Scribing Wheel Recess Design for Panel Crack Prevention
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Solution Overview
Problem
Conventional scribing wheels cause significant cracks and reduce the bending strength of flat panels due to their recess structure, leading to increased material consumption and reduced productivity, especially when cutting thin panels for mobile devices.
Innovation Solution
A scribing wheel with a disk shape and a cutter part featuring a combination of side and edge recesses, where the side recesses converge to form a linear structure, reducing stress concentration and allowing precise depth adjustment, is designed to minimize cracks and enhance bending strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional scribing wheels with V-shaped or U-shaped recesses are used, then the cutting process can be performed, but significant cracks are formed in the flat panel and bending strength is markedly reduced
Solution Approach 1:
The patent applies local quality by creating recesses with specific geometric characteristics (rounded bottom, controlled depth, and width) at the cutting edge of the scribing wheel. This local structural optimization prevents stress concentration that would otherwise propagate cracks into the panel, thereby maintaining bending strength while enabling the cutting process.
Solution Approach 2:
The patent changes the geometric parameters of the recesses from conventional V-shaped or U-shaped forms to a specific configuration with a rounded bottom, controlled depth (0.5-6 μm), and width (10 μm or less). This parameter optimization eliminates the corner contact issue that causes stress concentration and crack formation, resolving the contradiction between cutting capability and panel strength.
2Ease of manufacture
If conventional scribing wheels are used, then cutting can be performed, but relatively large cracks are formed in side surfaces of the flat panel requiring additional side surface grinding
Solution Approach 1:
The optimized recess structure with rounded bottom and controlled dimensions prevents stress concentration at the cutting edge, eliminating the formation of large cracks in the side surfaces of the panel. This eliminates the need for additional side surface grinding processes, thereby maintaining productivity while enabling cutting capability.
Solution Approach 2:
The patent extracts and eliminates the harmful effect of stress concentration by redesigning the recess geometry. By removing the corner contact mechanism that causes crack formation, the need for subsequent side surface grinding is eliminated, resolving the productivity issue while preserving cutting capability.
3Ease of manufacture
If conventional scribing wheels with large recesses are used, then cutting can be performed, but the recess structure causes stress concentration in X- and Y-axial directions leading to cracks between axial directions
Solution Approach 1:
The patent applies local quality by optimizing the recess geometry at the cutting edge with a rounded bottom and controlled dimensions. This local structural modification prevents stress concentration in both X- and Y-axial directions, eliminating the harmful effect of crack formation between axial directions while maintaining the cutting process.
Solution Approach 2:
The patent changes the recess parameters from large conventional dimensions to optimized values (depth 0.5-6 μm, width 10 μm or less) with a rounded bottom configuration. This parameter optimization eliminates stress concentration and the resulting crack formation, resolving the contradiction between cutting process capability and harmful stress effects.
Data Source
AI summary
Disclosed herein is a scribing wheel having a predetermined thickness and a disk shape. The scribing wheel includes: a wheel body configured in such a way that at least a peripheral edge portion thereof is gradually reduced in thickness from the center to the radial outside; and a cutter part including recesses and cutting blade teeth which are alternately arranged along the peripheral edge portion. Each recess is formed by a combination of side recess portions formed in opposite side surfaces of the peripheral edge portion of the wheel body and an edge recess portion formed in the peripheral edge of the wheel body.