Fine Hole Drilling Using Electrochemical Machining

Several variations on the technique for the drilling of holes of small diameter using Electrochemical Machining exist. These are described and the relative advantages discussed. In all of the techniques the two major considerations are seen to be Qvercut and Surface Finish. The nature of the electrolyte, the effect of concentration and flou, the use of additives to the basic electrolyte, and the use of non-aqueous electrolytes are discussed. The nature of Electrojet drilling and some problems associated with the geometry of the holes and with the surface finish are discussed. It is found that plasma formation in the high voltage techniques does not contribute to the metal removal: even up to 1000 V, removal is purely Faradaic.