Investigation on surface structuring generated by electrochemical micromachining

Abstract

Surface geometrical features and their functionality depend on the manufacturing process which is employed for fabrication of surface structures. Maskless electrochemical micromachining (EMM) is used to generate various surface structures for diminishing and controlling friction and wear to increase the lifetime, reliability, and efficiency of mechanical systems. This paper presents a method for the generation of structured surfaces on stainless steel (SS-304) surfaces by using maskless EMM. The micropatterned tool is composed of 800 µm diameter circular holes in a 5 × 5 matrix form. The indigenously developed EMM set up consists of an EMM cell, electrical power supply system, and a controlled vertical cross-flow electrolyte circulation arrangement to control the influence of process parameters during the generation of the micro features of structured surfaces. The single structured cathode tool is used for the mass production of structured surfaces with a short fabrication time in the industrial context by avoiding the use of an individual masking process for each workpiece. The process has been characterized in terms of the effects of predominant process parameters such as machining voltage, electrolyte concentration, duty ratio, pulsed frequency, and machining time on the machined surface characteristics such as current efficiency, machining accuracy, and depth of the circular pattern on the stainless steel surfaces. A mathematical model is also developed to determine the theoretical depth of the dimple pattern and correlate the theoretical depths with actual depths as obtained by experimentation. Moreover, an effort has been made to study the structuring characteristics on the basis of micrographs obtained during the EMM.

Keywords

Electrochemical micromachining (EMM) / Surface structuring / Circular pattern / Machining parameters / Current efficiency / Machining accuracy / Machining depth

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