Increase In Tool Wear Rate Research Articles

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.

A comparative study relating machining properties and surface characteristics of Inconel 625 during powder mixed electric discharge machining

In the current study, the machinability during the machining with powder mixed electric discharge machining was studied on Inconel 625 sample along with their surface characteristics. During the machining, separatelythree powders viz. titanium, graphite and silicon carbide were mixed in EDM oil dielectric fluid with a concentration of 4 g/l. The other electric parameters were kept constant. The comparative study was made to study the changes in MRR, surface roughness and tool wear rate. The analysis clearly indicates that. by the addition of titanium, graphite and silicon carbide in the order, the MRR decreases, surface roughness increases and tool wear rate increases. The SEM results of the machined sample indicate that the surface unevenness is increasing with changing of powders. The EDX result of the surface correlated the amount of copper transferred to the surface and the tool wear rate . Like the SEM result, EDX result also indicated the enhancement of the tool wear during the machining of above-said order of the powders.

Experimental investigation on simultaneous machining of EDM and ECM with different electrode materials

In order to improve the machining efficiency and the surface quality of EDM/ECM, adding a small amount of sodium nitrate into deionized water as the working medium, a novel simultaneous machining approach of EDM and ECM (SEDCM) was developed. In this work, a comparative study was conducted on the SEDCM performance of TC4 alloy using different electrode materials viz. brass, copper and copper-tungsten alloy. In addition, the effects of process parameters, such as peak current, pulse on time and gap voltage on material removal rate (MRR), tool wear rate (TWR), surface roughness (Ra), and surface micromorphology were investigated. The results show that brass electrode provides the smallest MRR, the highest TWR and the worst surface quality. The copper electrode has the smallest average diameter of a single discharge craters and the best surface finish. The MRR and TWR of copper-tungsten electrode are similar to those of copper electrode. As peak current increases, TWR increases and Ra deteriorates for all the electrodes, as well MRR increases and then decreases for copper and copper-tungsten electrodes. Increase in pulse on time and gap voltage, MRR and TWR increases and then decreases gradually. At higher pulse on time and gap voltage, Ra becomes greater for three type electrodes.

Effects of Tool Coatings on Energy Consumption in Micro-Extrusion of Aluminum Alloy 6063

The tool wear rate and energy consumption were typically unknown in micro-extrusion, which made it difficult to optimize the tool design for both the final part quality and production cost. This study investigated the effects of tool coatings on energy consumption in the micro-extrusion of aluminum alloy 6063. Three main factors were considered in this study: (1) tool coating types, (2) bearing length, and (3) extrusion ratio. The micro-extrusion finite element simulation model was developed and validated with the micro-extrusion experiment. The results showed that increasing bearing lengths led to the increase in tool wear rate and energy consumption for all the coating types. The decreasing coefficient of friction values of the tool-billet interface led to a decrease in energy consumption. High hardness values of the tool surface and low bearing lengths helped increase tool life. Low values of coefficient of friction and bearing lengths helped decrease energy consumption.

Effect of cryogenic cooling and tool wear on surface integrity of turned Ti-6Al-4V

The aim of this work is to investigate the influence of flank wear and cutting fluid (emulsion vs. liquid nitrogen) on surface integrity in turning of titanium alloy Ti-6Al-4V. Longitudinal turning tests with pre-worn uncoated cemented carbide inserts are performed, after which the surface and subsurface layer of machined workpieces is studied. Results for residual stresses on the surface as well as in depth profiles, obtained by X-ray diffraction, are also presented. Scanning electron microscopy (SEM) is used to investigate the microstructure of the workpieces. The same tool holder was used for both cooling conditions, with the same nozzle configuration. The flow rate of liquid nitrogen was therefore limited and as a result, tool wear development was observed to be faster for cryogenic cooling than emulsion-based flood cooling. However, the results show limited differences in terms of achievable residual stresses when comparing cryogenic and conventional cooling at similar levels of tool wear. Despite an increase in tool wear rate, the cryogenic cooling conditions thus provide similar surface integrity results as emulsion cooling. The results suggest that the consumption of the cryogenic coolant can be reduced or optimized without a significant impact on surface quality.

Experimental investigation of the effects of tool initial surface roughness on the electrical discharge machining (EDM) performance

Electrical discharge machining (EDM) has become an essential process in the modernized manufacturing, as it has been applied in diverse applications such as die cavities manufacturing for automotive components, connecting rods, and different intricate shapes. The proper choice of EDM machining conditions is one of the most critical aspects to consider in the die-sinking electrical discharge machining, as they have great influence on machining performance. Among the parameters and conditions that may affect the machining characteristics, the electrode’s initial surface roughness has not been considered in previous researches. In this study for the first time, the effects of the tool initial surface roughness on the EDM performance are investigated. Experiments are conducted on a die-sinking EDM machine with several different tool initial surface roughness values and EDM parameters to find out the effects on the EDMed workpiece surface roughness, tool wear rate (TWR), material removal rate (MRR), and the tool surface roughness after machining. The results show that TWR increases and MRR decreases by increase in tool surface roughness during finish, semi-rough, and rough EDM processes. In addition, workpiece surface roughness after EDM machining slightly depends on initial tool surface roughness, while the tool surface roughness after machining depends greatly on EDM machining parameters.

Investigation of Weight Percentage of Alumina Fiber on EDM of Al/Al2O3 Metal Matrix Composites

This paper aims to study the influence of Al2O3 particle addition to Al alloys. The effects of reinforcement volumes in a metal matrix alloy on response variables were investigated towards the highlighting of this process with the goal of achieving high process performance. In this study, the comparison between EDM of Al/Al2 O 3 metal matrix composites with different volumes of reinforcement and 2024 alloys was investigated to determine the influence of weight percentage of Al2 O 3-reinforced particles on output parameters. The results show that addition of Al2 O 3 particles in the composites has significant effects on material removal rate, surface roughness and tool wear rate. Tool wear rate and surface roughness were increased with increased Al2 O 3 ceramic contents. Surface roughness was obviously affected by the discharge current as well as pulse on-time. Rapid increase in tool wear rate was seen when reinforced with higher weight percentage of Al2O3 particles. The pulse on-time and discharge current significantly affect the material removal rate, tool wear rate and surface roughness. Tool wear rate, material removal rate and surface roughness were high if the discharge current and pulse on-time were set at a higher level. In other words, high current and pulse on-time resulted in high tool wear rate, material removal rate and surface roughness. The material removal rate was decreased by increasing the weight percentage of Al2O3 particles.

Comparative Analysis of the Performance Effectiveness of Sinking Electrical Discharge Machining (EDM) process with Enhancement in Hardness of the parent EN-31 Alloy Steel

This paper presents an investigation on Comparative analysis of the effect in sinking electrical discharge machining (EDM) process on EN-31 super alloy steel using Response surface methodology (RSM) approach with four controllable input parameters such as Pulse on time (TON), Pulse off time (Toff), Peak current (I P) and Gap voltage (V) for analysis of Material removal rate (MRR) and Tool wear rate (TWR) as the desired quality targets. The design matrix for experimentation with different treatment conditions is chosen utilising Central Composite Design (CCD) with rotability. It is confirmed that Enhancement of hardness has a predominant effect on the output responses like MRR and TWR. In this study, the variability of reduction of MRR and increase in Tool wear rate (TWR) are represented through mathematical modelling .This preliminary assessment for the deviation will be quite useful for the control settings in the job shop production reducing set-up cost and the lead time in the computer integrated manufacturing environment.

Electric Discharge Machining of Cryo-Treated NiTi Alloys

NiTi alloys possess superior material properties such as high specific strength, high corrosion resistance, high wear resistance and high anti-fatigue property. Due to these properties it is difficult to machine these alloys using conventional machining process. Nowadays non-conventional machining processes are widely used for machining such adavanced materials. Electrical Discharge machining (EDM) is one such non-conventional process, which can machine electrically conductive materials of any hardness values. Present study aims at drilling mesoscale 3 mm square holes on NiTi alloy by varying the electrical parameters namely, gap current, pulse on time and pulse off time. Additional, the present work includes finding out the effect of cryogenic treatment of NiTi work material on electrical discharge machining performance measures namely material removal rate (MRR) and tool wear rate (TWR). Based on experiments conducted, it can be concluded that with increase in current both material removal rate and tool wear rate increases. It is also noted that cryo-treatment of workpiece material improves MRR with respect to gap current. Similarly there is an increase in MRR with respect to pulse on time and pulse off time for cryo-treated workpiece material. There is a slight improvement of TWR with respect to gap current, pulse on time and pulse off time for cryo-treated workpiece material.

EFFECT OF CHROMIUM POWDER MIXED DIELECTRIC ON PERFORMANCE CHARACTERISTIC OF AISI D2 DIE STEEL USING EDM

In this paper, the effect of chromium powder mixed dielectric fluid on machining characteristics of AISI D2 die steel has been studied. Peak current, pulse on time, pulse off time, concentration of powder are the process parameters. The process performance is measured in terms of material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR). The research outcome will identify the important process parameters that maximize MRR, minimize TWR and SR. The design of experiment has been undertaken using Taguchi method. ANOVA analysis has been used to investigate the percentage contribution of each process parameter for optimizing the performance. The study indicates that all the selected parameters except pulse off time have a significant effect on MRR. Current is found to be the most significant factor for MRR and TWR. With increase in current, TWR increases. Also, surface roughness increases with increase in pulse off time.

An experimental investigation of pulsed laser-assisted machining of AISI 52100 steel

Abstract Grinding and hard turning are widely used for machining of hardened bearing steel parts. Laser-assisted machining (LAM) has emerged as an efficient alternative to grinding and hard turning for hardened steel parts. In most cases, continuous-wave lasers were used as a heat source to cause localized heating prior to material removal by a cutting tool. In this study, an experimental investigation of pulsed laser-assisted machining of AISI 52100 bearing steel was conducted. The effects of process parameters (i.e., laser mean power, pulse frequency, pulse energy, cutting speed and feed rate) on state variables (i.e., material removal temperature, specific cutting energy, surface roughness, microstructure, tool wear and chip formation) were investigated. At laser mean power of 425 W with frequency of 120 Hz and cutting speed of 70 m/min, the benefit of LAM was shown by 25% decrease in specific cutting energy and 18% improvement in surface roughness, as compared to those of the conventional machining. It was shown that at constant laser power, the increase of laser pulse energy causes the rapid increase in tool wear rate. Pulsed laser allowed efficient control of surface temperature and heat penetration in material removal region. Examination of the machined subsurface microstructure and microhardness profiles showed no change under LAM and conventional machining. Continuous chips with more uniform plastic deformation were produced in LAM.

Research on Tool Wear Rate of Powder Mixed near Dry Electrical Discharge Machining

Powder mixed near dry electrical discharge machining (PMND-EDM) is one of the novel EDM processes, which uses gas-liquid-powder mixture as the dielectric medium. The tool wear rate (TWR) in PMND-EDM is researched based on single factor experiments. Effects of process parameters, such as peak current, pulse on time, pulse off time, flow rate, powder concentration, tool rotational speed and air pressure, on TWR are found out. TWR increases with the increase of peak current. TWR decreases with increasing of pulse on time. TWR increases firstly and then decreases while pulse off time increases. Increase of flow rate results in the increase of TWR. With the increase of powder concentration, TWR increases firstly and then decreases. Existence of tool rotation facilities decrease of TWR, however, further increase of rotational speed leads to increase of TWR. Increase of air pressure leads to lower TWR.

An investigation of tool wear and the vibration spectrum in milling

The findings of an experimental study conducted on carbide face milling cutters wherein the effect of the interaction between the tool wear and the vibrations that occur during the process was investigated are reported. The effect of the machine tool-cutting tool-workpiece (MCW) system stiffness on tool wear was also investigated. It is demonstrated that the vibration behaviour of the MCW system is characterized by a number of frequencies, each of which corresponds to a particular element or unit of the MCW system. It is shown that the increase in tool wear rate due to the presence of vibration is mainly governed by the stiffness of the MCW system elements which are responsible for the high frequency components of the vibration spectrum. The increase in vibration frequency was, in general, observed to lead to higher tool wear rates, provided that the vibration amplitudes are in excess of a certain critical value. From the point of view of tool wear, the vibrations of the cutter blade were found to be the most crucial, as they are characterized by high frequency as well as sufficiently large amplitudes.