La fabrication des grandes pièces structurelles aéronautiques en alliage d'aluminium nécessite la réalisation de multiples étapes de mises en forme (laminage, matriçage, etc...) et de traitements thermiques. Les différents chargements mécaniques et thermiques subis par les pièces pendant ces étapes de fabrication induisent des déformations plastiques ainsi que des modifications de la microstructure, qui sont sources de contraintes résiduelles. La géométrie finale des pièces est obtenue par usinage, qui est généralement la dernière étape de fabrication. Jusqu'à 90% du volume de matière initial peut être enlevé durant l'usinage de grandes pièces aéronautiques, qui peuvent également présenter des géométries complexes. La redistribution des contraintes résiduelles pendant l'usinage est une des principales causes de non-conformité des pièces avec les tolérances géométriques et dimensionnelles et donc de non-acceptation de celles-ci.De nos jours, les contraintes résiduelles et leurs effets pendant l'usinage ne sont généralement pas pris en compte lors de la définition des gammes d'usinage. Ce travail de thèse vise donc à proposer une évolution dans l'établissement des gammes d'usinage des pièces de structures en alliage d'aluminium et a été construit autour de deux principaux axes de recherche: un axe numérique et un axe d'analyse mécanique.L'axe numérique est basé sur la mise en place d'une approche de modélisation et le développement d'un outil numérique adapté à la simulation de l'usinage. L'approche de modélisation a été définie à partir d'hypothèses déduites d'études bibliographiques sur les alliages d'aluminium, le procédé d'usinage et les contraintes résiduelles. Une approche numérique d'enlèvements massifs de matière a ainsi été développée et tous les développements ont été intégrés dans les codes sources de FORGE® dans un environnement parallèle.L'axe d'analyse mécanique est basé sur l'étude de la redistribution des contraintes résiduelles et des déformations associées lors de l'usinage. Une première étude appliquée à la méthode expérimentale utilisée pour déterminer les profils de contraintes résiduelles dans des tôles laminées en alliage AIRWARE® 2050-T84 a été réalisée. Les simulations de ces essais ont permis une première validation de l'outil numérique développé et ont démontré la nécessité de définir des gammes d'usinage en fonction des contraintes résiduelles. D'autres études sur l'influence de certains paramètres définis dans les gammes d'usinage sur la qualité d'usinage ont également été menées. Les simulations réalisées ont été validées par de multiples comparaisons avec des résultats expérimentaux, montrant la capacité de l'outil numérique à prédire précisément la géométrie finale des pièces.A l'aide des résultats obtenus sur les précédentes études, une procédure numérique et de premières recommandations pour la définition de gammes d'usinage permettant d'obtenir la qualité d'usinage souhaitée en tenant compte des contraintes résiduelles initiales ont été mises en place. / The manufacturing of aluminium alloy structural aerospace parts involves multiple forming (rolling, forging, etc.) and heat treatment steps. The mechanical and thermal loads that the workpieces undergo during these manufacturing steps result in unequal plastic deformation and in metallurgical changes which are both sources of residual stresses. Machining is usually the last manufacturing step during which the final geometry of the parts is obtained. Up to 90% of the initial volume of the workpiece can be removed during the machining of aerospace structural parts which can furthermore have complex geometries. The residual stress redistribution is one of the main causes of the non-conformity of parts with the geometrical and dimensional tolerance specifications and therefore of the rejection of parts.Nowadays, initial residual stresses and their effect during the machining are often not taken into account in the definition of the machining process plan. This work aims to propose an evolution in the establishment of machining process plans of aluminium structural parts. It has been organised along two principal lines of research: a numerical line and a mechanical analysis line.The numerical line is based on the development of a modelling approach and of a numerical tool adapted to the simulation of the machining process. The modelling approach has been defined based on assumptions deduced from literature reviews on aluminium alloys, on the machining process and on residual stresses. A massive material removal approach has then been developed. All the numerical developments have been implemented into the finite element software FORGE® and are suited to a parallel computing environment.The mechanical analysis line is based on the study of the residual stress redistribution and its effect on the workpiece deflections during the machining as well as on the post-machining distortion. A first study on the layer removal method used to determine the initial residual stress profiles in an AIRWARE® 2050-T84 2050-T84 alloy rolled plate has been realised. The simulation of these experiments has allowed a first validation of the numerical tool and to demonstrate the necessity to define machining process plans in function of the residual stresses. Other studies on the influence of some machining process parameters on the machining quality have then been performed. Simulation results have been validated by multiple comparisons with experimental tests, showing the capability of the numerical tool to predict the final machined part geometries.Using the results of the studies mentioned above, a numerical procedure and first recommendations for the definition of machining process plans allowing to obtain the desired machining quality depending on the initial residual stresses have been established.

Striving for increased productivity while maintaining hole quality and high process robustness when drilling requires knowledge about the working principles of heat generation, mechanics and a proper cutting fluid that aids in cooling, lubricating and evacuating chips from the cutting zone. If the heat generated in the tool-workpiece and tool-chip interfaces does not exit the cutting zone adequately through the chips, the workpiece material or the redistribution of coolant the hole quality can be impacted negatively and breakdowns may occur which reduces overall productivity. During product testing, a sudden type of drill failure was observed when machining 316L stainless steel. When modifying the coolant design this was avoided which led to the assumption that the failure was caused by a large amount of heat being generated due to poor conductivity in the material combined with insuffcient cooling. However, this theory couldn't be investigated because of a lack of an existing method. To evaluate, three modifications of the CoroDrill 870 with dimensions Ø16mm and length 3xD were designed using Siemens NX 12 to observe whether coolant design choices have a significant impact on heat generation when drilling. To examine this a testing methodology was developed which utilizes IR-thermography and a combination of type K and J thermocouples inserted into the workpiece and onto the back surface, which measures its temperature in the cutting zone. Several tests were conducted with the developed setup to gather a larger data set to reduce impact from random error and to perform further analysis. Although the experiment setup is promising due to being simple and applicable to different materials there are large sources of variation associated with the placement of thermocouples. The results indicate some difference in registered temperature between the modifications however it is diffcult to draw conclusions based on the relatively few trustworthy measurements made. / För att förbättra produktiviteten vid borrning utan att kompromissa på hålkvalité och processäkerhet krävs bakomliggande kunskaper inom områden som, värmebildning, skärförlopp, och kylvätska vilket kyler, smörjer, och transporterar spånor från skärzonen. Om värmen som bildas i ytorna mellan verktyg-ämne och verktyg-spåna inte lämnar skärzonen på ett tillförlitligt sätt genom spånor, ämnet eller genom kylvätskans cirkulation kan hålkvalitén påverkas eller haverier kan orsakas vilket minskar produktivitet. Under en testning som genomfördes där 316L rostfritt stål borrades upptäcktes en ny typ av abrupt brott. När borrens kyllösning modiferades kunde detta fel undvikas varpå man drog slutsatsen att haveriet var en konsekvens av den stora temperaturgradient som bildas då materialets värmeledningsförmåga är relativt dålig. Dessvärre kunde denna teori inte prövas då det saknades en befintlig testmetodik. För att undersöka detta utvecklades tre modifikationer av CoroDrill 870 med dimension Ø16mm och längd 3xD i Siemens NX 12 i syfte att observera huruvida en signifikant temperaturskillnad skulle uppstå. För att utreda detta skapades en testuppställning som kombinerar IR-termografi med termoelement av typ K och typ J, fästa i ämnet respektive påämnets baksida vilket mäter materialets temperatur i skärzon. Ett flertal tester genomfördes med denna uppställning för att samla en större mängd data för fortsatt analys samt för att minska inverkan av slumpmässiga fel.Även om metoden är lovande då den är relativt enkel och tillämpbar på olika material så finns det stora potentiella källor till variation kopplade till mänsklig faktor och placering av termoelement. Resultatet som analyserats antyder att det finns en viss temperaturskillnad mellan modifikationerna men för att göra välgrundade slutsatser skulle fler mätningar behöva genomföras.

The dissertation thesis is focused on the optimization of control parameters of an EDM machine; the subject of optimization is cutting speed and surface topography. The first part of the thesis contains a research study on the technology of electrical discharge machining with the attention paid to the optimization methods use for control parameters of this process. The second part of the thesis is focused on real application of knowledge gained from studied sources. Here, a design of experiment aim at optimizing the parameters of the EDM machine is designed and carried on to maximize the cutting speed with the highest possible surface quallity. The result of the work is to build adequate regression models and find the optimal setting of machine control parameters.

The master‘s thesis deals with the design of the spindle and tool magazine for multispindle machining centre.

This master’s thesis deals with the operating production cost in machining process and further optimalization. Individual costs items which are related to machining process are specified. Attention is paid to the time consumption of individual machining methods. The aim of the thesis is to find an optimal combination of cutting speed and durability in order to meet the minimum cost criteria and maximum productivity. The calculations are used for turning the outer cylindrical surface and the face surfaces at a constant cutting speed. The work is accompanied by tables and calculations in Microsoft Excel.

The diploma work focuses on designing an automated machining, finishing and assembly line. Described in the chapters are the current technology of production, suggestions, the choice of a new solution and a technological-economical evaluation including capacitive and costs of running the production line and a comparison with the current technology. The result is proof that the return of the investment is roughly in one third.

This thesis deals primary with design of a woodworking machine focused on woodworking technology by cutting – rip saw. The introduction to the work is get to acquainted with the material to be processed – wood, and also the search of associated machines with the same technology of workpiece processing. Next part is focused on the safety of machining on woodworking machines and the individual safety features that the machines must contain are also analyzed. From this survey, a saw model with all the necessary features is created. The conclusion of the thesis is devoted to the risk analysis of the proposed machinery and their reduction.

This master thesis scrutinizes maintenance of production line made of two grinding machines used in bearing production. In the first section of the work, general principles of industrial maintenance are summarized. In the following practical section, maintenance of the production line is analysed. A calculation for determining production line downtime costs caused by machine failure is designed enabling an analysis of the effectiveness of investment into the diagnostic system of the machine. Lastly, possible measures for optimization of the production line’s maintenance are proposed.

This diploma thesis deals with palletization of heavy workpieces that are used by multi-purpose machining centers. The final outcome introduces a suitable option for palletization heavy workpieces of multi-purpose machining centers. In the first part of the thesis is draft of machining centers with parameters which were chosen by exploration of market for selecting suitable solution. The second part of thesis is dealing with a detailed draft palletization made by parts of exploration of market then design palletization system and design pallet changer. The designed construction of pallet changer is dimensioned with help of analytical calculating methods and numerical simulations methods. Outcome palletization system allows automatic change of twenty tons workpieces including pallet between two storage places.

This master‘s thesis deals with the suggestion of suitable tools for milling aluminum alloys profiles for the construction of aperture fillings and their aplication to a CNC machining center for increasing the efficiency of the cutting process. The first part of the thesis is focused on the description of the company and the workplace of production of aluminum alloys constructions. The following pages contain description of standardized products, which are used to identify the test profile that is part of the experimental verification. Next part of this thesis is characteristic of aluminum alloys and tool materials suitable for their machining. Second part of this work contains an analysis of the current state, suggestion of new cutting tools and their application to the production proces. At the end of this thesis there is the technical-economic evaluation that deals with the time and economic savings of the applied design.