8)Static machining

The example processes discussed so far all had some relative movements between the tool electrode and the work piece where the electrodes are fed into the work pieces as the process progressed. One of the variations is called Static Machining where there is no relative movement between each other. Only the electrolytes move through the gaps between the two.

The process shown in [Fig.1] is an example of Static Machining process. A cylindrical electrode with unwanted section insulated is inserted inside a cylindrical work piece, the electrolyte is circulated in the gap and electrical current is applied. The inner surface of the work piece is electrolytically etched and the bore diameter is enlarged. This method is also called "electrolytic bulge" and "electrolytic boring". Enlarging of blind holes can be performed by the same technique. With the static machining methods, there is no gap adjusting involved, and the final accuracy depends on the original machining accuracy.

9)Electrolytic de-burring

This can be considered as a variation of the static machining process. By pre-shaping and placing the static electrode properly, burrs on parts are removed by electrolytic actions only.

Conventionally, de-burring operations are performed using hand tools such as portable die grinders, files, and chisels. However, as more automated machining and assembling are used in recent scenes, the need for precision de-burring and percentage weight of the hand operations has become non-negligible.

Electrolytic de-burring process can not only meet these demands but also enables de-burring of difficult-to-reach areas as well. [Fig.2] shown an example of electrolytic de-burring.

The [Fig.2] shows a de-burring process for branching areas of small cross-drilled holes. The tool electrode is fixed in place in the center bore by the electrode mount fixture, and is insulated other than the areas directly exposed to the branching area of the cross-drilled holes. By insulating, only the targeted areas are exposed to the electrolysis. The tool electrode and the work piece are held fixed together, and the electrolyte flows through the mount fixture to the target area and expelled through the cross-drilled holes.
Electrolytic de-burring is better suited for large scale production schemes since the tools and fixtures must be tailor produced for particular part.