Intelligent electrical discharge machining (EDM) molybdenum‑titanium‑zirconium alloy by an extended adaptive control system

Abstract

In electrical discharge machining (EDM), weak machining stability hindered development of EDM Tools for decades. The developed adaptive control system for EDM brought an exuberant vitality to EDM Tools. However, the fast developed new kinds of materials, such as molybdenum‑titanium‑zirconium alloy, titanium matrix composite and titanium alloy and so on, have brought once existed the old issue revival of scientifically balancing machining rates and machining stabilities in machining. The authors in this paper proposed an innovative electrical discharge machining approach called intelligent EDM to solve this issue. The intelligent EDM mainly included three functions: the first one was “perception” that detected the discharging pulses in gap between electrode and workpiece; the second one was “cognition” that acquired gap environment index, machining state index from manipulating the detected discharging pulses and provided action guidance that the last function needed in calculating control laws; the last one was the optimal reactions that an adaptive control system regulated variables to achieve maximum machining rates under the action guidance of the “cognition”. The intelligent EDM composed of two adaptive systems in series which was also named as an extended adaptive control scheme. One system generated the action guidance of “cognition”, which was used maximize discharging efficiency allowed by current gap environment. The other adaptive control system timely regulated electrode discharge time and gap servo voltage to maximize the machining rates under the action guidance of the “cognition”. In this way, the stable machining and fast machining rates were realized simultaneously in machining the newly developed materials. Verification experiment of machining a blind hole of molybdenum‑titanium‑zirconium alloy demonstrated that the developed intelligent EDM displayed much an excellent machining ability.