Study on dynamically variable attitude EDM machining method of deep narrow slots

Deep narrow slots (DNSs) are typical difficult-to-machine structures. At present, EDM is the main machining method of DNSs. However, due to the difficulty in evacuating discharge products, machining of DNSs becomes difficult and time-consuming when the machining depth grows. Preliminary studies have shown that certain machining attitudes have a higher machining efficiency than the traditional downward-feeding machining attitude during a fixed attitude machining. To further accelerate the evacuation of discharge products and improve the machining efficiency of DNSs, a dynamically variable attitude EDM machining method for DNSs is proposed. The simulation of motions of discharge products in the gap flow field shows that the dynamically variable attitude EDM machining method can promote the evacuation of discharge products. Experiments are carried out to investigate the effect of different process parameters in the dynamically variable attitude method on the machining efficiency of machining DNS structures. The results show that the dynamically variable attitude method has higher machining efficiency than the fixed attitude machining method. The machining time under the dynamically variable attitude method is shortened by 13.02% compared with the horizontal fixed attitude machining and 19.04% shorter than the traditional downward-feeding machining. To find out the reasons for the improvement of the machining efficiency caused by the dynamically variable attitude method, gap states during the whole machining process are collected and analyzed.