Abstract：As for machining film cooling holes in the turbine blades at the hot end of aero-engines, the research status in nearly a decade is reported about the electro discharge machining (EDM) of film cooling holes. The emphasis is focused on our innovation ideas and research progress in the electro machining processes and equipment technologies for solving machining problems of the film cooling holes with composite materials (high temperature alloy substrate and ceramic thermal barrier coating), composite structure (circular hole section and diffusion structure section), and low/no damage surfaces. Key methods and core technologies were researched and developed including a functional spindle head, a pulse power supply with high energy density, a servo control method of machining gap, a combined flushing system, and a method of drilling-penetration detection. The feasibility of three processes was verified including the hybrid process of EDM and ECM (electrochemical machining) for drilling the holes without recasting layers, the block divided EDM process for machining diffuser shaped structures, and the spark assisted chemical engraving (SACE) process for machining the thermal barrier coating of zirconia ceramic. The six-axis NC EDM equipment for machining film cooling holes was developed, which realized the automated machining process of straight holes and inclined holes with the drilling efficiency >20mm/min, dimensional accuracy better than ±20μm, and the controllable average thickness of recasting layer <10μm.
佟浩，李勇，李宝泉. 气膜冷却孔电加工工艺与装备技术研究[J]. 航空制造技术, 2021, 64(18): 34-45.
TONG Hao, LI Yong, LI Baoquan. Research on Technologies and Equipment of Electro Machining Film Cooling Holes. Aeronautical Manufacturing Technology, 2021, 64(18): 34-45.
2021, 
