Design of Portable EDM Machine Tool

Abstract

Electro Spark Erosion also known as the Electro Discharge Machining (EDM) technology is an important part of the advanced manufacturing technology and an important complement and development of machinery manufacturing in terms of mechanical cutting and grinding. EDM technology has become a significant processing method in modern production. With the constant development of manufacturing and EDM technology, a higher-level demand is put forward with regard to maneuverable, processing efficiency and processing qualify of EDM machine. Based on the research of existing electric spark processing machine tool, especially the mechanical structure, and focusing on the demand of the mechanical industry, this article designs a portable EDM machine. Keywords-EDM; portable; machine tool; design. I. INTRODUCTION Electro Spark Erosion also known as the Electro Discharge Machining (EDM) is a processing method making use of electricity and heat. During processing period, Pulse-spark discharge is continuously generated between the electrode and the work piece. The broken tap in the hole can be removed by the high temperature instantaneously generated during the discharge. As sparks can be seen during this process, it gets its name electric spark machining. The conventional method to remove the tap or drill is not perfect. Sometimes even after treatment, can also damage the work piece. Therefore, People look for better ways to process except the further development and improvement of the mechanical processing methods. The EDM not only meet the needs of development, but also highlighted the excellent performance. Therefore, this method obtained rapid development and wide application. The EDM in this project can be used as a portable machining tool. It is very important in some mechanical fields which is not easy to use large-scale processing equipment or difficult to machine material, wall hole and structure. II. PRINCIPLE OF EDM ANALYSIS The principle of EDM is based on an electric corrosion phenomenon, during pulse spark discharge between the tool and the work piece (positive, negative electrode). The discharge process can remove excess metal and to achieve the predetermined machining requirements on the size, shape and surface quality of the parts. Electrical discharge machining is a controlled metal removal technique whereby an electric spark is used to cut the work piece, which takes a shape opposite to that of the cutting tool or electrode. The cutting tool (electrode) is made from electrically conductive material, usually carbon. The work piece is both submerged in a dielectric fluid, which is generally light lubricating oil. This dielectric fluid should be a nonconductor (or poor conductor) of electricity. A servo mechanism maintains a gap of about 0.0005 to 0.001 inch (0.01 to 0.02 mm) between the electrode and the work, preventing them from coming into contact with each other. A direct current of low voltage and high amperage is delivered to the electrode at the rate of approximately 20000 (Hz). These electrical energy impulses become sparks which jump the dielectric fluid. Intense heat is created in the localized area of the surface of the work piece. The dielectric fluid, which is constantly being circulated, carries away the eroded particles of metal and also assists in dissipating the heat caused by the spark. The above is the basic principles of EDM. Fig1 shows it.