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In end milling operation, cutting forces induce vibration on tool, workpiece and clamping devices which affects surface integrity and quality of the product. In this process, to select the optimum end mill and machine tool, the prediction of exact cutting forces is of prime importance. In the present work, modeling and simulation of cutting forces in end milling operation are performed. Instantaneous chip geometry is predicted using a 3D simulation software, the effect of cutting depth and feed rate are calculated and cutting conditions are predicted before any machining operation.

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Because of coating metals for use in various applications including the food industry is of particular importance, therefore, in this paper new method for coating aluminum sheet for use in food packaging industry are presented and examined. Reviewing formation of solid solution through providing powder from the surface of ball and also feasibility of surface mechanical coating (SMC) by using mechanical alloying method and effect of the two parameters, milling time duration and ball diameter on these two matters are items that are being reviewed in this article. In this respect, mechanical alloying process in the presence of copper powder and nickel ball has been used. Parameters which are being reviewed are: 1- milling time (5, 10, 20, 60 and 120 hours) and 2- ball diameter (5 and 9 mm). Various analyses including analysis of X-ray diffraction (XRD), scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA) have been used in order to obtain the desired results. The reviews indicate that providing powder from surface of ball increases with the increase of milling time and ball diameter. It was also specified that formation of coating on the surface of ball is possible at the time of mechanical alloying process.

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Nanostructured (Al-8wt%Zn-3wt%Mg) alloy was synthesized by simultaneous fracture and cold welding mechanisms in mechanical alloying with initial elemental powders and subsequently, this alloy was applied as matrix to fabricate Al/Short glass fiber nanocomposite in 1, 3 and 5 percent of glass fibers. The resulting powders were consolidated under 400 MPa at 380 °C in cylindrical die to produce consolidated nanocomposites. Relative density of samples reduced with increasing the percentage of glass fibers and this trend was more intense from 3 to 5 percent. Also compressive strength and hardness were investigated for these samples in different percent of glass fiber. The results showed that strength and hardness were enhanced with increasing glass fiber but decrease of mechanical properties was observed in 5 percent due to reducing in relative density. Compressive strength was compared between nanocomposite with pure Al and Al alloy matrix, and results show more reinforcement in Al based sample.

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In this research, grey cast iron scraps were recycled into powders and were then used in combination with iron powder for producing iron based powder metallurgy parts. Design of experiments was conducted by response surface method for both the green and sintered parts. For the green properties, the parameters cast iron powder percentage and compaction pressure, and for the sintered parts, the mentioned parameters in addition to sintering temperature and sintering time were selected each in five levels as the input process parameters. Transverse rupture strength and elastic modulus were measured as the responses. Regression analysis and analysis of variance were used to investigate the effect of input parameters, develop the mathematical models and evaluate the validity of the models. Scanning electron microscopy and optical microscopy micrographs were provided to better understanding. The obtained results, in addition to determine the effects of the input parameters, demonstrated the adequate mechanical properties of the produced parts in industrial scales and the validity of the proposed models. Also, the proposed method demonstrated its good capability for estimation of elastic modulus of powder metallurgy parts.

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In this research, the effects of cutting parameters on material removal rate and surface roughness, are investigated. Therefore, after that the comprehensive model of low-immersion milling is developed, the optimum cutting conditions has to be found for optimizing all of them. The stability criterion is considered as the optimization constraint which is calculated by TFEA. On the other hand, instead of using explicit equation for calculating surface roughness, such as previous works, surface roughness is calculated by TFEA for all of the cases that are needed. Finally, the ability of Genetic algorithm, Particle Swarm Optimization and Imperialist Competitive Algorithm for searching optimum cutting parameters are compared and the results are reported. By comparing the results of the three algorithms it is shown that the ICA is more powerful to deal with nonlinearity aspects of the problem and to tackle sticking in local minimums. Also it is demonstrated that the convergence rate of the ICA is faster than the other two methods. Finally, experiments to confirm the changes of the objective function toward optimal point are done and error percentage of objective function at obtained optimal point compared with experimental result is determined.

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Calculation the cutting force in machining processes is of great importance. In this paper, undeformed chip thickness in one-dimensional ultrasonic vibration assisted milling is calculated and then, a model for determining the cutting force in this process is presented. Analytical relations show that in ultrasonic assisted milling (UAM), the maximum cutting force is greater than in conventional milling (CM), but the average cutting force is decreased. To verify the proposed relations, with the aid of a particular experimental setup, one-dimensional vibration in feed direction is applied to workpiece and cutting force in CM and UAM is measured experimentally. Greater maximum cutting force in UAM and decrease of average cutting force in UAM compared to CM is observed experimentally as well. Comparison of average values of cutting force shows that the analytical relations for predicting the cutting force have 16% average error in CM and 40% average error in UAM. Given that the analytical calculation of undeformed chip thickness and cutting force in UAM and also comparison of experimental forces with the modeled ones has been done in this paper for the first time, the accuracy of proposed relations are acceptable.

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In this paper, in order to avoid the problems induced by cutting liquids like higher cost, environmental pollution and dangerous for operator health in milling process and also using the benefits of them such as increasing tool life and machined surface quality, machining by minimum quantity of lubrication (MQL) or near dry lubrication was introduced and that’s effects on main outputs (consumed power and surface roughness) was compared with other lubrication methods such as lubrication by cutting fluids and by air. In order to perform a series of experiments and investigate the effects of different process parameters such as tools rotational speed, feed rate, gas pressure and liquid flow rate on main outputs, the Taguchi method of design of experiments was employed and then the analysis of variance (ANOVA) was used to find the most important factors effecting main outputs. The results obtained by experiments showed that employing near dry lubrication leads to lower electrical power and comparable surface roughness as compared with other lubrication methods. The analysis of variance showed that feed rate is the most important factor affecting consumed power and liquid flow rate is the most important factor influencing surface roughness.

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In this research, the machinability of iron-recycled grey cast iron powder metallurgy parts is investigated. For this purpose, grey cast iron swarfs were transformed to powders by target jet milling method and were then used to prepare powder metallurgy parts in combination with commercial iron powder. Green compacts were prepared with the variables of cast iron powder percentage and compaction pressure. Design of experiments was conducted by response surface method for sintered parts with the variables of cast iron powder percentage, compaction pressure, sintering temperature and sintering time each in five levels. Regression analysis and analysis of variance were used to investigate the effect of input parameters, develop the mathematical models and evaluate the validity of the models. In the green section, machinability was qualitatively investigated in drilling. For sintered parts, machinability was evaluated by measuring the thrust and torque forces and the obtained surface finish in drilling. The obtained results certificated the accuracy of the extracted regression equations for predicting the machining properties of the parts. Also, the results demonstrated that the addition of jet milled grey cast iron improves the machinability of iron-based powder metallurgy parts.

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AISI4340 hardened steel have a vast functionality in industries. Hard machining of this steel have several benefits such as, higher productivity, lower production cost and improved workpiece properties. In machining operation, ultimate surface roughness is the most important characteristic of machined surface and plays an important role in workpiece life. One of the effective factors on surface integrity is cutting fluid used in machining operation, which have health and environmental problems is spite of positive effects. As a result, using minimum quantity lubrication is considered as an alternative method. In present study, relations between milling parameters and final surface quality in milling of AISI4340 hardened steel, in the presence of lubrication systems including; dry, wet and minimum quantity lubrication have been investigated. Cutting speed, feed rate, axial and radial depth of cut have been considered as main parameters of milling operation. Totally, 90 experiments have been done using response surface method to analyze the effects of process parameters on surface roughness. Results revealed that feed rate and cutting speed have the most Influences on surface roughness. Also higher values of cutting speed and lower values of feed rate are necessary to reduce surface roughness. In addition, compared to other lubrication methods, minimum quantity lubrication have the best performance in surface quality, especially in high cutting speed and depth of cut.

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The productivity of a part is assessed based on factors such as dimensional and geometrical tolerances. In fact, tolerance features are the most important factors in shop drawing of an industrial part. The aim of present study is to empirically investigate the precision of holes created by helical milling method on AISI 4340 alloyed steel. This method refers to create the hole using milling tool, which moves along a helical path. By using helical milling, a high quality hole has been produced and there is no need for boring. Taguchi design of experiment was used to study the effects of process parameters including; cutting speed, feed rate, axial depth of cut and workpiece hardness on dimensional and geometrical tolerances of created hole. In addition, effect of minimum quantity lubrication method with two different oils and dry milling methods was studied. Results showed that the helical milling can be a suitable replacement for conventional drilling. In addition, cutting speed as the main parameter had significant effect on quality improvement of the created hole. On the other hand, in the helical milling, minimum quantity lubrication method using vegetable-based oil showed the best performance compared to mineral oil or dry cutting.

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Helical milling has been known as an innovative method for making high quality holes. In this method, milling tool generates efficiently a high quality hole by moving along a helical path. The hole diameter can be adjusted through the diameter of this helical path. Regarding accuracy of hole in industrial parts, it is necessary to compare this method with conventional hole drilling. Therefore, in this study helical milling and conventional drilling, have been compared with each other. Eight experiments were conducted considering two levels of cutting speed and feed rate on the samples made of AISI 4340 steel at 45 HRC. Minimum quantity lubricant system with two nozzles was used. 100 ml/h of Behran-11 mineral oil at air pressure of 4 bar was employed in this system. Machining forces, surface roughness, nominal diameter, roundness, and cylindricity were output parameters. According to the obtained results, cutting speed was the only one with positive effect on all qualitative parameters of the machined holes. On the other hand, independency of cutting parameters, helical milling lessened machining forces, surface roughness, and geometrical tolerances in compare with conventional drilling.

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Micromilling is a machining process in manufacturing of the miniature parts. Because of high oxidation and corrosion resistance, high fatigue strength and application of Ti6Al4V in hi-tech industries, in this paper surface roughness and burr formation in micromilling of this alloy have been investigated. Cutting parameters including spindle speed, feed rate and axial depth of cuthave been considered as input parameters of tests. Experiments have been performed for two cases: a) in presence of the minimum quantity lubrication and b) wet conditions. Carbide micro-end mill tool of diameter 0.5 mm and TiAlN coating was used. The Taguchi experimental design method has been used to design and analysis of results. Results showed that the spindle speed and feed rate were the most effective parameters on the surface roughness and burr width of titanium alloy, respectively. Also, by increasing both of these parameters, surface roughness and burr width were decreased. In addition, application of minimum quantity lubrication technique significantly improved the surface quality, and it was more effective in upper levels of spindle speed and axial depth of cut. Finally, the best surface quality was attained in spindle speed of 30000 rpm, feed rate of 0.8 μm/tooth and cutting depth of 60 μm.

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Employing of complex surfaces in different industries such as aerospace and die and mold is increasing. For milling of such surfaces, considering factors such as strategies and machining parameters which affect the machinability is necessary. The objective of this study is to investigate the effect of different strategies and machining parameters on microhardness of a typical curved surface (convex) of stainless steel 1.4903. The cutting tool used in this study was ball nose end mill coated TiN and the strategies employed were Raster, 3D-offset, Spiral and radial. Design of experiments was done using Taguchi method. The input parameters were cutting speed, feed rate and step over. After conducting experiments, surface layers hardness of milled samples were measured. The results showed that various tool paths have different influence on microhardness of milled surfaces. Regardless of cutting condition, surface hardness after machining in all strategies was more than the primary hardness of the workpiece material. Spiral strategy provided the most hardness and radial strategy the least hardness. In addition, increasing the feed rate, cutting speed and step over, rised surface hardness and step over had least influence on hardness. The most hardness magnitude was reported in cutting speed of 180 m/min, feed rate of 0.18 mm/tooth and step over of 0.7 mm which shows 56 % of increase.

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Presence of porosity and gas layers around the Al2O3 particles are one of the most important reasons of decreasing in mechanical properties of aluminum metal matrix composites. In this research, for decreasing of porosity, increasing of wettability and uniformly distribution of particles in matrix three method were used; using inert gas for injection powder with 5 liter/ min flow rate, particles heat treatment in 1100 ̊C for 20 min and mill Al2O3 particles with Al particles in ratio of Al / Al2O3= 1. The effect of these parameters on microstructure and mechanical properties of composite were investigated. The results showed that amount of porosity and agglomeration of particles were high in metal matrix composite with handy injection of particles. While injection with inert gas, using heat treatment and Al / Al2O3 milled Cause improve wettability and uniformly distribution of particles in molten Al. the results showed the maximum value of hardness , compression strength and impact energy have obtained in metal matrix composite reinforced with Al / Al2O3 milled with value of 78.7 BHN, 539.1 MPa and 8.2 Joule, respectively.

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Reduction of cutting force in a machining process offers several advantages including increase in tool life, and improvement in the quality of the machined surface. One the new techniques for reducing cutting force relates to ultrasonic vibration assisted machining. In the present paper, one-dimensional ultrasonic vibration-assisted side milling process of Al7022 aluminum alloy has been studied. In order to investigate the effect of cutting speed, feed rate, radial depth of cut, and vibration amplitude on three cutting force components and their resultant, a special experimental setup has been designed and established which applies one dimensional ultrasonic vibration to work piece. Applying the ultrasonic vibrations on milling process, affects mostly on feed component of cutting force which is unidirectional with the work piece vibration, and decreases it by 33.5% in average. Decrease in cutting speed and increase in vibration amplitude, results to increase the separation of tool and work piece from each other in a portion of each vibration cycle, and larger decrease of the feed force. The average decrease of the resultant cutting force in ultrasonic-assisted milling process is 10.8%.

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High-speed milling of titanium alloys is widely used in aerospace industries for its high efficiency and good quality of product. The paper empirically studies surface roughness, topography and microhardness variations in high speed milling of Ti6Al4V alloy. The experiments were conducted under minimum quantity lubrication environment. Carbide end mill tool with TiAlN coating and 6 millimeter diameter was used. Full factorial method was used to design of experiments and analyze the effect of machining parameters including cutting speed and feed rate on surface roughness, topography and microhardness. The other cutting parameters i.e. axial depth of cut and radial depth of cut were constant. The results showed that a high quality surface with roughness of 0.2 µm can be obtained by using high speed machining method. Also, microhardness variations versus cutting speed has two-fold nature. It indicates that firstly, by increasing cutting speed up to 375 m/min, microhardness increases and after that, it declines remarkably. In addition, by increasing feed rate, surface microhardness rises and the maximum microhardness was obtained in cutting speed of 375 m/min and feed rate of 0.08 mm/tooth, which showed 57% increase in regard with hardness of the base material. The Images of surface topography showed that increasing of the cutting speed has a significant effect on reduction of surface tears and smears.

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Owing to direct contact with the machined surface, the flank surface can cause unfavorable effects on the surface integrity in high speed milling. Thus, in this study, the influences of flank wear width on the main characteristics of surface integrity like roughness, topography, microhardness and electrochemical corrosion resistance during high speed milling process is investigated. Milling tests were performed under constant cutting conditions with three repetitions and using 12 tools with flank wear widths on the AISI 4340 hardened steel. It was concluded that using the tool with flank wear width up to 0.4 mm increase roughness and microhardness, uniformly (95% for surface roughness and 6.3% for microhardness relative to new tool). However, using a tool with the flank wear of 0.6 mm increases these outputs up to 484% and 18.6%, respectively. Surface topography images also revealed that using the tool with the flank wear width of 0.6 mm can cause irregular forms of material flow on the surface. Using the tool with the flank wear of 0.4 mm or less had an insufficient effect on the in-depth microhardness distribution. In addition, electrochemical impedance spectroscopy of the milled surfaces showed that relative to new tool, using tools with 0.4 and 0.6 mm flank wear, reduce Rcorr up to 22% and 83%, respectively. It indicated lower electrochemical corrosion resistance of milled surfaces with 0.6 mm worn-out tools.

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Nowadays, emerging more advanced computer systems made it possible to simulate and model complex problems even with higher accuracy. Regarding lower time and cost, the use of simulations instead of physical experiments is increasingly considered as an alternative method in the analysis and optimization of process performance. The importance of such methods becomes more significant when talking about micro-processes, since there are lots of difficulties in experimental measurements as a results of scaling problems by scaling down from macro to micro. In this study, a 3D model is developed using Deform-3D software for prediction of micromilling process behavior. Effects of cutting parameters on such characteristics as cutting forces, temperature distribution and tool wear are investigated. To check the validity of the model, force results of simulation are compared with the measured ones. A high level of correlation exists between the obtained simulation and measured results which shows that the 3D developed model has good capability to predict process behavior.

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In this research, microhardness variations of subsurface in hole making on a AISI4340 steel workpiece was studied experimentally. For this purpose, four hole making methods were used including; helical milling, profile milling, drilling with and without predrilling. The design of experiments utilized full factorial method in which two main cutting parameters including cutting speed (Vc) and feed rate (fz) were changed in three levels. Nine experiments were performed for each process and Hardness variations of substrate layer along the hole radial and axial distances were investigated (216 hardness measurements points). Results showed that the measured hardness in all of the experiments were higher than bulk material hardness, regardless of cutting conditions and the maximum hardness value was found in the upper levels of cutting parameters of traditional drilling method (729 Vickers). In addition, due to workpiece temperature and work hardening increasing with prolongation of the process time, the maximum hardness value was obtained on the exit surface of hole in all processes. Also, least microhardness variations was found when using traditional drilling with predrill which represents superiority of non-continues, multistage hole making processes and conventional drilling using predrill in creation of holes with more uniform properties.

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Micro-milling is prominent among other micro-manufacturing processes due to their abilities in manufacturing of 3D features, high material removal rates and high precision. One of the most important challenges of this process is tool deflections which contribute even up to 90% of dimensional errors of the finished product. This paper addresses a novel method to estimate micro-milling tool deflections applicable in micro-milling machines equipped with linear motors. In this method, position feedbacks and inputs to the amplifiers are used to real-time estimation of cutting forces by applying Kalman filter. Outputs of the estimator include a resultant of all disturbing forces in servo control loop of the motors. Therefore, cutting forces need to be compensated for other disturbing forces that are mostly friction and force ripples in linear motors. To compensate them, neural networks were used. A neural network with a hidden layer and 16 nodes inside, and with two time-delayed lined (TDL) could well model friction and force ripples. Results showed that the proposed tool deflection method is able to estimate 22% of micro-milling tool deflections.