EDM Fastener Removal Using Controlled Ligament Segmentation
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Solution Overview
Problem
Existing electrical discharge machining (EDM) technologies face challenges in efficiently separating the head of a fastener from its shank without damaging the frame, particularly in maintaining precise alignment and minimizing external forces required for separation.
Innovation Solution
An EDM device with an erosion electrode configured to create an eroded space within the fastener, defining a ligament of specific thickness, which can be severed by either an external or intrinsic force, allowing for precise separation of the fastener head from the shank without damaging the frame, using a power supply to provide a voltage difference and potentially rotating the electrode for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional EDM methods are used to separate fastener head from shank, then separation can be achieved, but the frame may be damaged and excessive external forces are required
Solution Approach 1:
The invention segments the separation process into two distinct phases: first creating a ligament of controlled thickness that maintains frame integrity, then severing the ligament to complete separation. This segmentation allows the frame to remain intact during the EDM process while minimizing the force needed for final separation.
Solution Approach 2:
The EDM process performs preliminary action by creating a precisely controlled ligament before the actual separation occurs. This ligament serves as a pre-prepared separation plane that requires minimal force to sever, eliminating the need for excessive external forces that would damage the frame.
2Ease of operation
If the erosion electrode creates a large eroded space, then separation is easier, but alignment precision is compromised
Solution Approach 1:
The invention changes the critical parameter from eroded space size to ligament thickness. By controlling the ligament thickness to a specific range (0.010-0.045 inches), the process achieves both ease of separation and alignment precision. The ligament acts as a controlled feature that guides the separation process while maintaining tight tolerances.
3Measurement precision
If the erosion electrode is rotated during advancement, then alignment precision is improved, but the device complexity increases
Solution Approach 1:
The invention merges the rotation function and longitudinal advancement function into a single integrated electrode mechanism. This allows the erosion electrode to simultaneously rotate and advance through the fastener, creating a cylindrical eroded space with precise alignment while using one unified component rather than separate mechanisms.
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 efficient and precise separation of fastener components, minimizing damage to the frame and reducing the need for excessive external forces, while maintaining the structural integrity of the frame and ensuring accurate alignment during the separation process.
Implementation Method 1
an erosion electrode configured to create an eroded space within the fastener
Implementation Method 2
a power supply configured to provide a voltage difference between the erosion electrode and at least one of the fastener and the frame
Data Source
AI summary
A device and method for removal of fasteners by Electro-discharge Machining (EDM) such that portions of the fastener, such as a flange, may be separated from other portions of the fastener, such as a shank.