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    Multi-objective optimization of surface roughness, thrust force, and torque produced by novel drill geometries using Taguchi-based GRA
    (Springer London Ltd, 2019) Meral, Guven; Sarikaya, Murat; Mia, Mozammel; Dilipak, Hakan; Seker, Ulvi; Gupta, Munish K.
    A significant part of today's chip removal processes are drilling holes. Many parameters such as cutting parameters, material, machine tool, and cutting tool, etc., in the hole-drilling process affect performance indicators such as surface roughness, tool wear, force, torque, energy consumption, and costs etc. While cutting parameters are easily planned by the operator during drilling, the selection and planning of the drill geometry are more difficult. In order to design and produce the new drill geometry, a wide time and engineering research are needed. In this study, the design and fabrication of new drill geometry were performed to improve the hole-drilling performance. The performance of the fabricated drills was judged with regard to surface roughness, thrust force, and drilling torque. In the performance tests, four different drill geometries, four different cutting speed levels, and four different feed rate levels were selected. Holes were drilled on AISI 4140 material. In addition, the optimization was performed in two phases. Firstly, the mono-optimization was carried by using Taguchi's S/N analysis in which each performance output was optimized separately. Secondly, the multi-objective optimization was employed by using Taguchi-based gray relational analysis (GRA). For the purpose of the study, two different drill geometries were designed and fabricated. Experimental results showed that the designed Geometry 4 is superior to other geometries (geometry 1, geometry 2, and geometry 3) in terms of thrust force and surface roughness. However, in terms of drilling torque, geometry 2 gives better results than other drill geometries. It was found that for all geometries, obtained surface roughness values are lower than the surface roughness values expected from a drilling operation and therefore surface qualities (between 1.2 and 2.4m) were satisfactory.
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    Öğe
    Multi-response Optimization of Cutting Parameters for Hole Quality in Drilling of AISI 1050 Steel
    (Springer Heidelberg, 2015) Meral, Guven; Sarikaya, Murat; Dilipak, Hakan; Seker, Ulvi
    In this study, the surface roughness, dimensional accuracy, and circular and cylindrical deviations characterizing the hole quality were investigated experimentally. AISI 1050 steel in experiments was chosen as reference material due to its extensive applications in many areas. Uncoated and TiAlN coated by physical vapor deposition (PVD) method HSS twist drills with different diameters were used. Experiments were conducted on a CNC vertical machining center under dry condition with different cutting speeds and feed rates. The hole depth was 17 mm to ensure L < 3D condition. After each experiment, hole properties such as surface roughness, dimensional accuracy, circular deviation, and axial misalignment between inlet and outlet holes (cylindrical deviation), all of those that show the hole quality, were measured, and the results were evaluated. In addition to experimental analysis, a statistical analysis was carried out to indicate the effects of drilling parameters on test results. Process parameters such as tool type, drill diameter, feed rate, and cutting speed were optimized with consideration of multiple performance characteristics using desirability functional analysis. As a result, coated tools compared with uncoated tools gave positive results for each evaluation criterion. As the most important parameter on surface roughness (Ra) was drill diameter, the most effective parameter on dimensional accuracy, and circular and cylindrical deviations was cutting speed for both uncoated and coated tools except from cylindrical deviation occurring in uncoated drill.
  • [ X ]
    Öğe
    Optimization of hole quality produced by novel drill geometries using the Taguchi S/N approach
    (Springer London Ltd, 2019) Meral, Guven; Sarikaya, Murat; Mia, Mozammel; Dilipak, Hakan; Seker, Ulvi
    Reportedly, the drill geometry influences the drilling operation. In fact, the performance of the drill bit is strongly associated with productivity, thus with economy of production. Moreover, the typical performance indicators, i.e., deviation from diameter, cylindricity, perpendicularity, and concentricity, are altered by drill geometry. This fact stresses the need for a novel design of drills with further optimization of performance indicators of hole quality. In that perspective, herein, new drill geometries were designed and fabricated. Afterward, those drills were employed to create holes on AISI 4140 steel, and their performances were investigated and optimized to suggest cutting parameters of best interest. For performance tests, four different drill geometries, four different cutting speeds (90, 100, 110, 120m/min), and four different feeds (0.15, 0.20, 0.25, 0.30mm/rev) were practiced. To measure the performance of the drills, the quality of the drilled holes was studied in terms of the deviation from diameter, cylindricity, perpendicularity, and concentricity. During the experiment, geometry 3 that was developed as the original drill geometry exhibited poor chip evacuation. As such, geometry 4 was developed by considering these negativities, and it was found to demonstrate superior performance compared to other geometries in terms of hole quality. Furthermore, ANOVA revealed that the drill bit flute geometry is the most influential factor. Lastly, the Taguchi S/N approach disclosed that drilling with geometry 4 at the cutting speed of 90m/min and feed rate of 0.15mm/rev produced optimum machining performance.