To realize the demand of processing the air film hole of aviation turbine blade without metamorphic layer

the EDM–drilling combined machining system was developed. According to the demand of the system mentioned above

to work and control in coordination with two axes

system architecture needed to be designed and optimized

which ensures that EDM and drilling operate independently of each other. Meanwhile

the system can realize automatic control of motor spindle speed and the stepless adjustment of feed rate. Based on the combined machining system

a processing technology of micro-hole composite without metamorphic layer was developed. During the processing

firstly

a micro-hole was processed by EDM. In order to removal the metamorphic layer on the hole wall completely

where the hole needed reaming with drilling tool. The basis of the technology mentioned above

a series of compound processing experiments of straight hole and 20° inclined hole were carried out. The tolerance range is (0.315±0.003) mm. The experimental results show that the EDM–drilling composite machining has the advantages of high machining efficiency

high hole shape accuracy and no metamorphic layer on the hole wall.