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Öğe Analytical Modeling Methods in Machining: A State of the Art on Application, Recent Challenges, and Future Trends(Springer Heidelberg, 2024) Korkmaz, Mehmet Erdi; Gupta, Munish Kumar; Sarikaya, Murat; Gunay, Mustafa; Boy, Mehmet; Yasar, Nafiz; Demirsoz, RecepInformation technology applications are crucial to the proper utilization of manufacturing equipment in the new industrial age, i.e., Industry 4.0. There are certain fundamental conditions that users must meet to adapt the manufacturing processes to Industry 4.0. For this, as in the past, there is a major need for modeling and simulation tools in this industrial age. In the creation of industry-driven predictive models for machining processes, substantial progress has recently been made. This paper includes a comprehensive review of predictive performance models for machining (particularly analytical models), as well as a list of existing models' strengths and drawbacks. It contains a review of available modeling tools, as well as their usability and/or limits in the monitoring of industrial machining operations. The goal of process models is to forecast principal variables such as stress, strain, force, and temperature. These factors, however, should be connected to performance outcomes, i.e., product quality and manufacturing efficiency, to be valuable to the industry (dimensional accuracy, surface quality, surface integrity, tool life, energy consumption, etc.). Industry adoption of cutting models depends on a model's ability to make this connection and predict the performance of process outputs. Therefore, this review article organizes and summarizes a variety of critical research themes connected to well-established analytical models for machining processes.Öğe Comparison of experimental, analytical and simulation results for hot rolling of S275JR quality steel(Elsevier, 2020) Kurt, Gazi; Yasar, NafizHot rolling allows the material to be shaped in successive steps in different steps since the material is at a temperature above 0.5 Tm which is the recrystallization temperature and gives the possibility of deformation with large deformation rates. In the industry, direct applications show negative effects on time and cost. Practical processes by experimenting can be completed in short periods in some symmetrical profile section products and long periods in some asymmetric profile section products. Finite element method (FEM) can be applied in order to predict the results obtained by simulating the designed calibrations in the computer environment before testing in the rolling mill. In this study, the production of HEA 240 profile in S275JR quality is experimentally made in 21 passes and the geometric dimensions of the first three passes of this structure was compared with 3D FEM analysis results. The comparison results are compatible and high similarity ratio as 95-99.1% was found. Following to this, the analytically calculated dimensions of calibrated IPE 140 pro- file in S275JR quality was compared by the verified 3D FEM analysis. Considering the first 5 passes of 15 passes for saving time, the simulation and analytical results are in close rela- tionship less than 5% deviation ratio. It is possible to say that this simulation, which has small acceptable differences, has a significant effect on minimizing losses in production processes and achieving production targets. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Öğe Comprehensive analysis of tool wear, surface roughness and chip morphology in sustainable turning of Inconel-601 alloy(Elsevier Sci Ltd, 2023) Korkmaz, Mehmet Erdi; Gupta, Munish Kumar; Guenay, Mustafa; Boy, Mehmet; Yasar, Nafiz; Demirsoez, Recep; Ross, K. Nimel SwornaThe objective of this research was to explore the impact of various cooling conditions on machinability, as potential alternatives to traditional cooling methods. To achieve this aim, a series of experiments were performed, where dry machining, minimum quantity lubrication (MQL), nanofluids, cryogenic (cryo) cooling, and hybrid cooling (cryo+nano MQL) methods were tested. Under distinct nanofluids conditions hBN(0.2 %) + graphene(0.2 %) performed well and overall cryo+nano MQL produced better result in terms of tool wear, microhardness, surface and chip morphology. The results demonstrated that the cooling effect of the Cryo-MQL regime, which maintains the cutting temperature at a tolerable level and preserves the lubricant performance of the MQL, is the cause of the lowest Vb value of 90 & mu;m.Öğe The effect of drilling parameters for surface roughness in drilling of AA7075 alloy(E D P Sciences, 2017) Yasar, Nafiz; Boy, Mehmet; Gunay, MustafaAA7075 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 degrees, cutting speed of 40 m/min and feed rate of 0.1 mm/rev, thereby the validity of optimization was confirmed with Taguchi method.Öğe Evaluation of the Mechanical Properties and Drilling of Glass Bead/Fiber-Reinforced Polyamide 66 (PA66)-Based Hybrid Polymer Composites(Mdpi, 2022) Demirsoz, Recep; Yasar, Nafiz; Korkmaz, Mehmet Erdi; Gunay, Mustafa; Giasin, Khaled; Pimenov, Danil Yurievich; Aamir, MuhammadIn this study, mechanical testing of glass bead (GB), glass fiber (GF), and hybrid (GB/GF) composites was carried out. Following that, drilling tests were undertaken on glass bead/fiber-reinforced hybrid Polyamide 66 (PA66) polymer composites. The purpose of this study is to determine the mechanical properties of the cutting elements and the effect of cutting parameters (spindle speed and feed rate) and reinforcement ratios on thrust force and surface roughness (Ra). The contribution of the cutting parameters to the investigated outcomes was determined using statistical analysis. Optical microscopy and scanning electron microscopy (SEM) was used to inspect the hole quality and damage mechanisms. The results revealed that the feed rate was the most contributing factor to thrust force (96.94%) and surface roughness (63.59%). Furthermore, in comparison to other hybrid composites, the lowest R-a value was obtained as 0.95 mu m in samples containing 30% GB, while the R-a value was 1.04 mu m in samples containing 10% GF + 20% GB. Polymer PA reinforced with 30% GF had the highest strength, modulus of elasticity, impact strength, and hardness.Öğe Experimental investigation on novel drilling strategy of CFRP laminates using variable feed rate(Springer Heidelberg, 2019) Yasar, Nafiz; Gunay, MustafaThis study focused on the influences of drilling parameters on hole quality and thrust force in drilling of carbon fiber-reinforced polymer (CFRP) composite laminates via variable feed rate. Drilling experiments were carried out by using three different cutting speeds, feed rates and the qualities of tungsten carbide drill. Scanning electron microscopy and coordinate measurement machine were used for hole surface damage and diameter analyses, and also a portable instrument and 3D optical profilometer were utilized for surface roughness measurement. It was identified that thrust force (F-z), delamination factor (F-d) and average surface roughness (R-a) values attained in drilling processes by variable feed rate are lower than those of constant feed rate with average of 14%, 3% and 18%, respectively. Besides, the hole diameter (D) values obtained with variable feed rate in hole exit were higher than those of constant feed rate. Moreover, the higher F-z values were obtained with diamond-coated and TiAlN-coated drills than those of uncoated drill with 55% and 77%, respectively. The interactive influences of drilling parameters on machinability factors were evaluated via analysis of variance, and then, the most significant parameter was specified as the feed rate for F-d, just as the drill quality for F-z, R-a and D. According to the experimental and statistical results, we suggested that the novel drilling strategy is a significant alternative for the step hole and conventional drilling of CFRP laminates.Öğe Indirect monitoring of machining characteristics via advanced sensor systems: a critical review(Springer London Ltd, 2022) Korkmaz, Mehmet Erdi; Gupta, Munish Kumar; Li, Zhixiong; Krolczyk, Grzegorz M.; Kuntoglu, Mustafa; Binali, Rustem; Yasar, NafizOn-line monitoring of the machining processes provides to detect the amount and type of tool wear which is critical for the determination of remaining useful lifetime of cutting tool. According to Industry 4.0 revolution, the machining performance in terms of cutting forces, surface roughness, power consumptions, tool wear, tool life, etc. needs to be automatically monitored because the unfavorable conditions in machining cause chatter vibrations, tool breakage, and dimensional accuracy. Therefore, the usage of advanced sensor systems plays a key role in achieving the improved machining characteristics in terms of less human effort, errors, production time, etc. and fulfills the requirement of Industry 4.0. Hence, this review presents the holistic knowledge of online detection systems including sensors and signal processing software preferred in mechanical machining operations. Initially, this paper is starting with the up-to-date literature introduction section followed by type of sensors used in machining, online detection methods in machining, challenges and suggestions, etc. Eventually, the article concluded the findings and future remarks especially focused on the theme of Industry 4.0. In the end, it is worthy to mention that this review paper is very helpful for researchers and academicians working in the industrial sectors.Öğe Influence of duplex jets MQL and nano-MQL cooling system on machining performance of Nimonic 80A(Elsevier Sci Ltd, 2021) Korkmaz, Mehmet Erdi; Gupta, Munish Kumar; Boy, Mehmet; Yasar, Nafiz; Krolczyk, Grzegorz M.; Gunay, MustafaNickel 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.Öğe The Influences of Varying Feed Rate on Hole Quality and Force in Drilling CFRP Composite(Gazi Univ, 2017) Yasar, Nafiz; Gunay, MustafaThe selection of drill geometry and drilling parameters has high importance due to thermo-mechanical formations in drilling of carbon fiber reinforced polymer (CFRP) which has anisotropic structure. This study focused on the effects of drilling parameters on thrust force and hole quality in drilling of CFRP composites by applying constant and varying feed rate with uncoated WC drills having different point angles. Surface roughness, delamination factor and diameter plays a crucial role in the production of close-tolerance holes in hole quality. The quality of the hole surface was examined via surface roughness measurements and surface damage by scanning electron microscopy (SEM). Machinability experiments were performed with three different levels of drilling parameters that are point angle, cutting speed and feed rate. It was determined that thrust force (Fz), delamination factor (Fd) and surface roughness (Ra) values obtained in drilling processes by varying feed rate in hole exit are lower than that of constant feed rate with average of 21%, 14% and 36%, respectively. On the other hand, hole diameter (d) values obtained with varying feed rate in hole exit were higher than that of constant feed rate. The effects of drilling parameters on Fz, Fd and Ra were determined by analysis of variance with 95% confidence level and feed rate was found as the most significant parameter on them.Öğe Investigation of microstructure, mechanical and machinability properties of Mo-added steel produced by powder metallurgy method(Springer London Ltd, 2021) Erden, Mehmet Akif; Yasar, Nafiz; Korkmaz, Mehmet Erdi; Ayvaci, Burak; Ross, K. Nimel Sworna; Mia, MozammelThis study presents the impact of molybdenum (Mo) inclusion on microstructure, mechanical, and machinability behavior of steels manufactured with powder metallurgy (PM) approach. PM steel samples with different molybdenum ratios were pressed at 750-MPa pressing pressure and sintered in the atmosphere-controlled tube furnace at 1400 degrees C for 1 h. While particle size and distribution of phases of PM steels with different molybdenum ratios were determined by optical microscope, mechanical properties were determined by applying tensile test. The results were observed that 3% Mo weight-added steel displayed the maximum yield and tensile strength. In addition, the machinability properties of 3% Mo-added steel, which has the highest yield and tensile strength, were investigated. In this work, we researched the thrust force and surface roughness as machinability output, and drilling parameters on the output were determined by utilizing analysis of variance. Finally, SEM images were taken from the inner surfaces of the machined holes and the fractured surfaces from tensile test, and information about the machinability of this alloy produced with PM was presented. As a result, an increase in yield and tensile strength and a reduction in strain were identified with the increase in Mo content. Moreover, the coated cutting tools are better on the machining output than the uncoated cutting tools in terms of green environment. The most important factors on the Fz and Ra are the coating condition and the feed rate with 56.53% and 43.62% PCR, respectively.Öğe Investigation on hole quality of cutting conditions in drilling of CFRP composite(E D P Sciences, 2017) Yasar, Nafiz; Korkmaz, Mehmet Erdi; Gunay, MustafaSurface damages and delamination occurred in drilling of the carbon fiber reinforced polymer composite materials, which change depending on their physical and mechanical properties and cutting conditions, and so affect the hole quality. Therefore, it is requires to be selective with regards to drill geometry and drilling parameters during drilling of CFRP. This study investigated the effects of cutting parameters and drill geometry on the hole quality in terms of hole diameter and surface roughness during the drilling of CFRP composite laminate. Drilling experiments were performed with three different levels of drilling parameters that are point angle, cutting speed and feed rate. At the end of the drilling tests, it has determined that if the feed rate increases, the surface roughness value increases while the hole diameter decreases. The feed rate was determined as the most important parameter with a PCR of 78.02% according to analysis of variance. The better hole quality was obtained with 130 degrees drill among the three drill geometry.Öğe Measurement and analysis of machining induced tribological characteristics in dual jet minimum quantity lubrication assisted turning of duplex stainless steel(Elsevier Sci Ltd, 2022) Gupta, Munish Kumar; Boy, Mehmet; Korkmaz, Mehmet Erdi; Yasar, Nafiz; Gunay, Mustafa; Krolczyk, Grzegorz M.In this work, the sustainable machining approach is promoted by implementing the dry and minimum quantity lubrication (MQL) cooling conditions in the turning 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 mu m while MQL (flank + rake directions) produces the lowest surface roughness value of 1.55 mu m 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.Öğe Multiresponse optimization of drillability factors and mechanical properties of chitosan-reinforced polypropylene composite(Sage Publications Ltd, 2022) Yasar, Nafiz; Gunay, Mustafa; Kilik, Erol; Unal, HuseyinIn this study, the mechanical and machinability characteristics of chitosan (Cts)-filled polypropylene (PP) composites produced by injection molding method were analyzed. Uniaxial tensile, impact, hardness, and three-point flexural tests were used to observe the influence of Cts filler on the mechanical behavior of PP. For the machinability analysis of these materials, drilling experiments based on Taguchi's L(27)orthogonal array were performed using different drill qualities and machining parameters. Then, machining conditions are optimized through grey relational analysis methodology for machinability characteristics such as thrust force and surface roughness obtained from drilling tests. The results showed that tensile, flexural strength, and percentage elongation decreased while impact strength increased with adding the Cts filler to PP. Moreover, it was determined that the tensile and flexural modulus of elasticity increased significantly and there was a slight increase in hardness. Thrust forces decreased while surface roughness values increased when the Cts filler ratio and feed rate was increased. The optimal machining conditions for minimizing thrust force and surface roughness was obtained as PP/10 wt% Cts material, uncoated tungsten carbide drill, feed rate of 0.05 mm/rev, and cutting speed of 40 m/min. In this regard, PP composite reinforced by 10 wt% Cts is recommended for industrial applications in terms of both the mechanical and machinability characteristics.Öğe A novel method for improving drilling performance of CFRP/Ti6AL4V stacked materials(Springer London Ltd, 2021) Yasar, Nafiz; Korkmaz, Mehmet Erdi; Gupta, Munish Kumar; Boy, Mehmet; Gunay, MustafaIn 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 degrees point angle.Öğe Numerical and experimental investigation of cutting forces in turning of Nimonic 80A superalloy(Elsevier - Division Reed Elsevier India Pvt Ltd, 2020) Korkmaz, Mehmet Erdi; Yasar, Nafiz; Gunay, MustafaThe study presents the machinability of Nimonic 80A superalloys depending on the cutting forces in both the turning experiments and simulations by finite element method (FEM) in order to approve the precision of the predetermined Johnson-Cook (JC) parameters from our previous study. In the first part of the paper, the turning experiments have been performed on Nimonic 80A superalloy with coated carbide tools to determine the cutting forces namely main cutting force, feed force and radial force. Three different cutting parameters namely depth of cut, cutting speed and feed rate have been used with three levels. The effect levels of the cutting parameters on cutting forces have been also determined with the analysis of variance (ANOVA) at 95% confidence level. Secondly, predetermined JC material model parameters have been inputted into the software running by FEM. Thereafter, the turning simulations have been performed by FEM with the same cutting conditions as experimental ones. According to ANOVA results, depth of cut is the most important parameter on Fc and Ff while feed rate is the most important factor on the Fr. Through the closer results (the mean of 6.45% deviation) of cutting forces between the experiments and simulations, the JC parameters of the material and the boundary conditions of the simulations have been approved with high accuracy. (C) 2020 Karabuk University. Publishing services by Elsevier B.V.Öğe On tribological characteristics of TiC rollers machined under hybrid lubrication/cooling conditions(Elsevier Sci Ltd, 2022) Korkmaz, Mehmet Erdi; Gupta, Munish Kumar; Demirsoz, Recep; Boy, Mehmet; Yasar, Nafiz; Gunay, Mustafa; Ross, Nimel SwornaThe titanium carbide is considered as a hard to cut material and it is very helpful in critical applications especially in guide roller applications. This study investigated the machining based tribological characteristics of TiC rollers during hard turning under sustainable cooling/lubrication conditions. Surface quality, power consumption, tool wear, microstructural changes, microhardness after machining, and SEM-EDX analysis were evaluated under dry, minimum quantity lubrication (MQL), cryogenic and hybrid cryo+MQL environments. Although the surface quality did not meet the expectations in dry cutting, MQL improved slightly than cryo methods. However, the best surface quality, the smallest tool wear and power consumption was obtained in the hybrid cryo+MQL lubrication/cooling method.Öğe Optimization of 3D Printing Operation Parameters for Tensile Strength in PLA Based Sample(Gazi Univ, 2020) Gunay, Mustafa; Gunduz, Suleyman; Yilmaz, Hakan; Yasar, Nafiz; Kacar, RamazanIn this study, the mechanical properties of PLA+ samples produced by using fused deposition method (FDM) based 3D printer were investigated in detail for the effects of printing speed, infill rate and raster angle. For this purpose, standard tensile test specimens were prepared with a 3D printer according to Taguchi L-18 experimental design. The effects on the tensile strength of the process parameters (printing speed, infill rate and raster angle) were determined by analysis of variance (ANOVA). In addition, the process parameters for the tensile strength were optimized by applying the Taguchi methodology. Consequently, while the most effective parameter on the tensile strength was the infill rate, the raster angle and the printing speed were determined as other important parameters, respectively.Öğe Performance analysis of coated carbide tool in turning of Nimonic 80A superalloy under different cutting environments(Elsevier Sci Ltd, 2020) Gunay, Mustafa; Korkmaz, Mehmet Erdi; Yasar, NafizNimonic 80A is a difficult-to-machine nickel-based superalloy thanks to its superior tensile strength in high temperatures and oxidation resistance. However, cutting fluids applied to improve machinability performance during the processing of such materials increase tool life, while at the same time increasing machining costs and causing health and environmental problems. Thus, the present research has been focused on cutting tool life and wear characteristics and analysis of machined surface in turning of Nimonic 80A superalloy under different cutting environments namely dry, air-cooling and oil-spraying method. The performance of the coated tool has been characterized by using optical microscope, SEM and EDS analysis. The results of the tool life and microscopic analysis showed that the oil-spraying method has longer tool life than dry and air-cooling method in turning of Nimonic 80A alloy. Moreover, the volume of material removed has been modeled by response surface method for predicting tool performance under various machining conditions. Lastly, the microstructural and microhardness variations of the machined surface have been evaluated when the cutting tool reaching the wear criterion. The best performance in terms of tool life and surface integrity was obtained at cutting speed of 60 m/min in oil-spraying environment.Öğe Performance of MQL and Nano-MQL Lubrication in Machining ER7 Steel for Train Wheel Applications(Mdpi, 2022) Camli, Kerem Yavuz; Demirsoz, Recep; Boy, Mehmet; Korkmaz, Mehmet Erdi; Yasar, Nafiz; Giasin, Khaled; Pimenov, Danil YurievichIn 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 (R-a), 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.Öğe Thrust force modelling and surface roughness optimization in drilling of AA-7075: FEM and GRA(Korean Soc Mechanical Engineers, 2019) Yasar, NafizAA7075 aluminum alloy attracts scientific interest to participate in production of crucial components in aerospace, construction and automotive domains. Specifically, final products need to display equal quality to ensure the basic standards of safety in the aircraft industry. Despite the high machinability of the AA7075 alloy, hole quality may vary according to tool geometry and drilling parameters. In this study, the effects of different feed rate levels and cutting speeds on the surface roughness (Ra) and thrust (Fz) were investigated. Drilling experiments were conducted with drills of three different quality and geometry. The effects of drilling variables on the surface roughness and the thrust force according to the smaller-the better approach of the gray relation analysis (GRA) method have been investigated. Consequently, the highest and lowest gray relations degrees obtained were 0.828 and 0.338, respectively. Numerical analyzes for thrust force were performed with the ThirdWave AdvantEdge simulation software based on the finite element method. We also outlined that there exists an average difference of 4.9 % between the experimental and simulation thrust force values, and we proved the applicability of the finite element model.
