high spindle speed, and minimal runout is selected for successful micro-milling. Cumulative tool wear and tool life of these micro-tools are studied under various cutting conditions. Ideal abrasive wear is observed when applying mist cooling whereas inter-granular shearing is the major failure mode while flood cooling or dry cutting during micro-machining. Various experiments and computational studies suggest an optimal position of the mist nozzle with respect to a tool that provides maximum lubrication at the cutting edge. Mist droplets effectively penetrate the boundary layer of a rotating tool and wet the cutting edge and significantly improve the tool life.

This study includes examination of the machinability characteristics of two medium carbon steel types (SAE 1040 and SAE 1050) as a result of spherodizing treatment. Both steel types were handled into four categories according to their spherodizing treatment parameters (temperature and time). Microstructural investigation, hardness and ultrasonic sound velocity measurement (with both longitudinal and transverse waves) of these steels were performed, and effect of applied heat treatments on microstructure, hardness and ultrasonic sound velocity was investigated. Pulse-echo method has been used for ultrasonic sound velocity measurements, and measurements were performed with 5 and 10 MHz longitudinal and 5 MHz transverse wave probes. Tool life criterion was used for determining the machinability characteristics of the steels. For this purpose, flank wear land measurements were performed on the cutting tools. Results have showed that, by appliying heat treatment it is possible to change the microstructure, hardness, ultrasonic sound velocity and machinability characteristics of a steel.

Orientador: Anselmo Eduardo Diniz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-07T18:44:10Z (GMT). No. of bitstreams: 1 Krabbe_DanielFernandoMoreira_M.pdf: 4840835 bytes, checksum: 3db5447d6c84ae0db244c137740e2a84 (MD5) Previous issue date: 2006 / Resumo: No processo de desbaste, a máxima taxa de material removido por unidade de tempo (cm3 x min), dentro do intervalo de máxima eficiência, é o foco principal para as mais diversas empresas de usinagem. Afirmando este conceito, procurou-se neste trabalho obter para dois diferentes diâmetros de fresas inteiriças de metal duro, a máxima vida de ferramenta por volume removido de material, na usinagem da liga de aço inoxidável endurecível por precipitação 15-5 PH. As variáveis deste estudo foram os diâmetros da ferramenta (16 e 20 mm), a profundidade de corte ¿ap¿ (5 a 16 mm), a profundidade radial de corte ¿ae¿ (33%D e 77%D) a velocidade de corte ¿vc¿ (80 e 100 m/min). Mantiveram-se constantes o número de dentes da fresa, a classe do metal duro e revestimento, a espessura média de cavaco, o fluido de corte e a taxa de remoção de material para cada profundidade radial de corte. Os parâmetros de avaliação foram o desgaste de flanco ¿vb¿ da aresta principal de corte, a potência consumida e o comprimento de corte fresado por vida da ferramenta. Os resultados demonstram que a fresa de menor diâmetro (16 mm) apresentou sempre uma maior vida de ferramenta para a mesma taxa de remoção de material quando comparada à fresa de maior diâmetro (20 mm). Demonstram também que para a menor condição de profundidade radial de corte estudada a uma profundidade axial de corte elevada (baixo ¿ae¿ alto ¿ap¿), a vida da ferramenta é superior quando comparada à mesma condição de taxa de remoção de material, porém com profundidade radial alta (alto ¿ae¿ e baixo ¿ap¿) / Abstract: In the roughing machining process, the maximum removal rate (cm3 x min-1) inside of the maximum efficiency interval, is the main target of the most different machining shops. Based in this concept, the target of these experiments was to find for two different end mill diameters in the milling process, the maximum removal rate per tool life in the 15-5 precipitation hardening stainless steel alloy. The input variables of these experiments were the end mill diameter (16 and 20 mm), the depth of the cut ¿ap¿ (from 5 to16 mm), the radial depth of cut ¿ae¿ (33%D and 77%D) the cutting speed ¿vc¿ (80 and 100 m/min). The end mill number of teeth, the solid carbide and surface coating characteristics, the average chip thickness, the cutting fluid and the removal rate for each radial depth of cut were kept constants. The evaluation parameters were the wear on the main cutting edge, the spindle power and the work piece machined length. The analysis of results showed that for a smaller end mill diameter (16 mm) always a longer tool life was reached for the same removal volume rate when compared with the end mill with larger diameter (20 mm). It also shows that for a smaller radial depth of cut and big depth of cut (small ¿ae¿ large ¿ap¿), the tool life is higher than when compared with the same removal rate condition, however with larger radial depth of cut and smaller depth of cut (big ¿ae¿ small ¿ap¿) / Mestrado / Engenharia de Fabricação / Mestre em Engenharia Mecânica

The thesis is dealing with drilling deep holes. Theoretical part of thesis is focused on base knowledge of deep drilling. Experimental part deals with testing two different borers, with different cutting conditions and different purchase prize. Drilling was made into 1.2343 ESU material. Conclusion of this work is concept of purchase machinery for deep drilling.

This thesis deals with analysing component manufacture of valve lines. Firstly evaluating current condition of production including determinated manufacture times and costs. Secondly carrying out inmprovement proposals for manufacture and optimalisation of cutting conditions while considering the minimal costs given for operation sections. The final provision summarizes results which were achieved and overall benefits of the thesis.

The diploma thesis deals with the analysis of the wear of tools fitted with cermet cutting edge. The first part is focused on the theoretical aspects of the problem, which are applied in the practical part. The aim was to perform cutting tests in which carbon steel was turned under selected cutting conditions. Tool wear during turning and the quality of the machined surface were monitored. Machining continued until the selected wear criterion reached the limit value. Two different cermets were tested and the measured data were the basis for the analysis of the wear of the tool edges and the determination of the tool life.

The diploma thesis deals with the topic of machinability of materials. The theoretical part describes the aspects according to which machinability can be evaluated. The material side of the thesis is focused on various types of difficult-to-machine materials. The cobalt alloy UmCo50 belongs to the group of difficult-to-machine materials and it is the subject of the experimental part. UmCo50 is an alloy for high temperature use. The primary aim of the thesis was to monitor the wear of the selected cutting tool when turning this alloy. Other aspects of the selected machining process were also monitored, such as force effects or the quality of the machined surface. Despite the fact that machinability of tested materials cannot be expressed in terms of the absolute value of a quantity, it is necessary to compare the various aspects of the machining processes by reference materials. However, certain conditions of this comparison must be met. Based on this, a comparison of tested and reference material was performed.

Compacted Graphite Iron offers mechanical properties in between of gray cast iron and ductile iron. Thus,the material is seen as a hopeful alternative for engine cylinder blocks and heads satisfying environmentaland performance objectives. Nevertheless, CGI is more difficult to machine than conventional gray castiron due to the presence of MnS and thin wall section of probing high strength. This problem of CGI thenled to the initiation of large Optima Sweden project to study machinability and optimization of related toCGI.The thesis is centered on a study of tool life, cutting force and MRR with regards to machining parametersmainly feed rate and cutting speed for CGI milling. Tool life is measured; flank-wear is observed andcompared between several combinations of cutting parameters.Similarly cutting forces were measured using LMS software for full factorial design experiments. Extensivemachining experiments were carried out. Machining tests was done based on Design of Experiment (DoE)for high cutting data and lower data are performed separately. Comparison is made for tool life and cuttingforces. After data collection, analysis of tool life and force has been followed. Once the data is analyzedand checked its consistency. An approximate model is developed using MODDE software. Further, multiobjective optimization of tool life and Material removal rate (MRR) using cutting parameters mainly feedrate and cutting speed are investigated. Working on optimal parameters will allow for CGI is to becompetitive in manufacturing with gray CI, aluminum alloy, magnesium.Keywords: Compacted Graphite Iron (CGI), face milling, tool life, MRR, optimization, cutting force

PrimeTurning™ is a new turning technology, which consists of tools and programming method. By using this method, it has been demonstrated that higher material removal rates and flexibility in turning can be obtained.  The New Product Industrialisation department at AB Sandvik Coromant works with development of production processes and improvements in current processes.Machining tests are carried out in order to improve production performance, and find optimised solutions.  In this master thesis work, the effect of insert grades and entering angles on wear and tool life while machining hardened tool steel has been studied. Machining experiments have been carried out to analyse wear and tool life by using the PrimeTurning™ method.Two approaches of experimental design have been investigated, and a suitable design is selected for conducting the experiments.  The performance of these insert grades and tool holders (κ=21° and κ=25°) has been compared to each other and the existing production scenario, and a recommendation is made regarding insert grade,tool holder and cutting parameter selection for machining hardened tool steel using PrimeTurning™. The wear analysis has been performed by using a stereo microscope coupled with an image processing software to measure the flank wear length. Flank wear, flaking and chipping have been observed as the major wear types.  As a result, it has been identified that the insert grade GXXC, coupled with the tailor-made tool holder performs significantly better than the currently used insert and tool holder in production. A substantial increase in tool life increase is observed, even when machining at a higher Material Removal Rate of 29%. This would result in a significant increase productivity, if the results can be reproduced in production. / PrimeTurning ™ är en ny svarvningsteknik som består av verktyg och programmeringsmetod. Genom att använda denna metod har det visats att högre materialavlägsningshastigheter och flexibilitet vid svarvning kan uppnås.  Avdelningen för nyproduktionsindustrialisering på AB Sandvik Coromant arbetar med utveckling av produktionsprocesser och förbättringar av nuvarande processer. Maskintester genomförs för att förbättra produktionsprestanda och hitta optimerade lösningar  I det här examensarbetet som utförts vid AB Sandvik Coromant har effekten av skärsorter och ställvinklar på slitage och livslängd vid bearbetning av härdat verktygsstål studerats. Maskinbearbetningsexperiment har utförts för att analysera slitage och verktygslivslängd med hjälp av PrimeTurning ™ -metoden. Två metoder för experimentell design har undersökts och en lämplig design väljs för att utföra experimenten.  Prestandan hos dessa skärsorter och verktygshållare (κ = 21 ° och κ = 25 °) har jämförts med varandra och det nuvarande produktionsscenariot, och en rekommendation görs beträffande skärsort, verktygshållare och val av skärparametrar för maskinbearbetning av verktygsstål med PrimeTurning ™. Förslitningsanalysen har utförts med användning av ett stereomikroskop kopplat till en bildbehandlingsprogramvara för att mäta längden av fasförslitningen. Fasförslitning, urflisning och flagning har observerats som de viktigaste typerna av förslitning.  Studiens resultat visar att skäret GXXC, i kombination med den skräddarsydda verktygshållaren presterar avsevärt bättre än det för närvarande använda skäret och verktygshållaren i produktionen. En kraftig ökning av livslängden på verktyg observeras även vid bearbetning med en högre Spånavverkningshastighet på 29%. Om dessa resultat kan reproduceras i produktionen kan en betydande produktivitetsökning erhållas.