Wirecut electrical discharge machine
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsHiroaki Morishita, Yutaka Terada, Kazuo Tsurumoto, Akiyasu Ito
Life of this patent
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Abstract
Accurate control of the tension of a wire electrode in a wirecut electrical discharge machine is achieved by eliminating a direct-current (DC) component from a speed difference signal between a braking section and a recovery section of the machine. The DC component of the speed signal which is eliminated is associated with the stretching of the wire electrode while under tension. As a result, the tension can be maintained constant dynamically as well as statically, thereby improving machining accuracy.
Claims20
A wirecut electrical discharge machine, comprising:
- control means for supplying a tension command and a wire electrode speed command;
- tension applying means for applying tension on a wire electrode in accordance with the tension command from said control means;
- speed detecting means for detecting speed of the wire electrode at said tension applying means;
- comparing means for comparing the wire electrode speed command from said control means with the output of said speed detecting means;
- removing means for removing a direct-current component of the output of said comparing means;
- and
- compensating means for compensating the tension command from said control means for said tension applying means based on the output Of said removing means.
A wirecut electric discharge apparatus, comprising:
- a control unit for supplying a tension command and a wire electrode speed command;
- a tension unit for applying tension on a wire electrode based on the tension command from said control unit;
- a first speed detection unit for detecting speed of the wire electrode at said tension unit;
- a first comparison unit for comparing the wire electrode speed command from said control unit with a value based on the speed of the wire electrode at said tension unit output from said first speed detection unit to produce a first comparison result;
- and
- a stretch compensation unit for compensating the tension command from said control unit based only on an alternating-current component of the first comparison result.
A wirecut electric discharge apparatus, comprising:
- a control unit for supplying a tension command and a wire electrode speed command;
- a tension unit for applying tension on a wire electrode based on the tension command from said control unit;
- a first speed detection unit for detecting speed of the wire electrode at said tension unit;
- a pull unit for pulling the wire electrode based on the wire electrode speed command from said control unit;
- a second speed detection unit for detecting speed of the wire electrode at said pull unit;
- a first comparison unit for comparing the speed of the wire electrode output from said second speed detection unit with a value based on the speed of the wire electrode at said tension unit output from said first speed detection unit to produce a first comparison result;
- and
- a stretch compensation unit for compensating the tension command from said control unit based only on an alternating-current component of the first comparison result.
A method for controlling tension of a wire electrode in a wirecut electric discharge apparatus, said method comprising:
- (a) receiving a tension command and a wire electrode speed command;
- (b) tensioning a wire electrode based on the tension command;
- (c) determining the speed of the wire electrode at an upstream position which is upstream of a work area;
- (d) comparing the wire electrode speed command with the speed of the wire electrode determined in step (c) to produce a first comparison result;
- and
- (e) compensating the tension command used in step (b) based only on an alternating-current component of the first comparison result.
A method for controlling tension of a wire electrode in a wirecut electric discharge apparatus, said method comprising:
- (a) receiving a tension command and a wire electrode speed command;
- (b) applying tension on a wire electrode based on the tension command;
- (c) obtaining the speed of the wire electrode at an upstream position which is upstream of a work area;
- (d) pulling the wire electrode based on the wire electrode speed command;
- (e) obtaining the speed of the wire electrode at a downstream position which is downstream of the work area;
- (e) comparing the speed of the wire electrode at the upstream position with the speed of the wire electrode at the downstream position to produce a first comparison result;
- and
- (f) compensating the tension command used in step (b) based only on an alternating-current component of the first comparison result.
Dependencies are inferred from the claim text.