Machining of high aspect ratio micro-holes in steel using EDM

Abstract

Electrical discharge machining (EDM) is a non-conventional machining process widely utilized in industry. This thermal process utilizes discrete electrical discharges between two conductive materials to remove material to form specific geometries. This process has is a non-contact material removal method and is therefore is applied to micro components. This has led to the development of Micro Machining techniques and micro tool fabrication techniques for such applications. Therefore, using tools with simple geometries, to form micro features in metal components. This project investigates micro machining techniques. Particularly, EDM micro drilling to fabricate micro holes with a high level of accuracy. By investigating the Sodick AP3L EDM machine’s capability to machine micro sized holes at varying depths. By using oxygen free electrodes as tools and a mild steel workpiece, the machine’s ability is investigated. The main objective of the project is to establish the highest aspect ratio achievable using this machine while maintaining a high quality. The investigation also includes multiple electrode strategies to obtain a high dimensional accuracy. The accuracy and overall quality of the micro holes produced is assessed and compared using a quality rating procedure. This quality rating procedure considers different criteria that contribute to high quality results and provides a numerical rating according to pre-set ranges. This is aimed to quantify quality and clearly define a high-quality result.