Factors Affecting EDM Quality

EDM is one of the most widely used non-conventional machining processes. In EDM or electrical discharge machining, sparks or electrical discharges are used to melt or vaporize bits of material to shape the work piece. The cost of operation compared to rate of production makes it one of the best machining processes. The graphite electrodes which are used for sinker EDM is inexpensive and creates excellent results. It also offers excellent precision. Some EDM technologies offer sub-micron accuracy. However, using EDM does not always guarantee high quality pieces.

Good results require not only the proper selection of EDM materials, but also proper machine settings, such as peak current, on-off time, electrode polarity, size of gap and flushing conditions.

Because of the many variations in work piece geometry, the machine settings for new geometries are mainly chosen based on experience and calibrated as the work progresses. In effect, the quality of the piece being produced will determine the right selection of settings. The desired quality is achieved through repeated trial and error. This makes experience also a very important factor in creating high quality pieces.

The slightest variations between EDM machines can result to significant differences with the finished products. Two machines of the same models and settings are not guaranteed to produce the same output quality. Every machine is different and only time spent with the machine will give the operator a complete control over it.