Wire Electrode Cooling for EDM Cutting Stability
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Solution Overview
Problem
Existing wire-cut electric discharge machines face issues with electrode damage and decreased automatic wire connection success rates due to the generation of wire metal powder during cutting operations, leading to unstable contact and frequent minute discharges, which shorten the device's lifespan and affect connection quality.
Innovation Solution
The implementation of an upper and lower wire guide system with first and second wire electrode cutting energizing electrodes, a tensile force imparting mechanism, and a cooling system using compressed air or cooling water to prevent wire metal powder generation by locally cooling the contact areas between the wire electrode and cutting electrodes during the cutting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wire electrode is cut by annealing with energizing electrodes, then cutting operation is completed, but wire metal powder is generated and attaches to electrodes causing unstable contact
Solution Approach 1:
The harmful wire metal powder is extracted and removed from the contact area by blowing inert gas (nitrogen or carbon dioxide) through nozzles positioned near the energizing electrodes. This prevents the powder from attaching to the electrodes and maintaining stable electrical contact during and after the cutting operation.
Solution Approach 2:
Inert gas (nitrogen or carbon dioxide) is introduced as an intermediary substance to blow away the wire metal powder generated during cutting. This mediator prevents direct contact between the harmful powder and the energizing electrodes, eliminating the cause of unstable contact and minute discharges.
2Productivity
If wire metal powder attaches to electrode surfaces, then cutting can be performed, but minute discharges occur frequently reducing device lifespan
Solution Approach 1:
The inert gas flow, initially intended only to remove wire metal powder, is utilized to simultaneously cool the energizing electrodes. This converts a simple cleaning function into a dual-purpose system that both removes harmful powder and provides beneficial cooling, preventing electrode overheating and extending electrode lifespan.
Solution Approach 2:
Inert gas serves as an intermediary that not only removes wire metal powder but also acts as a cooling medium for the energizing electrodes. This dual-action intermediary prevents both contact instability and thermal damage to the electrodes.
3Manufacturing precision
If cooling air is supplied to control cutting position and straightness, then wire electrode is cooled down, but wire metal powder still generates at contact points
Solution Approach 1:
The cooling function is segmented into two separate systems: cutting air for cooling the wire electrode to control cutting position and straightness, and inert gas for removing wire metal powder from the electrode contact areas. This segmentation allows each system to perform its specific function without interfering with the other.
Solution Approach 2:
Different gas types are applied to different locations: cutting air is supplied to cool the wire electrode along its path, while inert gas is blown specifically at the contact points between the wire electrode and energizing electrodes to remove generated powder. This local differentiation addresses both cooling and powder removal needs effectively.
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 solution effectively suppresses the attachment of wire metal powder on cutting electrodes, reducing minute discharges and extending the electrode's lifespan, thereby maintaining a stable connection success rate and preventing electrode damage, as demonstrated by an increase in continuous running tests from approximately 200 to over 2000 times.
Implementation Method 1
the wire electrode is energized. Then, cutting tension is generated on the wire electrode, which is softened by heat generated by electric resistance
Implementation Method 2
tensile cutting is performed while maintaining the heat-generation part on a given position close to a nozzle outlet by cooling air or cooling water inside of an upper pipe
Data Source
AI summary
In a wire electric discharge machine in which chuck part electrodes that hold a wire electrode are provided on the upper side of an upper wire guide and electrodes of a detecting part are provided on a lower stream side of the chuck part electrodes, a part, which contacts with the chuck part electrodes, of a surface of the wire electrode is hardened by locally cooling down the part by air blowing during energization to the wire electrode. Accordingly, wire metal powder is hardly generated from the wire electrode even though the wire electrode rubs against the chuck part electrodes.