A soft anchor assembly according to an exemplary aspect of the present disclosure includes, among other things, a sheath, a first flexible strand affixed as non-sliding relative to the sheath and a second flexible strand slidable relative to the sheath. For the item-based solution found, the computer determines whether machine interference between the items is eliminated and whether a work-in-process inventory is sufficient. During the electro discharge machining process, the relative distance between the tool electrode and the plate electrode or the workpiece is changed at a prescribed frequency and discharge pulse output is controlled in synchronization with the change in the relative distance between the tool electrode and the plate electrode or the workpiece, so that high precision machining is enabled.