Method for predicting breaking of wire electrode in wire electrode type electric discharge machining operation
AssigneesNaotake Mohri, Mitsubishi Denki Kabushiki Kaisha
InventorsMohri Naotake, Nagao Saito
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Abstract
In a wire electrode discharge machining method the breaking of the wire electrode is positively detected by detecting a discharge signal between the wire electrode and the workpiece over a predetermined unit period of time, and then monitoring the average value of high frequency components included in the spectrum of the discharge signal which are independent of the vibration of the wire electrode. When the average value of the high frequency components is found to exceed a predetermined level, countermeasures are taken to avoid the breaking of the wire electrode.
Claims4
In a wire electrode type electric discharge machining operation in which an electrically conductive wire is employed as an electrode and advanced under tension through a workpiece to be machined, and electric discharge between said wire electrode and the workpiece is utilized to machine said workpiece, a method of predicting an imminent breaking of the wire electrode, comprising the steps of:
- detecting an electric discharge signal between said wire electrode and said workpiece during machining;
- and
- monitoring an average value of high frequency components included in a spectrum of the detected electric discharge signal above 20 KHz which are independent from discharge induced vibration frequencies of said wire electrode, an increase in said average value of high frequency components beyond a predetermined level being indicative of a stationary electric discharge and attendantly the imminent breaking of said wire electrode;
- wherein the steps of monitoring the high frequency components include:
- applying said discharge signal to a high-pass filter, and
- applying an output of said high-pass filter to an averaging circuit.
Dependencies are inferred from the claim text.