Circular Watch Hand Laser Machining Without Vibration Defects
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Solution Overview
Problem
Current manufacturing processes for watchmaking hands with circular sections are limited by geometric defects due to vibration and shifting during laser machining, which is not precise enough for thin and long needles.
Innovation Solution
A method involving a series of laser light modulations in power, geometry, and time to form cylindrical or conical sections in length portions with a diameter ratio less than or equal to 10, preventing vibration and ensuring precision, combined with additional steps for forming a one-piece watchmaking hand with a hole for the movement rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If laser turning process is used to machine thin and long needles, then circular cross-section can be obtained, but vibration and shifting occur causing geometric defects
Solution Approach 1:
The needle is divided into multiple segments along its length, with each segment being a separate component that is then assembled. This segmentation prevents vibration and shifting during laser machining of each individual segment, while the final assembly creates the complete circular cross-section needle. The segmentation allows precise machining of short segments without the instability problems of machining long thin needles in one piece.
2Ease of manufacture
If traditional cutting process is used on metal plate, then manufacturing is easy to implement, but only two-dimensional needles can be produced
Solution Approach 1:
The invention transitions from two-dimensional plate cutting to three-dimensional laser turning machining. By using laser turning process on cylindrical blanks, the method achieves circular cross-sections and three-dimensional needle shapes while maintaining ease of manufacture through automated laser processing. The dimensional change from 2D to 3D manufacturing enables the desired circular cross-section aesthetic.
3Shape
If single-piece circular needle is manufactured by laser turning, then three-dimensional shape is achieved, but vibration causes loss of machining precision
Solution Approach 1:
The single-piece circular needle is divided into multiple segments that are manufactured separately through laser turning and then assembled. Each segment is short enough to avoid vibration during machining, ensuring high geometric precision. The segments are then joined to form the complete three-dimensional needle, combining the benefits of precise machining with the desired three-dimensional shape.
4Shape
If needle is made with high length-to-diameter ratio, then aesthetic appearance is improved, but vibration and shifting increase during machining
Solution Approach 1:
The long thin needle with high length-to-diameter ratio is segmented into multiple shorter components, each with lower length-to-diameter ratio that avoids vibration during machining. The segments are precision-machined individually and then assembled to create the final long needle, preserving both the aesthetic appearance and machining precision.
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 the precise manufacture of three-dimensional needles with circular sections, reducing the risk of geometric defects and enhancing the rigidity and aesthetic appeal of the watchmaking hands, while simplifying assembly by integrating the hole directly into the one-piece design.
Implementation Method 1
a third step consisting of emitting a first modulation of said laser light, for example in power, and/or in geometry, and/or in time; a fourth step consisting of exposing a first portion of said at least one single-piece part to said first modulation of said laser light so as to form at least one first volume of circular section
Data Source
Figure 1~3
Figure 4~7
AI summary
The present invention relates to a watch hand (20) comprising a body of circular section in one piece, and its manufacturing process, the manufacturing process comprising a first step consisting of obtaining a one-piece part of predefined material, the part extending along a longitudinal axis; a second step consisting of rotating said one-piece part; a third step consisting of emitting a first modulation of said laser light in power, geometry and time; a fourth step consisting of exposing a first portion of said at least one one-piece part to said first modulation of said laser light so as to form at least a first volume of circular section of a length L1 and of an average diameter D1, the ratio L1D1 being less than or equal to 20 or 10, or even less than or equal to 5; a fifth step consisting of emitting a second modulation of said laser light in power, geometry and time;and a sixth step consisting of exposing a second portion of said at least one single piece to said second modulation of said laser light, so as to form at least one second volume of circular cross-section of length L2 and average diameter D2, the ratio L2D2 being less than or equal to 10, or even less than or equal to 5.;