High-Precision Cutting Edge Radius Measurement of Single Point Diamond Tools Using an Atomic Force Microscope and a Reverse Cutting Edge Artifact

At a Glance

Metadata	Details
Publication Date	2020-07-13
Journal	Applied Sciences
Authors	Kai Zhang, Yindi Cai, Yuki Shimizu, Hiraku Matsukuma, Wei Gao
Institutions	Dalian University of Technology, Tohoku University
Citations	12
Analysis	Full AI Review Included

High-Precision Diamond Metrology: Leveraging MPCVD Materials for Nanometric Tool Evaluation

This technical documentation analyzes the research paper, “High-Precision Cutting Edge Radius Measurement of Single Point Diamond Tools Using an Atomic Force Measurement and a Reverse Cutting Edge Artifact,” to highlight the critical role of high-quality diamond materials and connect the metrology requirements to 6CCVD’s advanced MPCVD capabilities.

Executive Summary

This research validates a novel, high-precision method for characterizing the cutting edge radius of Single Point Diamond (SPD) tools, a process highly dependent on the quality and geometry of the diamond material supplied by 6CCVD.

Method Validation: The study successfully implemented an edge reversal method combined with nanoindentation and Atomic Force Microscopy (AFM) to accurately measure SPD tool cutting edge radii.
Convolution Elimination: The technique effectively removes the geometric convolution effect caused by the AFM tip radius (R_tip), a major source of error in traditional nanometric metrology.
Ultra-Low Uncertainty: Measurement uncertainty was verified at an ultra-low level of 1.97 nm (k=2, 95% confidence) for a 1 mm nose radius tool, demonstrating exceptional precision.
Material Requirement: The success of this method relies on the geometric stability and defect-free nature of the SPD tool, requiring Optical Grade Single Crystal Diamond (SCD) blanks.
Process Control: A custom nanoindentation system was designed to control the replication depth precisely (20 nm to 200 nm), ensuring that elastic recovery effects were negligible.
6CCVD Relevance: This research underscores the demand for 6CCVD’s highly polished, custom-dimensioned SCD material for use in next-generation ultra-precision machining and nanometrology standards.

Technical Specifications

The following hard data points were extracted from the experimental results detailing the metrology performance and material parameters:

Parameter	Value	Unit	Context
Tool Nose Radii (Tested)	1 and 2	mm	Single Point Diamond Tools
Workpiece Roughness (RMS)	2.43	nm	Prepolished copper workpiece surface quality
Optimal Indentation Depth Range	20 to 200	nm	Range where elastic recovery is confirmed negligible
AFM Tip Nominal Radius (R_tip)	7	nm	Used for scanning both actual tool and artifact
Measured R_{tool_m} (1 mm tool)	40.32	nm	Convolution radius (before correction)
Corrected R_tool (1 mm tool, $\xi$=0)	30.68	nm	Actual cutting edge radius (approximate)
Measurement Uncertainty (k=2)	1.97	nm	Achieved uncertainty for cutting edge radius
Standard Deviation of Uncertainty	0.005	nm	Calculated across various indentation depths
Cantilever Spring Constant	155	N/m	Aluminum cantilever used for workpiece mounting
Indentation Depth (Test Case)	25	nm	Calculated from sensor outputs (52 nm inside, 27 nm outside)

Key Methodologies

The high-precision measurement relies on a three-step edge reversal process utilizing a custom nanoindentation system and AFM metrology.

Nanoindentation System Design: A specialized system was employed, featuring a Fast Tool Servo (FTS) unit and dual capacitive sensors (inside and outside) to monitor and control the displacement of the diamond tool and the deflection of the cantilever-mounted workpiece.
Artifact Fabrication: The Single Point Diamond (SPD) tool was indented into a prepolished copper workpiece. The indentation depth ($d_{depth}$) was precisely controlled between 20 nm and 200 nm to create a “reverse cutting edge artifact” while ensuring elastic recovery was minimized.
AFM Measurement of Actual Edge: The actual diamond tool cutting edge was scanned by the AFM cantilever. The resulting profile (R_{tool_m}) was recorded as a geometric convolution of the actual edge and the AFM tip radius (R_tip).
AFM Measurement of Reverse Artifact: The replicated reverse cutting edge artifact was subsequently scanned by the same AFM cantilever, yielding R_{mark_m}.
Edge Reversal Calculation: The actual cutting edge radius (R_tool) was calculated using the combined measurements (R_{tool_m} and R_{mark_m}) and the elastic recovery coefficient ($\xi$), effectively eliminating the influence of the AFM tip radius on the final result.

6CCVD Solutions & Capabilities

The successful replication and measurement of nanometric cutting edges demand diamond material with unparalleled purity, surface finish, and geometric stability—core competencies of 6CCVD’s MPCVD manufacturing process.

Research Requirement	6CCVD Material & Service	Technical Alignment & Sales Advantage
High-Purity Diamond Tool Blanks (Required for stable, defect-free cutting edges)	Optical Grade Single Crystal Diamond (SCD)	Our SCD is grown via MPCVD, offering superior purity and crystalline perfection necessary for achieving and maintaining nanometric edge radii in ultra-precision machining.
Extreme Surface Finish (Required for accurate replication and low measurement uncertainty)	Precision Polishing (Ra < 1 nm)	6CCVD guarantees SCD surface roughness of Ra < 1 nm. This finish is crucial for minimizing friction, ensuring accurate geometric transcription during nanoindentation, and reducing tool wear.
Custom Tool Geometry (Tools tested had 1 mm and 2 mm nose radii)	Custom Dimensions & Laser Cutting	We provide custom SCD plates/wafers up to 500 µm thick. Our in-house laser cutting services ensure precise shaping of tool blanks to meet exact geometric specifications (e.g., specific rake/clearance angles).
Integrated Sensor Applications (Future work may require force-sensing tools)	Boron-Doped Diamond (BDD) & Metalization	6CCVD supplies BDD material for creating conductive or semiconducting components, enabling the integration of force sensors directly into the diamond tool shank. We offer custom metalization (Ti/Pt/Au, W, Cu) for electrical contacts.
Large-Area Metrology Standards (Need for larger, highly uniform substrates)	Polycrystalline Diamond (PCD) Wafers	We offer PCD wafers up to 125 mm in diameter, polished to Ra < 5 nm, suitable for use as large-area metrology standards or high-stiffness workpiece materials.

Applicable Materials

To replicate or extend this research, 6CCVD recommends the following materials:

Optical Grade SCD: Essential for the Single Point Diamond tool itself, ensuring the highest possible crystalline quality and polishability required for nanometric edge integrity.
Heavy Boron Doped PCD (BDD): Recommended for developing advanced tool holders or integrated force sensors that require stable electrical conductivity under extreme mechanical stress.

Customization Potential

The paper utilized specific tool geometries and required high-precision alignment. 6CCVD offers:

Custom Metalization: We provide internal metalization capabilities (Au, Pt, Pd, Ti, W, Cu) for engineers needing to integrate sensors or create robust bonding layers on diamond components.
Precision Laser Cutting: We can supply diamond blanks cut to unique dimensions and orientations, optimizing crystal alignment for specific cutting applications, which is critical for minimizing anisotropic wear.

Engineering Support

6CCVD’s in-house PhD team specializes in the material science and application of MPCVD diamond. We can assist with material selection, crystal orientation, and surface preparation for similar ultra-precision machining and nanometrology projects, ensuring the diamond material meets the stringent requirements for sub-2 nm uncertainty.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

This paper presents a measurement method for high-precision cutting edge radius of single point diamond tools using an atomic force microscope (AFM) and a reverse cutting edge artifact based on the edge reversal method. Reverse cutting edge artifact is fabricated by indenting a diamond tool into a soft metal workpiece with the bisector of the included angle between the tool’s rake face and clearance face perpendicular to the workpiece surface on a newly designed nanoindentation system. An AFM is applied to measure the topographies of the actual and the reverse diamond tool cutting edges. With the proposed edge reversal method, a cutting edge radius can be accurately evaluated based on two AFM topographies, from which the convolution effect of the AFM tip can be reduced. The accuracy of the measurement of cutting edge radius is significantly influenced by the geometric accuracy of reverse cutting edge artifact in the proposed measurement method. In the nanoindentation system, the system operation is optimized for achieving high-precision control of the indentation depth of reverse cutting edFigurege artifact. The influence of elastic recovery and the AFM cantilever tip radius on the accuracy of cutting edge radius measurement are investigated. Diamond tools with different nose radii are also measured. The reliability and capability of the proposed measurement method for cutting edge radius and the designed nanoindentation system are demonstrated through a series of experiments.

Tech Support

Original Source

DOI: https://doi.org/10.3390/app10144799

References

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2006 - Nanometer edge profile measurement of diamond cutting tools by atomic force microscope with optical alignment sensor [Crossref]