Mahmat, Aybars; Agar, Salih; Tosun, Nihat

In this study, the effects of different cooling techniques and process parameters on the performance characteristics of ultrasonic and conventional micro-milling (1-micron fixed amplitude, 20 and 30 kHz frequencies) of Ti6Al4V alloy were experimentally investigated. The impact of independent factors on tool life, cutting force, surface topography, surface roughness and cutting temperature was determined in order to find out machinability characteristics in this paper. Machining operations were performed under 20,000, 40,000 and 60,000 rpm revolution speed. The cutting depth and feed rate of the machining were kept fixed at 0.02 mm and 0.66 mm/s, respectively. Uncoated carbide and TiSiN-coated carbide cutting tools were used in machining operations. Dry machining and two different minimum quantity of lubrication (MQL) methods were used as cooling methods. According to the results achieved in the existing study, the ultrasonic micro-milling improved the surface roughness, reduced cutting forces, cutting zone temperature, and cutting tool wear. It was also found that MQL methods among other methods used in the present study have a greater effect on performance characteristics. As the spindle speed increased, the workpiece surface roughness, cutting force and tool life decreased, while the cutting zone temperature increased.

AtıfScopus4·WoS4·OpenAlex4

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Mahmat, Aybars; Dogan, Gurkan; Ergen, Burhan; Tosun, Nihat

In some cases, the models targeted in machining processes are difficult to apply to industrial production. Artificial intelligence techniques applied to industrial production methods in recent times eliminate these problems in machining. The use of deep learning methods in solving these problems has recently increased. In this study, a new deep neural network (DNN) based on artificial neural networks is proposed to model the machining of AISI4140 steel by wire electrical discharge machining (WEDM). The proposed DNN model predicts surface roughness (SR) and wire wear ratio (WWR), which are the most important inferences in cutting with WEDM. Obtaining inferences such as SR and WWR in a real experimental environment means a lot of time and cost. With the proposed model, there is a significant reduction in time and cost factors. The dataset used to train and test the proposed model was obtained from the real experimental environment. For training and testing the model, the data set is divided into two parts: 20% test data and 80% training data. In the experimental tests carried out with the proposed model, error rates such as Mean Absolute Error (MAE), R2, and Mean Squared Error (MSE) accuracy rate between SR and WWR values estimated according to the SR and WWR values obtained from the real environment were examined. MAE, MSE, and R2 for SR reached 0.0495, 0.0005, and 98.48%, respectively, while MAE, MSE, and R2 for WWR reached 0.0156, 0.0036, and 98.39%, respectively. These results of the proposed model provided a lower error rate and higher accuracy than the state-of-the-art models in the literature.

AtıfScopus5·WoS5·OpenAlex7

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Agar, Salih; Tosun, Nihat; Mahmat, Aybars

This study focused on determining the effects of the cooling condition in the conventional and ultrasonic-assisted turning of AISI 52100 steel. AISI 52100 steel has been widely used in the bearing, mold, and automotive industries because of its superior wear resistance and mechanical properties. However, its high wear resistance caused poor machinability in conventional machining methods. Low surface quality, rapid tool wear, high cutting temperature, and high cutting force are the main difficulties in the conventional machining of AISI 52100 steel. On the other hand, ultrasonic-assisted machining has become widely used in the past decades for the machining of materials that have low machinability in conventional methods. Conventional turning and ultrasonic-assisted turning were selected as machining methods. Ultrasonic-assisted turning experiments were conducted under 20 and 30 kHz vibration frequencies. Cubic Boron Nitride (CBN) cutting tools were used in machining experiments. In machining operations 50, 100, and 150 m/min cutting speeds were selected, and feed rate (0.1 mm/rev) and depth of cut (0.5 mm) were kept constant in experiments. Minimum quantity lubrication technique which used 1% Al2O3 nanoparticle additives cutting fluid and dry cooling methods were used. CBN insert was used as a cutting tool. The effects of cutting speed, cutting method, and cooling condition on surface quality, cutting force, cutting zone temperature, and cutting tool wear were studied experimentally. Analysis of Variance (ANOVA) was carried out to determine the significance of the effects of input variables on process outputs. As a result of this study, it is determined that combined UAT and nanoMQL have significant effects on the process outputs.

AtıfScopus3·WoS3·OpenAlex3

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Tosun, Nihat; Rasul, Sleman Yahya; Mahmat, Aybars; Tosun, Gul

During the machining of aluminum alloys, the adhesion of chips to the tool affects the performance characteristics. Today, different cooling systems are used to eliminate these negativities. In this study, the effects of end milling using HSS and carbide cutting tools of 6061-T6 aluminum alloy on surface roughness, chip thickness ratio and tool wear were examined using different cooling techniques (dry, minimum quantity lubrication (MQL) and nanocutting fluid). Different cutting speeds (180, 200, 220 m/min) and different feed rates (0.05, 0.06, 0.07 mm/rev) were used in the experiments. According to experimental findings, tool wear and surface roughness decreased at low cutting speed and feed rate by using nanocutting fluid with carbide cutting tools. It has been observed that the chip thickness ratio increases with high cutting speeds using nanocutting fluid and decreases with dry machining and high feed rates. The best milling performance of the aluminum alloy was achieved in experiments using carbide cutting tools and nanocutting fluid.

AtıfScopus4·WoS4·OpenAlex4

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Tosun, Nihat; Mahmat, Aybars; Ağar, Salih

Bu çalışmada, AISI 52100 çeliğinin geleneksel ve ultrasonik tornalanmasında işlem parametrelerinin performans karakteristikleri üzerindeki etkileri yani AISI 52100 çeliğinin işlenebilirliği deneysel, sayısal ve istatistiksel olarak araştırıldı. Çalışmada, işlenebilirliğin tespit edilmesi amacıyla, bağımsız değişkenlerin takım ömrü üzerine olan etkileri belirlendi. Deneysel çalışmalar, 50, 100 ve 150 m/dak kesme hızları, 0.1 mm/devir sabit ilerleme ve 0.5 mm sabit talaş derinliği gibi işleme şartları altında, sementit karbür ve kübik bor nitrür (CBN) kesici takımlar kullanılarak yürütüldü. Ultrasonik tornalamada, kesici takıma iki farklı titreşim genliği (5 ve 10 µm) ve iki farklı titreşim frekansı (20 ve 30 kHz) uygulandı.

İncele

Mahmat, Aybars; Tosun, Nihat; AǦar, Salih

This study aims to investigate experimentally and analytically the effects of different machining parameters such as cooling methods and cutting tool materials on surface roughness and chip thickness ratio for milling of AA7075-T6 aluminum alloy. The carbide and high-speed steel (HSS) end mills were used as cutting tools and the conventional, vapor, and compressed air were used as cooling methods in the experiments. The experiment conditions for compressed air at the cutting zone were 6 bar pressure and 30 m/s speed flow rate. A mixture of boron oil and water (1/20 mixture ratio) was used as cutting fluid in conventional cooling. The study was carried out using three levels of feed rates (20, 40, 80 mm/min), rotational speeds (780, 1330, 2440 rpm), and a constant 2 mm deep cut. As a result of the experiments, the surface roughness values increased with the increasing levels of feed rate. Besides surface roughness values decreased with increasing levels of the rotational speed. In addition, a better surface quality was obtained in milling processes by using carbide cutting tools compared to HSS tools. It was concluded that the most important parameter affecting the surface roughness and chip thickness ratio is feed rate and the rotational speed, respectively. Better surface roughness and chip thickness ratio were obtained from the vapor processing than the conventional and compressed air.

AtıfScopus2·WoS1

İncele

Aǧar, Salih; Tosun, Nihat

High cutting force and high cutting tool-chip interface temperature occur during machining of high strength materials like AISI 52100 by using conventional turning method and this makes to the difficult machining operation. Besides, in conventional turning (CT) of these materials, which has high abrasion resistance and hardness properties, an additional process such as grinding is required to achieve the desired surface quality. Ultrasonic assisted turning (UAT) method has been widely used in the machining industry in recent years, as it exhibits better surface quality, lower cutting forces, and cutting temperature than the CT method. This paper focused on experimentally and statistically determining the effects of different cutting parameters and cooling conditions (dry and minimum quantity lubrication-MQL) on surface roughness, workpiece surface texture, tangential direction cutting force, and cutting tool-workpiece interface temperature in the machining of AISI 52100 material by using UAT and CT methods. The experimental results revealed that significant improvements determined in the cutting forces and the surface roughness occurred in UAT compared to CT in all the cooling conditions. However, the increasing cutting speeds caused to observe higher interface temperature values in dry turning by the UAT method. Variance Analysis (ANOVA) was carried out to determine the significance grade of independent variables on dependent variables. According to ANOVA results, while the cutting speed is the most important factor on the surface roughness and the cutting zone temperature, and the cooling method is the most important factor on the cutting force. The effects of turning methods on corresponding surface topography, including surface defects, were evaluated. It is determined that in the surface topography analysis, feed marks are the main texture of the workpiece in the CT method while micro-level indentations and protrusions occurred on the workpiece surface in the UAT method.

AtıfScopus14·WoS12·OpenAlex14

İncele

Tosun, Nihat; Mahmat, Aybars; Ağar, Salih

Teknolojinin sürekli değişip gelişmesiyle birlikte, birçok alanda yeni makine ve cihazlar insanlığın kullanımına sunulmaktadır. Bu çalışmada, metalografik incelemeler yapmak için, numune hazırlama aşamalarından biri olan ve tam otomatik olarak çalışacak bir numune zımparalama ve parlatma makinesinin tasarımı ve imalatı yapılmıştır. Bu amaçla, daha önceden imal edilmiş numune zımparalama ve parlatma makineleri incelenerek, bu makinelerde görülen eksiklik ve aksaklıklar dikkate alınarak, yeni bir tasarım gerçekleştirilmiştir. Yapılan tasarımda, makinenin otomatik olarak beş farklı istasyonda numuneyi zımpara üzerinde tutan basınç değeri ve zımparalama süresi ayarlanabilmektedir. Beş farklı istasyonda ve her istasyonda arzu edilen tane büyüklüğünde farklı zımparalar yerleştirilmek suretiyle istenilen kalitede numune yüzeyi elde edilecektir.

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