Patent ID: 8663449

Claim:
A feed control method for wire cutting electrochemical discharge machining, comprising: defining an initial wire tension value before a machining operation; performing the machining operation that sets a speed of a servo feed of a workpiece to a first speed; making and activating a timer to calculate the amount of time during the workpiece is not in contact with a wire electrode; reading a wire tension value of the wire electrode; generating a new wire tension value by filtering the wire tension value; determining whether the wire electrode is in contact with the workpiece by determining whether the new wire tension value is greater than a sum of the initial wire tension value and a boundary value, wherein the new wire tension value is greater than the sum of the initial wire tension value and the boundary value when the wire electrode is in contact with the workpiece; performing a separation operation to separate the wire electrode from the workpiece by a predetermined distance if the wire electrode is in contact with the workpiece; calculating a second speed lower than the first speed of the servo feed after the separation operation is finished; setting the speed of the servo feed to the second speed after the second speed is calculated; determining whether the amount of time of the timer has reached a predetermined non-contact time amount if the wire electrode is not in contact with the workpiece; instructing the workpiece to proceed with the machining operation with the first speed of the servo feed if the time has not reached the predetermined non-contact time amount; calculating a third speed higher than the first speed of the servo feed after the time amount reaches the predetermined non-contact time amount; and setting the speed of the servo feed to the third speed after the third speed is calculated.