Single-Crystal Diamond Grinding Below Graphitization Temperature
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Solution Overview
Problem
Current methods for grinding single-crystal diamonds face inefficiencies, low surface accuracy, and significant surface and subsurface damage due to high hardness and brittleness, with traditional mechanical grinding causing micro-cracks and poor surface quality, and thermochemical and friction chemical processing leading to softening of polishing discs and inadequate surface accuracy.
Innovation Solution
A method involving a grinding wheel composed of a base material, active abrasive, and hard abrasive, where the active abrasive reacts with the diamond to form carbides below the graphitization temperature, and the hard abrasive removes these carbides, using a controlled grinding process with a grinding liquid to achieve low surface roughness and minimal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical grinding is used with diamond grinding wheel or powder, then processing simplicity and stability are improved, but processing efficiency is low and surface quality is poor with micro-cracks and scratches
Solution Approach 1:
The invention uses a composite grinding wheel consisting of metal bonding material, active abrasive (reactive to diamond), and hard abrasive (non-reactive). This composite structure enables both chemical reaction for efficient material removal and mechanical abrasion for surface finishing, simultaneously improving processing efficiency and surface quality while maintaining process simplicity.
2Productivity
If thermochemical processing is used, then processing efficiency is improved and surface quality is better, but high temperature causes softening deformation and reduces wear resistance of polishing disc
Solution Approach 1:
The invention changes the temperature parameter by conducting the grinding process at room temperature or low temperature instead of high temperature. The active abrasive reacts with diamond at low temperature to form carbides, which are then removed by hard abrasive, achieving high processing efficiency without the softening deformation and wear resistance issues caused by high temperature.
3Ease of operation
If friction chemical processing is used with dynamic friction method, then processing equipment and environment are improved, but polishing disc softening due to high temperature is not solved and surface accuracy is still poor
Solution Approach 1:
The invention changes the temperature parameter from high temperature (in friction chemical processing) to low temperature or room temperature. This parameter change prevents polishing disc softening, maintains wear resistance, and improves surface accuracy by avoiding thermal deformation while retaining the benefits of chemical reaction for material removal.
4Productivity
If thermochemical processing or friction chemical processing is used to achieve reactive removal through graphitization phase transition, then material removal is achieved, but excessive consumption and excessive damage to diamond cannot be avoided
Solution Approach 1:
The invention uses a controlled phase transition approach where active abrasive reacts with diamond to form carbides at low temperature, which are then mechanically removed by hard abrasive. This controlled reaction-process avoids the uncontrolled graphitization phase transition that causes excessive diamond consumption and damage, achieving efficient material removal with minimal loss.
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 method enhances processing efficiency and surface quality of single-crystal diamonds by avoiding graphitization, reducing surface and subsurface damage, and lowering energy consumption, while maintaining environmental sustainability through the use of deionized water.
Implementation Method 1
the active abrasive comprises a first abrasive configured to react with the single-crystal diamond to form at least one carbide
Implementation Method 2
the hard abrasive comprises a second abrasive configured to remove the at least one carbide
Implementation Method 3
controlling a grinding temperature of surfaces of the active abrasive in the grinding wheel and the single-crystal diamond by controlling a revolution speed of the grinding wheel to enable the grinding temperature to be lower than a graphitization temperature
Data Source
AI summary
Carbon atoms of a single-crystal diamond and active abrasives are used to produce a chemical reaction to form carbides under a specific grinding condition of no higher than a graphitization temperature, and a hard abrasive is used to remove the carbides.