Wire EDM Impedance Switching for Core Retaining Current Suppression
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Solution Overview
Problem
Existing wire electrical discharge machines require expensive high-performance power supplies with wide voltage output ranges to suppress machining current during core retaining processes, increasing costs.
Innovation Solution
A wire electrical discharge machine configuration that includes a machining circuit with a switching element and switches to control impedance between the electrode unit and power source, allowing for sufficient suppression of machining current without a wide voltage output range, using a DC current power supply and switching elements like FETs to manage voltage and current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a machining power supply with wide voltage output range is used to suppress machining current during core retaining process, then current suppression capability is improved, but device cost increases
Solution Approach 1:
The patent divides the power supply function into two independent parts: a standard voltage machining power supply and a separate impedance switching circuit. The switching circuit segments the current control function from the voltage generation function, allowing current suppression without requiring the power supply to output wide voltage ranges. This resolves the contradiction by making the power supply configuration simpler while maintaining current suppression capability.
Solution Approach 2:
The patent introduces an impedance switching circuit as an intermediary component between the standard power supply and the electrode gap. This intermediary circuit controls the impedance to suppress machining current during core retaining processes, eliminating the need for the power supply itself to have wide voltage output capability. The intermediary resolves the contradiction by handling current suppression separately from voltage generation.
2Quantity of substance
If voltage is lowered to suppress machining current during core retaining process, then machining current is suppressed, but power supply performance requirements increase
Solution Approach 1:
The patent changes the control parameter from voltage (which would require wide voltage range) to impedance. By controlling impedance through the switching circuit rather than lowering voltage, the power supply can maintain standard voltage output performance while still achieving current suppression. This parameter change resolves the contradiction by decoupling current control from voltage range requirements.
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
Enables effective core welding to the workpiece with an inexpensive configuration by maintaining high impedance during core retaining processes, reducing the need for costly power supplies and ensuring reliable core fixation.
Implementation Method 1
a machining power source (22) for applying a voltage (Vm) across an electrode gap (EG) to flow a machining current
Implementation Method 2
flow a machining current through an electrode gap (EG) formed between a wire electrode (10) and a workpiece (W) to be machined
Implementation Method 3
a switch (SW) for changing impedance between the machining power source (22) and the electrode unit (20)
Data Source
Figure 1
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AI summary
A wire electrical discharge machine (12, 12A to 12C) includes: an electrode unit (20) for supplying a machining current to an electrode gap (EG); a switch (SW) for changing impedance between a machining power source (22) and the electrode unit (20); and a controller (14) for, at the time of a core retaining process, controlling the switch (SW) to set the impedance to be higher than the impedance in a cutting process and thereby suppressing the machining current flowing through the electrode gap (EG).