Multilayer Coated Tool Research Articles

Performance Evaluation of PVD and CVD Multilayer-Coated Tools in Machining High-Strength Steel

Performance Evaluation of PVD and CVD Multilayer-Coated Tools in Machining High-Strength Steel

Heat Transfer Modelling of Multilayer Coated Tools During Turning of H13 Hardened Steel: Analogous Coating Layer Approach

Heat Transfer Modelling of Multilayer Coated Tools During Turning of H13 Hardened Steel: Analogous Coating Layer Approach

Effects of tool coating materials and coating thickness on cutting temperature distribution with coated tools

AbstractCoated tools are currently widely used tool technology in machining. The influence of tool coating on heat transfer has become an active field of research enjoying constantly increasing attention in the field of machining. This paper is devoted to the cutting temperature in machining H13 hardened steel with monolayer coated tools (TiN, TiAlN, and Al2O3) and multilayer coated tools (TiN/TiC/TiN and TiAlN/TiN). Equivalent composite thermal conductivity and thermal diffusivity of multilayer coated tools were calculated using the equivalent approach. The established heat transfer analytical models estimated coating temperature in turning. The effect of tool coating in steady and transient heat transfer was studied, as well as the cutting temperature distribution. It reveals that the tool coating material and coating thickness can influence the cutting temperature distribution of coated tool. Thermal conductivity of coating material affects the steady cutting temperature distribution, and thermal diffusivity of coating material affects the transient cutting temperature distribution of coating tools.

Features of Machining Rotor Shafts of Diesel Engine Turbochargers with a Multilayer-Coated Tool

Introduction. The paper presents the results of experimental studies of power parameters when hard alloy steels are machined with tools, the cutting units of which have multilayer hard, heat-resistant and wear-resistant coatings. The obtained data will make it possible to optimize machining hard-to-machine materials. Materials and Methods. The aim of the study is to measure the power parameters of turning products and to create experimental formulas of power parameters for different technological modes. For this purpose, a special measuring multicomponent complex was used to estimate the influence of the mode parameters on the change in the cutting force components. Results. The numerically controlled machine tool was retooled by combining it with a three-component dynamometer and tooling. The cutting unit of the tool was coated with a multi-layer hard, heat-resistant and wear-resistant coating. The tool was equipped with instruments connected to a personal computer for measuring and processing experimental data. According to the results of the study, there have been obtained graphical dependences and empirical formulas, which take into account the influence of the mode parameters on the cutting force components when machining the units of alloy steels of high hardness, heat resistance and wear resistance. Discussion and Conclusion.The study allowed us to obtain experimental formulas of cutting force components for different mode parameters when machining parts by the tool equipped with cutting plates. The plates are coated with multilayer hard and wear-resistant coatings of titanium carbonitride, aluminum oxide and nickel nitride. The coating increases significantly the hardness, heat and wears resistance of the tool cutting unit and provides quality machining.

Investigation the fatigue impact behavior and wear mechanisms of bilayer micro-structured and multilayer nano-structured coatings on cemented carbide tools in milling titanium alloy

Hard coatings play an important role in increasing the ability of deformation and wear resistance due to the superior mechanical and tribological properties. Nano-structured coating is now being used for cutting tool and exhibits extremely fascinating and useful properties. In milling process, a typical failure mechanism of coating is the cyclic mechanical impact between the workpiece and cutting tool. This could induce intensive fatigue failure of coated tools. In this work, a novel cyclic impact tester has been designed by using the piezoelectric ceramic actuator to study the fatigue resistance of bilayer micro-structured and multilayer nano-structured TiSiN/TiAlN coating. Besides, the mechanical, tribological and adhesion properties of coatings were evaluated. The multilayer nano-structured coating showed higher hardness yet toughness, better adhesion and tribological properties, as well as more superior properties of fatigue impact resistance. The influence of coatings on the wear behavior and cutting performance of cutting tools was investigated in milling Ti-6Al-4V. The milling forces applied on the coated tools were measured and analyzed. It found that the friction force and normal force applied on the multilayer nano-structured coated tool were lower than that of bilayer micro-structured coated tool. The correlation between the mechanical properties in cyclic impact tests and cutting performance in milling experiments of coatings was studied. The multilayer nano-structured coated tool was much less susceptible to fatigue fracture and this could be attributed to the better fatigue resistance in the high frequency cyclic impact tests.

Experimental investigation and multi-objective optimization of process parameters during machining of AISI 52100 using high performance coated tools

AISI 52100 is a high carbon-chromium steel mostly used for the production of anti-friction bearing material. This paper presents performance comparison of a particular layer over others for various S-type advanced single and multilayer-coated tools. The effect of different cutting conditions and their influence on cutting forces, surface roughness, chip morphology, tool wear and chip reduction coefficient were evaluated. Eight tools were tested for microhardness, adhesion quality, characterization by X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), surface roughness and cutting force. Physical vapour deposition (PVD)-TiAlN coated tool showed less tool wear, highest hardness and good surface finish. Multi-objective optimization was performed by Taguchi-Grey relational analysis to predict the process parameters set among feed rate, cutting speed and tool type for a lower value of cutting force, surface roughness and chip reduction coefficient. Responses were significantly influenced by the interaction of feed rate and tool type.

Characterization of Ceramics Coatings Processed by Sol-Gel for Cutting Tools

In order to obtain better cutting tool performance, the coatings appear as an alternative in the machining process. The goal of the coating is to improve tribological conditions in the chip-tool and tool-workpiece interfaces. On the other hand, the use of coated tools decreases the wear of the tools. This study discusses the ceramic coatings characterization deposited in WC tools. The Al2O3 and TiO2 films present properties such as thermal stability, chemical inertia, high hardness, and good mechanical properties. These coatings were prepared by sol-gel technology. The results indicated that the multilayer coating presents better adhesion on the substrate. Moreover, lower coefficients of friction were found for the coated tools. The analysis of variance (ANOVA) was used to evaluate the influence of the cutting parameters and tool coating on the cutting force. The lower cutting force was obtained using the multilayer-coated tool. Thus, the sol-gel method appears as a novel technique to deposit coating in the WC tools to improve their performance.

Experimental investigation on the effect of multilayer TiCN/TiAlN/WC-C coating on the tribological behaviour of tool inserts for machining applications

This study investigates the effect of sliding speed and applied normal load on the wear and frictional behaviour of pure and coated (single layer titanium carbo nitride (TiCN), bilayer titanium aluminium nitride/tungsten carbide/carbide (TiAlN/WC-C), multilayer (TiCN/TiAlN/WC-C)) tool inserts. Dry sliding wear tests were performed using pin-on-disc tribometer. Higher hardness (25.83 GPa) and lower surface roughness (0.219 μm) are the main reasons for augmented performance of multi-layered tool in tribo tests. The result showed that multilayer coated tool depicts 217.67% improvement in wear resistance compared to uncoated tool under low load, while running at lower sliding speed. The same experiences nominal wear at higher sliding speed and showed 248.57% enhancement in wear resistance than uncoated tool. The average coefficient of friction for multi-layered tool under 15 N load portrays lower average coefficient of friction in the range of 0.47 compared to uncoated tool (0.53).

Evaluation on Effectiveness of CVD and PVD Coated Tools during Dry Machining of Incoloy 825

ABSTRACTWith wide applications of nickel-based superalloys in strategic fields, it has become increasingly necessary to evaluate the performance of different advanced cutting tools for machining such alloys. With a view to recommend a suitable cutting tool, the present work investigated various machinability characteristics of Incoloy 825 using an uncoated tool, chemical vapor deposition (CVD) of a bilayer of TiCN/Al2O3, and physical vapor deposition (PVD) of alternate layers of TiAlN/TiN-coated tools under varying machining conditions. The influence of cutting speed (51, 84, and 124 m/min) as well as feed (0.08, 0.14, and 0.2 mm/rev) was comparatively evaluated on surface roughness, cutting temperature, cutting force, coefficient of friction, chip thickness, and tool wear using different cutting tools. Although the CVD-coated tool was not useful in decreasing surface roughness and temperature, a significant reduction in cutting force and tool wear could be achieved with the same coated tool under a high cutting speed of 124 m/min. On the other hand, the PVD-coated tool outperformed the other tools in terms of machinability characteristics. This might be attributed to the excellent antifriction and antisticking property of TiN and good toughness due to the multilayer configuration in combination with a thermally resistant TiAlN phase. Adhesion, abrasion, edge chipping, and nose wear were the prominent wear mechanisms of the uncoated tool, followed by the CVD-coated tool. However, remarkable resistance to such wear was evident with the PVD TiAlN/TiN multilayer-coated tool.

A Preliminary Machinability Study of Flake and Compacted Graphite Irons with Multilayer Coated and Uncoated Carbide Inserts

Compacted graphite iron (CGI) is considered to be one of the most promising materials for many automotive applications and has adopted by some automotive companies. Comparing to widely used flake graphite iron (FGI), CGI has superior physical and mechanical properties. The main drawback of this material is known to be its poor machinability. A preliminary study on flank and crater wear was conducted by dry turning experiments with both FGI and CGI using uncoated WC tools and multilayer coated tools. Confocal Laser Scanning Microscopy (CLSM) was used to investigate worn areas of the cutting tools. Despite of the reported poor machinability of CGI, our turning experiments showed that both flank and crater wear were higher for FGI compared to CGI when using uncoated WC tools at the cutting speed of 150, 250 and 350 m/min. An unexpected adhesion layer on the flank side of carbide inserts was observed when turning CGI, which believe to protect the flank surface and reduce flank wear. The adhesion on rake face concentrated on the cutting edge when turning CGI while the sporadic attachments of work materials are observed throughout the rake interface with FGI. In contrast, no adhesion layer was presented when both FGI and CGI were turned using multilayer coated tools, which yielded more flank and crater wear when turning CGI.

On Applicability of Multilayer Coated Tool in Dry Machining of Aerospace Grade Stainless Steel

The present research work has been undertaken with a view to investigate the influence of CVD multilayer coated (TiN/TiCN/Al2O3/ZrCN) and cutting speed on various machining characteristics such as chip morphology, tool wear, cutting temperature, and machined surface roughness during dry turning of 17-4 PH stainless steel. In order to understand the effectiveness of CVD multilayer coated tool a comparison has been carried out with that of uncoated carbide insert. The surface roughness and cutting temperature obtained during machining with chemical vapor deposition (CVD) multilayer coated tool was higher than that of uncoated carbide insert at all cutting velocity. However, the results clearly indicated that CVD multilayer coated tool played a significant role in restricting various modes of tool failure and reducing chip deformation compared to its uncoated counterpart. Adhesion and abrasion were found to be dominating wear mechanism with flank wear, plastic deformation, and catastrophic failure being major tool wear modes.

Investigation on Some Machinability Aspects of Inconel 825 During Dry Turning

In the current study, attempt has been made to investigate the influence of cutting speed (Vc) (51, 84, and 124 m/min) on various machining characteristics like chip morphology, chip thickness ratio, tool wear, surface, and sub-surface integrity during dry turning of Inconel 825. Comparable study was carried out using uncoated and commercially available chemical vapor deposition multilayer coated (TiN/TiCN/Al2O3/ZrCN) cemented carbide (ISO P30 grade) insert. Chip morphology consists of chip forms obtained at different cutting conditions. Serrated chips were observed when machining Inconel 825 with both types of tool with more serration in case of uncoated insert. The chip thickness ratio increased as cutting speed was increased. Use of multilayer coated tool also resulted in increase in chip thickness ratio. Rake and flank surfaces were examined with scanning electron microscope and optical microscope. Abrasion, adhesion, and diffusion wears were found to be dominating tool wear mechanism during dry machining of Inconel 825. The beneficial effect of coated tool over its uncoated counterpart was most prominent during machining at high cutting speed (Vc = 124 m/min). The surface and sub-surface integrity obtained with coated tool were superior to that while machining Inconel 825 with uncoated tool.

Effect of cutting speed and CVD multilayer coating on machinability of Inconel 825

The current study aims at investigating the effect of cutting speed (51, 84 and 124 m min−1) as well as tool coating deposited using chemical vapour deposition (CVD) on machined surface roughness, tool wear characteristics, chip morphology and chip reduction coefficient (ζ) during dry machining of Inconel 825. Turning operation was carried out using ISO P30 uncoated cemented carbide and CVD multilayer coated (TiN/TiCN/Al2O3/ZrCN) insert with a constant feedrate of 0·198 mm rev−1 and depth of cut of 1 mm. Chip morphology and tool wear were studied using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and optical microscopy. Results indicated CVD multilayer coated tool resulted in more machined surface roughness compare to it uncoated counterpart. However, coated tool demonstrated excellent resistance to crater and flank wear, and decrease in chip reduction coefficient during dry machining of Inconel 825.

Effect of Cutting Speed and Tool Coating on Machined Surface Integrity of Ni-based Super Alloy

Inconel 825 belongs to the family of nickel-based super alloy and is widely used in the chemical and marine industry. Although most of the research work was concentrated on machinability of Inconel 718, no such work on the current grade of Inconel 825 has been reported so far. This grade of Inconel is particularly suitable for the applications requiring improved resistance to corrosion. The current study aims at investigating the effect of cutting speed and chemical vapour deposition (CVD) multilayer coating on machined surface integrity of Inconel 825 during dry turning, with particular emphasis on measurement of sub-surface hardness and white layers. Three regions were distinguished beneath the machined surface viz. (a) white layer, (b) plastic deformation region and (c) bulk material. It was observed that increase in cutting speed increased white layer thickness after machining with both uncoated and coated tools. CVD coated cemented carbide insert resulted in decrease in white layer thickness particularly in the lower range of cutting velocity when compared with that obtained by its uncoated counterpart. Vickers microhardness test clearly revealed the work hardening tendency of Inconel 825 with hardness being maximum in the sub- surface region and it decreased when measurements were gradually taken towards the centre of the workpiece. However, this tendency was found to be reduced with the use of multilayer coated tool.

Evaluation of Chip-tool Interface Temperature: Effect of Tool Coating and Cutting Parameters during Turning Hardened AISI 4340 Steel

In the present context of sustainable manufacturing, investigation of cutting temperature during machining is extremely valuable to address metal cutting issues such as dimensional accuracy, surface finish and tool life. In this study, average chip-tool interface temperature was investigated considering the effect of cutting parameters and the type of coating (coated tools), namely, PVD- applied single-layer TiAlN and CVD-applied multi-layer TiCN/Al2O3/TiN during turning of hardened steel. Mathematical model which can predict the average chip-tool interface temperature was developed based on experimental observations which were obtained in the wide range of cutting conditions. A calibration set-up based on tool-work thermocouple principle was developed to correlate the emf (electro motive force) and the interface temperature. R-squared value for the developed model found 0.9693, indicate that the developed model is reliable and could be used effectively for predicting the interface temperature within the domain of the cutting parameters for the given tool and work material pair. Experimental observations indicate that the interface temperature is higher for CVD-coated multi-layer coated tool in comparison to single-layer TiAlN, which get affected mostly by cutting speed followed by feed. However, depth of cut has negligible influence on interface temperature when using both the coated carbide tools.

An investigation on wear mechanism of high-speed turning of free-cutting steel AISI 1215 using uncoated and multi-layer coated tools

AISI 1215 is a new kind of green and non-toxic free-cutting steel with minimum environmental pollution and excellent machinability, which receives wide promotion, investigation, and application in manufacturing industries. In machining of AISI 1215 steel, tool wear has a close relation with the presence of manganese sulfide lubricant zone formed on the tool surface. In this work, with the aid of cutting temperature and tool Von Mises stress simulations, tool wear analysis on the uncoated and multi-layer (Al2O3/TiCN) coated carbide tools was performed in high-speed turning operation. Wear pattern and wear mechanisms were studied through the experimental results. The main findings showed that the uncoated tool suffered high cutting temperature and severe tool wear and was not conducive to form a manganese sulfide lubricant zone in the turning operation. In contrast, the multi-layer coated tool could form a manganese sulfide lubricant zone on the chip–tool contact area. The beneficial roles of the manganese sulfide lubricant zone formed on the coated tool surface can be summarized as lubrication and diffusion blocking. The main wear mechanisms of the uncoated tool were crater wear, oxidation wear, adhesive wear, and abrasive wear, whereas for the multi-layer coated tool, they were crater wear, adhesive wear, and abrasive wear.

A comparative study of multilayer and functionally graded coated tools in high-speed machining

Multilayer-coated tool systems have been effective in controlling mechanical and thermal loads, especially in high-speed cutting regime. In this study, cutting performance of tungsten carbide tools with restricted contact length and multilayer chemical vapour deposition deposited coatings, TiCN/Al2O3/TiN (in series) and TiCN/Al2O3–TiN (functionally graded), was investigated in dry turning. Cutting tests were conducted on low carbon alloy steel AISI/SAE 4140 over a wide range of cutting speeds between 200 and 879 m/min. Results including cutting forces, chip compression ratio, shear angle, contact area inclusive of sticking and sliding phenomena and tool flank wear are presented. In particular, prediction of heat partition into the cutting tool inserts was carried out using a combination of experimental tests and the finite element method. The results show that coating layouts and cutting tool edge geometry can significantly affect heat distribution into the cutting tool. The paper clearly shows the role and potential benefits of applying different top coats on the rake and flank faces with regards contact phenomenon, impact on thermal shielding and tool wear. An appropriate coating layout selection is crucial in controlling tool wear, especially in high-speed machining.

Flank wear of multi-layer coated tool

Abstract Flank wear analysis on the multi-layer (TiCN/Al 2 O 3 /TiCN) coated carbide inserts has been performed after turning AISI 1045 steel. Using advanced microscope and image processing techniques including wavelet transform, we have obtained the flank wear profiles and analyzed the surface roughness and groove sizes on the coating layers to understand the progress of flank wear and its wear mechanisms. The dominant wear mechanism was found to be the abrasion by the cementite phase in the work material. The adhesion took over after carbide substrate was exposed as the notch wear also became more significant. Based on the experimental result, it was concluded that the hardness of the coating is the most important requirement to resist flank wear due to its high wear resistance against abrasion. Therefore, the multilayer coating scheme does not provide any significant benefit to resist flank wear.

Wear Characteristics of Multilayer-Coated Cutting Tools when Milling Particleboard

This article presents the characteristics of delamination wear on the clearance face of newly coated K10 cutting tools when milling particleboard. The K10 cutting tools were multilayer coated with titanium aluminum nitride (TiAlN)/titanium silicon nitride (TiSiN), TiAlN/titanium boron nitride (TiBN), and TiAlN/chromium aluminum nitride (CrAlN). Particleboard with a density of 0.61 g/cm3 was cut using the multilayer-coated tools and a monolayer-coated (TiAlN) tool. Cutting tests were performed at a high cutting speed of 41.8 m/s and a feed rate of 0.2 mm/rev to investigate the delamination wear on the clearance face of these coated tools. Experimental results showed that the newly multilayer-coated tools experienced a smaller amount of delamination wear than the monolayer-coated tool when milling the particleboard. The best multilayer coating was TiAlN/CrAlN; that tool only suffered a slight chipping on the cutting edge at a cutting length of 1 km. The high hardness, low coefficient of friction, high resistance to oxidation, and high resistance to delamination wear of the multilayer-coated TiAlN/CrAlN tool indicate a very promising applicability of this coating for high-speed cutting of abrasive wood-based materials.

Numerical simulation of orthogonal machining process using multilayer and single-layer coated tools

In this study, numerical simulation was carried out to determine the effect of coating type on the cutting forces, tool stresses, and temperatures. The Lagrangian thermo-viscoplastic cutting simulation of AISI 4340 steel was conducted using two different coating types (TiCN + Al2O3 + TiN and Al2O3) and uncoated carbide tool having same geometry. Johnson–Cook work material model is used for plastic deformations. The predicted cutting forces for the coated and uncoated tools were compared with the experimental results. The variation of tool stress and temperature with coating type and number of coating layer were investigated. The predicted results indicated that the tool coated with Al2O3 showed minimum tool temperature value due to its decreasing thermal conductivity with increasing temperature. Maximum tool temperature occurs at the rake surface of the cutting tools (coated and uncoated) and decreases rapidly with depth in the coated tools. On the other hand, the tool stress within the coating increases along the thickness with increasing cutting speed and feed rate. Minimum shear angle is observed in uncoated carbide tool whereas maximum shear angle occurs for Al2O3-coated tool. This result also confirms the results obtained from cutting tests.