Tool Wear Behavior Research Articles

Experimental investigation of Aluminum Nitride ceramics based on compliant finishing process

Aluminum Nitride (AlN), as a type of advanced functional ceramic material, has found wide applications in many fields, owing to its advantageous properties such as excellent thermal conductivity, high hardness and strength, etc. Nevertheless, these beneficial features bring great challenges to its machinability using current existing methods that commonly result in unsatisfactory surface qualities. In this paper, we investigated the processing performance of AlN by introducing the compliant bonnet finishing approach based on different tool bonding materials and abrasive sizes. The distinctive finishing qualities, material removal rates, tool wear behavior, etc., were studied and compared under various process conditions. Unlike other ceramics, resin bonded diamond tools with a 3 μm abrasive size exhibit significant wear when used on AlN ceramics. The curves for tool wear amount and wear rate are investigated. Meanwhile, compliant tool with the smaller abrasive can obtain the sub-50 nm surface roughness. The comparison with traditional rigid pellet finishing further demonstrates the advantageous finishing performances by using compliant tools on the AlN ceramics.

Wear behavior and surface roughness analysis of carbide tools with varying coating for high-speed milling of compacted graphite cast iron

Wear behavior and surface roughness analysis of carbide tools with varying coating for high-speed milling of compacted graphite cast iron

Wear behavior of white alumina and seeded gel abrasive wheels in ultrasonic vibration-assisted grinding of nickel-based single-crystal alloy

This study investigated the tool wear behavior of white alumina (WA) and seeded gel (SG) abrasive wheels in the ultrasonic vibration-assisted creep feed grinding (UVACFG) of nickel-based single-crystal alloy. The abrasive wheel wear characteristics were examined, and their effects on the grinding force, temperature, and surface quality were evaluated. Finally, the wheel wear mechanism in the UVACFG was discussed by analyzing the intermittent cutting behavior and wear patterns of a single grain. Experimental results indicated that the workpiece material adhesion and pore-clogging were the main wear patterns of abrasive wheels without ultrasonic vibration. In contrast, these were adequately mitigated after introducing ultrasonic vibration, and the main wear pattern for both wheels became the grain fracture. The WA wheel in the UVACFG experienced reduced radial wear by around 60.7 % in the initial wear state, 40.2 % in the stable wear state, and 25.3 % in the rapid wear stage, respectively, compared to the conventional grinding (CG). The intermittent cutting behavior of SG grains caused by high-frequency vibration promoted the micro-fracture capacity and ensured the coolant entered the grinding zone sufficiently, which reduced the grinding force and temperature by up to 63.2 % and 46.7 %, respectively, and meanwhile introduced the defects of high bulges and slight plastic deformation on the workpiece surface.

Effect of forward and reverse cutting on tool wear behavior in ultrasonic vibration-assisted milling of 3D needle-punched C/SiC composites

C/SiC composites have excellent mechanical properties such as high specific strength and high temperature resistance, and are widely used in aerospace fields. However, due to its special structure and material properties, the tool wear is severe when machining with conventional methods, and the processing quality is poor. The purpose of this paper is to reveal the progressive wear behavior, wear mechanism of the tool, and its effect on machining performance in conventional milling (CM) and ultrasonic vibration-assisted milling (UVM) of C/SiC composites under forward fiber cutting (FC) and reverse fiber cutting (RC). The material removal and heat transfer models were established, and the stress distribution characteristics of cutting -edge were analyzed by finite element method (FEM). Combined with the wear morphology, cutting heat, and cutting force, the tool wear behavior and mechanism in UVM and CM under FC and RC were studied, and their effects on machining quality were analyzed. The results show that there are great differences in heat transfer and removal process between FC and RC. In UVM, the introduction of ultrasonic vibration reduces the adhesion of fine chips, weakens the strong friction and scratching between the hard chips and the cutting -edge, and alleviates the tool wear. The flank wear VB and cutting -edge wear area WA in RC are larger than those in FC, the abrasive wear is intensified, the material even peeling under mechanical shock, and the adhesive wear is more serious. When the tool wear intensifies to a certain extent, the difference of the cutting process caused by mechanical anisotropy of C/SiC composites is weakened, and the surface micro-defects and surface roughness Sa change little under FC and RC. This research contributes to the realization of high-quality and low-cost processing of C/SiC composites.

Wear behaviour of abrasive tools and its effect on surface integrity during polishing superalloy GH4169G with abrasive cloth flap wheels

In polishing nickel-based superalloys, the surface quality and dimensional accuracy of the workpiece are closely related to the wear of the abrasive tools. Over the years, several researchers have studied the wear of grinding wheels or abrasive belts, including the effects of various machining methods, abrasive materials, and machining parameters on the wear of abrasive tools. However, there is not enough research on the wear mechanism of the abrasive cloth flap wheel (ACFW). In this paper, during polishing GH4169G with ACFW, the wear evolution mechanism of ACFW and its effect on the surface integrity of GH4169G were investigated. First, the variations in material removal and ACFW wear amounts during the polishing process were analysed, and the different wear stages were divided based on the polishing ratio. Second, the mic-morphology and surface element distribution of ACFW at different wear stages were investigated using SEM and, EDS, and the wear evolution mechanism of ACFW was analysed. Finally, the effects of ACFW wear on the surface morphology, surface oxidation and microstructure of GH4169G were investigated by SEM, EDS, XRD, and EBSD. The results showed that the primary wear forms of ACFW were stepped fracture, cleavage fracture, blunt, pull-out, and adhesion wear. During the initial wear stage, the proportion of each wear form was relatively balanced. In the medium wear stage, fracture wear was the main wear form. Blunt and adhesive wear were the primary forms of wear during the final wear stage. In addition, with ACFW wear, the surface roughness tend to decrease first and then increase, however, the refinement level of the grains, the intensity of plastic deformation and the intensity of the oxidation reaction gradually increased. This study provides effective guidance for developing more wear-resistant abrasive tools and optimising the grinding and polishing processes.

Wear Behavior of TiAlVN-Coated Tools in Milling Operations of INCONEL® 718

The use of coatings on cutting tools offers several advantages from the point of view of wear resistance. A recent technique with great coating deposition potential is PVD HiPIMS. TiAlN-based coatings have good resistance to oxidation due to the oxide layer that is formed on their surface. However, by adding doping elements such as Vanadium, it is expected that the wear resistance will be improved, as well as its adhesion to the substrate surface. INCONEL® 718 is a nickel superalloy with superior mechanical properties, which makes it a difficult-to-machine material. Milling, due to its flexibility, is the most suitable technique for machining this alloy. Based on this, in this work, the influence of milling parameters, such as cutting speed (Vc), feed per tooth (fz), and cutting length (Lcut), on the surface integrity and wear resistance of TiAlVN-coated tools in the milling of INCONEL® 718 was evaluated. The cutting length has a great influence on the process, with the main wear mechanisms being material adhesion, abrasion, and coating delamination. Furthermore, it was noted that delamination occurred due to low adhesion of the film to the substrate, as well as low resistance to crack propagation. It was also observed that using a higher cutting speed resulted in increased wear. Moreover, in general, by increasing the milling parameters, machined surface roughness also increased.

Wear characteristics of PVD coated carbide tools in milling of TA15 titanium alloy

Titanium alloy, due to its small elastic modulus and poor thermal conductivity, is easy to exacerbate tool wear during milling which affects its machinability. In this work, an experimental investigation was conducted to analyze the effect of the properties and microstructure of different coatings on tool wear behavior and machining stability during the milling process of TA15 titanium alloy. Physical vapor deposition technology was applied to prepare AlTiSiN and AlZrTiN coatings on carbide samples, respectively, and their microstructures and mechanical properties were investigated. The results showed that AlZrTiN coating exhibited a higher elastic modulus, indicating that it had better resistance to peel off than AlTiSiN coating. Moreover, milling experiments were performed with AlTiSiN and AlZrTiN coated tools to investigate wear characteristics and mechanism. When milling TA15, the two coated tools mainly suffered adhesive wear and oxidation wear. AlZrTiN coated tool exhibited a better wear resistance during long time milling. The surface roughness of TA15 obtained by AlZrTiN coated tool was better than that by AlTiSiN coated tool, achieving approximately Ra0.089 µm. As a result, AlZrTiN coated tool exhibits a better cutting characteristic and is preferred for milling of TA15 titanium alloy.

Investigations on tool wear behavior in turning AISI 304 stainless steel: An empirical and neural network modeling approach

Machining with a cutting edge with extensive damage or a fractured cutting edge significantly influences the machining performance. Therefore, investigations on tool wear behavior, their forms, and wear mechanisms will be very helpful in the current environment of sustainable manufacturing. On the other hand, the machining economy is negatively impacted by replacing the tool well before its useful life. This proactive maintenance planning reduces the risk of sudden tool failure and potential workpiece damage. Accordingly, the current work creates empirical and ANN models to predict flank wear growth for turning AISI 304 stainless steel using a MTCVD-TiCN/Al2O3 coated carbide tool. The experiments were designed to cover a broad range of operating conditions to ensure the model's accuracy and applicability in practical machining scenarios. An ANN was modeled using a feedforward backpropagation machine learning technique. In this study, a higher prediction accuracy of 0.9975 was achieved with ANN model as compared to the empirical model. The most common wear mechanism observed is metal adhesion, followed by fracture due to the pulling away of adhered material. The developed models have been found to be valuable for optimizing cutting parameters and enhancing tool life in machining.

Performance Evaluation of Additively Manufactured and Hybrid Indexable Milling Tools in Machining of AISI4140+QT and Ti-6Al-4V

Abstract Additively manufactured (AM) cutting tools enable new design concepts in tool development concerning lightweight construction, damping behavior, and internal cutting fluid supply. So far, the impact of the layer-by-layer manufacturing technique onto the tool performance during machining of aerospace materials is widely unknown. In this study, the performance characteristics of AM indexable milling tools were investigated and compared to a conventionally manufactured tool of the same geometry. The AM tools were manufactured by laser powder bed fusion (LPBF) from a newly developed bainitic steel alloy. All tools were analyzed with two main focuses. Outside the machine tool, geometrical characteristics and mechanical properties were taken into account. Inside the machine tool, during roughing of AISI4140+QT (42CrMo4+QT) and Ti-6Al-4V (ASTM Ti-Grade 5), tool wear, cutting forces, surface roughness and vibration behavior were evaluated. Three tool concepts were compared, a conventional tool, an AM tool, and a hybrid tool with a conventionally manufactured preform and an AM head. Differences in the performance behavior could be traced back mainly to geometrical inaccuracies caused during postprocessing of the tools. Thus, LPBF-manufactured basic bodies seem to meet the requirements as applications for indexable milling tools. Based on this work, future investigations using AM cutting tools can be carried out assuming a negligible influence of the manufacturing technique onto the tool performance during machining.

Influence of cutting parameters and tool nose radius on the wear behavior of coated carbide tool when turning austenitic stainless steel

This study investigated the wear behavior of coated carbide tool with different tool nose radius under different cutting parameters when turning AISI 321 austenitic stainless steel. The full factorial turning experiments with three factors and two levels cutting parameters were carried out. The wear progression of the tool with cutting time was recorded. The tool wear mechanism and the influence of cutting parameters and tool nose radius on the tool wear behavior were analyzed. The results showed that the cutting tool mainly exhibited wear manners of abrasive wear, adhesive wear, and oxidation wear. The tool life varies a lot with the cutting parameters, with the feed rate the most sensitive. Decrease the nose radius makes the strength of the tool blade worsened, thereby increasing the tool life sensitivity to cutting parameters. However, decreasing the tool nose radius can effectively increase the tool life. The reason is that when the tool nose radius is reduced, the cutting temperature can be decreased and at the same time the chip breaking performance can be improved, which decrease the mechanical damage of chips to the tool and related wear, and thus resulting in a longer tool life.

Cutting Performance and Wear Behavior of Self‐Developed Silicon Nitride Ceramic End Mills with Optimized Structure for High‐Speed Machining of GH4099

Ceramic tool materials possess a wide range of potential in machining nickel‐based superalloys due to their superior wear resistance, high‐temperature hardness, and strong chemical stability. Herein, a structural optimization scheme of self‐developed silicon nitride ceramic end mill based on stiffness enhancement and performance improvement is proposed, and the key geometric angular parameters scope of the self‐developed ceramic end mills are prioritized via the finite‐element simulation method. Through precision grinding manufacturing and sandblasting pretreatment, the cutting performance and tool wear behavior of three optimized self‐developed silicon nitride ceramic end mills (called S4‐1, S4‐2, S4‐3 respectively) are comprehensively analyzed in comparison, including cutting force, milling temperature, surface quality, and tool life. The results indicate that the cutting force and cutting temperature of all the optimized ceramic end mills are effectively restrained compared with the nonoptimized ceramic tool(S4), and the final workpiece surface roughness is significantly reduced. Further, better surface quality can be obtained by optimized ceramic mills. In terms of tool life, ceramic end mill with optimized construction in best can be increased by up to 1.9 times. The wear mechanism and pattern of the three optimized ceramic milling tools are similar, which is adhesive wear, diffusion wear, and notch wear. Overall, the effectiveness of the optimization scheme for ceramic end mill is successfully verified.

Wear Behavior of Metal Bonded Grinding Tools When Grinding Ti-6Al-4V in an Oxygen-Free Atmosphere

In the current study, the wear behavior of bronze-bonded grinding tools when grinding the titanium alloy Ti-6Al-4V was explored. In this process, oxidation plays a key role since both the bronze bond and the titanium workpiece chemically react with oxygen. The oxidation effect is intensified further due to increased temperatures during grinding and can cause tribo-oxidation. This wear effect can be reduced or even eliminated by grinding in an extreme high-vacuum (XHV) adequate atmosphere. This atmosphere is nearly oxygen-free and is generated using a silane-doped argon gas that chemically reacts with oxygen. This reaction is able to decrease the oxygen partial pressure (pO2 ≤ 10−12 mbar) down to an XHV-adequate atmosphere. The aim of this paper is to investigate the influence of oxygen in the atmosphere on the application and wear behavior during grinding and to demonstrate the potential of this novel approach. The results presented show that during grinding with cBN, the process forces are significantly influenced by the atmosphere. Depending on the process parameters, a reduction of up to 93% is thus possible. This force reduction correlates with radial tool wear. When grinding under oxygen-free conditions, it can be reduced by up to 64%.

Effect of milling parameters on machinability of SA508-3 steel in high-speed milling with uncoated and coated carbide tools

SA508-3 steel is popularly used to produce core unit of nuclear power reactors due to its outstanding ability of anti-neutron irradiation and good fracture toughness. Additive forging is a new technology for manufacturing SA508-3 steel forgings. However, the production efficiency and interface bonding quality of heavy forgings are respectively limited by the processing efficiency and surface quality of substrates in the additive forging process. High-speed milling technology is an effective method for improving machining efficiency and quality. Unfortunately, only a few studies on the milling of SA508-3 steel have been reported. In this study, we studied high-speed milling of SA508-3 steel and compared the cutting performances of uncoated, titanium aluminum nitride (TiAlN)-coated, and Al2O3-coated carbide tools. The tool life and cutting force were evaluated using various milling parameters under dry milling conditions. The wear modes and mechanisms were also investigated. The results show that adhesive wear occurs more frequently in the uncoated carbide tool, whereas coating flaking is predominant in the Al2O3- and TiAlN-coated carbide tools. Furthermore, the Al2O3-coated carbide tool showed better cutting performance than the TiAlN-coated and uncoated carbide tools considering the tool life and surface quality. The tool life of the Al2O3-coated carbide tool reached 200 min and the removed workpiece material was 182 × 103 mm3 under the blunt tool criteria. The study of tool life and wear behavior based on the practical cutting experiments contribute to the improvement of the milling quality and provides a theoretical basis for tool material selection and process optimization in milling SA508-3 steel.

Ball-end micro-milling of material measures: wear behavior in field use

AbstractMicro-milling is a precise method for micro-structuring component surfaces. When complex or free-form structures like material measures are to be manufactured, ball-end milling tools are particularly suitable. In preliminary studies by the authors, areal material measures for the calibration of optical topography measuring instruments were manufactured via micro-milling. The demands on the surface quality of the material measures are extremely high. Therefore, worn tools must not be used if the wear has a direct effect on the resulting topography of the manufactured material measures. At the same time, the micro-milling tools used are very costly and should therefore be used as long as possible. A comprehensive experimental study was carried out on the wear behavior of different ball-end micro-milling tools for the specific use case of areal material measures. In the investigations, brass CuZn39Pb3 was machined and different areal material measures were manufactured. The tool life dependent wear was determined and critical wear was identified.

Influence of crystallographic effect on tool wear, cutting stress, cutting temperature, cutting force and subsurface damage in nano cutting of single crystal silicon carbide

Single crystal 3C-SiC as a typical hard and brittle material. Due to its extremely high hardness and brittleness, diamond tools can have drastic wear problems in a short period of time when performing nano-machining processes. Single-crystal 3C-SiC has good anisotropy. In order to gain insight into the effect of crystal orientation on the tool wear behavior during nano-cutting, this paper investigated the tool wear for six cutting crystals downward using molecular dynamics simulation. The tool wear process was analyzed in terms of tool wear, cutting stress, cutting temperature, cutting force and subsurface damage. The results showed that the tool is subjected to large hydrostatic stress concentrations, radial forces and tool temperature concentrations during machining. Under these effects, abrasive wear, graphitic wear and amorphous phase change were produced. In addition, the clearance face of the tool is more severely worn than the rake face. By reasonably selecting the cutting crystal orientation, well control and improvement of tool wear and machined surface quality can be achieved.

Custom-tailored cross-cylinder tribotest to emulate wear mechanism in drilling of CFRP-Ti stacks

While drilling of CFRP-Ti stacks, tool experiences complex tribomechanical interaction due to dissimilar workpiece constituents. For emulating tool wear behavior, the typical tribotest configuration such as reciprocating and pin-on-disc test are not representative for imitating contact scenario underwent during the drilling operation. Cross-cylinder tribotest is an effective test configuration to emulate contact in different manufacturing processes by providing fresh contact surface during sliding. In this work, for the first-time, tool wear of WC-Co cylinders was analyzed in cross-cylinder configuration against multi-material stack arrangement. Moreover, cross-cylinder testing against multi-material [CFRP-Ti]n workpiece showed cyclic variation in coefficient of friction against different workpiece constituents and wear mechanism is a combination of adhesive and abrasive wear on WC-Co tool, comparable to actual drilling operation.

Experimental analysis on the influence of the tool micro geometry on the wear behavior in gear hobbing

Gear hobbing is a well-established manufacturing process for cylindrical spur gears. The cutting edge of a hobbing tool is, among others, characterized by the cutting edge radius and the form-factor K. The magnitude of these parameters is ideally chosen based on the machining conditions given by the workpiece and cutting material and the cutting parameters as well as the gear and tool geometry. However, the influence of the cutting edge geometry on tool life and wear behavior is hardly known, which complicates an optimized tool design. Furthermore, the preparation process regarding the coating thickness distribution on the wear behavior is equally relevant. Therefore, the objective was to identify the influence of the cutting edge radius, the form-factor K, and the preparation process on the wear behavior of gear hobbing tools made of powder metallurgical high-speed steel (PM-HSS). Fly-cutting trials were performed as an analogy process for gear hobbing in order to study the wear behavior and identify the respective tool lives. The trials indicated that the form-factor K influences the wear behavior, while a variation of the cutting edge radius did not have a significant effect. A homogenous coating thickness could extend the tool life significantly.

Investigation of the influence of asymmetrical profiles on the wear behavior in gear hobbing

Asymmetrical gears have advantages in applications with a preferred load direction, such as automotive transmissions or wind turbines. The operational behavior of gears with asymmetrical profiles has already been thoroughly investigated. However, there are very few studies on the manufacturability of gears with asymmetric profiles regarding the possible interactions between pressure angle composition, tool and process design. In this report, the influence of asymmetrical profiles on the wear behavior of hobs is analyzed for the first time.For this purpose, eight different tool variants have been defined for an investigation on tool wear behavior based upon fly-cutting trials. These variants consist of two symmetric and four asymmetric variants. In addition, two asymmetric variants with additional protuberance have been defined. Tool performance decreased within the fly-cutting trials with a low pressure angle on the leading flank and also in the presence of a protuberance. As the pressure angle increases on the leading flank, an increase on the tool life was observed.

Study on In-Situ Tool Wear Detection during Micro End Milling Based on Machine Vision.

Most in situ tool wear monitoring methods during micro end milling rely on signals captured from the machining process to evaluate tool wear behavior; accurate positioning in the tool wear region and direct measurement of the level of wear are difficult to achieve. In this paper, an in situ monitoring system based on machine vision is designed and established to monitor tool wear behavior in micro end milling of titanium alloy Ti6Al4V. Meanwhile, types of tool wear zones during micro end milling are discussed and analyzed to obtain indicators for evaluating wear behavior. Aiming to measure such indicators, this study proposes image processing algorithms. Furthermore, the accuracy and reliability of these algorithms are verified by processing the template image of tool wear gathered during the experiment. Finally, a micro end milling experiment is performed with the verified micro end milling tool and the main wear type of the tool is understood via in-situ tool wear detection. Analyzing the measurement results of evaluation indicators of wear behavior shows the relationship between the level of wear and varying cutting time; it also gives the main influencing reasons that cause the change in each wear evaluation indicator.

Effect of TiC Content and TaC Addition in Substrates on Properties and Wear Behavior of TiAlN-Coated Tools

The present paper reports a new way to improve the wear resistance of coated carbide tools by increases in TiC content and the addition of TaC in substrates. The results suggest that the average grain size of the substrate increased with the increases in TiC (0–14 wt.%) content, and the hardness of the TiAlN coating deposited on the substrate exhibits a similar trend. In addition, the adhesion strength of the TiAlN-coated carbide increases with increasing TiC content, which can be attributed the formation of the (Ti,W)C phase and the similar hardness of the substrate and coating. The addition of TaC into the substrates inhibits the grain growth and thereby causes the hardness and adhesion strength of the TiAlN coatings to improve from 24.6 GPa and 16.7 N to 30.1 GPa and 17.3 N, respectively. In turning tests, the TiAlN coating deposited on the substrates with the TaC addition achieved the best wear resistance in turning stainless steel because it possessed the highest substrate and coating hardness and sufficient adhesion strength. However, the TiAlN coating deposited on the substrates with a higher TiC content shows the better wear resistance in turning titanium (TC4), which can be attributed to it having the highest adhesion strength.