Wire electric discharge machining apparatus
First Claim
1. An electric discharge machining apparatus comprising:
- a wire-shaped electrode disposed in confronting relation to a workpiece with an insulative machining liquid provided therebetween;
means for applying a DC pulse voltage between said electrode and said workpiece to produce an electric discharge therebetween;
means for superposing a high-frequency AC voltage, different from said DC pulse voltage, in a quiescent time of the DC pulse voltage applied between said electrode and said workpiece;
detecting means for detecting the degree of insulation of said insulative machining liquid which is present between said electrode and said workpiece in accordance with said high-frequency AC voltage;
comparing means for comparing the degree of insulation as detected by said detecting means in a gap between said electrode and said workpiece with a predetermined reference value and providing an output signal accordingly;
gap condition determining means for determining the condition of the gap and issuing at least one output signal indicative of the gap condition based on the output signal form said comparing means; and
control means for modifying the gap condition between said electrode and said workpiece based on said at least one output signal from said gap condition determining means.
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Accused Products
Abstract
A wire electrical discharge machining apparatus capable of adequately ascertaining whether the condition of the machining gap is good or bad without lowering the machining speed while preventing damage to the wire electrode. The apparatus includes a high-frequency voltage source that supplies voltage to the gap between applications of DC voltage machining pulses. In response to the application of high-frequency voltage to the gap a current detector and two voltage comparators detect the degree of electric insulation (i.e. dielectric strength) of the machining liquid in the gap. The condition of the gap is determined based upon comparison between the detected degree of electric insulation and a predetermined reference value. In response to the determined condition of the machining liquid gap conditions such as the machining pulse shape, gap width, wire tension, wire feed rate, rate of renewal of the machining liquid, and resistivity of the machining liquid may be changed.
50 Citations
20 Claims
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1. An electric discharge machining apparatus comprising:
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a wire-shaped electrode disposed in confronting relation to a workpiece with an insulative machining liquid provided therebetween; means for applying a DC pulse voltage between said electrode and said workpiece to produce an electric discharge therebetween; means for superposing a high-frequency AC voltage, different from said DC pulse voltage, in a quiescent time of the DC pulse voltage applied between said electrode and said workpiece; detecting means for detecting the degree of insulation of said insulative machining liquid which is present between said electrode and said workpiece in accordance with said high-frequency AC voltage; comparing means for comparing the degree of insulation as detected by said detecting means in a gap between said electrode and said workpiece with a predetermined reference value and providing an output signal accordingly; gap condition determining means for determining the condition of the gap and issuing at least one output signal indicative of the gap condition based on the output signal form said comparing means; and control means for modifying the gap condition between said electrode and said workpiece based on said at least one output signal from said gap condition determining means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification