Watch Balance Spring Geometry Optimization for Mass Production
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Solution Overview
Problem
Hairsprings in timepieces are sensitive to manufacturing and assembly defects, leading to operational deviations and difficulty in adjustment, which affects chronometric performance and makes them less suitable for mass production despite advantages like resistance to magnetic fields.
Innovation Solution
A method for manufacturing hairsprings that involves defining a digital model with adjustable variables, identifying optimal geometry to minimize performance sensitivity to defects, and manufacturing hairsprings with a geometry that reduces the impact of defects, ensuring robust operation even with manufacturing and assembly defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hairsprings are made from specific materials and/or using specific processes to allow complex shapes with variable thicknesses, then suitability for mass production and resistance to magnetic fields are improved, but sensitivity to manufacturing and assembly defects increases and reworkability decreases
Solution Approach 1:
The patent applies preliminary action by defining a numerical model with adjustment variables before manufacturing, and identifying optimal values that provide minimum sensitivity to defects. This pre-planning allows the hairspring geometry to be optimized in advance to compensate for potential manufacturing variations, enabling mass production while maintaining reliability.
Solution Approach 2:
The patent utilizes parameter changes by modifying the geometry parameters of the hairspring (such as thickness distribution, coil spacing, and shape characteristics) to achieve optimal performance. By adjusting these parameters within the numerical model, the invention finds configurations that are less sensitive to manufacturing defects, thus resolving the contradiction between mass production suitability and defect sensitivity.
2Object-affected harmful factors
If hairsprings are made from specific materials and/or using specific processes to allow complex shapes with variable thicknesses, then resistance to magnetic fields is improved, but ease of rework and adjustment decreases
Solution Approach 1:
The patent applies preliminary action by pre-defining optimal geometric parameters in the numerical model that compensate for potential defects. This allows the hairspring to be designed with built-in tolerance to manufacturing variations, eliminating the need for post-manufacturing adjustments or rework, thus improving ease of repair while maintaining magnetic field resistance.
Solution Approach 2:
The patent implements self-service by designing the hairspring geometry to automatically compensate for manufacturing defects through its optimized parameters. The numerical model identifies configurations where the hairspring's own geometric characteristics provide immunity to defects, making the component self-correcting and eliminating the need for external adjustment or repair interventions.
3Ease of repair
If traditional hairspring manufacturing methods are used, then ease of rework is maintained, but performance deviations due to manufacturing defects increase
Solution Approach 1:
The patent applies preliminary action by defining a numerical model with adjustment variables and identifying optimal values before manufacturing. This pre-optimization ensures that the hairspring geometry is specifically designed to minimize performance deviations from manufacturing defects, achieving high manufacturing precision while maintaining the ability to rework if needed.
Data Source
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AI summary
The invention relates to a method for manufacturing watch balance springs (10) that may have at least one manufacturing and/or assembly defect with other components, comprising the following steps: - (100) defining a numerical model representing a balance spring (10) that one wishes to obtain, said model having a plurality of adjustment variables, - (200) defining at least one performance indicator, representative of a desired behavior for the balance spring (10), - (300) identifying at least one optimal value for at least one adjustment variable, the optimal value providing a minimum sensitivity of the performance indicator to said at least one manufacturing and/or assembly defect, - (400) manufacturing at least one balance spring (10) with a geometry defined as a function of said at least one optimal value.The invention also relates to a spiral (10) whose particular geometry provides a minimum sensitivity of the performance indicator to said at least one manufacturing and/or assembly defect of the spiral (10).