Electrochemical drilling using alternating current

The attraction of using a.c. compared with d.c. is the opportunity it offers to simply transform normal workshop power supply down to a sensible potential value for electrochemical machining without having to incorporate rectifying equipment. Its success will normally depend on the ability to find tool materials which are not affected by electrolytic action while at positive potential and on the normal 50/60 Hz mains frequency being satisfactory. However, the possible use of higher frequencies should not be ruled out for small area work where total current can be in 10 s rather than 100 or 1000 s of amps; a high frequency oscillator could then be a sensible source of power. This paper is based on experimental work carried out using easily obtained tool electrode materials and illustrates the practical feasibility of a.c. for industrial use.