基于中心复合设计试验的SiC单晶片超声振动加工工艺参数优化

Central Composite Design Test Based Process Parameters Optimizing for Compound Machining with Ultrasonic Vibration on SiC Wafer

由于超声振动复合加工过程很难通过动力学分析得到有效的切割机理的数学模型,而试验研究不失为解决该问题的一种有效方法。采用中心复合设计(Central composite design,CCD)试验方法,设计四因素三水平的SiC单晶片超声振动复合加工试验方案;引入响应曲面法建立切向锯切力、表面粗糙度与主要工艺参数(线锯速度、工件进给速度、工件转速和超声波振幅)的二阶关系模型,通过对试验数据的多元二次拟合,分别获得切削力和表面粗糙度的二次方程表达式;进一步分析实际加工条件对工艺参数的约束,并以提高SiC单晶片表面的加工质量(即最小化加工表面粗糙度)为目标建立工艺参数优化模型;设计粒子群优化算法及其流程进行优化问题求解,通过实例验证,该算法可以快速有效地获得满足多约束的最佳工艺参数。

Since it is difficult for ultrasonic vibration compound machining to get effective cutting mechanism mathematical model through dynamic analysis, and experimental study is shown an effective method to solve this problem, following researches by means of central composite design（CCD） testing are carried out. 4-factor and 3-level SiC wafer ultrasonic vibration compound machining test scheme is designed, and then second-order relational model is established between tangential cutting force, surface roughness, and their main process parameters （wire saw speed, workpiece feed rate, rotational speed, and ultrasonic amplitude） by using response surface methodology. According to multiple quadratic fitting of testing data, quadratic equation of cutting force and surface roughness is obtained. Constrains of actual machining condition upon the parameters are analyzed further. With the goal of improving surface quality （minimized surface roughness） of SiC wafer, the parameters optimization model is established. Particle swarm optimization algorithm and its procedure are designed to solve the model. Test proves that the algorithm could achieve optimized process parameters which satisfy multiple constraints rapidly and effectively.