Watch Dial Overmolding for Scratch-Free Appliqué Formation
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Solution Overview
Problem
Existing dial manufacturing processes for watches are unsatisfactory in terms of aesthetic appearance, absence of defects or scratches, and robustness, particularly in creating appliqués on watch dials.
Innovation Solution
A method and system for manufacturing a watch dial that involves overmolding a decorative and/or functional material onto a dial blank using a reversible mold assembly, combined with temperature and vacuum control, and application of coatings to enhance durability and aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional machining operations are used to create appliqués on the dial, then the manufacturing process is simple and well-established, but the dial surface develops defects and scratches that compromise aesthetic appearance and robustness
Solution Approach 1:
The patent replaces traditional mechanical machining operations with an injection molding process. The mold directly forms the appliqués and dial features through injection of material into a cavity, eliminating mechanical contact that causes scratches and defects. This substitution of the manufacturing mechanism resolves the contradiction by achieving high robustness without the harmful effects of machining.
Solution Approach 2:
The patent changes the fundamental manufacturing parameter from mechanical removal/deformation to thermal and pressure-controlled injection. By controlling injection pressure, temperature, and mold cavity design, the process achieves complex three-dimensional appliqués without surface defects, resolving the contradiction between robustness and manufacturing simplicity.
2Reliability
If decals or screen printing are used to apply patterns, then the process is straightforward, but the aesthetic appearance and durability are insufficient
Solution Approach 1:
The patent merges the pattern application step with the base dial formation step into a single injection molding operation. The mold cavity integrates both the dial blank and the decorative patterns/appliqués, so that one injection process simultaneously creates the entire dial assembly with integrated decoration. This eliminates the need for separate decal or screen printing steps while achieving superior durability and aesthetics.
Solution Approach 2:
The patent uses composite material injection where the injectable material may include pigments, fillers, or multi-layer materials that provide both structural and decorative functions. This allows the dial to achieve enhanced aesthetic appearance and durability through material composition rather than surface application, resolving the contradiction between quality and process complexity.
3Reliability
If stamping and bonding metal plates are used to create appliqués, then the process is well-established, but the robustness and aesthetic appearance are compromised
Solution Approach 1:
The patent merges the appliqué creation and attachment steps into a single injection molding operation. The injected material forms the appliqués directly in their final position, bonded to the dial blank through the molding process itself, eliminating separate stamping and bonding operations. This achieves superior robustness through monolithic formation while maintaining manufacturing efficiency.
4Manufacturing precision
If overmolding is used to apply patterns, then aesthetic appearance improves, but the process complexity and control requirements increase
Solution Approach 1:
The patent designs the mold to perform multiple functions simultaneously: forming the dial blank, creating appliqués, applying decorative patterns, and integrating ventilation holes all in one injection operation. This multi-functional mold design achieves high manufacturing precision for aesthetic appearance while consolidating process control rather than increasing it, as all features are created in a single controlled injection cycle.
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
The process ensures high-quality, durable, and versatile watch dials with improved aesthetic appearance and robustness by minimizing defects and scratches, while allowing for the integration of decorative and functional materials.
Implementation Method 1
The overmolding substep includes a vacuum phase for said cavity before the injection phase of injectable material into this cavity
Implementation Method 2
the overmolding substep includes a temperature control phase for said mold, particularly during a period extending from before the start of the injection phase of injectable material into the cavity until the end of this injection phase, or even after the end of this injection phase
Data Source
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AI summary
One aspect of the invention relates to a method for manufacturing a watch dial (4) (100) comprising at least one motif (10) on a visible face (21a) of the dial (4), said method comprising: - a design step (25) of a support plate (3) comprising a dial blank (4), said step (25) comprising the making (26a) of several through holes in the thickness of the body of the support plate, said holes delimiting in the plate the edge of the dial blank, and - a making step (29) of at least one motif on a visible face of said dial blank during which step (29) is carried out: an arrangement (33) of this support plate (3) in a mold (2), said arrangement step (33) comprising a sub-step of forming (36) at least one cavity (7) in this mold (2), and a construction (37) of a blank (20) of each motif (10) on the visible face (21a) of the dial blank (4),as well as a finalization (42) of the draft (20) of the motif (10).