基于微喷砂水射流技术的刀具切削刃处理工艺及其强化机理研究

发布时间：2018-06-17 04:50

本文选题：微喷砂技术 + 切削刃强化　；参考：《山东大学》2017年硕士论文

【摘要】：微喷砂技术具有加工效率高、灵活性好和资源利用率高的优势,将其应用于刀具的切削刃强化不仅可以提高刀具切削寿命和加工效率,还可以降低加工成本。为此本文开展三个方面的研究。通过微喷砂技术应用于刀具的切削刃处理,研究微喷砂工艺参数对YT15和YG6硬质合金、Ti(C,N)金属陶瓷三种刀片的去除量和切削刃质量的影响,获得了合适刃口半径和刃口质量的微喷砂工艺参数;研究三种刀片的刃口修形去除机理,并建立相应的刃口半径经验预测模型和半经验理论模型;研究微喷砂处理后刀片刃口半径对切削过程的影响,优化获得不同材质的刀片在一定切削参数下的刃口半径,并分析微喷砂切削刃强化对刀具切削性能的影响。采用正交实验方法研究微喷砂工艺参数对材料去除量和刃口线粗糙度的影响,并对微喷砂工艺参数进行初步优选;而采用全因素实验方法研究微喷砂工艺参数对刃口半径和刃口线粗糙度分布的影响,并确定获得合适刃口半径和刃口质量的微喷砂工艺参数。结果表明,对YT15、YG6和金属陶瓷刀片的材料去除量影响最大的因素分别为喷砂时间、磨料目数和喷砂时间,而对YT15、YG6和金属陶瓷刀片的刃口线粗糙度影响最大的因素分别为喷砂压力、磨料目数和磨料目数。以刃口线粗糙度为优化目标,兼顾材料去除量,优化出了 YT15和YG6刀片所适用的白刚玉磨料目数为320目,而金属陶瓷刀片所适用的白刚玉磨料目数为280目。三种刀片的刃口半径都随着喷砂压力和喷砂时间的增加而增大;当喷砂压力为0.2MPa和0.25MPa时,随着磨料比重的增加,刀片的刃口半径都先增大而后减小;而在喷砂压力为0.3MPa和0.35MPa时,随着磨料比重的增加,刀片的刃口半径都呈现一直增大的趋势。对刃口线粗糙度分布情况分析,三种刀片的刃口线粗糙度符合伽玛分布,YT15和金属陶瓷刀片的刃口线粗糙度小于0.7μm的概率分别为0.98和0.97,而YG6刀片的刃口线粗糙度小于0.73μm的概率为0.96。根据微喷砂全因素实验得到的刃口半径以及刃口线粗糙度分布确定了经正交实验初选后的微喷砂工艺参数的合理性。采用对比实验研究微喷砂水射流中水和磨料的作用,并对材料去除机理和刃口形状形成过程进行分析。利用BP神经网络和单颗粒磨料材料去除模型分别建立刃口半径的经验预测模型和半经验理论模型。结果表明,单纯的水射流并不能去除材料,材料的去除是通过磨料对刃口材料的冲蚀作用实现的,三种刀片的材料去除方式都包括脆性去除和塑性去除。圆弧形刃口的形成是由刃口材料裂纹扩展的脆性去除和磨粒微切削的塑性去除共同作用导致的。在微喷砂工艺范围内三种刀片的BP神经网络模型的相对误差在10%以内,而刃口半径的半经验理论模型可以定性的分析微喷砂工艺参数以及刀片材料力学性能对刃口半径的影响。采用有限元仿真与单因素切削实验相结合的方法研究刃口半径对切削过程的影响,并优化三种刀片的刃口半径;采用对比切削实验研究微喷砂切削刃强化对刀具切削性能的影响。结果表明,随着刃口半径的增加,三种刀片的切削力都增大,相对主切削力和进给力而言,刃口半径对切深抗力的影响较大。以刀具寿命为优化目标兼顾工件表面粗糙度得到的YT15、YG6和金属陶瓷刀片的最优刃口半径分别为26μm、36μm和15μm。与未强化的刀片相比,微喷砂切削刃强化的YT15、YG6和金属陶瓷刀片的刀具寿命分别提高了 63%、37%和86%。随着刀片磨损的增加,微喷砂切削刃强化的YT15、YG6和金属陶瓷刀片的切削力被未强化刀片的切削力超越,随着切削时间的增加,微喷砂切削刃强化的YT15和YG6刀片的工件表面粗糙度逐渐被未强化刀片的工件表面粗糙度超过,而对于金属陶瓷刀片而言,微喷砂切削刃强化的刀片的工件表面粗糙度一直低于未强化刀片的工件表面粗糙度。切削刃强化会稍微造成锯齿形切屑的锯齿密度增加,但对带状切屑的形貌影响不大。而刀片后刀面磨损机理主要为扩散磨损、粘结磨损、磨粒磨损和氧化磨损。
[Abstract]:Micro blasting technology has the advantages of high processing efficiency, good flexibility and high utilization of resources. Applying it to cutting edge of cutting tools can not only improve the cutting life and machining efficiency, but also reduce the machining cost. Therefore, this paper has carried out three aspects of research. The effect of micro spray process parameters on the removal of three kinds of blades of YT15 and YG6 cemented carbide, Ti (C, N) cermet and the quality of cutting edge is studied. The parameters of micro blasting technology are obtained, which are suitable for the radius of the blade and the quality of the blade. The mechanism of the cutting and removal of the cutting edge of the three kinds of blades is studied, and the empirical prediction model of the radius of the blade is built and the semi empirical theory is built. The influence of blade radius on the cutting process after micro blasting is studied. The blade radius of different cutting blades under certain cutting parameters is optimized, and the effect of micro sanding cutting edge strengthening on cutting performance is analyzed. Orthogonal experimental method is used to study the material removal and edge thread roughness of micro blasting technology. The effect of roughness on the process parameters of micro blasting is preliminarily optimized, and the effect of the parameters of micro blasting on the edge radius and the edge profile of the blade is studied by the full factor experimental method, and the parameters of the micro spray process to obtain the appropriate edge radius and edge quality are determined. The results show that the materials for YT15, YG6 and cermet blades are made. The most influential factors of the removal amount are sand blasting time, abrasive visual number and sand blasting time, while the most influential factors on the edge roughness of YT15, YG6 and cermet blade are sandblasting, abrasive and abrasives, with the edge roughness of the edge as the optimization target, and the material removal amount is taken into consideration, and the YT15 and YG6 blade are optimized. The number of white corundum abrasives is 320 mesh, and the number of white corundum abrasives is 280 mesh. The edge radius of the three kinds of blades increases with the increase of sand injection pressure and sand injection time. When the sand injection pressure is 0.2MPa and 0.25MPa, the blade radius first increases and then decreases with the increase of the proportion of abrasive. When the sand injection pressure is 0.3MPa and 0.35MPa, with the increase of the proportion of the abrasive, the blade radius of the blade shows a tendency to increase all the time. The roughness of the three blade lines conforms to the gamma distribution, and the probability of the edge roughness of the YT15 and the metal ceramic blade is less than 0.7 m, respectively, with the probability of 0.98 and 0.9, respectively. 7, the probability of the edge roughness of the YG6 blade is less than 0.73 u m, which determines the rationality of the micro sand spraying process parameters after the orthogonal experimental preliminary selection according to the radius of the blade and the edge profile of the blade line. The effect of water and abrasive in the micro spray water jet is studied by contrast experiments, and the material is used to the material. In addition to the mechanism and the formation process of the blade shape, an empirical prediction model and a semi empirical model are established by using the BP neural network and the single particle abrasive material removal model. The results show that the pure water jet can not remove the material, and the material removal is achieved through the erosion of the cutting edge material. The material removal methods of the three kinds of blades include brittle removal and plastic removal. The formation of the circular arc edge is caused by the brittle removal of the crack propagation of the edge material and the joint effect of the plastic removal of the abrasive micro cutting. The relative error of the BP neural network model of the three kinds of blades within the range of micro blasting is less than 10%, and the radius of the blade is the radius of the blade. The semi empirical model can qualitatively analyze the process parameters of micro blasting and the influence of the mechanical properties of the blade material on the edge radius. The effect of the edge radius on the cutting process is studied by the combination of finite element simulation and single factor cutting experiment, and the edge radius of the three kinds of blades is optimized. The effect of sand jet cutting edge strengthening on cutting performance shows that with the increase of the radius of the blade, the cutting force of the three kinds of blades increases. In terms of the main cutting force and feed force, the edge radius has great influence on the cutting depth resistance. The tool life is the YT15, YG6 and the metal ceramic knife to the surface roughness of the workpiece. The optimum blade radius is 26 m, 36 m and 15 mu m., compared with the unreinforced blade, the tool life of the YT15, YG6 and the cermet blade enhanced by the micro bladed cutting edge is increased by 63%, 37% and 86%. with the blade wear, and the cutting force of the YT15, YG6, and cermet blade strengthened by the micro blasting cutting edge is not strengthened by the blade. The cutting force transcends, with the increase of cutting time, the surface roughness of the workpiece surface of the YT15 and YG6 blades strengthened by the micro bladed cutting edge is gradually exceeded by the surface roughness of the unreinforced blade, while for the cermet blade, the surface roughness of the blade strengthened by the micro bladed cutting edge has always been lower than the surface of the workpiece with the unreinforced blade. The roughness of the cutting edge increases the sawtooth density slightly, but has little effect on the shape of the banded chip, and the wear mechanism of the blade surface is mainly diffusion wear, bond wear, abrasive wear and oxidation wear.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG71

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