METHOD FOR ONLINE ELECTRODE CORRECTION USING ELECTRICAL DISCHARGE MACHINING
Publication Date: 2012-Dec-31
The IP.com Prior Art Database
The present invention relates to a method for online electrode correction using electrical discharge machining (EDM). According to an embodiment of electrode correction method, depending on the type of electrode used, such as formed or shaped electrode, similar machine motion and different electrical settings are applied to restore worn from electrodes. In another embodiment of electrode correction method, a simple electrode rod is used to correct electrode. Different electrical settings and CNC machine motion is applied to restore worn from electrodes. In yet another embodiment of electrode correction method, an active mechanical cutting or grinding tool is mounted on ram of EDM machine and CNC machine motion is applied to remove layer of metal from worn electrode for correction.
The present invention relates generally to electrical discharge machining, and more particularly to a method for on-line electrode correction in electrode discharge machining.
Electrical discharge machining (EDM) converts electrical energy to thermal energy in form of high temperature plasma to remove metal and intricate parts. Generally, EDM die sinking is employed for making tools, dies, molds and other single piece parts. Capabilities of EDM are exploited in production of difficult machine parts such as buckets and nozzles which are made of heat resistant nickel alloys. In the production of such parts, a major issue is electrode wear. Usually, several electrodes are required to finish a complex shape with geometrical accuracy and sharpness of corners.
Tool electrode wears more at corners and edges. Simple electrode such as rotating cylindrical rod in electrical discharge milling is compensated whenever it is worn. To prevent electrode loss, additional linear feeding is provided according to estimation of loss. However, electrodes formed in specific shape cannot be restored by simple electrode compensation as linear feeding cannot recover shape of a formed electrode.
Modern EDM machines reduce electrode wear considerably for copper and graphite, the wear distribution is uneven. An electrode correction process that machines worn surface and restores original electrode shape is required. Further, metal removal for electrode correction is small and the correction process can be rather quick.
Therefore, it would be desirable to have a method for electrode correction using EDM.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates electrode correction using electrical discharge machining for die sinking.
Figure 2 illustrates electrode correction using electrical discharge machining for milling.
Figure 3 illustrates electrode correction using electrical discharge machining for cutting or grinding.
The present invention is a method for online electrode correction using electrical discharge machining. Such method does not require additional tool machines for electrode correction provides on-site electrode correction. As illustrated in Figure 1, according to an embodiment of the electrode correction method comprises using a correction electrode shaped like a part that is applied to remove thin layer from the worn electrode. Such a removal of thin layer is achieved by reversing polarity of electrodes and applying different pulse settings to promote erosion of the worn electrode. The correction electrode is made of same material as the worn electrode, usually copper or any other material that ensures stable processes. Further, corners and edges of the correction electrode are better protected to withstand wear pattern of worn electrode. The corrected electrode therefore recovers original shape of worn elec...