Precision Clockplate Pivot Pin Manufacturing via Micro-Wire EDM
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Solution Overview
Problem
Traditional methods for manufacturing precision clockplates with pivot pins are costly and complex, particularly when using micro-machining techniques like LIGA, which require large radiation sources and high complexity.
Innovation Solution
The method combines conventional machining to rough-machine pivot pins with micro-wire EDM for finishing, allowing for the creation of precise bearing surfaces with lower costs and complexity, using a precision multi-axis machining center and micro-wire EDM tools to achieve LIGA-like precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional machining methods are used to manufacture precision clockplates, then manufacturing cost and complexity are reduced, but manufacturing precision deteriorates
Solution Approach 1:
The manufacturing process is divided into two distinct stages: rough machining using conventional methods to remove most material, and precision finishing using micro-wire EDM to achieve final tolerances. This segmentation allows each process to be optimized independently, combining the cost-effectiveness of conventional machining with the precision of EDM.
Solution Approach 2:
The rough machining operation is performed first to pre-form the pivot pins to near-final dimensions, removing the bulk of material before the precision finishing operation. This preliminary action reduces the amount of material that needs to be removed in the final EDM operation, improving both efficiency and precision.
2Manufacturing precision
If micro-machining methods like LIGA are used, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts only the essential precision-finishing function from the complex LIGA process by using micro-wire EDM. This eliminates the need for complex radiation sources, photoresist processing, and electroforming steps while maintaining the ability to achieve sub-micron tolerances on pivot pins.
Solution Approach 2:
The patent replaces expensive, complex LIGA equipment with more accessible micro-wire EDM technology. The EDM wire is a simple, replaceable consumable that can be easily replaced if worn, eliminating the need for maintaining complex radiation sources and specialized equipment.
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 precision clockplates with tolerances comparable to LIGA methods at significantly lower costs and complexity, achieving final diameters with tolerances of +/-0.0002 inches, suitable for miniature devices like watches and medical instruments.
Implementation Method 1
micro-wire electrical discharge machining (EDM) to form precise bearing surfaces on pivot pins
Data Source
AI summary
Methods are disclosed for producing a precision clockplate with rotational bearing surfaces (e.g. pivot pins). The methods comprise providing an electrically conductive blank, conventionally machining oversize features comprising bearing surfaces into the blank, optionally machining of a relief on non-bearing surfaces, providing wire accesses adjacent to bearing surfaces, threading the wire of an electrical discharge machine through the accesses and finishing the bearing surfaces by wire electrical discharge machining. The methods have been shown to produce bearing surfaces of comparable dimension and tolerances as those produced by micro-machining methods such as LIGA, at reduced cost and complexity.