Flank Surface Research Articles

Investigation of the performance of cermet tools in the turning of Haynes 25 superalloy under gaseous N2 and hybrid nanofluid cutting environments

Co-based superalloys such as Ni-based, Fe-based, and other such superalloys are classified as difficult-to-machine materials. Due to the poor machinability of superalloys, their machining is a big challenge for metal cutting industries. However, the machining of superalloys under ecological cutting environments (e.g., MQL, nanofluids, cryogenic cooling, etc.) has shown promising results. The present study investigated the effects of ecological cutting environments on the performance of cermet cutting tools. To this purpose, Co-based Haynes 25 superalloy was turned under MQL, graphene nanoplatelet (GnP) doped mono nanofluids, multiwalled carbon nanotube (MWCNT) doped mono nanofluids, GnP/MWCNT doped hybrid nanofluids, gaseous N2 based cutting environments, and mono/hybrid nanofluids combined with N2. Viscosity, pH, thermal conductivity, and wettability properties were investigated to determine the characteristics of the nanofluid mixtures. Cutting temperature, tool wear, wear mechanisms, surface roughness, surface topography, and chip formation morphology were chosen as the machining performance criteria. The experimental results showed that the cermet cutting tool and the GnP/MWCNT+N2 hybrid cutting environment contributed significantly to the Haynes 25 machining performance. Compared to the dry cutting environment, the N2 cutting environment showed the best performance improvement (63.57%) for cutting temperature, whereas the GnP/MWCNT+N2 hybrid cutting environment yielded the best performance and the best the improvement in tool flank wear (45.13%) and surface roughness (36.36%).

Research of the Influence of Cutting Conditions on the Temperature Field during Turning

Numerical simulation of the temperature field and parameters of the turning process of workpieces made of 45 and 12Kh18N10T steels is performed. The front angle of the cutter, as well as the coefficients of chip friction on the front surface of the tool μ1, the flank surface on the workpiece μ2, and the coefficient of friction on the yield stress μ were selected as variable parameters. The degree of influence of the variable parameters on the tangential component of the cutting force, the friction force on the front and flank surfaces of the cutting tool, the power of heat sources, contact temperatures and the average temperature of the workpiece is estimated.

High-Performance Processing of Complex-Shaped Parts Using Combined Methods

This article describes application of the method of turning the cylindrical surface of the part using the flank surface of the cutting plate. The comparison of classical turning and the use of ‘back turning’ was carried out, the area of rational application was revealed and the combined use of the methods was proposed. A finite element model of the part, tool and equipment was created for calculating deformations in the system and internal stresses. A control program for part machining using a combination of both machining methods was designed.

Influence of tool hardness on tool wear, surface roughness and acoustic emissions during turning of AISI 1050

In this work, chemical vapor deposition (CVD) coated carbide inserts with different hardness of P types entitled as hard, semi-hard and tough are utilized for turning of AISI 1050 steel. Flank wear, surface roughness, cutting force, acoustic emissions and chips morphology were considered under dry turning conditions for the comparison of the effect of cutting speed, feed rate and cutting tool hardness. The novelty of the study is to investigate comprehensively the effect of tool hardness along with cutting parameters on the the machinability characteristics. This approach provides to understand the underlying mechanism of tool wear and its influence on the surface properties of the workpiece which is useful in practice for upgraded machinability. The results indicated that the tool hardness affects flank wear dramatically followed by surface roughness and acoustic emissions values and ideal values of cutting conditions are attained with semi-hard tool. Scanning electron microscope (SEM), energy dispersive spectrum (EDX) and mapping analysis also demonstrated the wear developments are distinctive with using different types of tool hardness values. The findings depicted that tool hardness has significant impact on machining characteristics which need to be dealed under particular cutting conditions. 65 HRC of cutting tool provides better machinability in terms of surface roughness, tool wear, acoustic emissions and cutting forces followed by 60 HRC and 70 HRC respectively.

Experimental investigation into machinability of hardened AISI D6 steel using newly developed AlTiSiN coated carbide tools under sustainable finish dry hard turning

In the present study, a newly developed AlTiSiN coating material deposited on carbide insert by scalable pulsed power plasma (SPPP) technique is used for machinability investigation of hardened AISI D6 die steel (65HRC) in finish dry turning. Also, the cutting tool is characterized by various diagnostic tests to evaluate the effectiveness of nanocomposite AlTISiN coating material and its cutting performance. A series of machining trials have been performed under varied cutting conditions (feed, depth of cut, speed) to investigate the machinability concerning surface roughness, flank wear, and chip morphology. Further, an approach towards multi-response optimization and predictive modelling for minimization of flank wear and surface roughness have been performed using response surface methodology. Finally, a unique approach has been proposed for economic analysis and sustainability assessment in hard turning. Result shows that the nanostructured AlTiSiN coating developed lower range of tool wear (VB = 0.044–0.076 mm), produced surface finish (Ra) within 0.322–0.905 µm which is approaching the surface quality to that of cylindrical grinding because of minimum friction coefficient, good bonding capability and enhancement in hardness as well as wear resistance of coating material. Statistical analysis reveals that Ra and VB are influenced principally by feed (84.14%) and cutting speed (53.43%), respectively. With the tool life of 34 min, Gilbert's machining economic model calculated the overall machining cost per part of Rs.61.04 in hard turning using coated carbide insert. Chip morphology confirmed the formation of serrated type saw tooth chips. It is established that machining under dry condition provides environment friendliness, techno-economically feasible to improve sustainability.

A hybrid particle swarm optimization and recurrent dynamic neural network for multi-performance optimization of hard turning operation

Abstract In the present work, a new hybrid approach combining particle swarm optimization (PSO) algorithm with recurrent dynamic neural network (RDNN), which is described as PSO-RDNN algorithm, is proposed for multi-performance optimization of machining parameters in finish turning of hardened AISI D2. The suggested optimization problem is solved using the weighted sum technique. Process parameters including cutting speed and feed rate are optimized for minimizing operation cost, maximizing tool life, and producing parts with acceptable surface roughness. Based on experimental results, two neural network models were developed for predicting tool flank wear and surface roughness during the machining process. Based on trained neural networks and structured hybrid algorithm, optimum cutting parameters were obtained. The coefficient of determination for trained neural networks was calculated as R2 = 0.9893 and R2 = 0.9879 for predicted flank wear and surface roughness, respectively, which proves the efficiency of trained neural models in real industrial applications. Furthermore, the offered methodology returns a Pareto optimality graph, which represents optimized cutting variables for several various cutting conditions.

Evaluation and Comparison of Turning Process Performance during Machining of D2 Steel Material under Two Sustainable Machining Techniques

In the present work, two sustainable machining techniques namely Minimum Quantity Lubrication (MQL) and dry machining were investigated during turning of AISI D2 steel material using tungsten carbide tools. Cutting velocity, feed rate and depth of cut were considered as turning process variables whereas cutting temperature, tool rake wear, tool flank wear and surface roughness were taken as turning process performance characteristics for investigation purpose. Based on the obtained results it was found that MQL machining technique significantly controlled the cutting temperature, tool rake wear, tool flank wear and surface roughness values to a maximum of 46%, 22%, 23% and 35% when compared to dry machining condition. It was noticed that MQL cooling technique uses tiny quantity of coolant and contributes for sustainable requirements in present industry. Further, it was observed that more chip entanglement marks as major surface defectives and edge chipping as major tool wear mechanism in dry machining.

Effect of multilayer coatings based on zirconium and titanium on wear resistance of carbide tools during turning of stainless steel

In this article, the influence of coatings of the type (Ti—Zr)N—TiN, TiN—ZrN and ZrN—(Ti—Zr)N—TiN obtained by physical vapor deposition on the wear resistance of T15K6 cemented carbides plates during longitudinal turning blanks from stainless steel 12X18H10T is considered. It has been experimentally established that the presence and composition of the coating on the working surfaces of the tool in all cases contributes to a significant decrease in the wear rate of cemented carbides inserts. According to the research results, the composition ZrN—(Ti—Zr)N—TiN should be considered the best option. During the cutting process, for a tool with this type of coating, the minimum wear along the flank surface and the length of chip contact with the rake surface, as well as the smallest values of the shear angle in the zone of primary plastic deformations, were recorded.

A Finite Element Analysis Based Approach to Understand the Effects of Targeted Minimum Quantity Cutting Fluid Application on Surface Integrity

Minimum quantity cutting fluid application is targeted upon the rake face and the flank face of the tool to improve the tool life and surface integrity. By strategically targeting/applying the cutting fluid on the tool rake and flank surfaces, the temperatures along the rake face and flank face are altered, thereby affecting surface machining-induced residual stresses. The magnitude of temperature alteration and thereby the machining-induced residual stresses can be affected by the amount of targeted cutting fluid and the composition of the targeted cutting fluid. In this paper, the authors use a numerical finite element approach to understand the effects of the strategically targeted cutting fluid on the flank face improves the sub-surface residual stresses by reducing the tool-tip machining temperatures when machining AISI 1045 annealed steel with an uncoated cemented carbide tool. The machining-induced residual stresses generated from the finite element model have shown that the temperatures near the tool tip reduce by targeting cutting fluid on the flank face. The targeted cutting fluid reduced the machined workpiece temperatures and also assisted in cooling the cutting tool from the flank and rake side.

Analytical modeling of residual stress in end-milling with minimum quantity lubrication

Milling with minimum quantity lubrication (MQL) is now a commonly used machining technique in industry. This paper proposed an analytical model for residual stress prediction in milling with MQL based on chip formation orthogonal cutting model and boundary lubrication effect. The effect of lubrication is considered to the change of friction coefficients and the heat loss at the flank surface, which would further affect the prediction of the cutting force and temperature. The proposed model is validated with experimental data done to AZ61A magnesium alloy and obtained a reasonable validation result. The predictive results show at the case investigated, neither feed per tooth nor depth of cut has a significant influence to the general trend of residual stress, where at the surface the residual stress is highly tensile and come to compressive at deeper depth. However, the application of MQL is shown to be able to significantly reduce the average magnitude of the residual stress.

Multi-output optimization during MQL based face milling of EN-31 steel employing Taguchi coupled grey relational analysis

High productivity with low cost is the main requirement of the industries while producing the components with the desired quality. To achieve this goal, industries are machining at high speed and feed which causes the development of high temperature at the cutting area. This high temperature harmfully affects the surface finish and cutting tool performance. Therefore, the determination of the optimal value of cutting speed along with the effective and economical cooling strategies becomes an essential task. In the present work, this task is accomplished for face milling of EN-31 steel by combining cutting speed with variables associated with minimum quantity lubrication employing Taguchi's proposed L18 array. Taguchi coupled Grey Relational Analysis is executed to concurrently optimize the flank wear and surface roughness. The optimum parameter setting for the concurrent decrease of tool wear and surface finish are discovered as 110 m/min cutting speed, 150 ml/hr lubricant flow rate, 50 mm spraying distance, and 45° nozzle elevation angle Using Regression analysis, 1st and 2nd order equation are formulated to determine the relationship in the input and output variables. The 2nd order quadratic equation is found best fitted which is developed considering different interactions between input process variables.

Investigating flank face friction during precision micro cutting of commercially pure titanium via plunging tests with diamond grooving tools

This study investigates flank face friction while micro machining commercially pure titanium (cp-Ti grade 2) work material considering size effects. It is important to understand friction phenomena at the tool flank and work material surface since they affect the surface integrity of the machined parts. A single crystal diamond grooving tool is used in machining experiments to reduce the influence of cutting edge radius. In addition, plunging type of cutting experiments were performed to investigate the influence of flank face contact on the machined surface. A friction model which is based on work and tool material properties is proposed to model the contribution of adhesion and deformation of the flank face coefficient of friction. The results show that for the cp-Ti and diamond tool pair, adhesion seems to be the dominant model of friction and also contributes to the size effect. The deformation friction becomes more dominant during the chip formation stage. When cutting edge effect is eliminated, the influences of flank and rake face friction on the size effect are shown.

Eruption cycles of Mount Etna triggered by seasonal climatic rainfall

The ability to mitigate and predict volcanic risk is a long-standing question in the Geosciences’ community, while the extent of volcanic activity may be regulated by a predictable and periodic external excitation induced by seasonal rainfall, hydrological loading, or Moon-Sun gravitational force. Moreover, the complex stress-triggering, hydro-mechanical coupling in response to seasonal rainfall, and associated feedback mechanism with deep magmatic process remains enigmatic and indeed deserves more attention in view of recent climate change scenario. In this letter, a compelling scenario of seasonal rainfall-triggered eruption cycles of Mount Etna (Italy) is found and presented on the eastern coast of Sicily which continuously erupting since last 200 kyr. Results show that the seasonal rainfall significantly weakened the Mount Etna edifice and initiated mechanical tensile failure in the complex magmatic plumbing system and adjacent flank surface by changing the pore pressure build-up, probably promoting dyke intrusion and eventual triggering of eruptive cycle. Further, the possibility of seasonal hydrological loading on the Mount Etna volcano and adjacent flank region, hydrological load-induced sliding along the impermeable outer ‘shell’ of the flank are discussed, and the effect of tidal stress perturbations on the eruptions cycle cannot be ruled out completely.

Characterisation, Performance and Optimisation of Nanocellulose Metalworking Fluid (MWF) for Green Machining Process

The present research attempts to develop a hybrid coolant by mixing alumina nanoparticles with cellulose nanocrystal (CNC) into ethylene glycol-water (60:40) and investigate the viability of formulated hybrid nanocoolant (CNC-Al2O3-EG-Water) towards enhancing the machining behavior. The two-step method has been adapted to develop the hybrid nanocoolant at various volume concentrations (0.1, 0.5, and 0.9%). Results indicated a significant enhancement in thermal properties and tribological behaviour of the developed hybrid coolant. The thermal conductivity improved by 20-25% compared to the metal working fluid (MWF) with thermal conductivity of 0.55 W/m℃. Besides, a reduction in wear and friction coefficient was observed with the escalation in the nanoparticle concentration. The machining performance of the developed hybrid coolant was evaluated using Minimum Quantity Lubrication (MQL) in the turning of mild steel. A regression model was developed to assess the deviations in the tool flank wear and surface roughness in terms of feed, cutting speed, depth of the cut, and nanoparticle concentration using Response Surface Methodology (RSM). The mathematical modeling shows that cutting speed has the most significant impact on surface roughness and tool wear, followed by feed rate. The depth of cut does not affect surface roughness or tool wear. Surface roughness achieved 24% reduction, 39% enhancement in tool length of cut, and 33.33% improvement in tool life span. From this, the surface roughness was primarily affected by spindle cutting speed, feed rate, and then cutting depth while utilising either conventional water or composite nanofluid as a coolant. The developed hybrid coolant manifestly improved the machining behaviour.

HARD TURNING PERFORMANCE EVALUATION USING CVD AND PVD COATED CARBIDE TOOLS: A COMPARATIVE STUDY

This study emphasizes the comparative cutting performance evaluation of CVD- and PVD-coated carbide inserts in hard turning of AISI D2 steel. The cutting factors, namely cutting speed (100[Formula: see text]m/min), tool feed rate (0.08[Formula: see text]mm/rev), and depth of cut 0.2[Formula: see text]mm, have been fixed for the entire study. The comparative study is based on the analysis of the obtained test results of flank wear, tool life, auxiliary flank wear, surface roughness, and surface texture. Both tools are catastrophically failed when tool wear reached limiting flank wear ([Formula: see text][Formula: see text]mm) criteria. SEM and EDS analysis of both the tools (at their end of tool life) are carried. Diffusion followed by adhesion is found to be the prime mechanism at the end of tool life. Based on limiting flank wear criteria, the tool life of CVD and PVD tools was estimated as 65 and 57[Formula: see text]min, respectively, i.e. the tool life of the CVD tool is 14% longer than that of the PVD tool. Considering the limiting criteria of surface roughness ([Formula: see text]m), the tool life of the CVD tool was estimated as 63[Formula: see text]min while for the PVD tool, it was found as 54[Formula: see text]min i.e. about 14.3% higher tool life was found for the CVD tool relative to the PVD tool. The auxiliary flank wear was observed to be lower for the CVD tool relative to the PVD tool. Surface roughness for both the tools increased with cutting time and the relatively larger rough surface was obtained with the PVD tool. The machining cost of one pass of the CVD tool is 2.5% less than that of the PVD tool. However, for mass production, the CVD tool is more efficient than the PVD tool for machining hard D2 steel ([Formula: see text] HRC).

INFLUENCE OF MICRO-HOLES ON RAKE FACE OF THE CARBIDE INSERT ON MACHINING PERFORMANCE

The performance of the PVD coated carbide insert with micro-holes is experimentally compared with that of the conventional inserts while machining Inconel 718 under Dry and MQL condition (Canola Oil, 0.25% Gr with Canola Oil). The machining performance of textured tool is found to be relatively good when compared to untextured tool in terms of the cutting force, surface roughness, flank wear and crater wear occurred on the cutting inserts. It is being inferred that Canola oil with 0.25% Gr-nanoparticle has improved the cutting force by 17.39%, decreased the flank wear and surface roughness by 20% and 36.23% respectively while machining with the textured tool.

A Comprehensive Investigation on Development of Lightweight Aluminium Miniature Gears by Thermoelectric Erosion Machining Process.

Nowadays, size, weight, and durability are crucial factors in product development that draw the attention of many researchers and engineers towards research and innovation in the micromanufacturing area. This paper reports on the development of a lightweight aluminium gear of miniature size with a bore and hub using wire-assisted thermoelectric erosion machining (WTEM). The external spur gear was cut from 7075 aluminium alloy round stepped gear blank by WTEM using 0.25 mm brass wire. Further, the miniature gear was tested for various manufacturing quality parameters such as microgeometry, surface roughness, and microstructure, along with evaluating process productivity in terms of volumetric gear cutting speed To understand the mechanism of development of aluminium miniature gear, an investigation on the influence of WTEM parameters namely servo-voltage, pulse-on time, pulse-off time, and wire speed on surface roughness was conducted. A total of 18 gears were fabricated following Taguchi L9 (34) orthogonal array approach of design of experiments considering the randomization and replication. A typical average surface roughness value of 1.58 μm and manufacturing quality of DIN standard number 7 based on gear microgeometry were successfully achieved. Microscopic investigation revealed uniform and accurate tooth profiles, flank surfaces free from burrs and contaminants, and uniform microstructure that confirm the good performance characteristics of the developed lightweight miniature gear of aluminium. This investigation will add new results in the field as regards the development of lightweight microparts.

Multi-objective optimization of machining parameters during green machining of aerospace grade titanium alloy using Grey–Taguchi approach

This paper presents multi-objective optimization of aerospace-grade titanium alloy using the Gray–Taguchi approach. Experimentation has been conducted with varying cutting conditions according to Taguchi's L9 orthogonal array. Tool nose wear, tool flank wear, surface roughness and material removal rate are employed as process characteristics. The experimental outcomes are statistically analyzed using the Grey–Taguchi approach. Statistical and sensitivity analysis are also performed. Studies revealed that cutting speed and feed rate are having a significant influence on process performances. Micro analysis of cutting tool is also performed to study the kind of wear. Furthermore, chips were also analysed using scanning electron microscope to study its features and morphology to obtain a better insight into the process.

CFD analysis on the oil flow of a gear stage with guide plate

Gearbox housing geometry and oil guide plates strongly influence gearbox oil flow and interaction of oil with machine elements. Guided oil flow can increase gearbox efficiency and improve heat management. Recent research studies have demonstrated the potential of Computational Fluid Dynamics (CFD) simulations to predict the gearbox oil flow and no-load losses. Thereby, the influence of housing geometry and guide plates has rarely been addressed. This study focuses on a CFD analysis on the oil flow of a dip lubricated spur gear stage with a guide plate. Grid-based CFD models with different simulation setups were confronted and evaluated. Results show that the selection of the simulation setup with respect to the acceleration ramp and mesh size needs to address the considered object of investigation and the desired depth of information. An appropriate simulation setup shows great accordance with recordings of the oil distribution by a high-speed camera. A detailed analysis of the simulation results identified the contribution of different gear surface zones to the no-load gear loss torque. For the considered guide plate a strong interaction of oil flow and loss torque due to pressure forces on the tooth flank surface zones and due to shear forces on the front and tip circle surface zones of the gears was determined.

Effects of Different Hard Finishing Processes on Gear Excitation

Gearboxes are essential in mechanical drive trains for power transmission. A low noise emission and thus an optimized excitation behavior is a substantial design objective for many applications in terms of comfort and operational safety. There exist numerous processes for manufacturing gears, which all show different properties in relation to the process variables and, therefore, differences in the resulting accuracy and quality of the gear flank. In this paper, the influence of three different manufacturing processes for hard finishing—continuous generating grinding, polish grinding and gear skiving—on the surface structure of gear flanks and the excitation behavior is investigated experimentally and analyzed by the application force level. A tactile scanning of the gear flanks determines the flank surface structure and the deviations from the desired geometry. A torsional acceleration measurement during speed ramp-ups at different load levels is used to analyze the excitation of the gears. The results show only a minor influence of the surface structure on the application force level. The excitation behavior is dominated by the influence of the flank modification and its deviation from the design values.