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Surface Quality of Carbide Metal After Electrical Discharge Machining
31-38Views:141Recently, the requirements for machining shape-complex products made of hard-to-machine materials, including carbide, have been increasing significantly. However, their machining is rather problematic. Additionally, a high-quality standard of the machined surface is generally required, not only in terms of roughness but also in terms of the geometric accuracy of the machined surface. All this while maintaining a high level of economy in the machining process. However, meeting these demanding requirements in real technical practice is not always an easy task. Moreover, in combination with modern machining processes, only a limited number of production technologies can meet this requirement. Therefore, due to the high demands placed on today's modern production and the required high standard of the machined surface, progressive EDM technology is increasingly finding its application. And it is through this progressive technology that it is possible to achieve relatively good success in carbide machining. The aim of this paper was therefore to describe in detail the results of an experimental investigation aimed at identifying the quality of the machined surface achieved in terms of the roughness parameters of the machined surface in the electrical discharge machining of selected types of carbides using a wire tool electrode.
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Surface Activation of High Impact Polystyrene Substrate Using Dynamic Atmospheric Pressure Plasma
80-87Views:159Over the last decade, the number of researches has increased in the field of bonding technologies. Researchers attempt to improve surface adhesion properties by surface treatments. Adhesive bonding is one of these bonding techniques, where it is important to see what surfaces will be bonded. One such surface property is wetting, which can be improved by several types of surface treatment. In recent years, atmospheric pressure plasmas have appeared, with which research is ongoing on surface treatments. In our research, we will deal with the effects of plasma surface treatment at atmospheric pressure and its measurement. In addition, we summarize the theoretical background of adhesion, surface tension and surface treatment with atmospheric pressure plasma. Our goal is to improve adhesion properties and thus the adhesion quality.
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Evaluating the Efficiency of Polyhedral Mesh Elements in Solving the Problem of the Flow around Ship’s Rudder
241-256Views:245Meshing is one of the crucial key features to the success of CFD based simulations, this study is evaluating the efficiency of polyhedral elements in solving the problem of the flow around ship rudder, using a Reynolds-averaged Navier-Stokes turbulence model (SST k-ω), and compares it to a tetrahedral based mesh, considering that polyhedral elements were neglected in the past due to difficulties in implementing them, this was solved by introducing a tool by ANSYS that converges tetrahedral elements to polyhedral element, and integrating it into FLUENT software, the model was validated by comparing it with previously validated model which used the full version of ANSYS, this study was concluded using the academic version, but still it was able to produce satisfying results in predicting the lift and the drag coefficient, the pressure around the rudder surface, the velocity and the turbulent kinetic energy, finally the mesh quality was evaluated using the orthogonal quality criteria, the results showed the supremacy of the polyhedral elements in saving time and computational resources and improving mesh quality, and keeping high level of accuracy in predicting the results.
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Estimation of the Potential Runoff Quality Improvement as a Result of Applied Green Infrastructure Measures in a Hungarian Town
34-41Views:220Green infrastructure measures improves the quality of surface and subsurface waters along with increasing the water balance on the town level. The aim of the study is to estimate the potential runoff quality improvement by applying stormwater BMP-s along traffic roads in the town. This is of high priority in the aquifer protection area where runoff water may infiltrate into the aquifer carrying pollutants from the surface. Estimations are applied: first we determine the surface of traffic roads, then estimate the quantity of different kinds of pollutants accumulated on the surface and thirdly we estimate the expected performance of the applied green infrastructure elements based on findings in the literature. We determine the impervious urban surface area associated with transport-related functions within the protected drinking water recharge area using GIS technic using orthophotos. We estimate the expected reduction of runoff pollution assuming that stormwater BMP-s are applied in the area. The overall goal is to make the significance of diffuse pollution more obvious and enhance drinking water protection through taking diffuse pollution into consideration.
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Influence of MTP on Surface Roughness and Geometric Accuracy of Machined Surface at WEDM
91-97Views:139Electrical discharge machining technology is one of the most precise machining methods. Therefore, even the smallest deviation of micro and macro geometry generally has a significant impact on the overall quality of products produced by this progressive technology. The quality of the machined surface after Wire Electrical Discharge Machining (WEDM) is influenced by a large number of factors, most of which are influenced by the Main Technological Parameters (MTP). The aim of the paper was to describe the results of experimental research aimed at assessing the impact of MTP for WEDM on the quality of machined surface in terms of geometric accuracy and roughness parameters Ra and Rz. The samples were made of high alloyed ledeburitic chromium-molybdenum-vanadium steel designated EN X155CrVMo12-1 on a Sodick AQ535 electroerosion machine. The tool used was a standard compact brass wire 0.25 mm with the designation Elecut Brass CuZn37.
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Efficiency of the Machining Process of Circular Shapes by Electrical Discharge Technology
53-61Views:115Due to its high machining precision, EDM technology is nowadays very important in the production of high-precision parts for various industries. The high precision of the machined surface in combination with the ability to machine circular surfaces brings, in addition to several advantages, some negatives. The most significant negative of this machining technology is the relatively low productivity as well as the overall production efficiency. The latter is affected by many accompanying phenomena. The main accompanying phenomenon that contributes to the decline in the overall economic efficiency of EDM is the microgeometry errors that occur due to the non-homogeneity of the EDM process. Another accompanying negative phenomenon is the geometric accuracy errors of the machined surface, as a consequence of systematic destruction of the wire tool electrode, faulty interpolation in its guidance, and, last but not least, its vibration. These aspects consequently lead to the requirement for multiple applications of additional finishing cuts, which significantly reduces the overall economic efficiency of the machining process. Therefore, the experimental research aimed to search for options that can effectively help to achieve higher productivity but especially the overall economic efficiency of the machining process.
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Improving of Geometric Precision in the Manufacture of Circular Holes Using Technology WEDM
238-245Views:215WEDM technology is among the final technology. It is characterized by the high quality of the machined surface. Therefore, a small geometric deviation from the desired shape, position, orientation or run out may have a significant impact on the functionality of the finished component. Its range is largely influenced by the accuracy of the applied electroerosion device, the precision of the workpiece and tool setting, the machining method, but also the combination of each other and the adjustment of all process parameters. They result in the final quality of the machined surface not only in terms of roughness parameters but also in terms of geometric precision of the machined surface. The aim of the paper was to describe the possibilities of improving the geometrical accuracy of WEDM with thin brass electrodes. At the same time, it contributes to an existing database of knowledge that defines the influence of selected aspects on the geometrical accuracy of the machined area in the production of circular openings.
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Manufacturing Process Optimization and Tool Condition Monitoring in Mechanical Engineering
72-89Views:194The optimization of manufacturing and production processes with various computer software is essential these days. Solutions on the market allow us to optimize and improve our manufacturing and production processes; one of the most popular software is called Tecnomatrix, which is described in this paper. Tool condition monitoring is a vital part of the manufacturing process in the industry. It requires continuous measurement of the wear of the cutting tool edges to improve the surface quality of the work piece and maintain productivity. Multiple methods are available for the determination of the actual condition of the cutting tool. Vibration diagnostics and acoustic methods are included in this paper. These methods are simple, it requires only high sensitive sensors, microphones, and data acquisition unit to gather the vibration signal and make signal improvement. Extended Taylor equation is applied for tool edge wear ratio. Labview and Matlab software are applied for the measurement and the digital signal processing. Machine learning method with artificial neural network is for the detection and prediction of the edge wear to estimate the remaining useful lifetime (RUL) of the tool.
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The Effect of Fluxes on the Melt Quality of AlSi7MgCu Alloy
372-380Views:209The presence of inclusions such as oxides, carbides or refractory particles can be harmful to the mechanical and surface characteristics of castings. Inclusion-rich metals result in lower fluidity and feeding capability during casting. Nowadays, solid fluxes are widely used in foundries in order to reduce the inclusion content of aluminium melts. In this study, the effect of four different fluxes on the melt quality was studied. First, the inclusion content of the flux-treated melt, and then the properties of the fluxes (i.e. chemical composition and melting temperature) were examined.
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Effect of the Changes in Bulk Density and Granulometric Properties on the Strength Properties of the Moulding Sand Mixtures
116-122Views:189Foundry technology uses a lot of several natural materials. Sands use for preparing mixtures whereby making moulds or cores. Sand is defined as a granular, refractory major portion of mixture (90 – 98% in dependence on used binder). Sand properties depend on it has chemical and mineralogical composition; mainly particle size distribution and shape of grains and its size and sand surface texture. A comparative measurement of two quartz sand with different surface quality was carried out. Greensand mixtures were prepared to measure their permeability, compressive strength and wet tensile strength. The strength of sand mixtures has two main components. One of them is the cohesion of the binder; the other one is the adhesion between the binder and the foundry sand. The aim of this research is to determine the ratio of cohesion and adhesion within the strength values.
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The Investigation Of Heat-Resistant PLA Produced By Additive Manufacturing Technology
24-29Views:189In recent years, additive manufacturing technologies have been increasingly used in both custom and small-series production. In such cases, the component must remain functional under realistic conditions.. This means that there must also has a load‑bearing capacity. In many cases, materials are already suitable for strength. However, in many cases (machine parts, outdoor use) the models need to operate reliably at higher temperatures. This seems to be solved by the most widespread additive manufacturing technology (FDM), with a new heat-resistant material, HT PLA. In many cases, the use of cooling is essential during manufacture, especially for parts with high overhangs where hardening of the material is required as soon as possible to achieve the correct surface quality. In this paper, we investigated the effect of cooling applied during manufacturing on the mechanical strength
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Greywater Treatment with Oxidative Agents
27-31Views:233In our research we pretreated synthetically produced greywaters with filtration on various filters, then we treated the samples with oxidative agents. We characterised the quality of greywater samples with several parameters. We investigated these parameters on the untreated, pretreated, and oxidated samples as well. We evaluated the efficiency of the treatments by measuring the characteristic parameters. In addition, we investigated the changes on the filter media’ surface with a scanning electron microscope (SEM). It was shown, that the most effective treatment combination for the greywater’s preparation for reuse is the filtration on silica sand or activated charcoal and silica sand combined filter media, then oxidation with hydrogen peroxide (10 mmol/dm3).
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Determination of the Accumulation of the Heavy Metal Content of the Sediment of River Danube by Plants
163-170Views:126In these days, the surface waters and their floodplains and oxbow lakes are operating as ecological corridors, although their touristic role is not negligible. The monitoring and saving of these wetlands need for sustain these areas for the future generations. The environmental parameters of floodplains and oxbow lakes is revealed with the analyses of the quality of the water and sediment. The main sampling place of our research is a sediment dump was created by excavation from the Open Beach of Dunaújváros in 2009. In 2010 the whole sediment dump was planted with trees, and many kinds of weeds were also grown here. The main aim of this research is to analyse the heavy metal content of the sediment dump in Dunaújváros. Furthermore, the heavy metal content of the parella (Rumex obtusifolius L.), perennial rye-grass (Lolium perenne) and riparian sedges (Carex riparia) which are growing on the sediment dump were also analysed. The distribution and the accumulation of the heavy metals inside this plant can be also determined with these measurements.
