激光加工陶瓷裂纹行为的理论分析及实验验证  

Theory Analysis and Experiment Verification on Crack Characters during Laser Processing Ceramics

作　　者：闫胤洲[1] 季凌飞[1] 鲍勇[1] 蒋毅坚[1] 

机构地区：[1]北京工业大学激光工程研究院,北京100022

出　　处：《中国激光》2008年第9期1401-1408,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(10674041);北京市科技新星计划(2006B11)资助项目

摘　　要：通过建立脉冲激光陶瓷打孔二维温度场模型,计算了相应的热应力分布,预测了打孔过程中的两种裂纹形态——径向裂纹和环形裂纹,并由此预测出激光脉冲切割过程中的两种裂纹扩展方式——发散型和回归型,提出通过降低加工处温度、减少热影响区以及增大孔径(或切缝宽度),可以达到降低热应力,抑制加工裂纹产生的目的。通过讨论模型参数和激光加工工艺参数之间的对应关系,提出低占空比、高辅助气体压力和离焦加工是激光加工工艺参数优化的基本方向,通过对氧化铝陶瓷和单晶硅的激光加工实验,对裂纹的产生及扩展预测进行了验证,并对加工参数优化实现了陶瓷的激光无裂纹加工。A thermal-stress field of laser drilling ceramic is calculated by building a two dimensional （2D） thermal field model. Two types of cracks during pulsed laser drilling are predicted. One is along radial direction, and the other is along tangent direction. Further more, spreading characteristics of two types of cracks, emanatlve and regressive, during pulsed laser cutting are analyzed and predicted. It is concluded that the restraint of cracks can be achieved by reducing temperature of processing point, decreasing size of heat affected zone and increasing hole diameter （or kerr width）. Based on analyzing parameters of the theoretical model, relationships between model parameters and processing parameters are discussed. It is proposed that optimizing laser processing parameters should depend on lower duty cycle, higher gas pressure and focal position outside the workpieee. The prediction results of crack formation and spread analyzed by the mathematie model are accordant with the experimental results of laser drilling and cutting of alumina ceramic and single-crystal silicon. Laser crack-free processing of ceramics is achieved by optimizing laser processing parameters based on the theoretical model.

关 键 词：激光技术 激光加工陶瓷 裂纹行为 温度场模型 切割实验 

分 类 号：V261.8[航空宇航科学与技术—航空宇航制造工程] TQ174.75[化学工程—陶瓷工业]