Abstract
In the electrochemical machining of steels, it is well known that the articles machined in an electrolyte containing NaCl is not of good dimensional precision, compared with those machined in NaNO3 or NaClO3 electrolyte. The difference is interpreted that oxide films are formed on the articles in NaNO3 and NaClO3 solutions, which can prevent the dissolution of steel at low current density, but not in the NaCl solutions. In order to improve the dimensional precision in the NaCl electrolyte system, insulated films were used in place of the oxide films on the steel surface. Photo-resists such as PVA, Casein, KTFR, KMER, EPPR, OFPR and TPR were used as the insulated film. It was concluded that the photo-resists except PVA and Casein could be used practicaly. Among them, OFPR and TPR provided the best dimensional precision.
