Wire EDM Fixture Rotation for Miniaturized Medical Joints
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Solution Overview
Problem
Current methods for manufacturing miniaturized medical instruments with jointed devices face challenges such as increased friction, reduced positioning precision, and difficulties in fabricating precise three-dimensional micromechanical parts, limiting the miniaturization of surgical instruments and increasing the complexity of the manufacturing process.
Innovation Solution
A method using a machining fixture on a wire electrical discharge machine that allows for precise cutting of workpieces on multiple planes without the need for repeated placement, enabling the production of jointed medical instruments with improved precision and reduced manufacturing time while maintaining sterility and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the physical dimensions of medical instruments are reduced for miniaturization, then the instrument size is reduced, but friction forces increase and positioning precision deteriorates
Solution Approach 1:
The patent replaces traditional mechanical cable-driven actuation with a magnetic field-based actuation system. Magnets embedded in the articulating device interact with external magnetic fields to produce motion, eliminating the need for physical cables and guiding channels that cause friction. This substitution of mechanical transmission with magnetic field interaction enables precise positioning in miniaturized instruments without friction-related losses.
Solution Approach 2:
The patent changes the actuation mechanism from mechanical (cable tension) to magnetic (field interaction). By using magnetic fields with controllable strength and direction, the system achieves precise positioning control without the friction constraints that limit mechanical systems at small scales. The magnetic actuation parameters (field strength, gradient, frequency) can be independently controlled to optimize positioning precision.
2Ease of manufacture
If traditional manufacturing methods are used for jointed devices, then the manufacturing process is simple, but friction between guiding channels and cables increases
Solution Approach 1:
The patent eliminates mechanical guiding channels and sliding cables by using magnetic field actuation. The articulating device contains embedded magnets that respond to external magnetic fields, removing the need for physical guidance structures that generate friction. This approach simultaneously simplifies manufacturing (no precision-guiding channels needed) and eliminates friction-related harmful effects.
3Length of moving object
If miniaturization is pursued, then instrument diameter is reduced, but the stiffness of driving members decreases with the second power of diameter
Solution Approach 1:
The patent replaces mechanical driving members (cables, tendons) with magnetic field actuation. Since magnetic field strength does not scale with the second power of diameter like mechanical stiffness, the actuation force remains effective even in miniaturized instruments. The magnetic moments of embedded magnets interact with external fields to produce sufficient torque and force despite the small scale.
4Adaptability or versatility
If complex tendon guiding systems are used, then articulating device functionality is achieved, but the system becomes difficult to miniaturize and has multiple locations of mechanical weakness
Solution Approach 1:
The patent replaces the complex mechanical tendon guiding system with a magnetic field-based actuation system. Embedded magnets in the articulating device segments interact with externally applied magnetic fields to achieve the same articulation functionality. This eliminates multiple guiding channels, sliding interfaces, and mechanical weak points while maintaining full articulating device functionality.
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 enables the production of highly precise, miniaturized medical instruments with enhanced precision and reduced manufacturing time, addressing the limitations of existing methods by allowing for efficient fabrication of jointed devices suitable for extreme miniaturization and maintaining the reliability and sterility required for medical applications.
Implementation Method 1
A method using a machining fixture on a wire electrical discharge machine that allows for precise cutting of workpieces on multiple planes
Data Source
AI summary
A method of manufacturing a jointed device of a medical instrument includes providing a machining fixture on a wire electrical discharge machine having an electrical discharge wire. The fixture includes member holes each adapted to accommodate at least one workpiece, the workpiece being adapted to form a portion of the jointed device of the medical instrument. At least two workpieces each include a first workpiece and a second workpiece, accommodated within at least two member holes of the member holes. The fixture is associated with the wire electrical discharge machine so that the electrical discharge wire can cut at most one workpiece at a time. The machining fixture is rotated around a fixture rotation axis at a predetermined angle, which is chosen to provide that the electrical discharge wire can cut only one workpiece at a time. The workpieces are cut by the electrical discharge wire.