Controller for wire electric discharge machine
First Claim
1. A controller for a wire electric discharge machine for performing electric discharge machining by generating electric discharge between a wire electrode and a workpiece while relatively moving the wire electrode and the workpiece, said controller comprising:
- machining rate determining means for determining rate of machining by the electric discharge between the wire electrode and the workpiece; and
motion control means for controlling relative motion of the wire electrode and the workpiece based on the rate of machining determined by said machining rate determining means such that a speed of the relative motion is decreased when the rate of machining is increased.
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Accused Products
Abstract
A controller for a wire electric discharge machine which can achieve stable machining with high surface accuracy without requiring adjustment of a gain or the like in wire-electrode feed control. A discharge gap detection unit detects a voltage between a wire electrode and a workpiece. An amount-of-machining-per-unit-distance change detection unit obtains an average machining voltage, and a voltage drop EX that is a difference between the obtained average machining voltage and a no-load voltage. A comparative determination unit obtains a ratio ES/EX between a reference voltage drop ES stored in a reference-amount-of-machining-per-unit-distance relative value storage unit and the drop voltage EX. A feed pulse arithmetic unit obtains a feed speed that makes the amount of machining per unit time constant, on the basis of the ratio ES/EX and a predetermined feed speed, and distributes feed pulses to motors to thereby move the wire electrode relatively to the workpiece. Since the amount of machining per unit time is kept constant, the surface accuracy in finishing is high and stable machining can be performed.
29 Citations
6 Claims
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1. A controller for a wire electric discharge machine for performing electric discharge machining by generating electric discharge between a wire electrode and a workpiece while relatively moving the wire electrode and the workpiece, said controller comprising:
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machining rate determining means for determining rate of machining by the electric discharge between the wire electrode and the workpiece; and
motion control means for controlling relative motion of the wire electrode and the workpiece based on the rate of machining determined by said machining rate determining means such that a speed of the relative motion is decreased when the rate of machining is increased. - View Dependent Claims (2, 3)
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4. A controller for a wire electric discharge machine for performing electric machining by generating electric discharge between a wire electrode and a workpiece while relatively moving the wire electrode and the workpiece to each other, said controller comprising:
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voltage drop calculation means for determining a voltage drop of an average machining voltage with respect to a preset no-load voltage in each predetermined period;
movement means for moving the wire electrode relative to the workpiece along a machining path according to motion commands;
reference value storage means storing a predetermined value representing a voltage drop of a reference average machining voltage with respect to the preset no-load voltage;
comparison means for comparing the voltage drop determined by said voltage drop calculation means and the predetermined value stored in said reference value storage means; and
control means for controlling the relative motion of the wire electrode in each predetermined period by outputting the motion command to said movement means based on a result of the comparison by said comparison means.
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5. A controller for a wire electric discharge machine for performing electric machining by generating electric discharge between a wire electrode and a workpiece while relatively moving the wire electrode and the workpiece to each other, said controller comprising:
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voltage drop determination means for determining a voltage drop of an average machining voltage with respect to a preset no-load voltage in each predetermined period;
movement means for moving the wire electrode relatively to the workpiece along a machining path according to motion commands;
reference value storage means storing a predetermined value representing a voltage drop of a reference average machining voltage with respect to the preset no-load voltage;
means for obtaining a ratio between the voltage drop determined by said voltage drop calculation means and the predetermined value stored in said reference value storage means; and
means for obtaining a motion amount by multiplying a distance of relative motion determined by a preset feed speed and the predetermined period by said ratio, and outputting the obtained motion amount to the movement means as the motion command in each predetermined period. - View Dependent Claims (6)
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Specification