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.