Matte Ceramic Watch Parts Surface Roughness Control
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Solution Overview
Problem
Matte ceramic parts used in timepieces and jewelry lose their scratch-proof appeal as they tend to leave marks on softer materials due to their rough surface, which can scratch and fill crevices, giving the impression of being scratched themselves.
Innovation Solution
A manufacturing process involving sintering, sandblasting with corundum particles to create aggressive peaks, and tumbling to achieve a smooth, flat surface that prevents scratching while maintaining the matte appearance, with optional polishing by retrovalization to control roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the ceramic surface is made rough to achieve a matte appearance, then the aesthetic quality is improved, but the ceramic starts to scratch softer materials it comes into contact with
Solution Approach 1:
The patent applies parameter changes by precisely controlling the roughness parameter of the ceramic surface through sandblasting and lapping processes. The surface roughness is optimized to a specific range (Ra 0.2-0.8 μm) that provides matte appearance while minimizing scratching. This involves changing the physical state and texture parameters of the surface through controlled abrasion and smoothing processes.
Solution Approach 2:
The patent applies local quality by creating a specific surface structure with peaks and valleys at controlled dimensions. The sandblasting process creates localized rough features for matte appearance, while the subsequent lapping process selectively smooths the peaks while preserving the valleys, creating a hierarchical surface structure that achieves both aesthetic and functional requirements.
2Illumination intensity
If the ceramic surface is made rough to achieve a matte appearance, then the aesthetic quality is improved, but the crevices of the surface state clog up leaving traces that suggest scratching
Solution Approach 1:
The patent applies parameter changes by precisely controlling the roughness parameter of the ceramic surface through sandblasting and lapping processes. The surface roughness is optimized to a specific range (Ra 0.2-0.8 μm) that provides matte appearance while minimizing scratching. This involves changing the physical state and texture parameters of the surface through controlled abrasion and smoothing processes.
Solution Approach 2:
The patent applies local quality by creating a specific surface structure with peaks and valleys at controlled dimensions. The sandblasting process creates localized rough features for matte appearance, while the subsequent lapping process selectively smooths the peaks while preserving the valleys, creating a hierarchical surface structure that achieves both aesthetic and functional requirements.
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 that matte ceramic parts remain scratch-proof and prevent crevice clogging, allowing objects to slide smoothly without scratching, while retaining the desired matte aesthetic.
Implementation Method 1
step a) is obtained by sintering
Implementation Method 2
step b) consists in sandblasting at least a part of the ceramic part
Implementation Method 3
step c) consists in lapping the ceramic part
Data Source
Figure 1
Figure 2~6
AI summary
The invention relates to a method (1) for manufacturing a matte ceramic part (13, 14, 15, 17, 19) comprising the following steps: a) manufacturing (2) a ceramic part; b) sandblasting (7) parts of the ceramic part to make them matte. According to the invention, the method comprises the following final step: c) grinding (9) the matte parts to smooth the surface finish of the matte parts. The invention relates to the field of watch parts.