Abstract: A movement control apparatus, which can be constructed as an accessory, provides in addition to the primary process-controlled movement of the electrode circular a secondary movement. The secondary movement is imparted to the electrode through a drive arm fixed at one end to the bottom slide of a cross-slide on which the electrode is also fixed and attached pivotably at the other end to an eccentric point of a rotating spindle. The mechanism for rotating the spindle is so designed that the degree of eccentricity of the eccentric point may be adjusted mechanically while the spindle is rotating. The eccentricity may also be controlled by the action of a cam follower which runs along a template, so that the circular movement of the electrode is controlled by the template in a copying mode.

Abstract: A workpiece-supporting table of an electro erosion machining equipment is provided with a mechanism for subjecting the workpiece to a circling motion of continuously variable radius during operation from zero to a maximum value. The same tool electrode can be used, without withdrawal from the work, for coarse machining at first and fine machining under circling movement immediately thereafter.