Kubilay Aslantas

Investigation of the Effect of Axial Cutting Force on Circular Diamond Sawblade Used in Marble Cutting Process

In the marble cutting process, generally, normal and tangential forces are taken into account. However, the axial forces (F z ) on the cutting disc affect the economic life of the disc and segment wear significantly. In this study, the effect of the axial forces on discs, which are used in the marble cutting process, on cutting performance was investigated. Therefore, by taking into account different cutting parameters (peripheral speed, traverse speed and depth of cut), the axial forces on circular saw were measured by means of a dynamometer. In addition to this, using a laser displacement meter, the amount of axial deviation for each cutting parameter in the course of cutting was determined. According to the experimental results obtained, the increase of traverse speed and depth of cut also significantly increases the axial deviation of the cutting disc. Moreover, it is observed that traverse speed and depth of cut have an impact on axial deviation of the saw at the initial moment when the saw starts to cut.

Prediction of cutting temperature in orthogonal machining of AISI 316L using artificial neural network

Exp. (experimental) and num. (numerical) cutting forces were obtained by the exp. studies and FEM analysis.The best convergence between exp. and num. cutting forces was provided.Num. cutting temperatures were predicted by ANN within very low error interval.Exp. cutting temperatures were obtained using exp. cutting forces.Exp. temperature results were quite satisfactory. In this study, an approach based on artificial neural network (ANN) was proposed to predict the experimental cutting temperatures generated in orthogonal turning of AISI 316L stainless steel. Experimental and numerical analyses of the cutting forces were carried out to numerically obtain the cutting temperature. For this purpose, cutting tests were conducted using coated (TiCN+Al2O3+TiN and Al2O3) and uncoated cemented carbide inserts. The Deform-2D programme was used for numerical modelling and the Johnson-Cook (J-C) material model was used. The numerical cutting forces for the coated and uncoated tools were compared with the experimental results. On the other hand, the cutting temperature value for each cutting tool was numerically obtained. The artificial neural network model was used to predict numerical cutting temperatures by means of the numerical cutting forces. The best results in predicting the cutting temperature were obtained using the network architecture with a hidden layer which has seven neurons and LM learning algorithm. Finally, the experimental cutting temperatures were predicted by entering the experimental cutting forces into a formula obtained from the artificial neural networks. Statistical results (R2, RMSE, MEP) were quite satisfactory. This demonstrates that the established ANN model is a powerful one for predicting the experimental cutting temperatures.

Tool Wear Mechanism in Interrupted Cutting Conditions

In this study the machinability of ductile iron having ferritic structure was examined in interrupted cutting conditions. For this purpose, cylindrical samples with 1, 2, and 4 axial slots were prepared. Uncoated cemented carbide cutting tool was used in this work. Two different cutting speeds, feed rate and depth of cut were chosen as cutting parameters. According to results, the number of slots seriously affects the tool wear. Increasing the number of slots results in a decrease in the dimension of chip. Another result observed during the tool wear experiments was that increasing the number of slots results in increase of flank wear. However, the cutting tool wears out rapidly at higher feed rate or depth of cut when one or two slotted workpiece are used. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray microanalysis (EDX) of the worn tools showed that abrasive, adhesion and oxidation wear mechanisms are predominant in the machining of continuous and interrupted cutting of ductile iron.

Effect of tool coating materials on surface roughness in micromachining of Inconel 718 super alloy

Surface roughness is an important parameter that determines the post-manufacturing product quality. In this study, effect of cutting parameters, coating material and the built-up edge phenomenon on the surface roughness were investigated in micro end milling process of Inconel 718 using a white light interferometer and scanning electron microscopy. A micro end mill with a diameter of 768 µm coated with five separate coating materials (AlTiN, AlCrN, TiAlN + AlCrN, TiAlN + WC/C and diamond-like carbon) was used in this study. According to the results obtained, mean surface roughness values of surfaces machined with a diamond-like carbon-coated and AlTiN-coated cutting tool were lower than for other coatings. However, surface roughness values of surfaces obtained with tools coated with TiAlN + AlCrN and AlCrN were higher. Specifically, the formation of built-up edge causes chips to be smeared on machined surfaces, which has a negative impact on the surface quality. As can be expected, wear occurs faster on uncoated tools. As a result of this, the edge radius may increase excessively, and the mean surface roughness value may decrease. Also in this study, multivariate analysis of variance was carried out and the parameter that was most effective on surface roughness was established.

Finite element modeling of micro-milling: Numerical simulation and experimental validation

ABSTRACT In this study, micro-milling of Inconel 718 was investigated. For this purpose, cutting tests were conducted by using uncoated tools and taking four different feed rates (1.25, 2.5, 3.75, and 5 µm/flute) and a constant cutting velocity (48 m/min) into account. In numerical modeling, thermomechanical behavior was modeled using the modified Johnson–Cook material model. Analyses were also conducted for different cutting tool edge angles (+8°, 0, and −8°). In the numerical analyses, cutting force, tool stress, and cutting temperature values were estimated depending on tool rotation and cutting tool edge type and compared with experimental results. When the results obtained from the study are considered, it is seen that the experimental cutting force and temperature values are in harmony with the numerical results. Moreover, it is seen that there is an increase in cutting force, cutting temperature, and stress values depending on the feed rate. In addition, in the numerical analyses for different cutting tool edge geometries it was observed that cutting force temperature and tool stress values varied depending on the edge geometries.

The effect of minimum quantity lubrication and cryogenic pre-cooling on cutting performance in the micro milling of Inconel 718

In this study, the effects of different cutting conditions on the cutting performance were investigated in the micro milling of Inconel 718. In this context, dry cutting, minimum quantity lubrication and cryogenic pre-cooling were considered as the cutting conditions. Tool wear, surface roughness and burr formation were determined as performance criteria in the cutting processes carried out using an AlCrN-coated tool. At the end of the study, cryogenic pre-cooling led to increased tool wear. In contrast, a significant reduction in surface roughness as well as burr formation was observed in the cutting process with cryogenic pre-cooling. However, the minimum quantity lubrication process increased tool life, but it was not seen as the clear effect for decreasing surface roughness and burr formation.

3D numerical modelling of micro-milling process of Ti6Al4V alloy and experimental validation

Abstract In this study, three-dimensional (3D) finite element analysis was carried out for micro milling of Ti-6Al-4V alloy. The Johnson–Cook material model equation was used, by considering the effects of strain, strain rate and temperature on material properties. The simulation for the milling process of Ti-6Al-4V was conducted through DEFORM based on the established 3D finite element modelling. Additionally, a series of micro-milling experiments on Ti-6Al-4V alloy were carried out to validate the simulation results. For this purpose, cutting tests were conducted using uncoated tools at three different feed rates (2, 3 and 4 μm/flute) and two different cutting velocities (15 and 30 m/min). In the numeric analyses, the cutting force, tool stress and chip formation were estimated and the cutting force, and chip shapes compared with the experimental results. The results of this study show that the experimental cutting force values and chip shapes are in harmony with the numerical ones. In addition, it is observed that cutting force and stress values increase in with increasing the feed rate.

Effect of cooling liquids on cutting process using diamond segmented disc of natural stones

In this study, various cooling liquids considered as alternatives to water were investigated for cutting performance of diamond sawing disc utilized in cutting process of natural stones. In experiments, four various cooling liquids such as water, Ace-Cool, boron oil and liquid soap and two different natural stones (Blue Pearl and Nero Zimbabwe) were used. Down-cutting mode was selected for cutting experiments. In experiments, power consumption, cutting forces, specific energy, diamond segment wear and diamond crystal failures were determined. Power consumption of diamond sawing disc was measured through an energy analyzer and cutting forces through a three-directional dynamometer (ESIT). Specific energy values were calculated through an analytical method on the basis of the resulting power consumption and cutting forces. Besides, diamond segment wear was measured through a laser device (KEYENCE) and diamond crystal failure in cutting process was analyzed through scanning electron microscopy on the basis of cooling liquids. Results of the study show that various cooling liquids proposed as alternatives to water increase significantly cutting performance of the diamond sawing disc. While maximum cutting performance was achieved with a mixture of water and boron oil, minimum performance was achieved through use of water.

Mikro İşlemede Takım Aşınması-Kanal Geometrisi İlişkisi Üzerine Deneysel Bir Çalışma

Bu calismada, mikro frezeleme isleminde takimda meydana gelen asinmanin kanal geometrisi uzerinde etkisi deneysel olarak arastirilmistir. Deneylerde, is parcasi olarak Inconel 718 alasimi tercih edilmis olup, sabit kesme parametreleri dikkate alinmistir. Deneyler kuru kesme sartlarinda yapilmis olup, ardisik kesme islemleriyle mikro kanallardaki boyutsal degisim, capak olusumu ve kesme kuvvetlerindeki degisim arastirilmistir. Elde edilen sonuclara gore takim capinda meydana gelen cevresel asinma artan kesme mesafesi ile artmaktadir. Takimda cevresel asinmanin yani sira eksenel bir asinma da meydana gelmektedir. Eksenel asinma, takim kose radusunun zamanla degismesine neden olmaktadir. Kose radusunun artmasi kanal geometrisinin bozulmasina ve capak olusumunun artmasina neden olmaktadir. Ayrica kesici takima yapisan talas ta kose radusunun buyumesine neden olmaktadir. Bunun sonucunda kesme islemi, kazinma agirlik bir kesmeye donusmekte ve kesme kuvvetleri de artmaktadir.