Patent ID: 7259347

Claim:
An electric discharge machining apparatus comprising: an input unit that receives input of data about three-dimensional shape of an electrode, three-dimensional shape of a workpiece, and machining conditions; a machining volume calculation unit that calculates, based on the data about the shape of the electrode, the shape of the workpiece, and the machining conditions, a machining volume that changes as machining of the workpiece by the electrode progresses; a machining time calculation unit that calculates, based on the machining volume calculated by the machining volume calculation unit, a machining time that is a time required to complete the machining of the workpiece by the electrode; an extraction unit that extracts a characteristic of the shape of the electrode that influences a machining rate; a correction unit that corrects the machining time according to the characteristic extracted by the extraction unit; and a display unit that displays the machining time calculated by the machining time calculation unit; wherein the extraction unit extracts a plurality of cross-sections of the electrode, divides the cross-sections to meshes, allocates solid or hollow mesh data to respective division elements, and extracts the characteristic of the electrode shape from the mesh data.