In the present study, fuzzy logic (a tool in artificial intelligence) was used for the prediction of cutting parameters in plasma arc cutting (PAC) process of AISI 4140 steel. The parameters considered in this study were plasma arc current, cutting speed, and thickness of cut material. Fuzzy rule–based modeling was employed for prediction of surface roughness. These models can be effectively used to estimate the surface roughness. The experimental results were compared with fuzzy logic, and good agreement between them was observed. Analysis of the influence of the individual important machining parameters on the surface roughness have been carried out and presented. Statistically, cutting speed was found the most important factor on surface roughness, while the plasma arc current had the least. The characteristics of machined surfaces and microstructural changes are also studied.

The main aim of machining is to provide the dimensional preciseness together with surface and geometric quality of the workpiece to be manufactured within the desired limits. Today, it is quite hard to drill widely utilized Ti-6Al-4 V alloys owing to their superior features. Therefore, in this study, the effects of temperature, chip formation, thrust forces, surface roughness, burr heights, hole diameter deviations and tool wears on the drilling of Ti-6Al-4 V were investigated under dry cutting conditions with different cutting speeds and feed rates by using tungsten carbide (WC) and high speed steel (HSS) drills. Moreover, the mathematical modeling of thrust force, surface roughness, burr height and tool wear were formed using Matlab. It was found that the feed rate, cutting speed and type of drill have a major effect on the thrust forces, surface roughness, burr heights, hole diameter deviations and tool wears. Optimum results in the Ti-6Al-4 V alloy drilling process were obtained using the WC drill.

Bu çalışmada, AA 5754-O alaşımının ılık derin çekilmesine kalıp yüzey açısı, baskı plakası kuvveti ve sıcaklığın etkisinin deneysel olarak belirlenmesi amaçlanmıştır. Bunun için, kalıp yüzeylerine 0-15° arasında açılar verilerek deneyler oda sıcaklığı(OS) ,100 o C, 175 o C ve 250 o C sıcaklıklarında, 1.2 kN, 2.4 kN ve 3.6 kN baskı plakası kuvvetlerinde gerçekleştirilmiştir. Deneylerde, kalıp boşluğu 1.35 mm, zımba ve kalıp radyüsleri ise 8 mm sabit tutulmuştur. Kalıpla iş parçası arasındaki sürtünme kuvvetini düşürmek için yüksek sıcaklık ve baskılar altında özelliğini yitirmeyen MoS 2 katı yağlayıcı kullanılmıştır. Yapılan çalışmalar neticesinde et kalınlığı, zımba kuvveti ve geri yaylanma üzerine kalıp yüzey açısı ve baskı plakası kuvvetinin etkisinin OS ve 100 o C’de daha belirgin olduğu, sıcaklık arttıkça et kalınlığı dağılımının daha homojen hale geldiği; şekillendirme kuvveti, geri yaylanma miktarı ve sertlik değerinin ise önemli ölçüde düştüğü belirlenmiştir. Yine kap duvarı boyunca sertlik değerinin kap ağzına doğru gidildikçe arttığı ve sıcaklığın önemli etkisinin olduğu görülmektedir.

Deep drawing is the process of obtaining three-dimensional containers of certain depths and shapes under pressing forces with the help of drawing molds of sheet materials. In this study, the numerical shaping of rectangular cups in angled deep drawing dies was investigated experimentally and by using the finite element method (FEM). For this purpose, die/blank holder surfaces have α=0°, α=3°, α=6°, α=9°, α=12° and α=15° angles in order to facilitate material flow into the die cavity. The punch and die corner radii are taken as 8 mm. St37 steel sheet with a thickness of 0,9 mm was used as the test material. The experiments were carried out by applying die/blank holder forces of 2500 N, 5000 N, 7500 N and 10000 N. The effects of angles and die/blank holder force on limit draw ratio, wall thickness and the damage of cups were investigated experimentally and numerically, and optimum punch force was determined. Obtained experimental results were compared with ANSYS results. As a result, it has been determined that the increase in die/blank holder surface angles in drawing dies with rectangular geometry with different angles provides a higher limit drawing rate than conventional dies. It has been seen that the experimental results and numerical results are approximate values.

In thermal friction drilling (TFD) operations, the geometrical dimensions of bushing shape, height and wall thickness are the most vital consequences, since these increase the connecting length and strength. In this paper, AA7075-T651 aluminum alloys with 2, 4, 6, 8, and 10 mm thicknesses were drilled with the TFD process in order to investigate density, volume ratio, and height and wall thickness of the bushings. The experiments were conducted at constant spindle speed and feed rate conditions by using High Speed Steel (HSS) conical tools of 5, 10, 15, and 20 mm in diameter. It was experimentally found that the bushing height and the wall thickness had a tendency to increase linearly with the increase in both material thickness and tool diameter. The effect of tool diameter was found to have more influence on the measurable values than the thickness of the drilled material. The density of the bushing changed trivially. Approximately 70–75 percent of the evacuated material formed the bushing shape in TFD operations.