Electrochemical machining of microgrooves on flexible metallic foil using a tungsten arrayed microtool

Abstract

Electrochemical machining (ECM) is a promising method to generate microgrooves in difficult-to-cut materials. This paper utilizes a tungsten arrayed microtool to fabricate microgrooves on a flexible metallic foil via ECM. A pulsed current was employed for refreshing the electrolyte, and a mathematical model was built to explore which factors affect the inter-electrode side and bottom gaps. It implies that several factors such as the pulse-related parameters, microtool size and feed rate, indeed, influence the microgroove dimensions and profiles. Experiments indicated that as the pulse duty cycle and pulse period increased, the effective machining time for the microgrooves was prolonged, thereby increasing both the width and depth of microgroove. Thus, a pulsed current with a small pulse duty cycle and a short pulse period was useful for improving the machining quality of the microgrooves. Moreover, the microgroove dimensions were inversely proportional to the spindle speed due to the higher feed rate. However, the trends of change in the width and depth of the microgrooves were similar as the spindle speed increased, which led to a slight change in the localized etching ratio. For a thicker arrayed microtool, the effective machining time increased, the electrolyte flow path was longer, and the flow field at the machining gap became worse, thereby deteriorating the dimensional consistency and profiles of the microgrooves. Accordingly, the machining quality of microgrooves for a tool electrode thickness of 0.50 mm were considerably better than for a thickness of 1.00 mm.