Study of cutting force and tool wear during turning of aluminium with WC, PCD and HFCVD coated MCD tools
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-01-01 |
| Journal | Manufacturing Review |
| Authors | Sisira Kanta Pattnaik, Minaketan Behera, Sachidananda Padhi, Pusparaj Dash, Saroj Kumar Sarangi |
| Institutions | Veer Surendra Sai University of Technology |
| Citations | 7 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive Summaryâ- Core Achievement: Micro-Crystalline Diamond (MCD) films were successfully deposited on Tungsten Carbide (WC-Co) cutting inserts using the Hot Filament Chemical Vapor Deposition (HFCVD) technique.
- Performance Benchmark: The MCD tools were tested against commercial Polycrystalline Diamond (PCD) and uncoated WC tools during the dry turning of rolled aluminum.
- Cutting Force Results: MCD tools consistently generated the lowest cutting forces across most tested conditions, indicating reduced friction and potential for maximum tool life compared to both WC and PCD.
- Surface Finish: MCD tools produced low surface roughness (Ra) values, performing comparably to PCD, especially at higher feed rates (0.18 mm/rev) and medium speeds (250 m/min).
- Wear Resistance: SEM analysis confirmed that MCD inserts exhibited negligible wear, performing significantly better than WC and showing high durability, though slightly higher wear than the premium PCD tool.
- Value Proposition: The MCD tool provides machining performance nearly equivalent to PCD tools but is reported to be five times less expensive, establishing MCD as a superior, cost-effective alternative for nonferrous machining.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Substrate Material | WC-6 wt.% Co (K-10 series) | N/A | Cutting tool insert (SPGN type) |
| Filament Material | Tungsten wire (Ă0.25 mm) | N/A | Carburized HFCVD source |
| Filament Temperature | 2050 ± 50 | °C | HFCVD deposition condition |
| Substrate Temperature | 700 ± 20 | °C | HFCVD deposition condition |
| Chamber Pressure | 20 | Torr | HFCVD reaction pressure |
| Gas Composition | 1% CH4 in H2 | N/A | Carbon source and carrier gas |
| Deposition Time | 8 | hr | Duration of MCD coating process |
| Seeding Powder Size | 0.50 | ”m | Natural Diamond Powder |
| Workpiece Material | Rolled Aluminium | N/A | Diameter 200 mm, Length 600 mm |
| Cutting Speed (v) Range | 200, 250, 325 | m/min | Turning test parameters |
| Feed Rate (f) Range | 0.09, 0.12, 0.18 | mm/rev | Turning test parameters |
| Depth of Cut (d) | 0.2 | mm | Turning test parameter |
| MCD Tool Nose Radius | 0.8 | mm | Geometry specification |
| PCD Tool Nose Radius | 0.4 | mm | Geometry specification |
| Diamond Raman Peak | 1344 | cm-1 | Confirms presence of microcrystalline diamond |
Key Methodologies
Section titled âKey Methodologiesâ- Substrate Cleaning and Etching: WC-Co inserts were ultrasonically cleaned in acetone, followed by chemical etching for 15 minutes using an acid solution (HCl + HNO3 + H2O at 1:1:1 ratio) to remove the cobalt binder from the surface, creating voids for nucleation.
- Diamond Seeding: Samples were seeded ultrasonically for 5 minutes using 0.50 ”m natural diamond powder mixed with isopropanol to maximize nucleation density within the etched surface voids.
- HFCVD Coating: Diamond film was deposited for 8 hours in the HFCVD unit under a 1% CH4 in H2 gas flow, maintaining a chamber pressure of 20 Torr, a filament temperature of 2050 °C, and a substrate temperature of 700 °C.
- Material Characterization: The resulting MCD coating was structurally analyzed using X-ray Diffraction (XRD) and micro Raman Spectroscopy (”-RS), and surface morphology was examined using Scanning Electron Microscopy (SEM).
- Machining Setup: Dry turning tests were conducted on rolled aluminum using a precision Gottwaldov R5 Capstan and turret lathe, comparing the MCD, PCD, and WC inserts under identical cutting conditions.
- Force Measurement: Static and dynamic cutting forces were measured using a Kistler 3D-dynamometer (Model 9257B) coupled with a charge amplifier and LabVIEW software.
- Surface Roughness Measurement: Mean surface roughness (Ra), average peak-to-valley height (Rz), and maximum roughness (Rmax) were measured using a Tylor Hobson Talysurf surface roughness tester.
- Tool Wear Analysis: Tool wear and chip underface morphology were analyzed post-machining (270 seconds duration) using SEM imaging, focusing on the rake and flank faces.
Commercial Applications
Section titled âCommercial Applicationsâ- Nonferrous Machining: Ideal for high-speed, dry turning of aluminum and its alloys, commonly used in aerospace and automotive manufacturing.
- Cost-Effective Tooling: Provides a high-performance, low-cost alternative to expensive Polycrystalline Diamond (PCD) tools, offering significant economic advantages for industrial applications.
- Precision Finishing: Suitable for finishing operations requiring minimal cutting force and excellent surface finish (low Ra values), particularly at high cutting speeds.
- Wear-Resistant Components: Application of HFCVD diamond coatings to components requiring extreme hardness and chemical stability, minimizing abrasive and adhesive wear mechanisms.
- Complex Geometry Coating: HFCVD is noted for its ability to produce uniform coatings with good step coverage, making MCD suitable for coating tools with complex shapes.
View Original Abstract
Enormous developmental work has been made in synthesis of metastable diamond by hot filament chemical vapor deposition (HFCVD) method. In this paper, micro-crystalline diamond (MCD) was deposited on WC-6 wt.% Co cutting tool inserts by HFCVD technique. The MCD coated tool was characterized by the scanning electron microscope (SEM), X-ray diffraction (XRD) and micro Raman spectroscopy (Ό-RS). A comparison was made among the MCD tool, uncoated tungsten carbide (WC) tool and polycrystalline diamond (PCD) tool during the dry turning of rolled aluminum. The various major tests were conducted such as surface roughness, cutting force and tool wear, which were taken into consideration to establish a proper comparison among the advanced cutting tools. Surface roughness was measured during machining by Talysurf. The tool wear was studied by SEM after machining. The cutting forces were measured by Kistler 3D-dynamometer during the machining process. The test results indicate that, the CVD coated MCD tool and PCD tool produced almost similar results. But, the price of PCD tools are five times costlier than MCD tools. So, MCD tool would be a better alternative for machining of aluminium.