Transparent Acrylic Timepiece Component Hardening via UV Polymerization
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Solution Overview
Problem
Molded transparent plastic components for timepieces are thick, lack wear resistance, and cannot be produced with sharp angles due to low surface hardness, limiting their use in exterior components where durability and optical properties are required.
Innovation Solution
A method involving the use of a base body made from optically transparent acrylic polymers, covered with layers of polymerizable materials that include acrylic monomers, thermal and photochemical initiators, and additives, which are polymerized and exposed to UV radiation to enhance hardness and durability, allowing for the production of components with sharp angles and improved wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If transparent plastic components are molded to be thin, then production cost is reduced and material independence is achieved, but manufacturing precision and quality reproducibility deteriorate
Solution Approach 1:
The component is divided into two distinct parts: a base body made from transparent plastic material and a surface layer made from glass-forming material. This segmentation allows each part to be optimized independently - the base body can be molded with standard precision while the surface layer provides the enhanced optical and mechanical properties, thus resolving the contradiction between cost reduction and quality reproducibility.
Solution Approach 2:
The invention uses composite materials by combining transparent plastic material with glass-forming material in a layered structure. The glass-forming surface layer provides high precision, durability, and optical quality, while the plastic base body provides cost-effectiveness and design flexibility. This composite approach resolves the contradiction between ease of manufacture and manufacturing precision.
2Shape
If molded plastic components are made with sharp angles, then aesthetic and functional requirements are met, but wear resistance deteriorates due to low surface hardness
Solution Approach 1:
The glass-forming surface layer is applied locally to the surfaces and edges of the component where wear resistance is critical. This local application of hard, scratch-resistant material preserves the sharp angles and aesthetic appearance while providing the necessary durability against wear and environmental factors, resolving the contradiction between shape and reliability.
3Reliability
If surface hardness is increased to improve wear resistance, then durability is enhanced, but optical properties and flexibility may deteriorate
Solution Approach 1:
The glass-forming material undergoes parameter changes through controlled cooling and heat treatment processes that optimize both hardness and optical clarity. By carefully controlling the thermal parameters during manufacturing, the surface layer achieves high wear resistance while maintaining the necessary optical transparency and flexibility for timepiece applications, resolving the contradiction between reliability and adaptability.
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 method achieves high-dimensional precision and surface hardness greater than standard molded plastic components, providing excellent resistance to scratches and abrasion, enabling the production of durable and optically functional timepiece components with enhanced longevity.
Implementation Method 1
These boxes are molded in elastic synthetic rubber or silicone moulds, which are attached to glass plates and then irradiated with UV for 30 seconds to 30 minutes depending on the intensity of the radiation
Data Source
Figure 1~10
Figure 2~8
AI summary
The invention relates to a method for the production and mechanical and/or optical functionalisation of a transparent timepiece component (1), in which: a polymethyl methacrylate body (1, 6) is formed, comprising a lower surface (3) and an intermediate surface (7) that is mechanically and/or optically functionlalised; the body is covered with a layer that is formed by injecting a second polymerisable transparent material (6) into a cavity (14) between a mould (9) and the body (16) or an intermediate body (6A) defined by a complementary intermediate surface (7A) of a contact surface (10) of a previous mould (9), the latter mould (9) being the negative of the upper surface (2) of the component (1); the second material (6) is polymerised; and the component (1) is detached from the flexible mould (9) by deforming the latter. Hardness is enhanced by insulating the component (1) against UV.