An Analysis of the Wear of Tungsten Carbide and Polycrystalline Diamond Inserts Turning Ti-6Al-4V

2011 ◽  
Author(s):  
David Schrock ◽  
Xin Wang ◽  
Patrick Kwon
Keyword(s):  
Thermal Conductivity ◽  
Grain Size ◽  
Tool Wear ◽  
Flank Wear ◽  
Polycrystalline Diamond ◽  
Laser Scanning Microscopy ◽  
Rake Face ◽  
Crater Wear ◽  
Pcd Tools ◽  
Face Temperature

Dry turning experiments on Ti-6Al-4V were conducted using two grades (finer and coarser) of carbides and polycrystalline diamond (PCD) inserts to study tool wear. Despite of minor compositional difference between two carbide grades, both grades contain 6% Co. Crater wear and flank wear were measured using Confocal Laser Scanning Microscopy (CLSM). Three dimensional rake surface topographies were reconstructed from the CLSM data and wear profiles were extracted. Finite Element Analysis (FEA) was conducted to study the effects of cutting conditions and thermal properties on rake face temperature. Flank wear on the carbide tools indicated that the inserts with the finer grain size exhibited smaller flank wear than the insert of the coarser grain size. This was attributed to reduced abrasive wear in the finer grained inserts as a result of a higher hardness. The carbide grade with a coarser grain size had an enhanced ability to resist crater wear, likely from lower rake face temperatures and the differences in the compositions. It is known that coarser grain carbides have a higher thermal conductivity resulting from increased grain contiguity. FEA was used to study the temperature difference between the two grain-sizes and the effect of thermal conductivity on temperature gradients. Tool wear of the PCD inserts was also studied. The PCD tools showed significant adhesive wear at the 200sfm cutting speed, transitioning to crater wear at 400sfm. With a high thermal conductivity, it is possible that rake face temperatures were low enough to alter the wear mechanism. FEA supports this hypothesis, as the maximum rake face temperature for the PCD inserts were only around 900°C at 200sfm.

Phase Dependent Tool Wear in Turning Ti-6Al-4V Using Polycrystalline Diamond and Carbide Inserts

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
David J. Schrock ◽  
Di Kang ◽  
Thomas R. Bieler ◽  
Patrick Kwon
Keyword(s):  
Phase Transformation ◽  
Tool Wear ◽  
Cutting Speed ◽  
Polycrystalline Diamond ◽  
Alpha Phase ◽  
Laser Scanning Microscopy ◽  
Phase Transformation Temperature ◽  
Rake Face ◽  
Work Material ◽  
Pcd Tools

Tool wear of polycrystalline diamond inserts was analyzed in turning experiments on Ti-6Al-4V. Evidence of phase transformation in turning titanium work material is presented and its impact on tool wear is discussed. Confocal laser scanning microscopy was used to analyze the rake face of the turning inserts. At cutting speed of 61 m/min, the rake face exhibited scalloped-shaped, fractured wear, characteristic of typical attrition wear. At cutting speed of 122 m/min, a smooth crater was observed, which is a typical characteristic of diffusion/dissolution wear. At the cutting speed of 91 m/min, the wear features were a combination of those observed at speeds of 61 m/min and 122 m/min. A comparison of the wear on the polycrystalline diamond (PCD) tools to that of WC-6Co from our earlier work is also discussed. Microstructural analysis of the of both the undeformed work material and the chip using electron-backscatter diffraction provided evidence to support the phase transformation. Temperature estimates on the rake face of the tool previously extracted from Finite Element Method (FEM) support the possibility of phase transformation at the high cutting speed tested. The difference in the wear pattern was also linked to the extent of recrystallization in the titanium work material. At 61 m/min there was more alpha phase in the work material without much recrystallization, which generated uneven scalloped wear. At 122 m/min, phase transformation of the existing alpha phase to the beta phase in the work material and recrystallization increased the dissolution/diffusion wear process.

scholarly journals The Performance of Polycrystalline Diamond (PCD) Tools Machined by Abrasive Grinding and Electrical Discharge Grinding (EDG) in High-Speed Turning

2021 ◽  
Vol 5 (2) ◽  
pp. 34
Author(s):  
Guangxian Li ◽  
Ge Wu ◽  
Wencheng Pan ◽  
Rizwan Abdul Rahman Rashid ◽  
Suresh Palanisamy ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
High Speed ◽  
Flank Wear ◽  
Polycrystalline Diamond ◽  
Machining Efficiency ◽  
Crater Wear ◽  
Wear Process ◽  
High Speed Turning ◽  
Tools Wear ◽  
Pcd Tools

Polycrystalline diamond (PCD) tools are widely used in industry due to their outstanding physical properties. However, the ultra-high hardness of PCD significantly limits the machining efficiency of conventional abrasive grinding processes, which are utilized to manufacture PCD tools. In contrast, electrical discharge grinding (EDG) has significantly higher machining efficiency because of its unique material removal mechanism. In this study, the quality and performance of PCD tools machined by abrasive grinding and EDG were investigated. The performance of cutting tools consisted of different PCD materials was tested by high-speed turning of titanium alloy Ti6Al4V. Flank wear and crater wear were investigated by analyzing the worn profile, micro morphology, chemical decomposition, and cutting forces. The results showed that an adhesive-abrasive process dominated the processes of flank wear and crater wear. Tool material loss in the wear process was caused by the development of thermal cracks. The development of PCD tools’ wear made of small-sized diamond grains was a steady adhesion-abrasion process without any catastrophic damage. In contrast, a large-scale fracture happened in the wear process of PCD tools made of large-sized diamond grains. Adhesive wear was more severe on the PCD tools machined by EDG.

Experimental Study on Performance of CBN-Coated, CBN-Uncoated and PCD Tools in Turning Al 2124 SiC (45%wt) PMMC

2013 ◽  
Vol 567 ◽  
pp. 27-31 ◽  
Author(s):  
Muguthu Joseph Njuguna ◽  
D. Gao
Keyword(s):  
Experimental Study ◽  
Tool Wear ◽  
Metal Matrix ◽  
Flank Wear ◽  
Tool Material ◽  
Crater Wear ◽  
Pcd Tool ◽  
Particulate Metal ◽  
Tools Wear ◽  
Pcd Tools

The machining of PMMCs is very difficult due to the highly abrasive and intermittent nature of the reinforcement. It is therefore necessary to choose tool material wisely. The focus of this paper was to assess performance of CBN-uncoated, CBN-coated and PCD tools with respect to tool wear, wear mechanism and cutting force while turning of Al 2124 SiC (45%wt) Particulate Metal Matrix Composite. Experimental results reveal that abrasion and chipping presented the most prevalent mode of wear among the CBN-uncoated, CBN-coated and PCD tools. Flank and crater wear were observed in all tools with flank wear being more prevalent in CBN-coated and CBN-uncoated tools. Wear among PCD tool was low as compared to CBN-uncoated CBN-coated. PCD tool is more suitable for cutting Al 2124 SiC(45%wt) PMMC.

Evidence of Phase Dependent Tool Wear in Ti-6Al-4V Turning Experiments Using PCD and Carbide Inserts

2012 ◽  
Author(s):  
David J. Schrock ◽  
Patrick Kwon
Keyword(s):  
Phase Transformation ◽  
Tool Wear ◽  
Cutting Speed ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Rake Face ◽  
Work Material ◽  
Significant Difference ◽  
Pcd Tools ◽  
Cutting Speeds

This paper presents evidence of phase transformation in turning titanium work material and discusses its impact on tool wear. Tool wear of polycrystalline diamond inserts was studied in turning experiments on Ti-6Al-4V. Confocal laser scanning microscopy was conducted to analyze the rake face of the turning inserts. At cutting speeds of 61m/min, the rake face exhibited scalloped-shaped, fractured, uneven, and rough wear. This is characteristic of attrition wear. At cutting speeds of 122m/min, wear was smooth and even in nature, which is a typical characteristic of diffusion/dissolution wear. At a cutting speed of 91m/min, the wear was a combination of those observed at speeds of 61m/m and 122m/m. A comparison of the wear on the PCD tools to that of WC-6Co from earlier work is also discussed. A significant difference in wear existed between the two different cutting tool materials at the low cutting speed. This difference in wear was linked to a transition from alpha to beta phase in the titanium work material. Temperature estimates on the rake face of the tool previously extracted from FEM support the possibility of phase transformation at the cutting data tested.

Cutting Tool Wear and Mechanisms of Chip Formation During High-Speed Machining of Compacted Graphite Iron

2007 ◽  
Author(s):  
Niniza S. P. Dlamini ◽  
Iakovos Sigalas ◽  
Andreas Koursaris
Keyword(s):  
Tool Wear ◽  
Surface Finish ◽  
Failure Criterion ◽  
Cutting Tool ◽  
Flank Wear ◽  
Cutting Tools ◽  
Compacted Graphite Iron ◽  
Crater Wear ◽  
Compacted Graphite ◽  
Cutting Speeds

Cutting tool wear of polycrystalline cubic boron nitride (PcBN) tools was investigated in oblique turning experiments when machining compacted graphite iron at high cutting speeds, with the intention of elucidating the failure mechanisms of the cutting tools and presenting an analysis of the chip formation process. Dry finish turning experiments were conducted in a CNC lathe at cutting speeds in the range of 500–800m/min, at a feed rate of 0.05mm/rev and depth of cut of 0.2mm. Two different tool end-of-life criteria were used: a maximum flank wear scar size of 0.3mm (flank wear failure criterion) or loss of cutting edge due to rapid crater wear to a point where the cutting tool cannot machine with an acceptable surface finish (surface finish criterion). At high cutting speeds, the cutting tools failed prior to reaching the flank wear failure criterion due to rapid crater wear on the rake face of the cutting tools. Chip analysis, using SEM, revealed shear localized chips, with adiabatic shear bands produced in the primary and secondary shear zones.

scholarly journals Enhancing Wear Resistance and Cutting Performance of a Long-Life Micro-Groove Tool in Turning AISI 201

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1515
Author(s):  
Jinxing Wu ◽  
Lin He ◽  
Yanying Wu ◽  
Chaobiao Zhou ◽  
Zhongfei Zou ◽  
...  
Keyword(s):  
Temperature Field ◽  
Service Life ◽  
Tool Wear ◽  
Cutting Forces ◽  
Cutting Tools ◽  
Cutting Temperature ◽  
Rake Angle ◽  
Rake Face ◽  
Crater Wear ◽  
Wear Area

Tool-chip friction increases cutting temperature, aggravates tool wear, and shortens the service life of cutting tools. A micro-groove design of the rake face can improve the wear performance of the tool. In this study, we used the finite element simulation “Deform” to obtain the temperature field distribution of the tool rake face. The size of the micro-groove was determined by selecting a suitable temperature field combined with the characteristics of tool–chip flow in the cutting process, and the tool was prepared using powder metallurgy. The three-direction cutting forces and tool tip temperature were obtained by a cutting test. Compared with the original turning tool, the cutting force and cutting temperature of the micro-groove tool were reduced by more than 20%, the friction coefficient was reduced by more than 14%, the sliding energy was reduced and the shear energy was greatly decreased. According to the analysis of tool wear by SEM (scanning electron microscope) and EDS (energy dispersive X-ray spectroscopy), the crater wear, adhesive wear and oxidation wear of the micro-groove tool were lower than those of the original turning tool. In particular, the change in the crater wear area on the rake face of the original tool and the micro-groove tool was consistent with the cutting temperature and the wear width of the flank face. On the whole, the crater wear area and the change rate of the crater wear area of the micro-groove tool were smaller. Due to the proper microgroove structure of the rake face, the tool-chip contact area decreased, and the second rake angle of the tool became larger. Hence, the tool-chip friction, cutting forces, cutting energy consumption were reduced, tool wear was improved, and the service life of the micro-groove tool was five times longer than that of the original tool.

scholarly journals Online Tool Wear Monitoring by the Analysis of Cutting Forces in Transient State for Dry Machining of Ti6Al4V Alloy

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1014 ◽  
Author(s):  
Sánchez Hernández ◽  
Trujillo Vilches ◽  
Bermudo Gamboa ◽  
Sevilla Hurtado
Keyword(s):  
Tool Wear ◽  
Feed Rate ◽  
Cutting Forces ◽  
Flank Wear ◽  
Cutting Speed ◽  
Transient State ◽  
Cutting Parameters ◽  
Dry Machining ◽  
Crater Wear ◽  
Force Amplitude

In this work, the analysis of the cutting speed and feed rate influence on tool wear and cutting forces in Ti6Al4V alloy dry machining is presented. The study has been focused on the machining in a transient state. The tool wear mechanisms, tool wear intensity and cutting forces evolution have been analyzed as a function of the cutting parameters. Experimental results show that the main cutting force amplitude exhibits a general trend to increase with both cutting parameters. Crater wear was more evident at high cutting speeds, whereas flank wear was present on the whole interval of the cutting parameters analyzed. Furthermore, the cutting speed shows a slightly higher influence on crater wear and the feed rate shows a higher influence on flank wear. Finally, several experimental parametric models have been obtained. These models allow predicting the evolution of crater and flank tool wear, as well as the cutting forces, as a function of the cutting parameters. Additionally, a model that allows monitoring the tool wear on the machining transient state as a function of the main cutting force amplitude has been developed.

The Genesis of Tool Wear in Machining

2015 ◽  
Author(s):  
Trung Nguyen ◽  
Kyung-Hee Park ◽  
Xin Wang ◽  
Jorge Olortegui-Yume ◽  
Tim Wong ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Flank Wear ◽  
Lamellar Microstructure ◽  
Dissolution Mechanism ◽  
Low Alloy Steels ◽  
Crater Wear ◽  
Alloy Steels ◽  
Cutting Speeds

This paper presents a series of experimental and theoretical efforts that we have made in unraveling the tool wear mechanisms under steady state conditions in machining for the last few decades. Two primary modes of steady state tool wear considered in this paper are flank and crater wear. We preface this paper by stating that flank wear is explained as abrasive wear due to the hard phases in a work material while crater wear is a combination of abrasive wear and generalized dissolution wear which encompasses both dissolution wear as well as diffusion wear. However, the flank wear was not a function of the abrasive cementite content when turning low alloy steels with pearlitic microstructures. The machined surfaces of these alloys are examined to confirm the phase transformation (ferrite to austenite), which diminishes the effect of cementite content. In particular, the cementite phase present in low alloy steels dissociates and diffuses into the transformed austenitic phase during machining. Dissolution wear is claimed to describe the behavior of crater wear at high cutting speeds. The original dissolution mechanism explains the crater wear in the machining of ferrous materials and nickel alloys at high cutting speeds, but the generalization of the dissolution wear is necessary for titanium alloys. In machining titanium alloys, the original dissolution mechanism did not show a good correlation with experimental results; generally the diffusivity of the slowest diffusing tool constituent in titanium limits the wear rate. The phase transformation from alpha (HCP) to beta (BCC) phases can also take place in machining titanium alloys, which drastically increases the crater wear due to the few orders of magnitude increase in diffusivity. The most puzzling issue is however the presence of the scoring marks even though no hard inclusion is typically present in titanium alloys. This is finally explained by the heterogeneity in the microstructure due to the anisotropic hardness of alpha (HCP) phase (the hardness in c-direction is 50% higher than the hardness in other directions) and the presence of lamellar microstructure (alternating layers of alpha and beta). The lamellar microstructure has not only the in-plane anisotropic hardness but also a greater hardness than other phases. Even though we cannot claim to fully understand the physics behind tool wear, our combined approaches have unveiled some elementary wear mechanisms.

Experimental Study on Milling of Titanium Matrix Composites

2013 ◽  
Vol 589-590 ◽  
pp. 281-286
Author(s):  
Hai Xiang Huan ◽  
Jiu Hua Xu ◽  
Hong Hua Su ◽  
Yu Can Fu ◽  
Ying Fei Ge
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Cutting Temperature ◽  
Polycrystalline Diamond ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composites ◽  
Pcd Tool ◽  
Induced Defects ◽  
Pcd Tools

Titanium matrix composites (TMCs) possess many outstanding properties and have increasing and potential application in aerospace, automobile and other industries. However, TMCs are typical difficult-to-machining material due to the rapid tool wear rate and excessive machining induced defects. In this paper, tool wear, cutting forces, cutting temperature and surface roughness were investigated when milling TMCs with Polycrystalline Diamond (PCD) and carbide tools. The results showed that the values of surface roughness obtained by carbide tools were higher than that of PCD tools under the same cutting conditions. The value of cutting temperature for PCD tool was about 75% of the carbide tools, and the main cutting force value of PCD tool was about 85% of the carbide tool. Abrasive and adhesive wear were the main wear mechanisms of PCD and carbide tools. In all, PCD tools had a better cutting performance than carbide tools during finishing milling titanium matrix composites.

Edge Preparation on Cutting Force, Cutting Temperature and Tool Wear for Hard Turning

2014 ◽  
Vol 800-801 ◽  
pp. 424-429
Author(s):  
Pei Rong Zhang ◽  
Zhan Qiang Liu
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Hard Turning ◽  
Flank Wear ◽  
Cutting Temperature ◽  
Cutting Edge ◽  
Crater Wear ◽  
Cutting Edge Preparation ◽  
Flank Face ◽  
Edge Preparation

The paper investigates the effects of cutting edge preparation on cutting force, cutting temperature and tool wear for hard turning. An optimized characterization approach is proposed and five kinds of cemented tools with different edge preparation are adopted in the simulations by DEFROM-2DTM. The results show that both the forces and cutting temperature on the rake face climb up and then declines with the increasing of factor K (Sγ/Sα). While the temperature on flank face decrease with the increasing of the factor K. When the cutting conditions are identical, flank wear reduces while crater wear exacerbates before easing with the increasing of the factor K. The simulation results will provide valuable suggestions for optimization of cutting edge preparation for hard turning in order to obtain excellent machining quality and longer tool life.

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