Reduce Tool Wear Research Articles

Effects of cryogenic gas jet cooling on milling surface roughness and tool life for GH4169 alloy additive manufacturing parts

Hybrid additive and subtractive manufacturing is development in metal additive manufacturing techniques, wherein the dry cutting cooling method for subtractive cutting is one of the key technologies. To improve the milling performance of GH4169 alloy (namely Inconel 718 nickel-based superalloy) additive manufacturing parts, a dry cutting cooling method with a cryogenic gas jet and its effects on the cutting performance were investigated in this study. The theoretical model of the cryogenic gas jet flow was established, and the geometric characteristics, motion characteristics, and temperature distribution of the jet flow were analyzed. Meanwhile, considering the design of the nozzle outlet, the jet flow core length with a single nozzle and jet flow field envelope effect on the cooling heat transfer process with multiple nozzles were analyzed using a finite element simulation. Then, milling experiments on GH4169 alloy additive manufacturing parts with different cryogenic gas jet flow parameters were carried out. To reduce tool wear and the machined surface roughness of various parts, the jet flow parameters were optimized using the response surface analysis method. The effects of the milling feed direction on the tool wear and machined surface roughness were investigated. Furthermore, the tool wear morphologies were observed under different continuous milling times. The chemical compositions of the worn zone and tool wear mechanism were analyzed. The results show that cryogenic gas jet cooling can significantly improve the tool life and machined surface roughness of parts for GH4169 alloy additive-manufacturing-part milling, and the continuous cutting time within the tool wear allowance can reach approximately 50 min.

Antibacterial Coating on Filtration Membranes for Treatment of Cutting Fluid

Abstract: Cutting fluids has greater significance in manufacturing processes to ensure work-piece quality, to reduce tool wear, and to improve process productivity. The specific chemical composition of an applied coolant should be strongly dependent on the scope of application. Even small changes such as presence of microorganisms such as Staphylococcus, Streptococcus, Pseudomonas, Alcaligenes etc. can influence the performance of cutting fluid and introduce risk of various skin diseases to the operator in the manufacturing processes considerably. In this project the antibacterial coating is brought into use by coating a thin layer of silver nano particles on a polypropylene filtration membrane. A coated and non-coated membrane was placed separately on the cutting fluid sump of a vertical milling machine. 10litres of cutting fluid with a Servo cut Soil content of 5% and distilled water with a concentration of 95% were used in the machine while a milling process was carried out. Then a sample of cutting fluid (about 250mL) was taken from the tank and preserved for testing purposes after passing through the filter membranes. On the same cutting fluid, the machine was run for another two days, and a third sample was taken at the end of the fourth day. The samples collected were tested at Azyme Biosciences Pvt Ltd for bacterial count (CFU/ml) and the results showed that the CFU/ ml in the sample filtered through the non-coated polypropylene filtration membrane was higher than in the sample filtered via coated polypropylene filtration membrane.

Performance of Al2O3/TiO2 Hybrid Nano-Cutting Fluid in MQL Turning Operation via RSM Approach

Cutting fluids can be used to cool workpieces at high cutting speeds and remove chips from cutting zones. The effectiveness of cutting fluids may be improved with the addition of hybrid nanoparticle dispersion. This study evaluates the effectiveness of an Al2O3-TiO2 hybrid as a cutting fluid in turning operations. The Al2O3-TiO2 hybrid nano-cutting fluid was prepared using a one-step method in computer numerical control (CNC) coolant with concentrations of up to 4%. Utilizing air-assisted nano-cutting fluids injected through a minimum quantity lubrication (MQL) setup, the effectiveness of turning cutting performance, cutting temperature (°C), average surface roughness (Ra), and tool wear (%) were evaluated. Then, the response surface method (RSM) was utilized as the design of experiment (DOE) to optimize the turning cutting performance parameters. The combination of 4% hybrid nano-cutting fluid concentration, 0.1 mm/rev feed rate, and 0.55 mm depth of cut yielded the lowest cutting temperature, surface roughness, and tool wear values of 25.3 °C, 0.480 µm, and 0.0104%, respectively. The 4% concentration of Al2O3/TiO2 hybrid nano-cutting fluid inclusion achieved the highest surface roughness reduction that led to better surface finish and the lowest tool-wear reduction led to longer tool life. Therefore, Al2O3/TiO2 hybrid nano-cutting fluids were strongly recommended in turning operations for CNC lathes.

Investigation of Surface Integrity of Selective Laser Melting Additively Manufactured AlSi10Mg Alloy under Ultrasonic Elliptical Vibration-Assisted Ultra-Precision Cutting.

Additive manufacturing technology has been widely used in aviation, aerospace, automobiles and other fields due to the fact that near-net-shaped components with unprecedented geometric freedom can be fabricated. Additively manufactured aluminum alloy has received a lot of attention, due to its excellent material properties. However, the finished surface of additively manufactured aluminum alloy with nanoscale surface roughness is quite challenging and rarely addressed. In this paper, a novel machining technology known as ultrasonic elliptical vibration-assisted cutting (UEVC) was adopted to suppress the generation of cracks, improve the surface integrity and reduce tool wear during the ultra-precision machining of selective laser melting (SLM) additively manufactured AlSi10Mg alloy. The experimental results revealed that, in the conventional cutting (CC) process, surface defects, such as particles, pores and grooves, appeared on the machined surface, and the machined surface rapidly deteriorated with the increase in cumulative cutting area. In contrast, an almost flawless machined surface was obtained in the UEVC process, and its roughness value was less than 10 nm. Moreover, the tool wear of the CC tool was remarkably greater than that of the UEVC tool, and the standard flank wear width of the CC tool was more than twice that of the UEVC tool. Therefore, the UEVC technology is considered to be a feasible method for the ultra-precision machining of SLM additively manufactured AlSi10Mg alloy.

Experimental and 3D-Deform Finite Element Analysis on Tool Wear during Turning of Al-Si-Mg Alloy

Aluminum alloys are becoming increasingly significant in the manufacturing industry due to their light weight and durable properties. Widely applied in aerospace and construction, precision machining is required to ensure the best possible surface quality. The surface quality of a machined component is directly affected by the tool wear incurred during machining. This research investigated the effect of process parameters and machining conditions on tool wear. The critical process parameters selected were cutting speed, feed rate, and depth of cut. Multi-walled carbon nanotube particles were dispersed in a base fluid of mineral oil to create a new lubricant applied during machining. Pure mineral oil was also used as a lubricant to reduce friction. Machining experiments were carried out with the two lubricants, and the tool wear incurred was measured and compared using a Dinolite microscope. All experiments were carried out with high-speed steel (HSS) cutting tools. Taguchi’s L9 orthogonal array was employed as a methodology to design the experiments. A finite-element 3D simulation was also carried out using DEFORM-3D to provide a scientific explanation of the turning process. Results showed a significant reduction in tool wear when machining with multi-walled carbon nanotubes (MWCNTs), with an average reduction of 14.8% compared to mineral oil. The depth of cut was also the most influential process parameter in terms of tool wear.

Investigation of mechanical processing during milling

The development of the engineering industry is determined by the efficiency of the technological processes used in it. In a market economy, improving the quality of products and reducing their costs increase commodity competitiveness and lead to further development of production. The quality and cost of the product produced, the simplicity of its design, labor productivity. On the basis of vibration diagnostics, it was found that the average signal amplitude decreased with increasing force and rigidity as the center of the workpiece was approached, as well as a decrease in the vibration frequency, which had a positive effect on the quality of processing and reduced tool wear.

Evaluation of Surface Roughness, Tool Wear and Chip Morphology during Machining of Nickel-Based Alloy under Sustainable Hybrid Nanofluid-MQL Strategy

Nickel-based super alloys exhibit high strength, oxidation and corrosion resistance; however, the machining of these alloys is a challenge that can be overcome with effective cooling/lubrication techniques. The use of a minimum quantity lubrication (MQL) technique is limited to lower cutting parameters due to the tremendous heat produced during the machining of Inconel 718. Sustainable and eco-friendly machining of Inconel 718 can be attained using MQL and lubricants based on nanofluids because of their improved heat transfer capabilities. For that purpose, the performance of hybrid nanofluid-MQL is examined. In this novel study, graphene and hexagonal boron nitride (hBN) nanoparticles are reinforced with palm oil and delivered to the machining interface using an MQL setup. The machining experiments are performed under the conditions of dry, wet, MQL and MQL with graphene/hBN deposited in palm oil. The machining performance under selected cutting conditions is assessed by analyzing the surface roughness, tool wear, chip morphology and surface quality of the machined workpiece. A comparison of results showcased the effectiveness of hybrid nanofluid-MQL with improvement in surface finish, reduction in tool wear and favorable chip forms concerning all other machining conditions.

Characterization of eco-friendly cutting fluid developed from neem seed oil

Cutting fluid is a key component in retaining workpiece quality, tool life and overall high productivity in machine operations. It is needed as input for minimal surface roughness, minimal tool wear and better machining finished product. This study addressed tool wear and surface roughness by evaluating optimal factor effectiveness of the surface roughness and tool wear during turning of AISI 304 alloy steel using an environmentally friendly fluid. The non-biodegradable and non-recyclable nature of conventional cutting fluids as mineral oils have raised serious concerns with the research community and prompted the renewal of research in this area with focus on replacing the mineral based cutting fluids with environmentally friendly cutting fluids such as neem seed prepared cutting fluid (N-PCF). The neem seed oil (NSO) was sourced locally and characterized by investigating the physiochemical properties as well as it’s fatty acid composition (FAC). The cutting fluid formulation was 1:9 of oil to water in the ratio. The cutting fluids which aided surface roughness and tool wear reduction during turning of the austenitic stainless steel AISI 304 and improved the carbide insert tool was evaluated and compared with mineral oil-based cutting fluid. Also, the response surface method (RSM) of experimental design and Grey relational analysis (GRA) multi-response optimization were employed respectively. The experimental results revealed that the formulated oil showed 8.67 pH value, 0.50 mm2/s viscosity, resistant to corrosion, stable and deep yellowish colouration. The multi-response optimal factor combination obtained from GRA showed multi-response effect of the formulated Neem seed prepared cutting fluid at feed rate of 0.82 mm/rev, depth of cut of 0.65 mm and cutting velocity of 800 rev/min while that of Mineral prepared cutting fluid (M-PCF) was achieved with feed rate (0.82 mm/rev), depth of cut (0.65 mm) and cutting velocity (500 rev/min). GRA and RSM results showed acceptable parameters that contribute to the science of machining and this is in good agreement when compared with those obtained from other cutting fluids used for turning operation.

Turning of titanium alloy with PCD tool and high-pressure cooling

Titanium alloys are difficult to cut materials due to their low thermal conductivity, which leads to intensive tool wear. The general issue is finding the best combination of cutting tool material and cutting conditions to achieve high productivity. This study used PCD cutting tool material in combination with high-pressure cooling (HPC). The main task was to find the most suitable HPC mode (various HPC settings on the rake and flank faces of the cutting tool) and intensity to reduce tool wear at a high cutting speed. Tool wear, chips, and forces were measured, and surface quality was evaluated to gain an understanding of the machining process under these particular conditions. An ANOVA test was used to determine the significance of control factors such as tool life and HPC mode and intensity. The most suitable cutting speed was 300 m/min, where a limit spiral cutting length (SCL) of 3000 m was achieved. Setting the HPC mode revealed the necessity of using the HPC on the rake face. However, the HPC on the flank face further decreased tool wear. HPC intensity should be chosen based on knowledge of the cutting process. A very intense HPC above 140 bars can lead to mechanical damage to the cutting edge or unmachined surface by chip blasting but using a 60-bar HPC can reduce tool wear similarly, without causing further damage to the cutting edge.

PCD 공구를 이용한 초경합금의 V자형 미세 채널 가공

Microchannels machining can be used to make micro molds for microfluidic chips. The fluid flow in the channel can be controlled, by changing the cross sectional shape of the channel. V-shaped channels with a specific angle are not easily made with the etching process. This study presents the mechanical machining of microchannels of V-shaped cross section, on cemented carbide (WC-Co). In this study, to reduce tool wear in the process of machining, the micro conical tool was fabricated using polycrystalline diamond (PCD). The tool wear of the conical tool and form accuracy of channels, were investigated during V-shaped microchannel machining.

A Theoretical and Experimental Investigation of High-Frequency Ultrasonic Vibration-Assisted Sculpturing of Optical Microstructures

Ultrasonic vibration-assisted cutting (UVAC) has been regarded as a promising technology to machine difficult-to-machine materials. It allows for a sub-micrometer form accuracy and surface roughness in the nanometer range. In this paper, high-frequency vibration-assisted sculpturing is used to efficiently fabricate quadrilateral microlens array with sharp edges, instead of using slow-slide-servo diamond turning with vibration. The machining principle of diamond sculpturing, the cutting dynamics of ultrasonic vibration, and the tool edge on the theoretical form error between the designed structure and the machined structure were investigated for this technique. Then, the quadrilateral microlens array was machined by means of conventional sculpturing (CS) and high-frequency ultrasonic vibration-assisted sculpturing (HFUVAS), respectively, followed by a study of the cutting performances including form accuracy, the surface morphology of the machined structure, and the tool wear. Results showed that conventional sculpturing fabricated microlens array with poor form accuracy and surface finish due to couple effect of material adhesion and tool wear, while the high-frequency ultrasonic vibration-assisted sculpturing achieved optical application level with sub-micrometer form accuracy and surface roughness of nanometer due to reduction of material adhesion and tool wear resulted from high-frequency intermittent cutting.

Development and performance of non-edible oil based green cutting fluid in manufacturing

ABSTRACT Cutting fluids are required for machining operations. However, the constituents of the mineral oil-based cutting fluids used in the industry have carcinogenic effects on the human and a negative impact on the environment. Non-edible vegetable oils can be a good potential to be used as a feasible alternative. A cutting fluid is formulated from non-edible vegetable oil using eco-friendly constituents and balancing the lipophilicity and hydrophilicity of the oil. The formulated cutting fluid and its concentrate was found to be stable for a long duration. Performance comparison was carried out with a conventional mineral oil-based cutting fluid and the results shows that the non-edible vegetable oil-based cutting fluid was able to reduce the cutting forces and surface roughness and also there was a significant reduction in tool wear. ANOVA results showed that the type of cutting fluid has a significant contribution on the surface roughness (69.15%) and tool wear (56.85%). The formulated cutting fluid has better performance and the results point positively toward promoting non-edible oil-based cutting fluid in machining.

Comparative Analysis of Stationary and Rotary Electrode on Dry EDM in Machining of Hastelloy C276

Dry EDM is a variation of the standard EDM method in which the liquid dielectric is replaced with a gaseous medium during the machining process. This paper presents comparative analysis of stationary and rotary electrode on Dry EDM in machining of Hastelloy C276 using copper EC grade rod as electrode and air as dielectric medium. Solid cylindrical (stationary and rotary) tool electrodes are used, and high-velocity gas is fed between the electrode and the workpiece through it into the discharge gap. The high-velocity gas flow into the gap assists debris clearance and reduces tool and workpiece overheating at the discharge areas. The dry EDM technique is currently known to have reduced tool wear, a smaller discharge gap, fewer residual stresses, a smaller white layer, and a smaller heat-affected zone, in addition to being ecologically friendly. To improve response factors such as material removal rate (MRR), surface roughness (Ra), and tool wear rate (TWR), Taguchi's L9 orthogonal array approach is utilised to design the trials and study the effects of different process parameters. Discharge current (I), pulse on time (Ton), Voltage (V), pressure (P), and tool rotational speed (N) were the varied input parameters. It is observed that the rotary electrode gives better MRR compared to stationary. The analysis of results show that current (I), pulse on time (Ton) and pulse off time (Toff) are the dominant factors that influence MRR and EWR.

Development of PCBN micro ball-end mill with multi-edge and spherical flank face

Micro mills play an important role in micro-milling applications for precision micro-parts such as optical molds, microsensors, etc. With the wide application of difficult-to-machine materials in such micro-parts, poor machining quality and rapid tool wear have become serious problems restricting the application of micro-milling technology. In order to achieve higher machining quality and longer tool life, a PCBN micro ball-end mill structure with multi-edge and spherical flank face (MSPBM) is designed. This structure enables multiple edges to participate in cutting at the same time, which can share the cutting force to reduce tool wear. In addition, the structure of the spherical flank surface makes the flank surface fully in contact with the machined surface, which enables CBN particles to micro-grind the machined surface to achieve the effect of milling-grinding combined machining, and the better surface quality can be obtained. The grinding experiments are carried out to optimize fabrication process parameters based on grey relational grade theory and the MSPBM with 0.2 mm diameter is fabricated through multi-axis linkage grinding and micro-compensation of motion axes. Then, slot milling experiments are carried out on the martensite stainless steel to investigate the micro-milling performance of the mill, and the surface topography, surface roughness, and the tool wear topography are observed and analyzed. The results show that the surface quality and wear resistance of the MSPBM are improved compared to the standard ball-end mill. The structural design principle of the micro mill can be used to guide the design of mills for high-quality machining of difficult-to-machine materials.

Optimal tool design in micro-milling of difficult-to-machine materials

The limitations of significant tool wear and tool breakage of commercially available fluted micro-end mill tools often lead to ineffective and inefficient manufacturing, while surface quality and geometric dimensions remain unacceptably poor. This is especially true for machining of difficult-to-machine (DTM) materials, such as super alloys and ceramics. Such conventional fluted micro-tool designs are generally down scaled from the macro-milling tool designs. However, simply scaling such designs from the macro to micro domain leads to inherent design flaws, such as poor tool rigidity, poor tool strength and weak cutting edges, ultimately ending in tool failure. Therefore, in this article a design process is first established to determine optimal micro-end mill tool designs for machining some typical DTM materials commonly used in manufacturing orthopaedic implants and micro-feature moulds. The design process focuses on achieving robust stiffness and mechanical strength to reduce tool wear, avoid tool chipping and tool breakage in order to efficiently machine very hard materials. Then, static stress and deflection finite element analysis (FEA) is carried out to identify stiffness and rigidity of the tool design in relation to the maximum deformations, as well as the Von Mises stress distribution at the cutting edge of the designed tools. Following analysis and further optimisation of the FEA results, a verified optimum tool design is established for micro-milling DTM materials. An experimental study is then carried out to compare the optimum tool design to commercial tools, in regards to cutting forces, tool wear and surface quality.

Surface Engineering of Woodworking Tools, a Review

The wide range of applications of wood are due to its strength properties. The mechanical properties of wood in various parts or directions are different. The complex structure of wood and its hygroscopicity prevent the use of coolants and lubricants, resulting in rapid tool wear disproportionate to the hardness of the processed material. This significantly affects machining efficiency and the quality of the processed surface. It seems that an effective method of reducing tool wear is its modification with a thin hard coating produced by the Physical Vapor Deposition or Chemical Vapor Deposition methods. The article presents tool materials used for woodworking, areas for improving the efficiency of their work, and the impact of thin hard coatings on the increase in tool durability, including binary coatings and also doping with various elements and multilayer coatings. Scientific centers dealing with the above-mentioned subject are also mentioned. A brief review of the effects of surface modifications of woodworking tools in the context of their durability is presented. It was found that the most promising coatings on tools for woodworking were multilayer coatings, especially based on chromium. Higher wear resistance was demonstrated by coatings with a lower coefficient of friction. This value was more important than hardness in predicting the service life of the coated tool.

On modelling coolant penetration into the microchannels at the tool-workpiece interface

A network of microchannels is formed at the interface between the cutting tool and the workpiece during machining due to their rough surface structures. The penetration of coolant into these microchannels has a great effect on the machined surface quality by changing the frictional behaviour and heat transfer characteristics of the interfaces. Most of the present studies focus on the macroscopic coolant delivery process but the mechanism of the microscopic penetration phenomena in the channels at the interface remains unclear. Thus, this study proposes a multi-scale and multi-phase comprehensive theoretical model by combining the machining process, coolant flowing in microchannels and lubrication process, to analyse the coolant transportation in the microchannels and investigate its lubrication effects and the friction mechanisms at the interface between the tool and the workpiece. Then, an orthogonal turning testing of Inconel 718 is designed to verify the proposed model. The cooling and lubrication effect of coolant in the microchannels on the reduction of tool wear, contact length, cutting force and temperature has been demonstrated. And the improvement of chip fragment and microstructure has also been revealed.

Impacts of Surface Texture and Nature of Friction on Energy-Force Efficiency of Surface Plastic Deformation during Burnishing

Burnishing, the plastic deformation of the workpiece surface due to sliding contact with a tool called burnisher, is a finishing operation widely used in various industries. In this work, impacts of the initial surface roughness Ra of the workpiece being burnished, the nature of friction in the contact zone, and the clamping force on the stability and energy efficiency of burnishing have been investigated. Experiments have been conducted with and without lubricant, represented by low-viscosity deep-hydrogenated fraction of sour oils, at initial surface roughness Ra of 0.8 and 1.25 μm and variable (100–200 N) clamping force. A key process indicator, which largely controls mechanics of burnishing, the temperature in the tool-workpiece contact zone has been measured using natural thermocouple method. Microhardness of the workpiece surface after burnishing has also been measured. It has been shown that changes in the temperature of the tool-workpiece contact zone are proportional to the changes in the squared tool clamping force. This dependence appeared to be universal and equally applicable to burnishing with and without lubrication. Based on the analysis of the experimental data, a new criterion of the burnishing efficiency has been developed. The new criterion simplifies the choice of optimum operational parameters and helps in preventing adverse impacts of structural phase transformations in the workpiece surface layer that unavoidably lead to reduced product quality and operational reliability and in reducing tool wear, which is critically important in the case of dry burnishing. The obtained results show that the nature of friction accompanying the surface plastic deformation has a significant impact on the stability and energy efficiency of the burnishing process. While the clamping force is equally important for burnishing with and without lubrication, the initial roughness Ra has an impact on dry burnishing only. Application of minimum quantity lubrication (MQL) under experimental conditions typical for industrial burnishing is found to be favorable. In particular, it was shown that MQL not only enhances the stability of burnishing process and but also increases its energy efficiency by more than 20%.

Molecular dynamics simulations of the machining of oxidized and deoxidized titanium work pieces

Advances in the machining of titanium work pieces are of particular interest to areas such as the aerospace and naval industry. However, titanium is known to be a difficult-to-machine material. Recent studies suggest that the presence of oxygen from ambient air has a significant influence on its wear mechanism. Removing oxygen from the system reduces tool wear and therefore improves the surface finish of the tool in the long term. However, the exact mechanism of wear caused by oxygen is still up to debate. In this work, we study molecular dynamics simulations of the cutting process of single crystalline hcp titanium on the (0001) plane with and without an oxide layer. Reference simulations with pure titanium of different crystal sizes are performed in order to reveal size effects. We find that the oxygen layer behaves very brittle compared to the bulk crystal material and influences the chip formation on the nanoscale. Instead of forming a smooth chip, as for pure titanium, the simulation with an oxide layer shows no chip formation at all in the observed time scale. The layer breaks and locally induces high temperatures of ∼1700 K in the material. These high temperatures could lead to enhanced interdiffusion of work piece and tool material and could therefore amplify the predominant tool wear mechanism.

Performance Prediction in EDM Process for Al 6061 Alloy Using Response Surface Methodology and Genetic Algorithm

The Electric Discharge (EDM) method is a novel thermoelectric manufacturing technique in which materials are removed by a controlled spark erosion process between two electrodes immersed in a dielectric medium. Because of the difficulties of EDM, determining the optimum cutting parameters to improve cutting performance is extremely tough. As a result, optimizing operating parameters is a critical processing step, particularly for non-traditional machining process like EDM. Adequate selection of processing parameters for the EDM process does not provide ideal conditions, due to the unpredictable processing time required for a given function. Models of Multiple Regression and Genetic Algorithm are considered as effective methods for determining the optimal processing variables of Electrical Discharge Machining. The material removal rate (MRR) and tool wear (Tw) were investigated using the process variables of pulse on time (Ton), pulse off time (Toff), and current intensity (Ip). The established empirical models were used to perform Genetic Algorithm (GA) to maximize (MRR) and minimize (Tw). The optimization results were utilized to establish machining conditions, validate empirical models, and obtain optimization outcomes. The optimal result that appears in this work was the pulse on (176.261 μs), pulse off (39.42 μs), and current intensity (23.62 Amp.) to maximize the MRR to (0.78391 g/min) and reduce tool wear to (0.0451 g/min).