固结磨料研磨蓝宝石材料去除速率研究

发布时间：2018-03-17 18:17

本文选题：单晶蓝宝石　切入点：固结磨料研磨　出处：《南京航空航天大学》2016年硕士论文　论文类型：学位论文

【摘要】：蓝宝石以其稳定的理化性能以及优异的光学性质,应用领域不断拓展。作为典型的硬脆材料,单晶蓝宝石高硬度和高脆性的特性使得其在加工过程中极易发生开裂,工件表面也极易形成裂纹和凹坑,这严重制约了蓝宝石的大规模应用。固结磨料技术将磨粒固结到研磨垫基体之中,使得磨粒轨迹可控,通过调整加工工艺参数,既保证了良好的材料去除效率,又能得到比较理想的加工表面质量。本文以固结磨料研磨加工单晶蓝宝石的材料去除率为研究对象,通过分析固结磨料研磨机理,建立了固结磨料研磨蓝宝石的材料去除率模型,并通过实验进行了验证。主要内容和研究成果如下:(1)基于固结磨料研磨过程的特点,将材料去除看作微小磨粒微观切削作用,通过对磨粒分布及磨粒出露的合理假设,建立实际参与材料去除的有效磨粒数;仅考虑出露磨粒与工件的接触,利用研磨过程中的力平衡关系,分别建立不考虑工件弹性回复的刚塑性假设磨粒平均切深模型和考虑工件弹性回复的弹塑性平均切深模型;结合有效磨粒数和磨粒平均切深,建立固结磨料研磨蓝宝石的材料去除率模型。(2)以建立的材料去除率模型为基础,利用MATLAB数值模拟功能绘制材料去除率随磨粒粒径、磨粒体积分数、研磨压力以及研磨速度的关系曲线,分析材料去除率与上述参数之间的关系。结果表明:刚塑性模型下磨粒粒径对材料去除率的影响不显著,材料去除率随着磨粒体积分数的增大而减小,随着研磨压力和研磨速度的增大而增大,弹塑性模型下的材料去除率整体明显低于刚塑性模型下的材料去除率。(3)开展了蓝宝石固结磨料研磨实验,并将其与相同参数下两种假设模型计算值进行比较。结果表明:实验得到的材料去除率的变化趋势与理论趋势一致,刚塑性假设下的模型计算值与实验值误差较大,弹塑性假设下的模型计算值与实验值误差较小。
[Abstract]:Because of its stable physical and chemical properties and excellent optical properties, sapphire is widely used in many fields. As a typical hard and brittle material, single crystal sapphire has high hardness and brittleness, which makes it easy to crack in the process of processing. It is also easy to form cracks and pits on the workpiece surface, which seriously restricts the large-scale application of sapphire. Both good material removal efficiency and ideal surface quality can be obtained. In this paper, the material removal rate of single crystal sapphire by consolidation abrasive grinding is taken as the research object, and the mechanism of consolidation abrasive grinding is analyzed. A model of material removal rate for sapphire grinding with consolidated abrasive is established and verified by experiments. The main contents and research results are as follows: 1) based on the characteristics of abrasive grinding process, material removal is regarded as micro-cutting action of micro-abrasive. Based on the reasonable assumption of the distribution of abrasive particles and the appearance of abrasive particles, the effective number of abrasive particles involved in material removal is established, and only the contact between exposed particles and workpieces is considered, and the force balance relationship in the grinding process is used. The elastic plastic average shear depth model without considering elastic recovery of workpiece and the elastic plastic average shear depth model without considering elastic recovery of workpiece are established respectively, and the effective wear particle number and the average cutting depth of wear particle are combined. Based on the model of material removal rate, the MATLAB numerical simulation function was used to plot the material removal rate with the particle size and the volume fraction of abrasive particles. The relation curve of grinding pressure and grinding speed, and the relationship between material removal rate and the above parameters are analyzed. The results show that the effect of abrasive particle size on material removal rate is not significant under rigid-plastic model. The material removal rate decreases with the increase of the volume fraction of abrasive particles, and increases with the increase of grinding pressure and grinding speed. The material removal rate under elastic-plastic model is obviously lower than that under rigid-plastic model. It is compared with the calculated values of the two hypothetical models with the same parameters. The results show that the change trend of the material removal rate obtained by the experiment is consistent with the theoretical trend, and the error between the calculated values of the model and the experimental values under the rigid-plastic assumption is larger than that of the experimental ones. The error between the calculated value and the experimental value of the model under elastic-plastic assumption is small.
【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】：2016
【分类号】：TQ164

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