High-aspect ratio micro-pin manufacturing using inverse slab electrical discharge milling (ISEDM) process

• DOI: 10.1007/s00170-012-4270-5
• Publication Date: 2012-06-13T05:00:31Z
• Authors: R. Gil; J. A. Sánchez; N. Ortega; S. Plaza; B. Izquierdo; I. Pombo
• Keywords: Slab; Electrical Discharge Machining; Aspect ratio (aeronautics)

Manufacturing of micro-pins with diameter less than 1 mm is a field of great interest both in research and in industrial application. There is a wide variety of components of low-diameter cylindrical geometry for various applications, including precision products such as gear shafts, valves, shafts, and channels of micro-fluidic systems, parts for micro-pumps and turbines, etc. Increasing interest can also be found in the manufacturing of micro-electrodes for micro-hole EDM drilling of Ti- and Ni-base alloys for the aerospace industry. The inverse slab electrical discharge milling (ISEDM) process has been recently proposed as an economical alternative for the manufacturing of high-aspect ratio low-diameter cylindrical parts. However, application of the process requires understanding the influence of the process variables. The technological data given by conventional SEDM machines (static workpiece) are not valid for this process due to the relative rotation movement of the part with respect to the electrode. In this work, a systematic study of the influence of the process variables on the efficiency of the ISEDM process is presented. The geometrical characteristics of the cylindrical part, its rotational speed, and the energy of the discharge have been included in the study as main input variables. Their effect on material removal rate, surface finish, and micropin accuracy is discussed. Results show that micropins of aspect ratio as high as 90:1 and 0.2 mm diameter can be economically manufactured.