In order to change the current situation of gun-receiver manual polishing, the paper presents a new process for abrasive belt grinding of gun-receiver material (C50 steel). Orthogonal test were conducted with abrasive belt grinding of C50 steel to do research on material removal rate and surface roughness. The best parameter combination to the optimization design which can guarantee high material removal rate and low surface roughness was obtained by using grey relational analysis method and verified by experiments. The above mentioned research not only can improve the removal rate of C50 steel, but also do help to prolong the service life of the belt. Whats more, it can guide a theoretical significance and practical value to the production practice.
The paper describes the heavy abrasive belt grinding technology and the conventional machining method to reduce the thickness of connecting rod head,on the basis of analyzing the technique difficulties,brings forward a reasonable new method which can reduce the thickness by heavy abrasive belt grinding,expatiates on the grinding result with the grinder which is designed by this method,finally summarizes and prospects to this new method.
This paper presents comprehensive theoretical analyses and experimental investigations for evaluating the ultrasonic vibration-assisted turning (UVAT) of die steels with single-crystal diamond tools. The diamond tool wear was found to rely heavily on the feed rate and the cutting speed while being insensitive to the depth of cut and the tool relief angle under the cutting conditions used in the tests. The tool wear characteristics were further studied based on the observation of wear zone using Raman spectral analysis and energy-dispersive X-ray (EDX) analysis. The detection results of the tool worn topography, the phase transformation and the carbon diffusion of diamond crystals revealed that tool wear mainly occurred on the tool flank face due to the graphitization and the diffusion of the diamond tool. Analytical results of the function mechanisms of the ultrasonic turning indicated that the friction force between the tool flank face and the machined surface, which depended mainly on the ratio of the cutting speed and the vibration speed, could be effectively reduced in ultrasonic turning process. The analytical and experimental results indicated that compared with conventional turning (CT), the cutting performance, in terms of the tool life, was markedly improved by applying ultrasonic vibration to the cutting tool.
Marine propeller blade is composite of the free form surface, its machining method has been a difficult thing. The blade is processed by 4-axis belt grinding machine in this experiment, this paper analyze that the wear of the abrasive belt and the processing precision and the material removal rate of the blade according to the grinding performance of the blade material, the structural features of the vane, and the theory of 4-aixs belt grinding machine. Draw formulas with time for the belt wear height and the actual grinding depth. The life expectancy of the ceramic abrasive belt is the longest, and its the material removal rate is maximum in Three kinds of belt，and when the belt line speed is 30m/s or so, the material removal rate is maximum.
Abstract As the core component of aero-engine, the service performance of aero-engine blade has an important influence on the engine’s reliability and safety performance. Existing studies have shown that machined surface characteristics affect the fatigue strength of components. However, current studies are all based on regular fatigue samples. The structure of blades different from fatigue samples, and the influence mechanism of structural differences on the service performance of blades is still unclear. In addition, the conventional fatigue test conditions are not representative for the blades’ actual service conditions, so it is difficult to realize the processing process for the service performance optimization. In this study, the aero-engine blades processed by abrasive belt grinding and the vibration fatigue test bench were used to explore the influence of surface roughness, surface texture, and surface residual stress on the fatigue performance of aero-engine blades under actual working conditions. The aero-engine blades were ground with different process parameters to obtain different single-factor surface characteristics. By comparing the vibration fatigue life of blades with different surface features, the influence degree of each surface feature on the fatigue life was explored. Results showed that surface roughness has the greatest influence on fatigue strength, followed by residual stress, and surface texture has the least influence on fatigue strength.
High precision and high efficiency in robotic grinding of aero-engine extremely thin blade edges is a challenging problem. In this article, a novel toolpath planning method is proposed based on the derived dwell time calculation model and the developed interpolation algorithm. The dwell time of each cutter contact point is solved based on the matrix method by consideration of the revised material removal model and machining allowance distribution. To optimize the previous interpolation algorithm based on geometric intersection, an arc length and Taylor binary expansion optimization are proposed to plan cutter contact points according to the dwell time and the curvature changes of blade edges. Subsequently, the tool orientation is corrected based on a double-vector controlling method to avoid the processing interference. Simulation results show that the proposed interpolation algorithm has improved the path coverage by 17.6%, and its computational efficiency is 34 times higher than that in previous algorithm. The comparative robotic grinding experiment results show that the proposed toolpath has improved the surface profile accuracy of blade edge to 0.042 mm, and its machining accuracy is 14.3–46.2% higher than that of other methods.
Abrasive belt grinding has unique advantages in avoiding machining defects and improving surface integrity while grinding hard materials such as superalloys. However, the random distribution of abrasive particles on the abrasive belt surface is uncontrollable, and chatter and machining errors accompany the machining process, leading to unclear mapping relationship between process parameters and surface roughness, which brings great challenges to the prediction of surface roughness of superalloy. Traditional empirical equations are highly dependent on empirical knowledge and the development of scientific theories and can only solve problems with relatively simple and clear mechanisms, but cannot effectively solve complex and mutually coupled problems. The method based on data-driven patterns has a better idea for mining the implicit mapping relationship and eliminating the uncertainty of complex problems. This study presents a data-driven roughness prediction method for GH4169 superalloy. First, a superalloy grinding platform is built. According to the grinding empirical equation, the mapping relationship between process parameters and surface roughness is analyzed, and a prediction model is established based on the error back propagation (BP) algorithm. Second, genetic algorithm (GA) and particle swarm optimization (PSO) algorithm are used to optimize the weights and thresholds of the neural network, and the global optimal solution is obtained. Finally, the prediction performance of different algorithms is compared. The results show that the non-uniform absolute errors of the BP algorithm, GA-BP algorithm, and PSO-BP algorithm are 0.12, 0.085, and 0.078, respectively. The results show that the roughness prediction algorithm based on PSO-BP is more suitable for GH4169 superalloy.
Abrasion ratio is an important parameter to estimate the wear resistance of abrasive belt grinding, reacting the relationship between the material removal and the abrasive belt wear, and also, its value is an important basis to instruct the process of abrasive belt grinding. The mathematical model of material removal is obtained by analyzing the basic mechanism theory of centerless cylindrical grinding in this paper, and the impact curve which react the relationship between the abrasion ration and the material removal or cutting depth is obtained by using the software of Mathematica. The abrasion ratio is testified in this paper by the experiment test of abrasive belt grinding for the titanium alloy, 45# steel and 304# stainless steel, systematic analyzing the affection of abrasion ratio on the hardness ratio and the belt speed. Experimental result shows that: belt speed is superior than hardness ratio to the abrasion ratio, and the mathematical model of material removal is testified by this experimental research. So the mathematical model of material removal could be used with theoretical basis in belt grinding process.
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