Problems and solutions of composite machining by electro-diamond methods for materials based on zirconium diboride
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2025-02-28 |
| Journal | Science intensive technologies in mechanical engineering |
| Authors | Andrey Yanyushkin, Dmitry Lobanov, Aleksandr Yanyushkin, Vladimir V. Skripnyak, Vladimir A. Skripnyak |
| Institutions | National Research Tomsk State University, Chuvash State University |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research details the successful implementation and optimization of combined electro-diamond grinding (ECDG) for machining ultra-high-temperature Zirconium Diboride (ZrB2) ceramics.
- Core Achievement: Established rational processing parameters for ECDG of high-strength ZrB2 composites, guaranteeing crack-free surfaces and high precision.
- Efficiency Gain: The combined method reduced diamond wheel consumption by 3 to 4 times compared to traditional grinding, achieving a specific consumption rate of 1.0 to 1.5 mg/g.
- Equipment Upgrade: A standard PP600F grinding machine was modernized with specialized components, including a current collector, a continuous electrochemical truing cathode, and an automated technological current source.
- Process Control: The system utilizes automatic control based on stabilizing cutting power. When the wheel dulls (power increases), the truing current is activated, ensuring continuous self-sharpening operation.
- Quality Output: Machined surfaces exhibited excellent quality, achieving a roughness (Ra) between 0.2 and 0.4 ”m, suitable for most critical engineering applications.
- Mechanism: Continuous electrochemical truing (dressing) of the metallic binder wheel surface prevents clogging and ensures constant renewal of sharp abrasive grains.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Material Processed | Zirconium Diboride (ZrB2) Ceramic | N/A | High-strength composite |
| Melting Temperature (ZrB2) | > 3000 | °C | Material property |
| Grinding Wheel Type | AC6 125/100 M1 | N/A | Diamond wheel on metallic binder |
| Diamond Concentration | 100 | % | Grinding wheel specification |
| Wheel Peripheral Speed (Vgwh) | 35 | m/s | Rational cutting mode |
| Longitudinal Feed (Spr) | 0.5 to 1.5 | m/min | Rational cutting mode |
| Cross Feed (Snon) | 0.02 to 0.05 | mm/double stroke | Rational cutting mode |
| Truing Current Density (ipr) | 0.2 to 0.6 | A/cm2 | Electrochemical dressing process |
| Etching Current Density (iimp) | 4 to 6 | A/cm2 | Electrochemical etching process |
| Surface Roughness (Ra) | 0.2 to 0.4 | ”m | Guaranteed quality of machined surface |
| Diamond Wheel Consumption | 1.0 to 1.5 | mg/g | Consumption rate (3-4x less than traditional) |
| Power Source Frequency (Pulse Mode) | 10-3 to 10-7 | Hz | Alternative pulse mode operation |
Key Methodologies
Section titled âKey Methodologiesâ- Equipment Modernization: A standard PP600F grinding machine was fundamentally upgraded to support combined electro-diamond grinding (ECDG).
- Current Collection System: A specialized current collector was integrated onto the spindle, utilizing three spring-loaded graphite brushes to ensure stable electrical contact with the metallic binder wheel.
- Truing Cathode Installation: A fixed cathode was mounted on the wheel guard in the working zone. Electrolyte is supplied through internal cavities of this cathode, enabling continuous electrochemical truing of the diamond layer.
- Technological Power Source: A dedicated power source was developed, capable of supplying current at standard industrial frequency (50 Hz) or in a pulsed mode (10-3 to 10-7 Hz) for both truing and etching.
- Automated Self-Sharpening Control: An automatic control unit was implemented to stabilize the cutting process. This unit monitors the cutting power (or forces) on the spindle drive. When power exceeds a critical threshold (indicating wheel dulling/clogging), the truing current is automatically activated.
- Electrochemical Truing Mechanism: Activation of the truing current causes anodic dissolution of the metallic binder and the removal of the clogged layer, exposing fresh abrasive grains and restoring the wheelâs cutting capacity (self-sharpening mode).
- Experimental Validation: Experiments were conducted using established standard methodologies, employing optical and scanning electron microscopy (SEM) to analyze the surface relief of the wheel and the integrity (absence of micro/macro cracks) of the machined ZrB2 samples.
Commercial Applications
Section titled âCommercial ApplicationsâThe ability to efficiently machine ultra-hard, high-temperature ceramics opens doors for applications in several critical engineering sectors:
- Aerospace and Defense: Manufacturing components for high-temperature environments, including rocket nozzles, thermal protection systems, and hypersonic vehicle leading edges, leveraging ZrB2âs melting point (> 3000 °C).
- High-Performance Cutting Tools: Producing protective coatings or monolithic cutting inserts made from ZrB2 composites, designed for machining hardened, difficult-to-process, and superalloy steels.
- Chemical Processing Equipment: Fabrication of durable parts requiring high chemical stability and resistance to aggressive media.
- Advanced Machinery: Creation of critical, wear-resistant components for high-temperature technical assemblies where traditional materials fail due to heat or abrasion.
- Tooling and Manufacturing: Providing a viable, cost-effective method for the precision grinding of other ultra-hard ceramic and composite materials used across various high-tech industries.
View Original Abstract
Problematic issues related to the development, machinability and application of new high-strength ceramic materials are viewed. Such materials possess high hardness comparable to the hardness of abrasive materials. Therefore, it makes difficult to produce such materials using traditional techniques. To solve this problem, we have proposed the modernization of the PP 600F machine with the implementation of combined electro-diamond processing of high-strength ceramic materials with diamond wheels on a binder metal. The modernization provides for the development of special components and structures of a current collector, a cathode for straightening a circle, a circuit for a technological current source and constructive solutions for automatic control of the straightening current. Based on the results of the study, rational cutting modes have been established to guarantee the quality of products made of high-strength composite materials. The experiments were performed with standard techniques using optical and electron microscopy. The tasks were solved taking into account the study of diamond wheels flow density on a metallic binder, as well as forces, power, cutting temperature, defects on the surface of the grinding wheel and the machined product. The solution for controlling the cutting capacity of a grinding wheel and the conditions of their operation in the self-sharpening mode is shown. Based on the stabilization of cutting power, the self-sharpening mode of diamond wheels on a metallic binder and grinding modes are switched on:Vgwh = 35 m/s; Spr = 0.5.1.5 m/min; Spr = 0,5âŠ1,5 m/min; Spop = 0,02âŠ0,05 mm/dv.stroke ipr = 0,2âŠ0,6 A/cm2; itr = 4âŠ6A/cm2. Using the example of grinding zirconium diboride with an A C 6 diamond wheel with a grain size of 125/100 in these modes, it guarantees the absence of micro, macro cracks, and the roughness of the machined surface within 0.2âŠ0.4 microns.