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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
621

Návrh a výroba břitu stabilizátoru pro formuli student / Design and Manufacturing of a Blade Stabilizer for Formula Student

Marko, Tibor January 2016 (has links)
The master´s thesis discuss about design and manufacture of blade stabilizer. It will be sets limit conditions for design blade and subsequent analysis of effects of stress and strain on the rod of blade and assembly of the stabilizer in various settings. For manufacturing of blade it will design materiál of the blank, manufacturing proces and machining conditions with the choice of cutting tools nad cutting machine. In conclusion will be comparison blades from formulas of last years from monopost Dragon 2 to Dragon 6.
622

Návrh výroby jednoúčelového stupňovitého obráběcího nástroje / Production Concept of Single-purpose Stepped Cutting Tool

Opršál, Ladislav January 2016 (has links)
The aim of this thesis is to propose a single-purpose stepped cutting tool for the drilling of the cylinder head. The thesis first introduces the current production of the cylinder head, including the description of the cutting conditions and the machines and tools used in the production process. The second part of the thesis is focused on the drilling of a three-step hole for which a step drill bit is proposed. The proposal describes the development of the drill bit, heat treatment, the method of clamping, the replaceable cutting tips used in the production process, additions for further machining and the cutting conditions. The last part of the thesis then deals with the technical-economic analysis, comparing the present and innovated stage of the production of the cylinder head.
623

Návrh na zefektivnění opracování desek z kompozitních materiálů / Efficiency Improvement Concept of Machining of Boards from Composite Materials

Holík, Radek January 2016 (has links)
This master thesis is dealing with the analysis of current technology of machining based on unconventional method of water jet cutting for sheet machining of composite materials. My goal is to analyze and calculate the cost of technologies. There is, in conclusion of the master thesis, the techno-economic evaluation and final decision whether it is appropriate to invest in a new technology or not.
624

Návrh zefektivnění technologie obrábění komínové vložky / Improving Efficiency Concept of Machining Technology of Chimney Liner

Kubů, Marek January 2016 (has links)
Diploma thesis contains introduction of a company P-D Refractories CZ a. s., where the manufacture of ceramic chimney liners is. Followed by a description and analysis of the product in the entire production cycle, material and product spectrum. Based on the results of current production is created proposal to streamline the machining technology with a view to increase productivity and reduce defective products, which means determine the material of a tool and the method of machining. The work is finished by technical-economic assessment, where the summary and recommendation of the proposed solution are.
625

Výpočtová analýza stojanu pro horizontální vyvrtávací centrum / Computational analysis of column for horizontal boring centre

Fargač, Michal January 2016 (has links)
The theoretical study of this thesis deals with different approaches that can be used to optimize the topology of various structures. Main attributes and principles which they are based on of individual methods are discussed. The first point of the practical part is to design the model for computational analysis of stand and other machining centre parts based on real machine TOS FU. Afterwards, the model is analyzed to determine the dynamic characteristic of the machine. Subsequently, several changes of the stand design are performed in order to improve the dynamic behavior. Eventually, new stand kernel is designed which aims to enhance these dynamic characteristic. This model is analyzed again and the results are compared with the original form of the machining centre.
626

Návrh kompaktního stroje pro třískové obrábění klíčů / Entwurf einer Kompaktmaschine zur Schlüsselbearbeitung

Žůrek, František January 2017 (has links)
This master thesis Design of a machine tool for a safety keys production deals with concept of a machine tool for production of safety keys. Solution variants are methodically elaborated, mainly concerning their achieved tact times and machine dimensions. A computation diagram for fast comparison of concepts in case of different customer key specification is presented. Chosen concept version is then detailed designed. The result fills a hole on the market of specific machine tools for machining of safety keys.
627

Možnosti systému Sinumerik 840D při soustružení hřídele pro JAWA 23 / Sinumerik 840D control system for turning of the shaft for JAWA 23

Motl, Martin January 2017 (has links)
This Master’s thesis deals with the proposal manufacturing technology of a shaft with gears on a CNC machine tool. The first part of the thesis is focused on the concise description selected shaft and its use. In the next part of the thesis are state selected materials, which are suitable used for shafts and gears. After that is create drawing component, suggest technological procedure, tool list and machine list which are suitable used for manufacturing selected shaft. In the final part of the thesis is create a CNC program for manufacturing the shaft on the turning and milling machine. Program is created in software SinuTrain 4.7 for control system Sinumerik 840D. The CNC program is verified by graphics simulation to determine a correct function
628

Návrh výroby speciálního obráběcího nástroje pro zhotovení detailu T-drážky / Production Concept of Special Machining Device for Making of T-Channel Detail

Opršál, Radek January 2017 (has links)
The objective of this diploma thesis was the design of a special machine tool that increases the efficiency of the production of a T-slot detail on the part of the clamp body. The thesis deals with the current production of this component as well as the description of the material, the machines that are used and the technological process. The next part focuses on the description of the new special machine tool, its production, heat treatment and the presentation of used indexable inserts. Another part analyses the production innovation that was comprised of the comparison with the former machine tool to the new one. The thesis concludes with a technical and economical evaluation of the former and innovated production.
629

Ruční programovaní CNC strojů / Manual programming of CNC machines

Cherepanov, Maksym January 2017 (has links)
Diplomová práce uvádí zakladní popis ručního programování CNC strojů, jeho výhod a nevýhod, možností automatizace. Aplikace CNC obrábění na součásti, její verifikace, vyhodnocení dosažených výsledků.
630

Modélisation numérique des distorsions post usinage pour les pièces aéronautiques en alliage d’aluminium : application aux parois minces / Computational modelling of post machining distortions of aluminium aeronautical parts : application to thin walls

Rambaud, Pierrick 23 September 2019 (has links)
La fabrication de grandes pièces structurelles aéronautiques en alliage d’aluminium nécessite la réalisation de multiples étapes de mise en forme (laminage, matriçage, forgeage…), de traitements thermiques et usinage. Pendant ces étapes de fabrication, les différents chargements thermomécaniques subis par la pièce avant son usinage induisent des déformations plastiques ainsi que des modifications de la microstructure qui sont sources de contraintes résiduelles. A ces contraintes résiduelles issues de l’histoire thermomécanique de la pièce, viennent s’ajouter celles issues directement de l'étape d'usinage. En effet lors de cette étape jusqu’à 90% de la matière initiale d'une pièce peut être retirée en utilisant des conditions de coupe parfois sévères. Les pièces aéronautiques présentent parfois des géométries complexes avec des parois minces. Ainsi, pendant et à l’issue de l’usinage, la géométrie de la pièce usinée se trouve fortement modifiée et une redistribution des contraintes résiduelle est alors à l’œuvre. Ces contraintes résiduelles qu’elles soient héritées ou induites par le procédé, influencent fortement la géométrie finale obtenue et sont une des causes principales de non-conformité des pièces avec les tolérances dimensionnelles du produit fini. Engendrant une perte conséquente pour les industries manufacturières. Au cours de ce travail de thèse, nous nous sommes concentrés sur la prise en compte de ces deux types de contraintes résiduelles dans un modèle numérique de prédiction des distorsions. Nous nous sommes uniquement focalisés sur les pièces en aluminium issues de l’aéronautique. Nous avons ainsi couplé des modèles numériques avancés d’immersion et de remaillage avec un logiciel industriel existant afin de proposer une nouvelle solution numérique, rapide et robuste. En se basant sur les hypothèses de la littérature nous avons décidé de simuler l’usinage comme un enlèvement de matière massif où la trajectoire de l’outil et les machine seront négligées. L’objectif numérique est donc de proposer une méthode qui puisse rendre compte de la redistribution des contraintes résiduelles au sein de la pièce. Chaque étape de la gamme d’usinage est ainsi représentée par une étape de remaillage où le « volume usiné » sera supprimé du maillage pour céder ensuite sa place à un calcul mécanique permettant de rendre compte de la réorganisation des contraintes et les déformations qu’elle induisent. Ce processus itératif, réalisé dans un environnement parallèle a nécessité de nombreux développements numériques. Ainsi une nouvelle stratégie de remaillage et de repartitionnement a été proposée pour pouvoir obtenir un maillage à même de capturer les contraintes résiduelles issues de l’usinage en proche surface ainsi que pour réduire de manière significative les temps de calcul liés aux modifications de la géométrie par la découpe. Un modèle d’élasticité linéaire simplifié a aussi été ajouté au programme pour réduire le coût numérique des calculs mécaniques et permettre de traiter des problèmes de taille plus conséquente sur des ordinateurs de puissance raisonnable. Afin de confirmer les résultats obtenus par ces calculs, les simulations ont été comparées à des résultats expérimentaux tirés de la littérature et réalisés spécifiquement pour ce travail de thèse. / The manufacture of large aeronautical structural parts made of aluminium alloys requires multiple forming steps (rolling, die forging, forging, etc.), heat treatment and machining. During these manufacturing steps, the various thermomechanical loads suffered by the part before its machining induce plastic deformations as well as modifications of the microstructure which are sources of residual stresses. In addition to these residual stresses resulting from the thermomechanical history of the part, others result directly from the machining step. Indeed, during this step, up to 90% of the raw material of a part can be removed using sometimes severe cutting conditions. Aeronautical parts sometimes have complex geometries with thin walls. Thus, during and after machining, the geometry of the machined part is significantly modified by the redistribution of residual stresses at work. These residual stresses, whether inherited or induced by the process, strongly influence the final geometry obtained and are one of the main causes of non-conformity of the parts with the dimensional tolerances of the finished product. This results in a significant loss for manufacturing industries. In this thesis work, we focused on considering these two types of residual stresses in a numerical model predicting distortions. We focused only on aluminium parts from the aeronautics industry. We have thus coupled advanced numerical fitting and remeshing models with existing industrial software to provide a new numerical solution, fast and efficient. Based on the assumptions in the literature, we decided to model machining as a massive material removal where tool path and interaction with the machine will be neglected. The numerical objective is therefore to propose a method that can account for the redistribution of residual stresses within the part. Each step of the machining plan is thus represented by a remeshing step where the "machined volume" will be removed from the mesh followed by a mechanical computation to account for the reorganization of stresses and the deformations they induce. This iterative process, carried out in a parallel environment, required many numerical developments. Thus, a new remeshing and repartitioning strategy has been proposed to obtain a mesh capable of capturing the residual stresses resulting from near-surface machining and to significantly reduce the calculation times associated with changes in geometry through cutting. A simplified linear elasticity model has also been added to the approach to reduce the numerical cost of mechanical computation and allow for larger problems to be addressed on computers of reasonable power. In order to confirm the results obtained by these computations, the simulations were compared with experimental results from the literature and carried out specifically for this thesis work.

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