Nanocrystalline Diamond Probe Tip for CMM Dimensional Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Probes with polycrystalline diamond layers used in coordinate measuring machines face issues with dimensional stability and delamination under mechanical stress, leading to unreliable measured values due to heterogeneous layer morphology and mechanical stresses.
Innovation Solution
A probe with a test body featuring a finely crystalline diamond layer having an average grain size of ≤100 nm, which ensures isotropic properties, reduced modulus of elasticity, and increased transverse rupture stress, minimizing delamination and enhancing mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polycrystalline diamond layer is applied to the test body, then hardness and corrosion resistance are improved, but dimensional stability deteriorates and delamination occurs under mechanical stress
Solution Approach 1:
The invention changes the critical parameter of grain size from micrometer scale (conventional polycrystalline diamond) to nanometer scale (≤100 nm, preferably ≤50 nm). This parameter change transforms the material structure from heterogeneous to homogeneous, eliminating the columnar grain growth that causes dimensional instability and delamination while preserving the hardness and corrosion resistance of diamond.
Solution Approach 2:
The invention creates a composite structure at the nanoscale by combining diamond crystallites with grain boundaries distributed throughout the layer. The nanocrystalline composite structure achieves a balance between the hardness of diamond crystallites and the stress-distributing effect of numerous grain boundaries, preventing the formation of large-scale cracks that lead to delamination in conventional polycrystalline diamond layers.
2Strength
If a polycrystalline diamond layer is applied to the test body, then surface hardness is improved, but reliability deteriorates due to delamination under point load
Solution Approach 1:
By changing the grain size parameter to the nanometer scale (≤100 nm), the invention eliminates the columnar grain structure that propagates cracks under point loads. The refined grain structure distributes stress more uniformly throughout the layer, preventing delamination and ensuring reliable measurements even under repeated point contact conditions in coordinate measuring machines.
3Ease of manufacture
If a crystalline diamond layer with larger grain size is used, then manufacturing is easier, but measurement precision deteriorates due to heterogeneous layer morphology
Solution Approach 1:
The invention adopts a nanometer-scale grain size parameter (≤100 nm) that creates a homogeneous layer morphology throughout the diamond coating. This homogeneous structure eliminates variations in material properties across the layer, ensuring consistent measurement precision while the CVD deposition process remains practically feasible with optimized processing conditions.
4Strength
If a polycrystalline diamond layer is applied, then corrosion resistance is improved, but dimensional stability worsens leading to shape errors
Solution Approach 1:
By reducing the grain size to the nanometer scale (≤100 nm), the invention creates a homogeneous nanocrystalline structure that maintains dimensional stability while preserving corrosion resistance. The fine-grained structure prevents the formation of large-scale defects and ensures uniform material properties, eliminating shape errors during measurements while maintaining the protective corrosion-resistant characteristics of diamond.
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 finely crystalline diamond layer provides improved dimensional stability, reduced surface roughness, and increased reliability by matching the modulus of elasticity with the substrate, allowing for more accurate and reproducible measurements under high mechanical stress.
Implementation Method 1
The nanocrystalline diamond layer of the invention is distinguished by the fact that it has a modulus of elasticity of 1000 GPa... the modulus of elasticity is also significantly reduced compared to polycrystalline diamond layers, so that better adaptation to the modulus of elasticity of the substrate is ensured... a 'more elastic' diamond layer that can better absorb deformation of the test specimen
Data Source
Figure 1a~1c
Figure 2
Figure 3
AI summary
The probe has processor that is connected to base of specimen. A surface of the specimen provided with crystalline diamond layer is engaged with component to be measured for measuring specific thickness, average particle size, and elasticity modulus of the component. The crystalline diamond layer is provided with fine crystalline diamond structure equipped with crystalline domains. An independent claim is included for a ball bearing.