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    Effects of various helically angled grinding wheels on the surface roughness and roundness in grinding cylindrical surfaces
    (Inst Za Kovinske Materiale I In Tehnologie, 2015) Gavas, Muammer; Kına, Muammer; Köklü, Uğur
    Grinding is generally used in the final step of machining metallic materials to achieve the necessary surface quality and dimensions. Grinding wheels with flat surfaces are commonly used in the process of grinding. However, due to the fact that there is a great deal of contact length (corresponding to the grinding-wheel width) between the grinding wheel and the workpiece, effective cooling during the grinding process may not be possible and, consequently, the heat in the deformation region is increased. Due to these reasons, some undesired results such as an unqualified surface and a roundness error take place. Various profiles of the grinding wheel were, therefore, proposed to improve the surface quality and decrease the roundness error by modifying the grinding wheel and developing various methods. In this study, AISI 1050, AISI 4140 and AISI 7131 steel materials were subjected to the cylindrical-grinding process using wheels helically grooved at 15 degrees, 30 degrees and 45 degrees and the obtained results such as the average surface roughness and roundness errors were compared with the results of the flat-surface grinding wheels. The experimental results show that the surface roughness and roundness error are reduced when using a helically grooved grinding wheel and, thus, the quality of the machined parts is improved.
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    Öğe
    Experimental investigation of the effect of specially manufactured blank (SMB) materials on deep drawing
    (Sage Publications Ltd, 2022) Dağtekin, Emrah; Gavas, Muammer; Köklü, Uğur
    Deep drawing, one of the sheet metal forming processes, has a large area of use in industry. In the deep drawing, sheets having a fixed thickness are usually deep drawn. In general, there are some limitations, which prevent the part from being drawn at the desired depth, in the deep-drawing processes. Some of these consist of the increase in the sheet thickness towards the end of the part, being exposed to ironing, increasing wrinkles, exposure of the material to deformation hardening, and as a result, the fractures occur in the drawn part. Many special methods have been developed to increase the drawing height. One of them is to use blanks having machined edges. In the present study, the edges of the blank material were thinned by using the turning process at certain angles to avoid the above-mentioned negative effects. In this study, Al-1050 aluminum alloy with a thickness of 2 mm and machined edges of 1°, 2°, 3°, and 4° were used. The results were compared with the unmachined blanks. The highest drawing height was obtained with the blank having a 1° machined edge and 95 mm diameter. In addition, the power (approximately 7–31%) needed for deep drawing and material weight were reduced with the help of the deep-drawing process applied by using a specially manufactured blank.