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Öğe Investigate the effect of pre-drilling in friction drilling of A7075-T651(Taylor & Francis, 2014-04-28) Demir, Zülküf; Özek, CebeliFriction drilling is a non-traditional hole achieving method that is a clean, chip-less process, which is called thermal drilling, form drilling, flow drilling, and friction stir drilling. In this study pre-drilling friction drilling was investigated for improving the bushing shape of A7075-T651, which is a brittle cast material. During the process, surface roughness and bushing shapes were analyzed and generated frictional heat was measured by the virtue of thermocouples. Experiments were carried out to 4mm and 6mm in thicknesses of A7075-T651 aluminum alloy at 1200, 1800, 2400, 3000, and 3600 rpm spindle speeds, 20, 40, 60, 80, and 100 mm/min feed rates with using high-speed steel rotating conical tool, whose diameter is 8 mm. Consequently, the bushing shapes were advanced without cracks and petal formation in pre-drilling Friction drilling in comparison with without pre-drilling process. With increasing pre-drilled hole diameter the generated frictional heat was decreased. The achieved temperature was realized to be 1/2-1/3 of the melting temperature of the workpiece. Surface roughness values were decreased with decreasing or increasing both spindle speed and feed rate correspondingly.Öğe Investigating the effects of cutting parameters on materials cut in CNC plasma(Taylor & Francis, 2013-10-03) Çelik, Yahya HışmanComplex-profile surfaces, of which measurement precision is not important, are cut serially using CNC plasma. These materials cut using CNC plasma are assembled with different manufacturing techniques. These materials can also operate under high pressure and resistance. In this study, S235JR sheet materials (4, 6, and 8 mm thick), used in pressure vessels, were cut using the CNC plasma cutting machine at different cutting speeds, amperes, and arc voltages. Temperature distribution, thickness of heat-affected zone (HAZ), surface roughness, and hardness were measured from the material cut at these different values. Based on values obtained from measurements, the ideal cutting conditions were identified for the materials exposed to the cutting procedures.
