Patent ID: 9421626
Filing Date: 2016-08-23
CPC Classification: B23H

Claim Text:
1. An apparatus for electrical discharge machining (EDM) modulation control, comprising: an EDM module, comprising an electrode, wherein the EDM module receives an open-circuit voltage; an open-circuit voltage modulation module, comprising a control switch, and the control switch comprising an output end electrically coupled to the EDM module, for providing the open-circuit voltage according to a first control signal, wherein the open-circuit voltage modulation module further changes magnitude of the open-circuit voltage according to a second control signal; a reference-voltage modulation and judgment module, comprising a voltage attenuation circuit coupled to the EDM module, for detecting a gap voltage of the EDM module, wherein the reference-voltage modulation and judgment module compares the gap voltage with a reference voltage to output an ignition result signal, and adjusts magnitude of the reference voltage according to a third control signal; a database, for storing reference voltages and open-circuit voltages required by a plurality of corresponding workpiece materials; and a controller, coupled to the open-circuit voltage modulation module, the reference-voltage modulation and judgment module and the database, wherein the controller, according to the ignition result signal, controls a time period of outputting the first control signal, the controller, according to characteristics of a workpiece material, selects a corresponding reference voltage and open-circuit voltage from the database, thereby generating the second control signal and the third control signal, and the controller further generates the first control signal to control the open-circuit voltage modulation module to provide the open-circuit voltage, wherein the controller, according to the ignition result signal, determines whether ignition happened; if the ignition fails to happen, the controller keeps sending the first control signal; if the ignition happened, the controller starts to count a machining time; after the machining time, the controller switches off the first control signal; after the off time, the controller repeats the above process.