WIRE ELECTRIC DISCHARGE MACHINE
First Claim
1. A wire electric discharge machine which comprises an auxiliary discharge circuit, configured to apply a voltage to an inter-electrode gap between an electrode and a workpiece, thereby inducing electric discharge, and a main discharge circuit configured to supply a machining current, and machines the workpiece by repeating a cycle in which the main discharge circuit is activated and stopped after the auxiliary discharge circuit is activated, the wire electric discharge machine comprising:
- discharge delay time measuring unit configured to measure a discharge delay time, which is a duration without electric discharge such that the machining voltage is applied from the auxiliary discharge circuit to the inter-electrode gap,wherein a short-circuit machining current is supplied from the main discharge circuit to the inter-electrode gap if the result of measurement by the discharge delay time measuring unit is zero after the lapse of a predetermined short-circuit determination period since the start of the application of the machining voltage to the inter-electrode gap by the auxiliary discharge circuit,no machining current is supplied from the main discharge circuit to the inter-electrode gap or a machining current lower than or equal to the short-circuit machining current is supplied when electric discharge is generated and if the discharge delay time is less than a reference value, despite the short-circuit determination period, anda normal machining current equal to or higher than the short-circuit machining current is supplied from the main discharge circuit to the inter-electrode gap when electric discharge is generated and if the discharge delay time is not less than the reference value, despite the short-circuit determination period.
1 Assignment
0 Petitions
Accused Products
Abstract
In a wire electric discharge machine, a discharge delay time is used to classify the inter-electrode state into three categories; a short-circuit state, small-gap state, and large-gap state. Based on this classification, the magnitude of a machining current supplied from a main discharge circuit is determined. If the discharge delay time is zero (i.e., if no electric discharge is generated) after the lapse of a predetermined time since the start of the application of a machining voltage to an inter-electrode gap by an auxiliary discharge circuit, the inter-electrode gap is determined to be short-circuited by machining chips. Thereupon, a short-circuit machining current is supplied from the main discharge circuit to the inter-electrode gap to remove the machining chips. In this way, establishment of a complete short-circuit state is prevented so that the machining efficiency is improved to increase the machining speed.
5 Citations
12 Claims
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1. A wire electric discharge machine which comprises an auxiliary discharge circuit, configured to apply a voltage to an inter-electrode gap between an electrode and a workpiece, thereby inducing electric discharge, and a main discharge circuit configured to supply a machining current, and machines the workpiece by repeating a cycle in which the main discharge circuit is activated and stopped after the auxiliary discharge circuit is activated, the wire electric discharge machine comprising:
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discharge delay time measuring unit configured to measure a discharge delay time, which is a duration without electric discharge such that the machining voltage is applied from the auxiliary discharge circuit to the inter-electrode gap, wherein a short-circuit machining current is supplied from the main discharge circuit to the inter-electrode gap if the result of measurement by the discharge delay time measuring unit is zero after the lapse of a predetermined short-circuit determination period since the start of the application of the machining voltage to the inter-electrode gap by the auxiliary discharge circuit, no machining current is supplied from the main discharge circuit to the inter-electrode gap or a machining current lower than or equal to the short-circuit machining current is supplied when electric discharge is generated and if the discharge delay time is less than a reference value, despite the short-circuit determination period, and a normal machining current equal to or higher than the short-circuit machining current is supplied from the main discharge circuit to the inter-electrode gap when electric discharge is generated and if the discharge delay time is not less than the reference value, despite the short-circuit determination period. - View Dependent Claims (2, 3, 4, 5, 6, 12)
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7. A wire electric discharge machine which comprises an auxiliary discharge circuit, configured to apply a voltage to an inter-electrode gap between an electrode and a workpiece, thereby inducing electric discharge, and a main discharge circuit configured to supply a machining current, and machines the workpiece by repeating a cycle in which the main discharge circuit is activated and stopped after the auxiliary discharge circuit is activated, the wire electric discharge machine comprising:
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inter-electrode state determination unit configured to output an open, discharge, or short-circuit signal, depending on an inter-electrode state during a predetermined inter-electrode state determination period, after the application of the machining voltage from the auxiliary discharge circuit to the inter-electrode gap is started, wherein a short-circuit machining current is supplied from the main discharge circuit to the inter-electrode gap if the short-circuit signal is output from the inter-electrode state determination unit, no machining current is supplied from the main discharge circuit to the inter-electrode gap or a machining current lower than or equal to the short-circuit machining current is supplied if the discharge signal is output from the inter-electrode state determination unit, the application of the machining voltage from the auxiliary discharge circuit to the inter-electrode gap is continued if the open signal is output from the inter-electrode state determination unit, and a normal machining current equal to or higher than the short-circuit machining current is supplied from the main discharge circuit to the inter-electrode gap if electric discharge is generated after the inter-electrode state determination period. - View Dependent Claims (8, 9, 10, 11)
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Specification