基于视觉的钛合金铣削刀具磨损及加工表面粗糙度研究

发布时间：2018-05-30 07:52

本文选题：钛合金叶片 + 铣削加工　；参考：《南京航空航天大学》2017年硕士论文

【摘要】：钛合金具有比强度高、耐高温、耐腐蚀等优良特性,在国防工业和民用航空领域得到了广泛的应用,特别是在航空航天发动机的应用上极为广泛。同时,钛合金的优良特性也使其成为了典型的难加工材料。钛合金在加工过程中,容易产生严重的刀具磨损,从而影响加工表面质量及加工效率,甚至会引起较高的废品率。本文为提高钛合金叶片加工过程中刀具磨损及工件表面粗糙度测量的便利性,开展基于视觉的便携式测量技术研究,为钛合金叶片加工提供方便可行的过程监测方法。所完成的主要研究内容及取得的成果如下:(1)开展了刀具磨损便携式在位检测技术研究。对比分析了现阶段刀具磨损检测技术及优缺点,结合加工现场的要求,提出了一种便携式刀具磨损在位检测方法。该方法通过将微型显微镜夹持于手机摄像头上,可对刀具磨损图像进行拍摄。然后将磨损图像传入计算机中,通过图像处理与数据分析,便可获得刀具磨损量。通过误差分析,验证了该方法的有效性。由于测量时不用卸下刀具,所以该方法显著缩短了刀具磨损的检测时间,并且与常规离线测量方法相比,无需重新对刀。(2)采用视觉检测方法,研究了铣削参数对刀具磨损的影响规律。设计了钛合金TC4的正交铣削实验,结合钛合金叶片实际加工需求,系统研究了铣削速度、每齿进给量和铣削宽度对硬质合金刀具耐用度的影响规律。研究发现,刀具在使用初期和后期的磨损比较严重,中期时比较平稳;获得了铣削参数对刀具磨损的影响规律。在实验数据的基础上,建立了刀具耐用度的经验预报模型。(3)研究了钛合金加工表面粗糙度Ra及其与图像特征间的关系。首先,采用触针式粗糙度仪对已加工表面粗糙度进行了测量分析,通过单因素实验,获得了冷却条件、铣削参数等对表面粗糙度的影响趋势。在此基础上,应用所提出的视觉测量方法,对加工试件的表面图像特征开展了研究,分析了直方图标准差与粗糙度之间的关系。研究表明,两者之间具有良好的相关性,所提出的视觉方法可用于实际加工过程中工件表面粗糙度的监测。
[Abstract]:Titanium alloys with high specific strength, high temperature resistance and corrosion resistance have been widely used in the field of national defense industry and civil aviation, especially in aerospace engines. At the same time, titanium alloy has become a typical refractory material because of its excellent properties. In the process of machining titanium alloy is easy to produce serious tool wear which will affect the quality and efficiency of machining surface and even lead to higher scrap rate. In order to improve the convenience of tool wear and measurement of workpiece surface roughness during the machining of titanium alloy blade, the portable measurement technology based on vision is studied in this paper, which provides a convenient and feasible process monitoring method for titanium alloy blade machining. The main research contents and achievements are as follows: 1. This paper compares and analyzes the present tool wear detection technology and its merits and demerits, and puts forward a portable tool wear in-situ detection method combined with the requirements of machining field. The tool wear image can be photographed by holding the micro microscope on the camera of the mobile phone. Then the wear image is introduced into the computer and the tool wear can be obtained by image processing and data analysis. The effectiveness of the method is verified by error analysis. Because the tool is not removed when measuring, this method can significantly shorten the testing time of tool wear, and compared with the conventional off-line measurement method, there is no need to rematch the tool. The influence of milling parameters on tool wear was studied. The orthogonal milling experiment of titanium alloy TC4 was designed. The effects of milling speed, feed per tooth and milling width on the durability of cemented carbide cutting tools were systematically studied according to the actual machining requirements of titanium alloy blades. It is found that the wear of the tool is more serious in the early and late stage of use and stable in the middle stage, and the influence of milling parameters on tool wear is obtained. Based on the experimental data, an empirical prediction model of tool life is established. The relationship between surface roughness Ra and image characteristics of titanium alloy machining is studied. Firstly, the roughness of machined surface is measured and analyzed by using a touch needle roughness instrument. The influence trend of cooling conditions and milling parameters on the surface roughness is obtained by single factor experiment. On this basis, the surface image features of processed samples are studied by using the proposed visual measurement method, and the relationship between histogram standard deviation and roughness is analyzed. The results show that there is a good correlation between the two methods, and the proposed visual method can be used to monitor the surface roughness of workpiece in the process of practical machining.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG54

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