Wire EDM Gap Control Using Speed-Compensated Discharge Voltage
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Solution Overview
Problem
The machining accuracy of a workpiece in wire electrical discharge machines decreases as the difference between the machining speed and setting speed increases, due to a weaker correlation between speed differences and side gaps.
Innovation Solution
A wire electrical discharge machine with a discharge state value acquisition unit, compensation unit, driving unit, and control unit that maintains a constant inter-electrode gap by compensating discharge state values based on machining speed using equations that relate discharge state values to machining speed, ensuring precise control of the wire electrode's movement relative to the workpiece.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the difference between machining speed and setting speed increases, then the machining speed can be adjusted more flexibly, but the machining accuracy decreases due to weaker correlation between speed differences and side gaps
Solution Approach 1:
The patent changes the control parameter from direct speed difference control to discharge state value-based control. By using discharge state values (average inter-electrode voltage, reciprocal of discharge pulses per unit time, or discharge delay time period) as the control parameter, the system can accurately control the side gap even when machining speed differs significantly from setting speed, thus maintaining machining accuracy while allowing flexible speed adjustment.
Solution Approach 2:
The patent implements a feedback control mechanism where the discharge state value is continuously monitored and used to adjust the machining parameters. The control unit acquires the discharge state value, compares it with target values, and adjusts the machining speed accordingly to maintain the desired side gap, creating a closed-loop control system that ensures machining accuracy regardless of speed variations.
2Manufacturing precision
If the side gap is maintained constant through speed control, then machining accuracy is improved, but the control complexity increases due to the need for discharge state value compensation
Solution Approach 1:
The patent introduces the discharge state value as an intermediary parameter that mediates between machining speed and side gap control. Instead of directly controlling the side gap through complex mechanical adjustments, the system uses the discharge state value (electrical parameter) as an intermediary to indirectly control the side gap, simplifying the control mechanism while maintaining precision.
3Speed
If the correlation between speed difference and side gap is weakened, then larger speed variations are possible, but the ability to control side gap precision is reduced
Solution Approach 1:
The patent replaces the mechanical speed-difference-based side gap control with an electrical field-based control system. By using discharge state values (electrical parameters such as voltage, discharge pulse frequency, or discharge delay time) to control the side gap, the system achieves precise control independent of mechanical speed variations, substituting mechanical control with electrical control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves machining accuracy by maintaining a consistent inter-electrode gap regardless of machining speed, enhancing the precision and reliability of the machining process.
Implementation Method 1
generating an electric discharge in an inter-electrode gap between a wire electrode and a workpiece
Data Source
AI summary
A wire electrical discharge machine comprises: an average inter-electrode voltage calculation unit that calculates an average inter-electrode voltage between electrodes; a correction unit that calculates a corrected average inter-electrode voltage, in accordance with a machining speed of a wire electrode with respect to a workpiece; and a motor control unit that makes a dimension between the electrodes during machining constant by controlling an X-axis motor and a Y-axis motor on the basis of the corrected average inter-electrode voltage. The correction unit calculates the corrected average inter-electrode voltage, on the basis of a formula with the average inter-electrode voltage as a numerator, and a value obtained by multiplying a coefficient by the machining speed as a denominator.