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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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In ultrasonic vibration-assisted turning, an ultrasonic vibration is added to the tool, which leads to the periodical disengagement of the tool and the work-piece. In this research, an experimental study of ultrasonic vibration-assisted turning and conventional turning on Ti6Al4V Titanium alloy is conducted. First, by analyzing different parameters, four parameters are selected as the main affecting input parameters (cutting speed, feed rate, depth of cut, and ultrasonic vibration), and the effects of these four parameters are studied on two output parameters, namely tool wear and surface roughness. After the experimental tests, a statistical analysis is performed on the results and a neural network model is developed to predict the tool wear and surface roughness. The results show that the developed neural network model has a good agreement with the experimental results. In all experiments using ultrasonic vibrations, the tool wear and surface roughness were lower in comparison with the conventional turning. The cause of the tool wear and surface roughness reduction in ultrasonic mode are reducing the average forces applied to the tool, the alternative disengagement between the tool and the workpiece and increased dynamic stability of the process.
 

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 Micro-milling process as one of the most widely used methods of making parts due to the small size and their delicate properties in the process. In this study, micro-milling operations were performed on a titanium piece made of Ti6Al4V alloy using a tool with a diameter of 0.5 mm. The effect of nanoparticles used in lubricants on the surface roughness of the micro-milled workpiece is the most important characteristic studied in this research. In this research, experimental test methods and design and analysis of experiments by Taguchi method have been used to study the surface roughness during the process. Experimental tests to compare the role of lubrication in dry, wet and Minimum Quantity Lubrication (MQL) in different machining environments with lubricants containing nanoparticles and without nanoparticles and the effect of shear parameters on different characteristics of micro-milling of Ti6Al4V alloy is done. The results show that the use of Minimum Quantity Lubrication (MQL), especially with lubricants containing nanoparticles, increased the surface quality and had a more effective role in lubrication during micro-milling of Ti6Al4V alloy. Spindle speed and type of lubrication are the most effective parameters in Ti6Al4V alloy micro-milling.
 

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The development of reliable numerical tools for predicting the integrity of machined surfaces is significant. This paper introduces a new customized FE model to predict the deformation during turning of electron beam fused (EBM) Ti6Al4V alloy under dry cutting. The needle microstructure and exotic nano-hardness types of materials are modeled and implemented using a user subroutine in the FE model. The developed FE model provides the possibility of predicting the microstructure (thickness of alpha lamella), the changes in nano-hardness caused by machining operations in dry conditions.

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Titanium and its alloys, especially the Ti6Al4V alloy, have many uses in the aerospace and medical industries due to their unique properties. The production of Ti6Al4V alloy by additive method has been very much considered due to the characteristic of this method. But due to the fact that these parts also require final machining. As a result, it is very important to achieve optimal parameters from a faster and more economical method. In this article, simulation of cryogenic machining of EBM Ti6Al4V alloy in order to study microstructural changes. done. It was validated by comparing the experimental results and simulation of the material model. Then, using the validated FE model, the effects of shear speed on forces, thermal loads and microhardness were discussed.