Multi-Layer Abrasive Tool for Edge Finishing Cover Glass
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Solution Overview
Problem
Existing abrasive tools for edge finishing of cover glasses in handheld electronics often leave microcracks, leading to reduced strength and require slow, labor-intensive slurry-based polishing processes that are costly and inefficient.
Innovation Solution
The use of abrasive articles with a multi-layer construction, featuring a harder first layer for consistent contact pressure and a softer, more compressible second layer for conformability, which are integrated into a computer-controlled machining system for precise edge finishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If diamond abrasive tools are used for edge finishing, then cutting rate and tool life are improved, but microcracks are created in the cover glass reducing its strength
Solution Approach 1:
The abrasive tool is segmented into multiple functional layers: a support layer, a compliant layer, and an abrasive layer. This segmentation allows each layer to perform its specific function - the support layer provides structural integrity, the compliant layer absorbs stress and conforms to the substrate, and the abrasive layer performs material removal, thereby achieving high cutting rates without creating microcracks
Solution Approach 2:
The tool uses composite material construction with a compliant layer made of elastomeric material having specific durometer hardness (40-80 Shore A). This composite structure combines the hardness needed for effective abrasion with the compliance needed to prevent substrate damage, resolving the contradiction between cutting rate and strength preservation
2Strength
If slurry-based polishing is used to improve edge strength and appearance, then microcracks are reduced, but processing time and labor requirements increase significantly
Solution Approach 1:
The invention merges the functions of cutting and polishing into a single abrasive tool by incorporating both coarse and fine abrasive particles in different layers. The coarse abrasive layer performs material removal while the fine abrasive layer simultaneously polishes the surface, eliminating the need for separate polishing steps and reducing processing time while maintaining edge strength
Solution Approach 2:
The abrasive tool maintains continuous material removal and surface finishing action in a single pass. The compliant layer ensures continuous contact with the substrate surface, allowing simultaneous cutting and polishing operations without interruption, thereby reducing total processing time while achieving the desired edge quality and strength
3Productivity
If a hard abrasive layer is used for material removal, then removal rate is improved, but conformability to the substrate surface decreases
Solution Approach 1:
Different layers of the abrasive tool have different local qualities tailored to their specific functions. The support layer is hard for structural integrity, while the compliant layer is soft (40-80 Shore A durometer) for conformability. The abrasive layer contains particles of varying sizes with different local properties, allowing simultaneous material removal and surface finishing with good conformability to irregular substrate surfaces
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
This approach enhances the consistency of contact pressure and conformability, improving removal rates and extending the tool's lifetime while reducing microcracking and labor costs, resulting in stronger and more cosmetically appealing edges.
Implementation Method 1
The first layer is generally configured to provide contact pressure to the abrasive layer against a substrate
Implementation Method 2
The second layer is generally configured to provide conformability of the abrasive layer to a substrate, such as through a higher compressibility than the first layer
Implementation Method 3
an abrasive layer having a contact surface... operating the computer-controlled machining system to abrade the edge
Data Source
AI summary
The present disclosure provides abrasive articles that include an abrasive layer having a contact surface, a first layer coupled to the abrasive layer, and a second layer coupled to the first layer. The first layer is configured to provide contact pressure to the abrasive layer, such as through a higher hardness than the second layer. The second layer is configured to provide conformability to the abrasive layer, such as through a higher compressibility than the first layer. The resulting abrasive articles may exert a consistent contact pressure against a substrate with increased conformability around the substrate, reduced hysteresis, improved removal rate consistency, and/or improved lifetime over abrasive articles that do not use the multiple layer construction described above.