Watch Spring Etching Orientation for Stiffness Homogeneity
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Solution Overview
Problem
The existing methods for manufacturing watch springs using etching techniques result in inconsistent stiffness across components from the same plate, leading to dispersion in oscillation frequency and requiring extensive classification and stock management.
Innovation Solution
The method involves etching watch springs with different orientations on an anisotropic material plate to reduce stiffness dispersion, utilizing an etching mask with varied orientations to achieve homogeneous stiffness across components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If etching is performed on a plate of material to manufacture multiple watch springs, then productivity increases, but stiffness dispersion increases due to non-homogeneous etching characteristics
Solution Approach 1:
The patent applies local quality by assigning different orientations to springs at different locations on the etching plate. Specifically, the etching mask is designed so that springs in different zones (e.g., central zone vs. peripheral zones) have different orientations relative to the crystallographic axes of the anisotropic material. This local variation in orientation compensates for location-dependent etching variations, ensuring uniform stiffness across all springs despite non-homogeneous etching characteristics throughout the plate.
2Ease of manufacture
If all springs are made with the same geometry, then manufacturing simplicity is maintained, but stiffness uniformity deteriorates due to etching inhomogeneity
Solution Approach 1:
The patent changes the orientation parameter of springs at different locations on the plate while maintaining geometric consistency. The etching mask is designed with position-dependent orientation parameters, where the angle between the spring axis and the crystallographic axes varies according to the spring's location. This parameter variation compensates for etching inhomogeneity, allowing all springs to have uniform stiffness despite being etched from the same plate with location-dependent etching characteristics.
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 results in a more homogeneous batch of watch springs with reduced stiffness variation, allowing for fewer classes and simplified stock management, improving precision and eliminating the need for extensive pairing with balance wheels.
Implementation Method 1
the plate being made of an anisotropic material in said at least one part of the thickness... Silicon <100> and silicon <110> are anisotropic... the modulus of elasticity varies according to depending on the orientation with respect to the crystallographic axes
Data Source
Figure 1~2
Figure 3~4
Figure 5(a)~5(f)
AI summary
The method for manufacturing watch springs according to the invention includes a step of engraving the watch springs (10) into a plate (14) made of anisotropic material. The engraving is carried out in such a way that the watch springs (10) have different orientations within the plate (14) to reduce their stiffness variation. The invention also relates to an engraving mask for implementing this method.