(1) Outline

As opposed to Chemical Etching which chemically dissolves the work material, the electrolytic etching dissolves the work material electro-chemically by applying DC current to anodic work pieces. Processes that utilize electrolytic etching are: Electrolytic machining; Electrolytic-grinding; Electrolytic-honing; and Electrolytic-lapping. These processes all use pre-formed cathode electrodes shaped into required configurations. Work pieces as anodes, they are placed very close to each other and let electrochemical dissolution take place. The electrochemical etching reactions are concentrated on to desired portions and controlled.

Both electrolytic and chemical etching are performed by concentrating and controlling the etching effects on certain parts of the work piece, but the electrolytic etching has more controlling options available as compared to the chemical counterpart.

With the chemical method, the only control option available is to use masks where etching effect is to be avoided. The same can also be used with the electrolytic method, but most applications utilize electrodes pre-formed into desired shapes for electrolysis to efficiently produce intended products.

1) Electrolytic machining

Electrolytic machining is also called electrochemical machining. The process uses electrolytes that do not generate any passivation film and utilizes only the electrolytic etching effects to perform complex milling work. Electro-machining has established its own position as an alternative among the other conventional methods.

2) Electrolytic-grinding

Electro-grinding is a combination of mechanical grinding and electrolytic etching. This grinding method uses grinding stones made of abrasives bound with conductive adhesive. The grinding stone mechanically grinds off passivation film to expose fresh metal surface, and the conductive adhesive facilitates the electrolytic dissolution of the metal. The benefits are: increased grinding efficiency, reduction of: grinding stone consumption; heat; and grinding resistance.

3) Electrolytic-honing, Electrolytic-lapping

Electro-honing and electro-lapping share the same principle with electro-grinding. They are the counterparts to mechanical honing and mechanical lapping. The benefits are the same as that of electro-grinding. Since honing and lapping are finishing processes and the amounts of metal removal are very small, they should perhaps be considered as part of surface etching classification.