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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.

Powder bed fusion based additive manufacturing techniques involve melting or sintering of powder particles via laser beams to join them in order to attain desired shapes. This study aims to provide basis for material constitutive parameters of widely used aluminum alloy AlSi10Mg alloy. Initially, tensile samples of AlSi10Mg alloy samples were manufactured by using SLM technology. Afterwards, through quasi-static and high temperature tensile tests, an attempt has been made to determine the Johnson-Cook material model of AlSi10Mg. in order to conduct quasi-static tensile tests, strain rates of 10-3 s-1, 10-2 s-1 and 5x10-2 s-1 were considered and tests were conducted at ambient temperature. Whereas, for high temperature tensile tests 24, 150, 300 °C temperature values were considered at the reference strain rate value of 10-3 s-1. The numerically simulated tensile results achieved by using the established Johnson-Cook model were then compared with experimental results. It was observed that the maximum error between the test and simulation results was around of 7.5%. The error percentage is well within the acceptable, thus proving the accuracy of the established material model.

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 the rail industry, there are four types of steel grades used for monoblock wheels, namely ER6, ER7, ER8 and ER9. ER7 steel is manufactured in accordance with the EN13262 standard and is utilized in European railway lines. These train wheels are formed by pressing and rolling after which they are machined using turning process to achieve their final dimensions. However, machining ER7 steels can be challenging due to their high mechanical properties, which can facilitate rapid tool wear and thermal cracking. Therefore, while the use of coolants is critical to improving their machinability, using conventional flood coolants adds extra operational costs, energy and waste. An alternative is to use minimum quantity lubrication (MQL) cooling technology, which applies small amounts of coolant mixed with air to the cutting zone, leaving a near-dry machined surface. In the current study, preliminary tests were undertaken under dry conditions and using coated carbide inserts to determine the optimal cutting parameters for machining ER7 steel. The impact of the cutting speed and feed rate on surface roughness (Ra), energy consumption and cutting temperature were investigated and used as a benchmark to determine the optimal cutting parameters. Next, additional machining tests were conducted using MQL and nano-MQL cooling technologies to determine their impact on the aforementioned machining outputs. According to preliminary tests, and within the tested range of the cutting parameters, using a cutting speed of 300 m/min and a feed rate of 0.15 mm/rev resulted in minimal surface roughness. As a result, using these optimal cutting parameters with MQL and Nano-MQL (NMQL) cooling technologies, the surface roughness was further reduced by 24% and 34%, respectively, in comparison to dry conditions. Additionally, tool wear was reduced by 34.1% and 37.6%, respectively. The overall results from this study demonstrated the feasibility of using MQL coolants as a sustainable machining alternative for steel parts for rail wheel applications. In addition, the current study highlight the enhanced performance of MQL cooling technology with the addition of nano additives.

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 paper, the regression analysis (RA) and artificial neural network (ANN) are presented for the prediction of tool-chip interface temperature depends on cutting parameters in machining. The RA and ANN model for prediction tool-chip interface temperature are developed and mathematical equations derived for tool-chip interface temperature prediction are obtained. The tool-chip interface temperature results obtained from mathematical equations with RA and ANN model and the experimental results available in the literature obtained by using AISI 1117 steel work piece with embedded K type thermocouple into the uncoated cutting tool (Korkut, Boy, Karacan, & Seker, 2007) are compared. The coefficient of determination (R-2) both training and testing data for temperature prediction in the ANN model are determined as 0.999791289 and 0.997889303 whereas; R-2 for both training and testing data in the RA model are computed as 0.999063 and 0.999427, respectively. The correlation obtained by the training ANN model are better than the one obtained by training RA model. The training ANN model with the Levenberg-Marquardt (LM) algorithm provides more accurate prediction and is quite useful in the calculation of tool-chip interface temperature when compared with the trained RA method in machining. On the other hand, prediction values obtained the testing RA model is slightly better performance than the testing ANN model. The results show that the tool-chip interface temperature equation derived from RA and ANN model can be used for prediction. (C) 2011 Elsevier Ltd. All rights reserved.

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.