Tool-electrode vibration, effect

As in the case of tool-electrode vibration, the electrolyte flow can be promoted by tool-electrode rotation. An example combining gravity-feed drilling with tool-electrode rotation is shown in Fig. 7.6. A tungsten carbide flat sidewall tool-electrode (Fig. 7.3b) with pulsed voltage supply was used [136]. The drilling time for the fixed depth of 450 p,m increases with the tool-electrode rotation rate due to the reduced heat power. The entrance diameter shows an inverse volcano dependence on the tool-electrode rotation rate. This effect was attributed by the authors to the competition between the promotion of the electrolyte flow and the increased drilling time [136]. 

Adding abrasive material to the electrolyte does not itself promote the local chemical etching. This effect can, however, be achieved in combination with the appropriate tool-electrode motion (e.g., rotation or vibration). In this way, machining quality is improved by reducing the surface roughness [133]. 

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