激光表面微加工硬脆材料的数学建模研究

Mathematical modeling research on laser surface micromaching of hard brittle material

为了满足微加工效率,便于数控编程,选用弓字型激光扫描路径,介绍了温度场控制方程,引入高斯激光功率密度随时间改变的特性对激光束强度分布进行计算。不考虑硬脆材料表面性质、氧化层、等离子体等因素对吸收系数产生的影响,假设硬脆材料吸收系数在激光表面微加工中是一个固定值,对激光表面微加工前沿表面元的局部吸收光功率进行计算。引入微元近似法获取热传导损耗的功率,给出熔化和蒸发表面硬脆材料消耗的功率计算公式,获取功率平衡方程。针对激光和硬脆材料作用区域逐点求出对应微加工量,获取整个微加工轮廓。实验结果表明,采用所构建模型实现激光表面硬脆材料的微加工,不仅加工质量好,而且效率高。

The bow type laser scanning path was programming selected in order to satisfy the micromachining efficiency and CNC convinence. Temperature field control equation was introduced and the characteristics of Gaussian laser power density changing over time was put forward to calculate laser beam intensity distribution. Regardless of hard brittle material surface properties,oxide layer,the impact of plasma and other factors of the absorption coefficient,assume that the hard brittle material absorption coefficient in the laser surface micromachining is a fixed value and can calculate the local absorption power of the front elements in laser surface micromachining. Introducing the microelements approximation method to obtain the loss power of heat conduction. Giving the melting and evaporating power calculation formula of surface hard brittle materials consumption to obtain the power balance equation. Getting the each related micro processing capacity in terms of the action area of laser and the hard brittle material to obtain the entire micromachining contour. Experimental results show that the constructed model was adopted to realize good quality and high efficiency.