Control strategy for high speed electrical discharge machining (die-sinking EDM) equipped with linear motors

Development of linear motors equipped spindle for direct drive EDM (electrical discharge machining) and a control strategy for high efficiency deep-hole EDM were reported. Since EDM´s slow machining process was dominated by its low removal rate and debris ejection process. The properties of EDM debris extruding under direct drive (LmEDM) was discussed. Conventional CNC controller allowed only fixed setting of jump parameters, which wasted effective working time significantly. By introducing a pulses discriminator to count the effective discharge pulses, an EDM jump control associated with this removal feedback was proposed. Several experiments for testing and verification were conducted. It is evident from the results that LmEDM with proposed jump control was faster than traditional EDM by 3.1 times for 35 mm deep high aspect ratio EDM. And not only the machining speed, but also its wear ratio and surface integrity were improved significantly.