【作者】 张峰烈；

【导师】 傅星；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2011， 博士

【摘要】 金属材料的激光抛光处理是近十年来发展起来的一项新技术,在电子设备、精密机械、仪器仪表、医疗器械等领域都得到广泛的应用。本论文针对金属材料激光微抛光需求,主要研究对金属材料激光微抛光过程的理论及数值模拟分析,并在此基础上提出一种激光能量密度的实时控制方法,进而自主设计完成了激光微抛光系统,利用此系统对不锈钢、钛(Ti)、镍(Ni)等三种金属材料进行激光微抛光的试验研究,获得了良好的效果。本文主要完成的工作如下:基于一维瞬态热传导基本方程对激光微抛光中热力学过程进行了理论分析,研究了激光微抛光过程的准静态模型和动态模型,并利用有限差分法对不锈钢316L、钛和镍等三种金属材料激光微抛光进行了模拟分析和计算,并对激光微抛光的工艺参数和抛光后表面形貌的变化进行了预测。为了能够获取较好的微抛光效果,研究了获取最佳激光能量密度的方法,采用两个激光器(用于抛光的高功率脉冲激光器,用于检测的低功率连续激光器)的激光能量密度实时控制方案,为获得较好的抛光效果奠定了基础。设计并搭建了双激光器的激光微抛光试验系统。实现了共轴光路的激光能量密度实时反馈控制。并利用该系统对不锈钢、镍和钛等三种金属材料进行抛光实验,研究分析了激光能量密度、扫描速度、离焦距离、重叠率等几个主要因素对微抛光效果的影响。利用优化的工艺参数进行了抛光实验,得到了较好的抛光效果:不锈钢316L抛光后表面粗糙度从592.88nm降低至329.47nm,钛表面抛光后从123. 90nm降低至80.96nm,镍表面抛光后从121.40nm降低至94.41nm。对倾斜和弯曲表面进行激光微抛光试验研究,也得到较好的光滑表面。更多还原

【Abstract】 The laser micro-polishing of metallic materials is a newly developed surface processing technology in recent decade, which have been widely used in electronic equipment, precision machinery, instruments, medical equipment and other fields.Adapting the increase of requirement in laser micro-polishing of metallic materials, the theoretical and numerical analysis of the laser micro-polishing process was researched in this dissertation, and a laser micro-polishing system with real-time control of laser energy density was designed. The micro-polishing experiments for stainless steel, titanium and nickel metallic materials were made, and the results were evaluated.The completed works in this dissertation are as follows:Based on the basic equations of transient one-dimensional heat conduction, the thermodynamic process of the laser micro-polishing for the metal surfaces was analysed, the quasi-static and dynamic models on the metal laser micro-polishing process were respectively discussed. Used one-dimension finite difference method, the laser micro-polishing processes on the three sorts of metallic materials, stainless steel 316L, nickel and titanium, were numerically simulated. In this dissertation the parameters of laser micro-polishing process were optimized and the variational trend of the metallic surface morphology by laser polished was predicted.In this dissertation the relationship of micro-polishing effect and optimum laser energy density was studied. And it was proposed that a method for the real-time control of laser energy density using two beams of lasers (high power pulsed laser used for polishing, the low-power continuous laser used for detecting). It will be very important to the reseach of laser micro-polishing.A laser micro-polishing system using two lasers was made, the real-time feedback control of laser energy density by using a coaxial optical system was realised. And using the system, the micro-polishing experiments on stainless steel, nickel and titanium were made. The several factors, such as laser energy density threshold, the optimum laser energy density, scanning speed, defocus distance and overlap rate, and those can influence to polishing effects were considered and analyzed. The optimum parameters of laser micro-polishing were obtained and some better polishing effects were achieved: the surface roughness of 316L stainless steel sample reduced from 592.88nm to 329.47nm after polishing, titanium’s reduced from 123.3nm to 80.96nm, nickel’s reduced from 121.4nm to 94.41nm, respectively. Some of laser polishing experiments on the tilt and bending metallic surface were made and better results were also gotten.更多还原