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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.
1

Návrh na zefektivnění procesu obrábění specifických komponent pneumatických válců / Efficiency improvement proposal of machining specific components of pneumatic cylinders

Židlický, Ondřej January 2019 (has links)
This Master thesis aims to increase the effectivity of the machining of pneumatic cylinders specific components. In the first chapter, the concurrent approach to the manufacture of corrosion resistant austenitic piston rod. This approach consists of the technological procedure, the analysis of the cutting tools used in the process and the cutting conditions. The machining process deals with low durability of cutting tools and the necessity of continual supervision by the operator. Therefore, an alternate design of cutting tools and cutting conditions is suggested in the next chapter. The new design has been tested in manufacture process. In the last chapter, the concurrent and the innovative approach are compared. By choosing the proper cutting tools and cutting conditions it was managed to increase the durability of cutting tools and to increase the effectivity of the whole manufacture process.
2

Characterization & modeling of chip flow angle & morphology in 2D & 3D turning process

Devotta, Ashwin Moris January 2015 (has links)
Within manufacturing of metallic components, machining plays an important role and is of vital significance to ensure process reliability. From a cutting tool design perspective,  tool macro geometry  design  based on physics based  numerical modelling  is highly needed  that can predict chip morphology.  The chip morphology describes the chip shape geometry and the chip curl geometry. The prediction of chip flow and chip shape is vital in predicting chip breakage, ensuring good chip evacuation and lower surface roughness.  To this end, a platform where such a  numerical model’s chip morphology prediction  can be compared with experimental investigation is needed and is the focus of this work. The studied cutting processes are orthogonal cutting process and nose turning process. Numerical models that simulate the chip formation process are employed to predict the chip morphology and are accompanied by machining experiments. Computed tomography is used  to scan the chips obtained from machining experiments and its ability to capture the variation in  chip morphology  is evaluated.  For nose turning process,  chip  curl parameters during the cutting process are to be calculated. Kharkevich model is utilized in this regard to calculate the  ‘chip in process’ chip curl parameters. High speed videography is used to measure the chip side flow angle during the cutting process experiments and are directly compared to physics based model predictions. The results show that the methodology developed provides  the framework where advances in numerical models can be evaluated reliably from a chip morphology prediction capability view point for nose turning process. The numerical modeling results show that the chip morphology variation for varying cutting conditions is predicted qualitatively. The results of quantitative evaluation of chip morphology prediction shows that the error in prediction is too large to be used for predictive modelling purposes.

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