Polymeric Lapping Media for Sapphire Flatness
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Solution Overview
Problem
Traditional metal lapping plates are heavy, expensive to maintain, and require frequent machining to maintain flatness and parallelism, leading to inefficiencies and increased costs due to downtime and material removal rate inconsistencies.
Innovation Solution
The use of polymeric materials, such as thermoset or thermoplastic foams, attached to a platen with abrasive particles in a slurry, which allows for high and uniform material removal rates from hard surfaces without the need for frequent reworking or replacement of the lapping media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metal lapping plates are used, then flatness and parallelism can be maintained, but the plates become heavy and require frequent machining to restore flatness and parallelism
Solution Approach 1:
The patent changes the material parameter from metal to polymeric foam, which fundamentally alters the wear characteristics. The polymeric foam maintains flatness and parallelism throughout its service life without requiring periodic machining restoration, eliminating the downtime associated with maintaining manufacturing precision.
Solution Approach 2:
The polymeric foam lapping media is designed as a consumable item that is replaced rather than restored. This disposable approach eliminates the time-consuming machining process needed to restore metal plates, as the foam media simply wears uniformly and can be replaced when needed.
2Productivity
If metal lapping plates are used, then lapping can be performed, but material removal rate uniformity decreases over time
Solution Approach 1:
Changing from metal to polymeric foam material alters the wear mechanism. The foam material exhibits more uniform wear characteristics that maintain consistent material removal rates across the substrate surface throughout the media's service life, preventing the uniformity degradation seen with metal plates.
3Loss of time
If polymeric material is used, then downtime and costs are reduced, but material removal rates must remain high and uniform
Solution Approach 1:
The patent optimizes parameters of the polymeric foam including density (0.04-0.2 g/cm³), hardness (10-40 Shore A), and cell structure to achieve the optimal balance between extended service life and maintained material removal rates. The specific foam parameters ensure high and uniform material removal while reducing downtime.
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 polymeric lapping system achieves higher material removal rates with improved uniformity and extended lifespan, reducing downtime and costs associated with lapping processes while producing surfaces with fewer defects.
Implementation Method 1
The lapping plate provides a hard surface for the abrasive particles to roll along as the substrate surface is moved relative to the lapping medium. Material is removed from the substrate surface using relative movement of the media and the substrate, which causes the abrasive particles roll or move. As the abrasive particles move, the particles scratch and/or puncture part of the substrate surface, causing small pieces of the substrate surface to be removed.
Data Source
AI summary
A polymeric material suitable for use in lapping processes, media including the polymeric material, systems including the media, and methods of forming and using the polymeric material are disclosed. The polymeric material can be used to lap hard surfaces, such as sapphire surfaces. The lapping process can be performed after a grinding process and before a polishing process.