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Abstract

Recent developments in automation and technology have revolutionized the way products are made. It is directly seen in the evolution of part miniaturization in the sectors such as aerospace, electronics, biomedicine and medical implants. Micromachining is a promising technology to fulfill the need of miniaturization. A review has been done on the micromachining processes such as micro electric discharge machining (micro-EDM) and wire EDM (WEDM), micro electrochemical machining (micro-ECM). Recent literature were studied and categorized in terms of materials, process parameters, performances, product manufactured, and miniature product generation. Starting with brief introduction to micromachining, classifications and applications, technical aspects of discussions from the literature have been presented on key factors such as parameters and the response variables. Important aspects of recast layer, heat effected zone, micro-hardness, micro cracks, residual stress, etc., have been given. A special focus is given to the status of the research on microgear manufacturing. Comparison has been made between other conventional process suitable for micro-gear manufacturing and WEDM. The miniature gear machined by WEDM shows the defect-free microstructure, better surface finish, thin recast layer and improved gear quality parameters such as profile and pitch. Finally, the research gaps and future research directions have been presented.
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Abstract

In the work results of research on electrodischarge machining (EDM) of titanium alloy Ti10V2Fe3Al with (α + β) structure were presented. Preliminary heat treatment of samples allows to obtain different morphology and volume fraction of the α phase. The main goal of research was to assessment of the material microstructure impact on EDM technological factors (ie. material removal rate, tool wear) and morphology of technological surface layer. Electrodischarge machining is alternative and increasingly used method of titanium alloys machining. Research allowed to indicate the possibilities and limitations of use EDM in this area. It is especially important in the aspect of parts produced for aircraft industry and related requirements for the technological surface layer quality.
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Abstract

The development of industry is determined by the use of modern materials in the production of parts and equipment. In recent years, there has been a significant increase in the use of nickel-based superalloys in the aerospace, energy and space industries. Due to their properties, these alloys belong to the group of materials hard-to-machine with conventional methods. One of the non-conventional manufacturing technologies that allow the machining of geometrically complex parts from nickel-based superalloys is electrical discharge machining. The article presents the results of experimental investigations of the impact of EDM parameters on the surfaces roughness and the material removal rate. Based on the results of empirical research, mathematical models of the EDM process were developed, which allow for the selection of the most favourable processing parameters for the expected values of the surface roughness Sa and the material removal rate.
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Abstract

To achieve better precision of features generated using the micro-electrical discharge machining (micro-EDM), there is a necessity to minimize the wear of the tool electrode, because a change in the dimensions of the electrode is reflected directly or indirectly on the feature. This paper presents a novel modeling and analysis approach of the tool wear in micro-EDM using a systematic statistical method exemplifying the influences of capacitance, feed rate and voltage on the tool wear ratio. The association between tool wear ratio and the input factors is comprehended by using main effect plots, interaction effects and regression analysis. A maximum variation of four-fold in the tool wear ratio have been observed which indicated that the tool wear ratio varies significantly over the trials. As the capacitance increases from 1 to 10 nF, the increase in tool wear ratio is by 33%. An increase in voltage as well as capacitance would lead to an increase in the number of charged particles, the number of collisions among them, which further enhances the transfer of the proportion of heat energy to the tool surface. Furthermore, to model the tool wear phenomenon, a egression relationship between tool wear ratio and the process inputs has been developed.
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Abstract

The use of quantitative methods, including stochastic and exploratory techniques in environmental studies does not seem to be sufficient in practical aspects. There is no comprehensive analytical system dedicated to this issue, as well as research regarding this subject. The aim of this study is to present the Eco Data Miner system, its idea, construction and implementation possibility to the existing environmental information systems. The methodological emphasis was placed on the one-dimensional data quality assessment issue in terms of using the proposed QAAH1 method - using harmonic model and robust estimators beside the classical tests of outlier values with their iterative expansions. The results received demonstrate both the complementarity of proposed classical methods solution as well as the fact that they allow for extending the range of applications significantly. The practical usefulness is also highly significant due to the high effectiveness and numerical efficiency as well as simplicity of using this new tool.
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