Watch Dial Overmoulding for Scratch-Free Pattern Formation
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Solution Overview
Problem
Existing dial manufacturing processes face issues with aesthetic appearance, defects, scratches, and robustness, particularly in machining operations for watch dials.
Innovation Solution
A process involving a reversible mould assembly, over-moulding with injectable material, and coating application to create durable and versatile watch dials with patterns, using a system that includes a support plate design, mould construction, and temperature regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional machining operations are used to create patterns on dial surfaces, then manufacturing precision can be achieved, but the dial surface becomes susceptible to defects and scratches that compromise aesthetic appearance and robustness
Solution Approach 1:
The patent replaces traditional mechanical machining operations with an overmolding process where a patterned insert is embedded into the dial material. This substitution eliminates contact between cutting tools and the dial surface, preventing scratches and machining defects while maintaining precise pattern reproduction through the molded insert geometry
Solution Approach 2:
The patent uses a patterned insert that serves as a mold to copy the desired pattern design onto the dial surface through overmolding. This copying approach reproduces the pattern without direct mechanical contact, avoiding the harmful effects of machining while achieving the required manufacturing precision
2Ease of manufacture
If appliques are produced using transfer or silkscreen operations on the bottom surface of the dial, then pattern production is achieved, but the aesthetic appearance and robustness are compromised
Solution Approach 1:
The patent merges the pattern creation process with the dial manufacturing process itself by embedding the patterned insert into the dial material through overmolding. This integration eliminates separate applique application steps while producing durable, aesthetically pleasing patterns that are structurally integrated into the dial rather than applied as surface coatings
Solution Approach 2:
The patent transitions from two-dimensional surface printing (silkscreen/transfer) to three-dimensional overmolding where the patterned insert extends through the dial thickness. This dimensional change creates more robust patterns that are part of the dial structure rather than surface decorations, improving both durability and aesthetic quality
3Ease of manufacture
If stamping and gluing operations are used to produce appliques on the visible surface, then pattern creation is achieved, but the robustness and aesthetic appearance are degraded
Solution Approach 1:
The patent combines the pattern insert and dial into a single integrated structure through overmolding, eliminating the need for separate gluing operations. This merging creates a robust construction where the pattern is structurally bonded to the dial material rather than attached with adhesives that can fail over time
Solution Approach 2:
The patent incorporates the patterned insert into the dial during the manufacturing process itself, before the dial is finalized. This preliminary integration ensures the pattern becomes an inherent part of the dial structure, providing long-term reliability without the need for subsequent attachment operations that could compromise robustness
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
Produces high-quality watch dials with durable patterns that address aesthetic and robustness concerns, ensuring defect-free and visually appealing results.
Implementation Method 1
a construction of a blank of each pattern on the visible face of the dial blank, said step comprising a sub-step of over-moulding by injecting an injectable material into the cavity via a through opening arranged in said dial blank provided with an entry orifice of said cavity
Implementation Method 2
the over-moulding sub-step comprises a phase of regulating the temperature of said mould particularly during a period spreading from before the start of the phase of injecting injectable material into the cavity to the end of this material injection phase or after this end of this injection phase
Implementation Method 3
the over-moulding sub-step comprises a phase of evacuating said cavity before the phase of injecting the injectable material into this cavity
Implementation Method 4
the application sub-step comprises a phase of depositing a decorative and/or functional material on a visible outer face of the blank of the pattern over-moulded on the dial blank
Data Source
AI summary
A process for manufacturing a watch dial including at least one pattern on a visible face of the dial, the process including: a step of designing a support plate including a dial blank, this step including producing several through holes in the thickness of the body of a support plate, the holes delimiting in such a plate the edge of the dial blank, and a step of producing at least one pattern on a visible face of the dial blank during which step the following is performed: an arrangement of this support plate including the external part element in a mould, and a construction of a blank of each pattern on the visible face of the dial blank, as well as a finalisation of the blank of the pattern.