Tool Wear Mechanisms Research Articles

On the tool wear mechanism of machining Zr-based bulk metallic glasses under varying corner radii

Revealing the tool wear mechanisms of machining Zr-based bulk metallic glasses (BMGs) is important for the processing of BMGs in engineering applications. The tool wear mechanisms of machining BMGs with PCBN tools under varying corner radii were investigated, and the results shown that the adhesive and oxidation wear were the main wear mechanisms. The low thermal conductivity of the BMG workpiece material increased the cutting temperature. The effect of corner radius on tool wear mechanism was characterized by the normal stress fields. It indicated that the extremely high maximum normal stress was the main reason for edge chipping. Finally, the influence of tool wear state on machined surface quality was related to the machined surface morphology. The findings have shown that the edge chipping and adhesive wear produced feed marks, material side flow and adhensions on the machined surface, leading to the increase of surface roughness.

The Study of Tool Wear Mechanism Considering the Tool–Chip Interface Temperature during Milling of Aluminum Alloy

ADC12 aluminum alloy has been widely used in the aerospace, ship, and automotive fields because of its high specific strength, excellent die-casting performance, and wear resistance. Adhesion wear is the main wear mechanism of high-speed milling ADC12 aluminum alloy. The most important factor affecting adhesion wear is the tool–chip interface friction, which is directly manifested in the tool–chip interface temperature. Therefore, the temperature variation during the milling of aluminum alloy is analyzed using a temperature field model and infrared temperature measurement technology. Then, the tool wear morphology and the tool wear land width are observed using a scanning electron microscope. Finally, the tool wear mechanism considering the tool–chip interface temperature is discussed. The tool–chip interface temperature is related to the friction angle, tool–chip contact length, and friction force at the rake face, which increases first and then decreases as the cutting speed and feed rate increase. During the formation of the adhesive layer, the tool–chip interface temperature increases, the change rate of the cutting force and the tool wear rate increase, and adhesion, oxidation, and abrasive and delamination wear are generated on the tool surface. With the increase in temperature, the tool wear rate increases, the molten adhesive layer on the tool surface is accompanied by crack propagation, and adhesion wear, oxidation wear, and abrasive wear occur on the tool surface.

Identification of tool wear and surface morphology measurements in sustainable milling of Al 6082 hybrid metal matrix composite

Aluminium hybrid metal matrix composites have significantly increased in many advanced applications owing to their unique properties. However, these hybrid composites are difficult to machine because of hard reinforcements in the matrix. After identifying the optimum cutting conditions, it's crucial to identify the tool wear mechanisms to keep surface roughness within the desired range, especially with hybrid composites. Hence, the present work mainly focuses on identifying the wear mechanism of PVD-coated TiAlN cutting tool inserts during the end milling of Al 6082 hybrid metal matrix composites. MQL, CO2, and a combination of MQL + CO2 cooling conditions were employed over the cutting zone to decrease tool wear. In the context of 300 mm of cutting length, employing CO2, MQL, and MQL + CO2 conditions led to a significant reduction in tool wear by 34.5 %, 50.1 %, and 74.7 %, respectively, compared to dry cutting. The results showed that the MQL + CO2 condition produced better results than the other cooling conditions, improving tool life and surface quality.

Effects of Hybrid Nanocooling-Lubricants MQCL on Machining Temperature and Tool Wear Mechanisms under Turning Process of Titanium Alloy

Effects of Hybrid Nanocooling-Lubricants MQCL on Machining Temperature and Tool Wear Mechanisms under Turning Process of Titanium Alloy

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.

Simulation and experimental study of the hole-making process of Ti-6Al-4V titanium alloy for selective laser melting

Towards improving the hole-making accuracy and surface quality of titanium alloy workpieces after selective laser melting (SLM), this paper carried out simulation and experimental research on hole processing. Specifically, it is divided into three process methods: directly milling without preformed holes, milling SLM-formed preformed holes, and drilling SLM-formed preformed holes, compared and studied the dimensional hole accuracy, surface morphology, cutting force, and tool wear, analyzing chip and burr formation mechanism. Firstly, the geometric model of SLM titanium alloy workpiece containing features such as collapse, sticky powder, and lack of fusion hole was established by ABAQUS finite element software, and cutting simulation analysis was conducted based on Johnson-Cook failure criterion to investigate the stress distribution and cutting force variation law under different hole diameter and cutting speed; Then hole-making experiments with hole diameters ∅1 mm-∅3 mm were conducted, and the experiment results showed that: The surface quality of milling SLM-formed preformed holes is better, as shown by smaller burr size, stable chip pattern, less tool wear, better hole size, and best overall forming quality; the average error rate of drilling SLM-formed preformed holes was the smallest 1.458 %, and dimensional accuracy improved by 67.3 %, but they had larger burr sizes and slightly poorer surface quality. The axial force obtained by a higher cutting speed and lower material removal rate at the same bore diameter is small. The experiment results verify the accuracy and validity of the simulation analysis, and the average error of the simulation results is 8.4 %.

An FEM-ANN Based Analysis of Cutting Force and Cutting Tool Deflection to Predict Tool Wear in Double Tool Turning Process

In the conventional turning process, cutting forces and cutting tool deflection plays an important role in tool wear mechanism. The cutting tool is subjected to uneven wear due to heavy cutting forces. This further leads to shear deformation of the tool which ultimately affects the surface texture of the workpiece. In this paper, an experimental setup is designed and fabricated which can hold rigidly the two cutting tools namely, the front and rear tool in opposite direction. Moreover, to check its robustness and feasibility, the numerical modelling of the experimental setup is performed using the experimental data. A total of nine simulation runs were performed according to the machining parameters used in the experimental study to check the accuracy of the Finite element model. Additionally, these experimental values of resultant cutting force were used to obtain the resultant deflection of both the cutting tools through simulation tests. Finally, the values of resultant cutting force and the resultant deflection of both the tools were predicted using Artificial Neural Networks (ANN) and compared to estimate the tool wear. It was found that the experimental results were in good agreement with the ANN predicted results.

Experimental and statistical investigation into surface characteristics in micro milling of bottom pouring/gravity stir cast Al6061 alloy

Micro milling offers the best way to create micro channels; however, the burr formation and surface roughness of the micro channel are difficult to control. Micro channel fabrication and their characterization of stir cast Al6061 are rarely investigated. In the present study, Al6061 alloy was processed by the bottom pouring stir casting method. The micro channels were fabricated on a base and stir cast Al6061 alloys using TiSIN-coated micro end mill tools. The influence of micromachining parameters such as spindle speed, feed rate, and depth of cut on burr formation, cutting force, burr size, and surface roughness was investigated. A comparison was made between the findings obtained from the micro milling of the base and stir cast Al6061 alloys. The surface morphology of fabricated micro channels was analysed and correlated with the roughness profile to understand the channel profile and burr formation. The top burr formation mechanism in stir cast Al6061 alloy was investigated in detail. Low feed rate, low depth of cut, and high spindle speed produced the micro channel with fewer burrs, low surface roughness, and low cutting forces. At the optimum parameter, stir cast Al6061 alloy showed an approximate 420%, 16%, and 300% increase in Fy, Fz, and Ra, respectively, as compared to the base Al6061 alloy. Adhesion wear, built-up edge, and microchipping were found to be the main tool wear mechanisms in micro machining of stir cast alloy. This study directs the choice of cutting parameters for the stir cast micro milling process.

Effect of tool wear on machining quality in milling Cf/SiC composites with PCD tool

Carbon fiber reinforced silicon carbide ceramic matrix (Cf/SiC) composites have great application potential in aerospace. But their high hardness and anisotropy cause rapid tool wear during machining, which affects machining quality and efficiency. However, tool wear mechanisms in milling Cf/SiC composites are still unclear. There is a lack of research on the relationship between tool wear and cutting performance. In this paper, milling experiments on 2.5D Cf/SiC composites were conducted using polycrystalline diamond (PCD) cutters. The tool wear mechanisms and effect of tool wear on surface roughness, milling force, burr damage, surface microstructure and chips were explored. The results show that abrasive wear caused by chips continuously scraping tool material and diamond particle fragmentation and falling off caused by sprouting and expansion of cracks inside grain were primary causes of tool failure. The formation mechanism of burr damage was analyzed. It was proved that the peak radius of cutting edge Rpeak and flank wear VB could reflect cutting capabilities. It was found that increasing flank wear had regrinding effects on the cutting edge, which affects the peak radius. The degree of burr damage was related to these two parameters. Tool wear changed the surface formation mechanism. Before tool wear, carbon fibers were primarily removed through the micro-brittle fracture, with low surface roughness. The flank face and chips scratched the workpiece like abrasive grains after tool wear, leaving scratches on the surface and increasing surface roughness from 1.27 μm to 2.25 μm.

Investigation of ultrasonic mechanism and development of tool wear model in ultrasonic elliptic vibration assisted cutting of stainless steel

By analyzing the kinematics and dynamics of ultrasonic vibration under various conditions, the tool wear mechanism in Ultrasonic Elliptic Vibration-Assisted Cutting (UEVAC) were investigated. Two distinct mechanisms for mitigating tool wear emerge: In non-separated UEVAC, the pivotal factor is the reduction of material yield stress through the acoustic softening effect. Conversely, in separated UEVAC, tool wear reduction is attributed to the decrease in average contact stress via stress superposition and the hammer effect. These findings highlight the effectiveness of aligning ultrasonic energy field action times and intensity to reduce stainless steel tool wear rates in non-separated UEVAC. Furthermore, the proposed tool wear model demonstrates robust reliability for separated UEVAC processes.

Investigation of CFRP damages induced by the interface high temperature and mixed tool wear mechanism in drilling of thin-walled CFRP /Ti stacks

Due to the poor thermal conductivity and machinability of CFRP and Ti6Al4V, significant heat accumulation at the interface and rapid tool wear are considered the main factors restricting the hole quality. This study conducted a thin-walled CFRP/Ti stack drilling experiment to investigate the evolution of the thrust force, temperature and tool wear versus different drilled hole numbers and spindle speeds, affected by which the novel material removal behavior was revealed. Results showed that the thrust force and interface temperature increased with the hole number and spindle speed, causing a significant increase in the cutting edge rounding and flank face wear dominated by the many fiber bundles and metal debris. In turn, the various tool wear led radial interface temperature to alternately transfer between Φ = 45° and 135°. Under the cyclic thermo-mechanical function, the fibers underwent significant bending deformation as they lost the support of the degenerated matrix resin, forming severe subsurface damage when the interface temperature exceeded the matrix glass transition temperature (Tg = 110 °C). Combined with the comprehensive evaluation of exit damages, a relatively higher spindle speed was preferred for selecting the initial drilling of thin-walled CFRP/Ti stack and gradually reducing the spindle speed with increasing tool wear extent.

Study on tool wear morphology and mechanism of coated tool on turning austenitic stainless steel

The dry cutting test of austenitic stainless steel 06Cr19Ni10 workpiece material was carried out with YBG205 coated tool. By scanning electron scanning microscope (SEM) and energy dispersive spectrum (EDS), the wear morphology and wear mechanism of the tool were analysed. The results showed that when cutting the stainless steel 06Cr19Ni10 with YBG205 coated tool, the main wear morphologies of the tool were flank wear, boundary wear, and tip damage. The wear mechanism were mainly adhesive wear and diffusion wear.

Experimental investigation on the machining performance of AISI D2 tool steel during ultrasonic-assisted turning under dry and MQL conditions

Ultrasonic-assisted turning (UAT) is a hybrid machining method that improves difficult-to-cut materials’ machinability and surface integrity. Minimum quantity lubrication (MQL) is a cooling condition employed in metal cutting operations to improve machining performance and environmental sustainability. This article presents the experimental investigations on the effect of machining and vibration parameters and cooling conditions on the surface roughness (Ra), flank wear (Vb), and surface hardness (HV) during UAT of AISI D2 tool steel. Experiments were designed based on L36 orthogonal array. Two levels of spindle speeds, feed rates, depth of cut, and three levels of percentage intensity of ultrasonic power (PIUP) were employed, and two cooling conditions, like dry and MQL. Analysis of variance (ANOVA) was used to find the significant input parameters that affect each response. ANOVA output revealed that feed rate was the most influential factor on Ra, the PUIP is the dominant factor on HV, and spindle speed is the significant factor on Vb. Optimisation is performed to find optimal parameters as per Taguchi multi-response method. The optimal parameters are 450 rpm spindle speed, 0.05 mm/rev feed rate, 0.1 mm depth of cut, 100 PIUP and MQL cooling resulted in minimum surface roughness of 0.439 μm, maximum hardness of 283 HV and minimum flank wear of 168 μm. Flank wear morphology results showed that abrasion and chipping are the tool wear mechanism in dry UAT, whereas minor abrasion alone was found in MQL UAT compared to CT. Chip morphology study showed that UAT produced continuous spiral-type chips under both cooling conditions compared to CT. A novel design approach is implemented to design the UAT tool. Along with the UAT tool, MQL is also given to improve the machinability of D2 tool steel. This UAT tool can machine intricate metals with a critical cutting velocity of less than 75.4 m/min.

A comprehensive research on wear resistance of GH4169 superalloy in longitudinal-torsional ultrasonic vibration side milling with tool wear and surface quality

To improve the service and machining performance of the workpiece, the tool wear mechanisms, surface machining quality, and wear resistance in conventional side milling (CSM) and longitudinal-torsional ultrasonic vibration side milling (LTUVSM) of GH4169 superalloy at different cutting lengths are investigated systematically. Tool wear mechanisms are revealed and the correlation between machined surface quality with tool wear is analyzed correspondingly. Tool wear patterns mainly include adhesive wear, diffusion wear, abrasive wear, and chipping sticking. Better surface quality is achieved in LTUVSM due to a maximum reduction of flank wear bandwidth and wear rate by 71.9% and 71.5%, respectively, compared to CSM. The friction coefficient, initial wear stage time, and wear volume of dry sliding wear were measured to evaluate the workpiece wear resistance. The maximum reductions in friction coefficient and wear volume in LTUVSM are 18.2% and 15.8% compared to CSM. The regular ultrasonic vibration textures suppress the friction and the growth of contact nodes in the contact area, decreasing the degree of surface wear, which is demonstrated by a 38.8% increase in initial wear stage time compared to CSM. In conclusion, the workpiece in LTUVSM exhibits higher wear resistance because of the improvement of tool wear and the guarantee of surface quality.

Research on tool stick-slip erosion wear mechanism in cutting nickel-based alloy GH4169

Nickel-based superalloys GH4169 are typical hard-to-machine materials. It can still maintain high strength and hardness at high temperatures, so the tools for cutting nickel-based superalloys are worn seriously. In this paper, the tool wear mechanism when cutting nickel-based superalloy using YG8 (K-type cemented carbide tool) is studied. The stick-slip erosion wear mechanism of cutting tool is put forward in this paper. At high temperature, micro plastic deformation and macro sliding occurs when the chip slides against the tool surface, resulting in wear similar to that of a viscous liquid when it erodes a solid. Erosion wear has a latent period. The faster the cutting speed, the worse the wear is. When chip stick-slip erodes the tool, two adiabatic zones are generated. One is the adiabatic impact zone I generated on the front surface of the tool. The other is the adiabatic shear band II formed under chip compression. The adiabatic impact zone I causes the temperature of tool surface to rise sharply. After high-temperature erosion, the surface of the cutting tool exhibits wear patterns such as lips, pits, layers, and furrows. Among them, the lips are a typical morphology of erosion wear, but the quantity is relatively small. Pits and layers are the main morphological features after erosion wear. The main reason for the above characteristics is that GH4169 has a small deformation coefficient and weak chip deformation ability. Therefore, most lips are impacted and sheared by micro-convex bodies, ultimately leaving pits on the tool surface. In addition, when a portion of the lip has not yet formed, the fracture of the cell boundary cracks in the adiabatic shear zone leads to the occurrence of lamellar detachment, leaving a lamellar damaged surface.

Study on Characteristics of Tool Wear and Breakage of Ultrasonic Cutting Nomex Honeycomb Core with the Disc Cutter

Ultrasonic cutting is an advanced technology for processing Nomex honeycomb materials. The disc cutter is one of the most commonly used tools, whose wear and breakage state have an important impact on the honeycomb material machining process. Currently, the disc cutter lacks systematic characterization methods, and its tool wear laws are not yet clear. This paper conducts a wear experiment of the disc cutter in an ultrasonic cutting Nomex honeycomb core and proposes the attributes of cutting edge rounding (CER), flank wear VB, diameter reduction, and cutting edge breakage width to characterize the tool wear and breakage forms quantitatively. Moreover, the tool wear and breakage forms of the disc cutter are categorized, and the variation laws of the disc cutter wear and breakage characteristics are studied. The experimental study reveals that the wear forms of the disc cutter are mainly cutting edge dulling and flank wear. The CER and flank wear VB increase with increasing cutting length, and the wear mechanism is mainly abrasive wear. The breakage forms are mainly chipping and cracking breakage. The diameter reduction changed slowly, and the cutting edge breakage width tended to increase. The surface quality of the honeycomb gradually deteriorates with the increase of tool wear and breakage. The experimental results are important to study the tool wear mechanism of ultrasonic cutting of the Nomex honeycomb core with the disc cutter as well as tool design and manufacture.

Surface integrity and acoustic emission characteristics during slot milling 3D carbon/carbon composites using superabrasive diamond grinding point

This study mainly investigated the effect of machining parameters on surface morphology and defects in three-dimensional carbon/carbon ceramic matrix composites during slotting with superabrasive diamond grinding points. Specifically, it discussed the mechanisms of burr and uncut fiber formation based on the relationship between grinding and fiber directions. The experimental work was conducted under different spindle speeds and feed speeds, revealing that the poor machining surfaces and severe defects occurred at the minimum spindle speed (2000 rpm) with maximum feed speed (160 mm/min), and most uncut fiber defects occurred when the fiber cutting angle exceeded 90°. Acoustic emission (AE) signals were analyzed via signal processing techniques to capture the energy and frequency characteristics of slotting process under various machining parameters. Results indicated that spindle speed had a significant impact on the frequency band distribution of AE signals, while feed speed primarily influenced the stability of signal profiles. The material removal and tool wear mechanisms were examined through SEM micrographs of machined surfaces and grinding points, revealing that fiber debonding and fracture were the primary material removal mechanisms, and were highly dependent on the fiber cutting angle. Abrasive particles with relatively lower cutting velocity at the center of the grinding tool suffered severe damage/wear.

Effect of T6I4 and T616 on the machinability of 7075 aluminum alloy and tool wear mechanism

Effect of T6I4 and T616 on the machinability of 7075 aluminum alloy and tool wear mechanism

Researches on tool wear progress in mill-grinding based on the cutting force and acceleration signal

Tool wear progression has greatly impact on the machining quality, tool wear evaluation is useful to obtain tool states. Mill-grinding experiments are performed using the electroplated diamond tool to reveal tool wear progression. Both time and frequency domain, dimensional and dimensionless characteristics of cutting force and acceleration signals are analysed. Among time domain characteristics, peak and average values exhibit low and stable amplitudes at the initial wear stage, and evolve to large and fluctuant amplitudes at the severe wear stage. For frequency domain analysis, gravity frequency exhibits a decrease trend with tool wear progression. Among dimensionless characteristics, kurtosis and margin factors show a maximum value when tool wear progression goes into the severe wear stage, and can be applied to evaluate tool wear progression. Tool wear modes include the wearing flat process and fracture of diamond grains, tool wear mechanisms include the abrasive wear, adhesive wear and grain fracture.

Design of discrete-edge polycrystalline diamond tool and its cutting performance in milling Cf/SiC composites

Carbon fiber-reinforced silicon carbide matrix (Cf/SiC) composites are used extensively in many fields because of their superior properties, such as high specific strength and high specific modulus. However, Cf/SiC composites are typically difficult to machine materials due to their high hardness and anisotropy. Its machining easily leads to high cutting force, short tool life, and poor surface quality. The tool structure shows a significant impact on the cutting performance, which can further affect the cutting force and surface quality. In this study, a novel polycrystalline diamond (PCD) tool with discrete-edge structure was designed for milling Cf/SiC composites, which was devised with tiny microgrooves on the peripheral edge, and the geometric parameters were optimized by finite element simulation method. The cutting performance of the designed discrete-edge PCD tool in milling of Cf/SiC composites was studied. Cutting force, machined surface quality, tool wear mechanisms, and tool life were comprehensively investigated. Comparative experiments were also carried out with conventional straight-edge PCD tools by using identical cutting parameters. The cutting force when using the discrete-edge PCD tool gradually decreased with increasing cutting speed. The machined surface roughness Sa reached 3.5 μm at cutting speed of 125 m⋅min−1 with the discrete-edge tool. Surface defects in terms of fiber pullout, debonding, and cavities were reduced by the discrete-edge tool. The life of the discrete-edge PCD tool was 1.875 times that of the conventional PCD tool. The study illustrates that the cutting performance of the designed discrete-edge PCD tool is better than that of the conventional straight-edge PCD tool.