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In the process of nickel-based alloy machining, chips are easy to bond on the tool surface, which weaken the tool performance and make the tool wear. Therefore, it is very important to study the mechanism of tool bond wear in the process of nickel-based superalloy machining. In order to reflect the wear process of the tool from the perspective of micro cutting, the molecular dynamics simulation model for cutting Ni–Fe-Cr-Co–Cu nickel-based alloy with SiC tool was established. The Morse potential functions between the tool and workpiece are calculated, and the simulation results are analyzed visually. It is found that the bond wear is the main wear form of tool in the process of cutting nickel-based alloy, and the wear processes are divided into three stages: contact, adhesion and shedding. The stress and strain in the cutting area are calculated and it is found that the bond occurs when the tool-workpiece extrusion is strong. Through the calculation of radial distribution function and formation energy, it is found that Ni-Si compound is formed on the tool surface, and the newly generated Ni-Si compound reduces the tool performance compared with the silicon carbide structure. This study provides a more complete microscopic explanation of the tool wear mechanism, which is helpful to find a method to prolong tool life.

Because nickel-based alloy Inconel718 has poor thermal conductivity and serious work hardening, it is identified as a difficult-to-process material. The serious tool wear leads to short tool life. In this study, physical vapor deposition-coated carbide tools were used to machine Inconel718. The material response for different cutting speeds at the tool–chip interface and its effect on tool wear were studied. The results showed that at low cutting speed (v c = 20 m/min), cold welding and adhesion occurred at the tool–chip interface under high stress, and then the built-up edge (BUE) formed. The peeling off of BUE led to chipping. When the cutting speed (v c) was 45 m/min, diffusion and oxidation occurred at the tool–chip interface. The new generated material reduced tool hardness and bond strength of Co. The wear debris was generated in tool rake face. Flakes of wear debris fell from the tool substrate, which increased tool wear. When the cutting speed was 32 m/min, the softer oxides generated at the tool–...

It is a key point that the surface machining feature plays an important role on machined surface morphology of high speed milling hardened steel. The machining surface morphology surface morphology plays an important role in the formation of surface roughness. In this work, the machining features are the target that find the law of effect on surface morphology. We experiment on the concave and convex surface respectively, find out the influence law of surface morphology with different machining features in the process of high speed milling hardened steel. The results show that. The residual height is lowest along a sinusoidal line, it is times in vertical direction, and it is the worst in the 45odirection. The curvature radius influence the residual height , but the effect in the convex surface is more significant than that of concave surface. By changing the Angle can effectively relieve the effects that the curvature radius influences on surface residual height.

Tool wear is a problem in machining nickel-based superalloy Inconel 718, and it is thus of great importance to understand and quantitatively predict tool wear. The experiments of machining Inconel 718 with cemented carbide tools (uncoated and coated) were carried out. Some new observations and analysis of tool wear through CCD, SEM and EDS were done. The results showed that at low cutting speed, the built up edge (BUE) formed easily and dropped at last which caused severe cutting tool breakage. When cutting speed came to 30m/min, the main reason that caused cutting tool wear was that the tool material fell off from the tool body at the form of wear debris. What’s more, the element diffusion between tool and workpiece and oxidation reaction all accelerate the formation and the cast of the wear debris.

Ti6Al4V has great affinity with tool material in machining process, which easily leads to tool diffusion wear. Turning experiments were carried out to study cutting temperature and pressure at tool-chip/workpiece. Based on the analysis, a scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS) was used to analyze tool wear morphology. The affinity of tool and workpiece material using the Ti-W, Ti-Co diagram was also studied to elaborate the diffusion mechanism in this present study. The results shows that the cutting temperature is very high and the temperature increases with the increase of cutting speeds in machining Ti6Al4V. At the contact area, the highest temperature is located in tool rake face near to tool tip. The resilience of workpiece results in serious attrition between tool flank face and the machined surface. The highest pressure is located in tool flank face near to tool tip and the pressure in tool-workpiece interface is much higher than that in tool-chip interface. Under the high cutting temperature and high pressure at tool-chip/workpiece interface, diffusion occurred both at tool rake an flank face in machining Ti6Al4V. Because of the higher temperature at tool rake face diffusion at tool rake face ia more sever than that at tool flank face.

Nickel-based alloy Inconel718 is widely used in the aerospace industry. However, it is difficult to machine. Tool wear is serious, which leads to lower machining efficiency, and it is thus of great importance to choose reasonable cutting parameters to decrease tool wear and increase machining efficiency. In this article, coated carbide tools were used to cut Inconel718. Scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS) was used to study tool wear mechanism. In light of the tool wear mechanism, tool flank wear model was established. The optimal cutting temperature was obtained using the established wear model. Further cutting parameter optimization was conducted according to the optimal cutting temperature. The optimized cutting parameters can be considered to increase tool life and machining efficiency.

The machining efficiency of titanium alloy Ti6Al4V is low and the tool wear is serious. In this paper, uncoated carbide tool and two kinds of coated cemented carbide tool were used for dry turning titanium alloy. The experiments used CCD Observing System and the EDAX analysis of SEM to study tool wear mechanism and analyze the cutting performance through tool life, cutting force and cutting temperature. The results show that the main wear reasons are adhesion, diffusion and oxidation wear. For coated tool, the coating peeled off first, and then tool substrate damaged. Compared with coated carbide tool, the uncoated carbide tool with fine grain has longer tool life and lower cutting force and cutting temperature. The changes of cutting force and cutting temperature with cutting speed are not obvious when using the ccomposite coating (TiAlN and AlCrN) carbide tool. The results can help to choose tool material reasonably and control tool wear.

Adopted the cutting-contact model of high speed ball-end milling hardened steel surfaces, researched distribution characteristics of cutting-contact stress; by researching the influence of the distribution of this stress on cutter wear, clarified the influence theory of milling pattern and cutting parameters on initial wear of milling cutter. By using the method of climbing, conventional milling alternating and changing cutting parameters, verified the influence of milling pattern and cutting parameters on initial wear pattern. The result showed that, initial wear mechanism of high speed milling hardened steel is an interaction of multiple wear mechanisms under the effect of friction and alternating pressure stress, by using conventional milling can significantly reduce concave curvature radius of hardened steel, the contact stress of blade area and front, rear flank, inhibit crushing and wear rate of the milling cutter surfaces. Under this condition, by increasing rotation speed and reducing the feed per blade, will further increase the strength of this effect, and achieve the purpose of reducing the initial wear, inhibiting the wear rate and extending the cutters life.

Tool wear is a problem in machining nickel-based alloy Inconel718, and it is thus of great importance to understand tool wear. Tool wear mechanism in dry machining Inconel718 with coated cemented carbide tools was analyzed in this paper. CCD and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS) were used to study tool wear mechanism. The results show that the main reason which causes cutting tool wear was that the tool materials fall off from the tool substrate in the form of wear debris. In addition,, element diffusion between tool and workpiece and oxidation reaction all accelerate the formation and the peeling of the wear debris. According to analysis of tool wear mechanism, tool flank wear model was established. The optimal temperature in machining Inconel718 with PVD-coated (TiAlN) tool was obtained through the established model. Excellent experimental agreement was achieved in optimal temperature calculated by the established model.

Because of the variety of processing methods, broad range and uncertainty of processing parameters when machining aeroengine structure parts, the method of fuzzy orthogonal optimization was used to optimize milling parameters in the light of machining efficiency in machining plane characteristics of aeroengine structure parts. According to analyzing the effects of milling parameters on processing efficiency, the optimized parameters were obtained. The results showed that the established fuzzy orthogonal optimization model can take full account of the uncertainty in the process of cutting parameters optimization. Excellent experimental agreement was achieved in cutting parameters calculated by the established model. The established model has good practicality and high precision. It is easy to understand and can be used to guide the actual production.

Experiment of cylindrical dry turning Ti6Al4V has been carried out employing coated and uncoated carbide tools to determine the characteristic of cutting force. Force signals have been extracted in the turning processes. The static component value of cutting force has been calculated and fractal behavior of cutting force has been studied by calculating fractal dimension. The results of studies indicate that radial force of static component is higher than the other forces. The static values of cutting force involving T2 (composite coating with TiAlN and AlCrN) and T3 (uncoated carbide) are less than T1 (composite coating with TiCN and Al2O3). The change of static value of cutting force using T2 with increase of cutting speed is smaller than the other tools. Fractal dimension can be used as the characteristic of the randomness of dynamic component of cutting force and reflect stability of cutting process. The fractal dimension of dynamic component of cutting force of T1 is the smallest, followed by the T3, and that of T2 is highest. Considering the static and dynamic characteristic of cutting force, T3 (uncoated carbide tool) is more suitable for high-efficiency cutting Ti6Al4V.

In order to obtain the influences of cutting edge radius on cutting deformation in high-speed machining Ti6Al4V, cutting temperature, equivalent stress distribution, the chip morphology and cutting deformation coefficient were analyzed in this paper. The results indicated that cutting edge changed the plastic flow of materials around tool tip and the actual tool rake angle, the tool-workpiece and tool-chip contact in cutting process which causes a greater impact on physical and mechanical performance in the given cutting conditions. When the cutting edge radius reached to 0.04mm,the cutting temperature and the equivalent stress existed mutations, which causes the mutation of chips. There was a chip thinning effect with the increase of the cutting edge radius. As the cutting edge radius increased, chip thickness and shear angle decreased, cutting deformation coefficient increased.

During the process of high-efficiency cutting Ti6Al4V the material presents serrated chips. Periodic high-frequency serrated ship will cause fluctuations in the cutting force, which then affect the tool wear and surface integrity of workpiece and so on. On the basis of experiment of turning Ti6Al4V, the frequency and the geometric characteristics of serrated chip has been analyzed through observing the microstructure of chip using optical microscope and SEM. The results show that cutting speed and feed rate have great influence on the frequency and the geometric characteristics of serrated chip. Involving low-speed, large feed and large cutting depth can reduce the generated frequency of serrated chip.

Simulation models of both dynamic cutting forces and cutting temperatures considering effects of tool rounded cutting edge are established based on analysis of the influences of rounded cutting edge on high speed milling process. Influence law of tool rounded cutting edge radius on force and heat distribution in high speed milling hardened steel has been obtained according to the simulation results and also the simulation results have been verified by experiments. The results indicate that dynamic performances of high speed milling cutter in cutting hardened steel are directly influenced by rounded cutting edge radius, and the cutting forces fluctuated greatly with the variation of rounded cutting edge radius. Variations of rounded cutting edge radius have greater impact on cutting temperatures when the rounded cutting edge radius is less than 40μm. Cutting temperature rise slowly with the increase of rounded cutting edge radius when the rounded cutting edge radiuses are larger than 40μm. Simulation can precisely predict cutting temperatures and cutting forces considering influences of rounded cutting edge radius. Rounded cutting edge radius should be kept around 40~45μm for optimal cutting performances according to its influences on cutting forces and cutting temperatures in high speed milling hardened steel.

On the basis of analyzing the cutting edge structure and cutting edge radius measurement of high-speed insert, thermal - mechanical coupling finite element method (FEM) is used in this paper, to obtain the effect law of different cutting edge radius on the mechanical-thermal distribution of high-speed cutting TiAl6V4. At last, cutting experiments are carried out to verify FEM results. There is a clear exposition of the intrinsic reason why the cutting edge radius has influence on the mechanical -thermal distribution of high-speed cutting process. The results indicate that the experimental results have a good agreement with FEM; with the cutting edge radius increases, cutting force increases; cutting temperature is not monotonic, but there exists an optimum edge radius that makes temperature lowest; cutting edge changes the plastic flow of materials around tool tip and broaden plastic deformation zone. The cutting edge radius has a greater impact on equivalent stress.

Titanium alloy membrane disk is a typical part in aerial engine and it belongs to variable cross-section thin-wall part, which is apt to change its nature and difficult to machine. Serrated chip is prone to create in the machining process. A periodic serrated chip will cause high frequency undulation of the cutting force, and further leads to the cutting tool wear and affect the surface’s integrity. Based on the turning of titanium membrane disk, this paper used metallographic microscope and SEM to observe the morphology and micro shape of the chip, and analyzed the influence of cutting conditions on chip formation and the reason for serrated chip. Finally, a FEM analysis on the chip formation process is completed. Analysis results show that under all the set cutting conditions the serrated chip was formed in the machining process. The shearing slippage and fracture caused by dislocation movement can better explain the formation mechanism of serrated chip. The feed rate has great effect on the chip formation and the forming frequency of serrated chip. The FEM analysis results primly consistent with the experiment results, which can accurately forecast the cutting force, the distribution of temperature and the surface quality.

In dry machining titanium alloys, tool wear is serious and machining efficiency is very low due to its low thermal conductivity and high chemical activity. The uncoated cemented carbide tool was used for the experiments of turning titanium alloy Ti-6Al-4V. Based on analysing the tribological characteristic of tool-chip and tool-workpiece interface using FEM, a scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS) and X-ray photoelectron spectroscopy were used to analyse tool wear mechanism. The results showed that there existed great differences of the friction between tool-chip/workpiece interface and general friction. There existed serious adhesion, diffusion and oxidation at the tool-workpiece interface. There was an optimal cutting condition under which the equilibrium of oxidation wear and adhesion wear can be achieved, which made tool wear reduce.