MANUFACTURING LINEAR AND CIRCULAR CONTOURS USING CNC EDM AND FRAME TYPE TOOLS

In traditional electro discharge machining (EDM) the usual practice is to form a 3D female cavity in the work piece by making a correspondin g male shaped tool and plunging this into the work piece. Recently, ho wever, computer numerical control (CNC) EDM machines have become avail able which have the potential to generate a detailed shape without usi ng complex electrodes. This paper describes a novel method of electro discharge machining which makes the generation of linear, circular and curved contours possible without any special electrodes. The experime ntal work employs CNC EDM, mild steel work pieces and inexpensive ''fr ame type'' copper tools. The results indicate, relative to the cavitie s produced, an improved effective material removal rate (MRR), a bette r surface finish and a lower powered machine. The paper also introduce s the effect of EDM parameters on the process performance by modelling and analysing the experimental results using statistical techniques. Finally, a few applications are discussed.