G1300103 Effect of Saw Wire Surface Texture on Slicing Performance of Rock in Vacuum

At a Glance

Metadata	Details
Publication Date	2015-01-01
Journal	The Proceedings of Mechanical Engineering Congress Japan
Authors	Katsushi Furutani, Kazuki Nomura, Tatsuaki Okada, Kazuto Saiki, Hiroyuki OHUE
Institutions	Toyota Technological Institute
Analysis	Full AI Review Included

Technical Documentation & Analysis: Diamond Slicing in Vacuum Environments

Research Paper Analyzed: G1300103: Effect of Saw Wire Surface Texture on Slicing Performance of Rock in Vacuum (Furutani et al., 2015)

Executive Summary

This research investigates the critical challenges of using diamond wire saws for rock sampling (Basalt, simulating lunar material) in high-vacuum environments, directly supporting future JAXA space exploration missions (SLIM/UZUME).

Core Challenge: Machining depth significantly decreases in vacuum (10³ Pa) compared to air, primarily due to the Nickel (Ni) electroplating bond material adhering to the rock surface.
Performance Drivers: Increased machining depth correlates strongly with saw wire surface texture, specifically high diamond grit exposure, strong grit retention, and low grit density.
Density Impact: Low grit density increases the localized pressure per grit, enhancing cutting efficiency, which is a key factor in overcoming the adhesion issue in vacuum.
Material Failure: Full-coated wires (where Ni is most exposed) showed the largest performance drop in vacuum, confirming the Ni bond as the primary failure mechanism in this extreme environment.
6CCVD Value Proposition: This research underscores the need for ultra-high-purity, robust diamond materials and advanced bonding techniques (non-Ni based) for space-grade tooling, a requirement perfectly met by 6CCVD’s custom MPCVD Single Crystal (SCD) and Polycrystalline (PCD) diamond solutions.

Technical Specifications

The following hard data points were extracted from the experimental setup and results:

Parameter	Value	Unit	Context
Vacuum Pressure	10³	Pa	Simulated space environment
Specimen Material	Basalt	N/A	Lunar rock simulant (Shizuoka, Japan)
Cutting Load	1.6	N	Constant applied force
Saw Wire Tension	2.0	N	Constant tension
Wire Speed (Range)	0.1 to 1.0	m/s	Tested machining speeds
Core Wire Diameter	0.20	mm	Standard wire core
Diamond Grit Size (Range)	30-40, 40-60	µm	Used in Ni-plated and Resin-bonded wires
Max Plating Thickness (Exposed A)	31.09	µm	Nickel electroplating thickness
Min Plating Thickness (Exposed B)	10.59	µm	Nickel electroplating thickness
Max Grit Density (Exposed C)	1678	1/mm²	Highest density tested
Performance Ratio (Vacuum/Air)	0.4 to 0.7	N/A	Ratio of machined depth, indicating performance drop
Temperature (Inferred)	Not high enough	°C	Temperature did not rise high enough to soften Ni bond

Key Methodologies

The experiment utilized a custom wire-sawing prototype designed for vacuum operation to test the influence of diamond wire surface texture on cutting performance.

Equipment Setup: A compact wire-sawing machine (370×110×198 mm) was placed inside a vacuum chamber, driven by external AC servomotors.
Specimen: 10×15×15 mm Basalt samples were used to simulate the composition of lunar mare rock.
Wire Types: Five distinct diamond wire types were tested, categorized by their bonding method (Nickel electroplated vs. Resin bond) and surface texture (Plating thickness and Grit Density).
Dressing Procedure: Coded wires were subjected to 10 reciprocations of cutting in air (dressing) to ensure initial exposure of the diamond grits from the Nickel coating prior to vacuum testing.
Machining Parameters: Tests were conducted under low-power conditions (1.6 N cutting load, 2.0 N wire tension) across various wire speeds (0.1, 0.5, 1.0 m/s) for 15 reciprocations.
Analysis: Machining depth was measured to quantify performance. Energy Dispersive X-ray Spectroscopy (EDS) was used to confirm the transfer and adhesion of Nickel bond material onto the rock surface in the cutting groove.

6CCVD Solutions & Capabilities

The research clearly identifies the Nickel electroplating bond as the primary limiting factor for diamond tooling in high-vacuum, low-load rock cutting applications. 6CCVD specializes in providing high-purity, robust diamond materials necessary to engineer next-generation tools that eliminate or mitigate metallic bond failure.

Applicable Materials for Extreme Environments

To replicate or extend this research, focusing on tools that minimize contamination and maximize grit retention in vacuum, 6CCVD recommends:

Optical Grade Single Crystal Diamond (SCD): For applications requiring ultimate purity, hardness, and thermal stability. SCD can be micro-machined into precise cutting geometries (e.g., micro-milling heads or specialized cutting edges) that eliminate the need for traditional electroplated bonds entirely.
High Purity Polycrystalline Diamond (PCD): Ideal for large-area tools or components requiring exceptional toughness and wear resistance. 6CCVD’s PCD is manufactured with superior control over grain size and purity, offering a robust alternative for advanced sintering or brazing techniques that utilize non-contaminating binders.
Boron-Doped Diamond (BDD): While not directly used for cutting in this study, BDD plates offer superior electrochemical stability and conductivity, making them excellent candidates for integrated sensors or actuators within the complex wire-sawing mechanism operating in vacuum.

Customization Potential for Advanced Tooling

6CCVD’s in-house capabilities directly address the need for highly customized, contamination-resistant diamond components:

Research Requirement	6CCVD Custom Capability	Benefit to Customer
Bond Failure (Ni Adhesion)	Custom Metalization Services: Au, Pt, Pd, Ti, W, Cu	Allows engineers to prototype non-Nickel bonding layers (e.g., Ti/Pt/Au stacks) for high-temperature brazing, ensuring superior grit retention and eliminating vacuum adhesion issues.
Precise Geometry/Density	Custom Dimensions & Laser Cutting: Plates/wafers up to 125mm (PCD)	Enables the fabrication of specialized, high-precision diamond cutting inserts or micro-tools where grit exposure and density are controlled by design, not by electroplating variability.
Surface Finish	Ultra-Low Roughness Polishing: Ra < 1nm (SCD), Ra < 5nm (PCD)	Provides highly polished diamond surfaces for low-friction guides or wear components within the vacuum mechanism, reducing parasitic drag and contamination.
Thickness Control	SCD/PCD Thickness Control: 0.1µm to 500µm	Supplies diamond material with exact thickness specifications required for integration into complex, miniaturized space hardware.

Engineering Support

6CCVD’s in-house PhD team specializes in the material science of MPCVD diamond for extreme environments. We offer consultation services to assist engineers in selecting the optimal diamond grade, thickness, and metalization scheme required to transition from traditional electroplated wires to robust, contamination-free diamond tools suitable for Lunar and Planetary Rock Slicing and other high-vacuum applications.

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

View Original Abstract

The performance of wire-sawing of rock in vacuum has been investigated for future lunar and planetary explorations. The machining amount was decreased with a decrease of the vacuum pressure. Nickel to fix diamond grits on a core wire adhered on a rock specimen in vacuum and the rock was hardly cut in the end. In this report, the slicing performance was tested with various saw wires. The machining depth was increased with an increase of feeding speed of the saw wire in air. The machining depth in vacuum, however, did not depend on the feeding speed. The exposure of the grits from the electroplated nickel, large gripping force of the grits and increasing the pressure due to the low grit density increased machining depth.

Tech Support

Original Source

DOI: https://doi.org/10.1299/jsmemecj.2015._g1300103-