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ER7 quality steels produced according to EN13262 standard used in European railway lines can be produced at Kardemir A.Ş Railway Wheel Production Facilities. These wheels, which are produced by pressing and rolling, are included in the machining process to be brought to their final dimensions after the production process. In this experimental study, the effects of cutting speed (CS) and feed rate (FR) on surface roughness (SR), power consumption (PC) and cutting temperature (CT) were investigated during turning of ER7 wheel material with 1mm depth of cut value under dry test conditions using MT-TiCN+Al2O3 CVD coated-RCMX 1606M0 K15 quality tool. Analysis of Variance (ANOVA) method was used to determine the effect rates of the input parameters on the results. In addition, estimation equations were obtained using the Response Surface Method. As a result of this study, the effective parameter for SR is FR with 57.158%, while the effective parameter for PC and CT is found to be CS, and it is found to be 58.071% and 64.977%, respectively.

Poor surface traits, short insert life, high manufacturing costs, and low productivity are associated with the machining of nickel alloys. Cutting fluids have well-known positive and negative effects on machinability performance. As a result, the machining industry has developed green cutting environments such as vegetable oil assisted minimum quantity lubrication (MQL) and cryogenic cooling. Despite the fact that MQL and cryogenic approaches can replace mineral oil-based flooding, their lack of lubrication and cooling properties at high speeds have prompted a search for a new hybrid approach (CO2 + MQL) that provides adequate cooling/lubrication (C/L). Moreover, as of now, no information concerning the effects of hybrid cooling on milling of Nimonic-80A is existing. To test the viability, the machining of Nimonic-80A under hybrid C/L was compared to other cutting environments (MQL and cryogenic). As crucial machinability factors, temperature, power consumption, surface and subsurface characteristics were thoroughly examined. Hybrid condition curtailed the burr formation, which paves the way for a reduction in specific cutting energy (SCE). The experimental results indicate that the hybrid condition considerably decreases the temperature and SCE by 34–53% and 17–19% in comparison with the MQL condition. Peak widening and intensity reduction were seen in the XRD examination, but no phase transition was found. Smaller grain size shows the superiority of hybrid environment.

Nickel based super alloys are considered as difficult to machine materials. These days, the sustainable cooling system are applied at the cutting zone for enhancing the machining performance of nickel based super alloys. Therefore, the present work focusses on the machining aspects of Nimonic 80A under different cooling conditions. Moreover, the turning experiments were performed under dry, minimum quantity lubrication (MQL different positions) and nano-MQL (different positions) conditions and the influence of nozzle position during MQL and nano-MQL were investigated. The tool wear, surface roughness, mechanism promoting tool wear, power consumption and chips morphology were investigated under these subjected conditions. The outcomes of this study state that the position of MQL nozzles plays an important role to improve the machining performance of Nimonic-80 alloy. The total tool wear is approximately 60% better for nano-MQL (mixed direction) than dry conditions. The results also stated that abrasion and adhesion are prompting tool wear mechanisms observed under dry conditions.

In the aviation and structural industries, the requirement of smooth holes is an important safety problem. Since holes are a part of the joints made with fasteners, they affect the fatigue strength of the structure. Therefore, it is necessary to be very selective in terms of cutting parameters and cutting tools, especially in drilling metal/composite or composite/metal stacked materials. In this context, cutting conditions in conventional machining methods should be optimized or novel machining methods should be applied. In this context, this study minimized the limitations in machining of carbon fiber-reinforced composite (CFRP)/Ti6Al4V alloy stack material and the delamination problem that occurs especially in composite laminates. For this purpose, cutting conditions have been optimized for each of CFRP/Ti6Al4V alloy material, depending on the thrust force (Fz), surface roughness (Ra), and delamination factor (Fd) obtained by preliminary tests. The drilling tests were performed at the cutting speed of 60 m/min, the feed rate of 0.05 mm/rev for CFRP material, the cutting speed of 15 m/min, and the feed rate 0.05 mm/rev for Ti6Al4V material. The novel method for this study is that the tool was kept in the air for 1 min after each 4 mm drilling of Ti6Al4V alloy to cool the tool during the rebounds to the safe approach distance. Finally, according to the optimized cutting parameters, Fz, Ra, and Fd were assessed to evaluate the performances of cutting tools in the drilling of CFRP/Ti6Al4V stacked material. According to the experimental results and images of the digital camera and SEM device, flank wear and cracking as the wear type in the U-WC tool; flank wear, cracking, and BUE as the wear type in the TiAlN-coated tools; and outer corner wear and coating removal in diamond-coated tools. Moreover, when the tool performance is evaluated according to the cutting tool tip angle, the highest amount of wear was seen in cutting tools with 140° point angle.

In this study, the variations of thrust force, surface roughness and delamination factor according to cutting parameters were investigated in the drilling of Poly-ether-ether-ketone (PEEK)-CF30 composite material with uncoated HSS drill. Drilling experiments were carried out under dry machining conditions using three different cutting speeds (40, 80, 120 m/min) and feed rates (0.1, 0.15, 0.2 mm/rev). The thrust forces in drilling were measured with the Kistler dynamometer and equipment, and the results were analyzed by taking the arithmetic average of the data. The roughness on the hole surface and the delamination damages on the hole exit were measured. With the increase of the feed rate, there was an increase of 3%-25% in the thrust force, while the increase in the thrust forces was observed in the range of 9%-28% with the increase of the cutting speed. The surface quality improved with the decrease in cutting speed and increase in feed rate while the delamination factor increased. The lowest surface roughness was obtained as 1.18 µm at 40 m/min cutting speed and 0.2 mm/rev feed, and the highest surface roughness was 2.96 µm at 120 m/min cutting speed and 0.1 mm/rev feed., Bu çalışmada, Poli-eter-eter-keton (PEEK)-CF30 kompozit malzemenin kaplamasız HSS matkapla delinmesinde oluşan itme kuvveti, yüzey pürüzlülüğü ve delaminasyon faktörünün kesme parametrelerine göre değişimleri araştırılmıştır. Delme deneyleri üç farklı kesme hızı (40, 80, 120 m/dk) ve ilerleme miktarı (0.1, 0.15, 0.2 mm/dev) kullanılarak kuru işleme şartlarında yapılmıştır. Delmede oluşan itme kuvvetleri Kistler dinamometre ve ekipmanlarıyla ölçülmüş ve elde edilen sonuçların aritmetik ortalaması alınarak analiz edilmiştir. Delik yüzeyinde oluşan pürüzlülük ile delik çıkışında oluşan delaminasyon hasarları ölçülmüştür. İlerleme miktarının artmasıyla itme kuvvetinde %3-%25’lik artış olurken, kesme hızının artmasıyla itme kuvvetlerinde %9-%28 aralığında artışlar görülmüştür. Kesme hızındaki azalma ve ilerleme miktarındaki artışla birlikte yüzey kalitesinde iyileşme olurken, delaminasyon faktöründe artış görülmüştür. En düşük yüzey pürüzlülüğü 40 m/dk kesme hızı ve 0.2 mm/dev ilerlemede 1.18 µm, en yüksek yüzey pürüzlülüğü 120 m/dk kesme hızı ve 0.1 mm/dev ilerlemede 2.96 µm olarak elde edilmiştir.

AISI 304 quality stainless steels are a very common type of stainless steel because they have high mechanical properties and high corrosion resistance. Stainless parts with complex and large dimensions are produced by the casting method. The machinability of stainless steels produced by casting is even more difficult than forging methods. In this study, the effects of three different cutting speeds, feed rates and constant cutting depth on the surface roughness and burr formation in dry and mist cold air (MCA) conditions were investigated in milling of AISI 304 stainless cast steel. As a result, an improvement between 15% and 48% was achieved in the average surface roughness (Ra) obtained in machining with MCA compared to dry machining conditions. In both cutting conditions, the increasing feed rate increased the burr height, while the increase in cutting speed decreased the burr height. MCA application provided an average of 9% reduction in burr height., AISI 304 kalite paslanmaz çelikler yüksek mekanik özelliklere ve yüksek korozyon direncine sahip olduklarından oldukça yaygın kullanılan bir paslanmaz çelik çeşididir. Karmaşık ve büyük ebatlara sahip paslanmaz parçalar döküm yöntemi ile üretilmektedir. Döküm ile üretilen paslanmaz çeliklerin işlenebilirliği dövme yöntemlerine göre daha da zor olmaktadır. Bu çalışmada, AISI 304 paslanmaz döküm çeliğinin frezelenmesinde kuru ve buharlı soğuk hava şartlarında üç farklı kesme hızı, üç farklı ilerleme miktarı ve sabit kesme derinliğinin yüzey pürüzlülüğü ve çapak oluşumuna etkisi araştırılmıştır. Sonuç olarak buharlı soğuk hava (BSH) ile işlemede elde edilen yüzey pürüzlülüklerinde kuru işleme şartlarına göre %15-%48 arasında bir iyileşme sağlanmıştır. Her iki kesme şartında, ilerleme miktarı çapak yüksekliğini artırırken kesme hızının artışı çapak yüksekliğini azaltmıştır. BSH uygulaması çapak yüksekliğinin ortalama %9 azalmasını sağlamıştır.

In this work, the sustainable manufacturing approach is promoted by implementing the dry and minimum quantity lubrication (MQL) cooling conditions in the machining of duplex stainless steel. Initially, the turning experiments were performed under dry as well as MQL conditions and then, the influence of different positions of MQL nozzles on tribological and machining performance of 2205 duplex steel was investigated. The cutting parameters were kept fixed and the performance is evaluated in terms of surface roughness, micro-hardness, energy consumption, tool wear, machined surface microstructure and chips morphology. The results demonstrated that the highest average surface roughness values were obtained under dry conditions, with a value of 2.20 µm while MQL (flank + rake directions) produces the lowest surface roughness value of 1.55 µm with an improvement of 30%. Moreover, dual-jet MQL gives the lowest energy consumption (229 kJ) and tool wear (0.15 mm) with 23.67% and 52.38% enhancement, respectively.

In this study, measurement of the chip-back temperature developed during cutting was investigated using an embedded thermocouple into the cutting tool. AISI 1117 steel was used as the workpiece material and a K type thermocouple was used for the temperature measurement. The cutting tool used was uncoated and without chip braker and in the form of SCMW 12 M508-S2F according to ISO 1832. This cutting tool was fixed on a tool holder in the form of SSBCR 25 25 M12 and the side cutting edge angle during tests was 75° as suggested in ISO 3685. The cutting tests were carried out on a Johnford TC35 CNC turning center. In selecting the cutting parameters, the reference values indicated in ISO 3685 were used. In order to locate the thermocouple on the cutting tool, a Flir Systems Therma Cam thermal camera was used. The results showed that increasing cutting speed, feed rate and depth of cut resulted in increase in the temperature at the back rake surface. However, cutting speed had the most influence on the temperature. © 2006 Elsevier Ltd. All rights reserved., Firat University Scientific Research Projects Management Unit: 07/2002–20, The authors would like to acknowledge Gazi University Scientific Research Projects (07/2002–20) for the financial support throughout this study.

AA7075 aluminum alloy has been very popular significantly interest in the production of structural components in automotive and aviation applications due to its high strength, low density, good plasticity and better machinability comparable to many metals. Particularly, final products must have uniformly high quality to ensure essential safety standards in the aircraft industry. The optimization of hole quality which can variable according to tool geometry and drilling parameters is important in spite of high machinability rate of AA7075 alloy. In this study, the effects of drilling parameters on average surface roughness (Ra) has been investigated in drilling of AA7075 with tungsten carbide drills. Machining experiments were performed with three different drill point angles and three different levels of cutting parameters (feed rate, cutting speed). The effects of drilling parameters on thrust force has been determined with ANOVA in %95 confidence level. Feed rate was determined as the most important factor on Ra according to ANOVA results. Moreover, it was shown that increasing feed rate leads to increase of Ra while increasing drill point angle leads to decrease of Ra. The optimum surface roughness was obtained with point angle of 130°, cutting speed of 40 m/min and feed rate of 0.1 mm/rev, thereby the validity of optimization was confirmed with Taguchi method.

In recent years, turning of hardened steels has replaced grinding for finishing operations. This process is compared to grinding operations; hard turning has higher material removal rates, the possibility of greater process flexibility, lower equipment costs, and shorter setup time. CBN or ceramic cutting tools are widely used hard part machining. For successful application of hard turning, selection of suitable cutting parameters for a given cutting tool is an important step. For this purpose, an experimental investigation was conducted to determine the effects of cutting tool edge geometry, feed rate and cutting speed on surface roughness and resultant cutting force in hard turning of AISI H13 steel with ceramic cutting tools. Machining experiments were conducted in a CNC lathe based on Taguchi experimental design (L16) in different levels of cutting parameters. In the experiments, a Kistler 9257 B, three cutting force components (Fc, Ff and Fr) piezoelectric dynamometer was used to measure cutting forces. Surface roughness measurements were performed by using a Mahrsurf PS1 device. For statistical analysis, analysis of variance has been performed and mathematical model have been developed for surface roughness and resultant cutting forces. The analysis of variance results showed that the cutting edge geometry, cutting speed and feed rate were the most significant factors on resultant cutting force while the cutting edge geometry and feed rate were the most significant factor for the surface roughness. The regression analysis was applied to predict the outcomes of the experiment. The predicted values and measured values were very close to each other. Afterwards a confirmation tests were performed to make a comparison between the predicted results and the measured results. According to the confirmation test results, measured values are within the 95% confidence interval.