ABSTRACT

This paper develops a new method to restrain the fracture of monocrystalline silicon machining in EDM (Electrical discharge machining) through controlling the topography of single discharge crater. By this method, the complex 3D micro-cavity can be machined without obvious fracture. The fracture of monocrystalline silicon in EDM was revealed according to the EDM pits and the machining debris, then it is inferred that there are two ways to cause fractures, one is the breakages at the edge of the effective-removing crater, and the other way is the deformation accumulation caused by the superposition of the ineffective-removing crater. Then, it was found that if the morphology of single discharge crater can be controlled, the less fracture can be guaranteed during the manufacturing. Using narrow pulse width discharge, plenty of experimental tests were carried out focused on carters and surface of monocrystalline silicon with different machining parameters, with the assistance of characterization and analysis. Using these new results, the complex 3D structure is machined by layered compensation strategy and step-by-step milling strategy. It is found from the as-machined complex 3D cavity that it has no obvious defects at the edges, and the fracture is controlled.

摘要

本文提出了一种通过控制单个放电坑的形貌来抑制EDM（电火花加工）中单晶硅加工断裂的新方法。通过这种方法，可以加工复杂的3D微腔而不会出现明显的断裂。根据电火花加工凹坑和加工碎屑揭示单晶硅在电火花加工中的断裂，推测断裂有两种方式，一种是有效去除弹坑边缘的断裂，另一种是是无效清除陨石坑叠加造成的变形累积。然后发现，如果能够控制单个放电坑的形貌，则可以保证制造过程中的断裂更少。采用窄脉冲宽度放电，在表征和分析的帮助下，针对不同加工参数的单晶硅的卡特和表面进行了大量的实验测试。使用这些新结果，通过分层补偿策略和逐步铣削策略加工复杂的 3D 结构。从加工后的复杂3D型腔中发现，其边缘无明显缺陷，断裂得到控制。