KDP晶体锯切应力场与初始内应力场的耦合分析

Coupling Analysis of Sawing Stress Field and Initial Stress Field on KDP Crystal Cutting by Wire Saw

本文采用有限元法建立了KDP晶体线锯切割的仿真模型,仿真分析了切割过程中晶体内部应力场分布的变化规律。结果表明,线锯切割加工过程应力变化整体平稳,属低应力锯切方式,当晶体即将切断时,最大拉应力显著增加;随着被加工材料的去除,晶体初始内应力释放,晶体内部距离待加工表面越近的点,切割过程中应力变化越剧烈;锯切切口处,锯切应力与内应力相互耦合,应力集聚,并且晶体初始内应力越大,应力集聚越明显,晶体切割开裂几率越大。仿真结果为保证KDP晶体线锯切割加工过程中避免开裂提供了理论基础。

The model of KDP crystals cutting by wire saw has been set up by finite element method. Analysis and research focus on the distribution rule of crystal internal stress field during the sawing process. The results show that stress changes smoothly in sawing process which belongs to low stress cutting way. When the KDP crystal wafer is about to be cut off, the maximum tension stress significantly increased. With the material removed, the crystal initial internal stress releases, and the stress of crystal internal point which is closer to the new surface machined by wire saw changes more significantly. Cutting stress and internal stress couple mutually around the sawing kerf, and appear stress concentration on it. The larger of crystal initial stress, the more obvious stress concentration around the kerf during the process of slicing, so the cracking probability increases. The simulation results provide a theoretical basis for safely sawing process of KDP crystals.