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In current years, enormous researches have accomplished about an effect of Non-metallic inclusions, in the direction of maximizing productivity and to reduce the effect at the environment. Nowadays many steel manufacturers, not able to produce completely pure steel. Inclusions are compound material embedded inside the steel during the manufacturing process, which primarily affects the homogeneity of steel. A literature review was performed to obtain the effects of inclusions in alloy steels on their machinability and compares the performances of EN alloy steels for different machinability aspects through the whole of machining under the dry circumstance. Cutting speed, feed, and depth of cut were the dominant governing parameters. The present works compares the machining of three different alloy steels and the behavior of numerous non-metallic inclusions in them. The effects of chemical composition and inclusions on machinability factors including resultant cutting force, chip morphology, and its microstructures are discussed. EN 1A Pb&Te alloy steel experiences the lower cutting force thus provides better machinability.

Natural fiber reinforced composites are gaining more consideration by automakers and researchers to exploit in industrial applications due to lightweight, eco-friendly and sustainability. The aim of this paper is to provide an overview of natural fiber reinforced composites, effect of chemical treatments on natural fibers, manufacturing techniques and potential applications. The effects of various chemical treatments on natural fibers leads to altering the mechanical and thermal properties are studied. The applications of natural fibers reinforced composites are used in various industries such as automobile, aircraft, building, musical, sports and household applications are presented. The conclusion reveals that chemical treatment of the natural fiber enhances bonding between the fiber and matrix which ultimately improved the mechanical and thermal properties of the composites.

This paper details the development of a hybrid process to machine micro-holes on a difficult to machine material like titanium (Ti-6Al-4V) alloy using a magnetic field-assisted electric discharge machining process. In EDM machining of micro-holes, there are certain issues like the circulation of dielectric and removal of debris which results in, a low aspect ratio of the hole, low material removal rate, deformed machined geometry, high tool wear rate and low surface integrity of workpiece. This research work aims to overcome these issues by combining processes like the magnetic field in the sparking region and the addition of powder particles to the dielectric medium. To study the effect of this hybrid process, the orthogonal array was formed and trials were conducted using the parameters input current (Ip), voltage (V), pulse on time (Ton) and pulse off time (Toff). The experimental results were compared with the non-hybrid machining process. The result shows that the material removal rate is considerably increased in the hybrid process.

In the present research, work focus has been given to determine mechanical properties of biodegradable industrial waste tea leaf fiber (WTLF), banana and flax fiber reinforced hybrid polymer composites using experimental approach. Banana fibers and WTLF were alkali treated with 5% NaOH solution. The hybrid composite laminates were manufactured using manually operated compression moulding machine with the volume fraction of 40:60 (Fiber: Matrix). As per ASTM standard, the mechanical characteristics were studied. The experimental results showed excellent mechanical characteristics for 5 wt% WTLF and 25- wt% banana fiber reinforced hybrid composites. The fractography analysis of untreated and alkali treated composites were examined using Scanning Electron Microscopy (SEM) and results revealed that superior mechanical bonding existed between fiber and polymer in case of alkali treated fiber composites.

The intention behind this research work was to analyse the mechanical as well as acoustic behaviour of Sansevieria ehrenbergii (snake grass) / Camellia sinensis (waste tealeaf) fibers with glass fiber (GF) – reinforcement to form the hybrid epoxy composites. Fibers of S.ehrenbergii/C.sinensis were chemically modified for their effective usage as reinforcement in hybrid composites. Five combinations of hybrid composites were fabricated using hand-operated compression molding techniques by changing the percentage weight of snake grass fiber (SGF) and waste tea leaf fiber (WTLF). The results indicated that the mechanical behaviour of SGF/WTLF composites have been substantially enhanced by hybridization with GF. Enhanced mechanical behavior of hybrid composites is observed as an incremental percentage of SGF composition. The experimental findings show that the weight fraction of 25 wt.% WTLF reinforced with SGF shows a strong acoustic absorption coefficient (AAC) of 0.59 in the frequency range of 2000–6300 Hz as well introduces the potential for acoustic sound proofing applications, such as loudspeaker design, perforated panels, sound recording, and reproduction room. The morphological behavior of hybrid composites, such as fiber pullout, matrix crack, void formation, and interfacial bond between the binder and fibers were observed using a scanning electron microscope.

This work aims to investigate the mechanical and sound absorption characteristics of industrial waste tea leaf fiber (WTLF), kenaf and E-glass fiber–reinforced hybrid epoxy composites through experimental studies. The WTLF and kenaf fibers were initially treated with 5% sodium hydroxide. Hybrid composites were fabricated by compression molding technique with a composition of 40 wt.% fiber and 60 wt.% matrix. The fabricated hybrid composites were subjected to mechanical and sound absorption studies as per ASTM standards. Results revealed better mechanical properties in the composites with 25 wt.% kenaf and 5 wt.% WTLF, whereas sound absorption characteristics were better for composites containing 25 wt.% WTLF and 5 wt.% kenaf fiber. The surface morphology of the fractured specimens such as fiber pullout and matrix crack was examined using scanning electron microscopy. Spectrum investigation of alkali-treated hybrid composites showed excellent interfacial bonding between the polymer and fiber compared to the untreated fiber.

Nowadays Titanium and its alloy materials are highly preferred for the parts of aircraft structures due to their unique properties such as good corrosive resistant and higher strength to weight ratio is sustained even at increased temperature. Even though these alloy materials are wicked for its low thermal conductivity and categorized as hard to machine alloys. Drilling of titanium alloys is a critical machining process in the fields such as medical, automobile and defence applications. In this alloy Ti–6Al–4V alloy is generally used for parts that need higher reliability therefore, surface finish and various failure to the adjacent surface layers of machined areas must to be resolved as per the customer requirement. This research work focuses on experimental study and optimization of machining parameter during dry drilling of titanium alloy (grade 5). An 8 mm diameter and 120 degree point angle solid carbide drill bits are used to carry out the experiments. The range of drilling spindle speed chosen for the experiment was between 20 to 50 m/min also feed rates were 0.05, 0.1, 0.15, and 0.2 mm/rev. Experimental analysis was done by focusing on surface roughness, circularity, hole diameter and exit burr for maintaining good quality hole. A Portable surface roughness measuring device was utilised to find surface roughness in the direction of feed on work piece material. Circularity and diameter of the machined hole was found by co-ordinate measuring machine (Contura-G2-Zeiss). From this experimental investigation it is found that feed has higher significance on surface finish when compared to drilling speed but when considering the circularity error speed has higher significance. Optimization and validation of experimental results was done by using the application of Taguchi’sdesign of experiments with signal to noise ratio graph and ANOVA

Fiber reinforced plastic composites replace wood and metals due to their light weight, high strength to weight ratio, noncorrosive nature and stiffness. Bio based fibers are used in place of petroleum based fibers because of environmental concerns. Natural fibers exhibit low specific strength and light density, processing and recycling are simple. New materials are being developed and grow every day. The high strength, light weight and biodegradability of natural fiber composites such as sisal, jute, kenaf, snake grass and banana fiber has made polymer composites were more attractive. The fiber is subjected to chemical pretreatments using alkali treatment (mercerization). This research has created composites of glass-jute-tea leaf fiber-reinforced polymers and assessed their mechanical characteristics such as tensile, flexural and impact test. Scanning Electron Microscopy (SEM) is being used to evaluate the interfacial characteristics, inner cracks and inner structures of broken surfaces. The experimental results showed 10% glass fiber, 20% jute fiber and 10% tea leaf fiber produced the optimum mechanical properties and it can be alternative material for pure glass fiber reinforced polymer composite.

International audience; This work aims to experimentally investigate the effect of the machining parameters (Spindle speed and feed) as well as the tool geometry on the drilling quality of ± 55° filament wound hybrid composite tubes consisting of mechanical and anti-corrosion layers. Drilling tests were performed with three different spindle speed (1000, 2000 and 3000 rpm) and five different feeds (0.05, 0.1, 0.15, 0.25 and 0.4 mm/rev). The average surface roughness Ra of both mechanical and anti-corrosion layers was also measured at two angles 0° and −45°. Furthermore, the delamination at the hole entry and exit as function of the feed was quantified by means of an optical microscopy. The experimental results revealed that the drilling of the filament wound layer generates a higher thrust force compared to anti corrosion layer. Moreover, it was found that the filament wound layer present a higher surface roughness than the anti-corrosion layer for all the investigated machining parameters. This result is confirmed by SEM observations and 3D surface topography. Finally, optical observations show that the delamination is predominant at the hole entry and increase with the increase in feed.

The influence of process parameters on thrust force during the drilling of pure and chemically treated Kevlar reinforced epoxy composites has been investigated. Surface treatment has been carried out to enhance the physical bonding between fiber and matrix. Four different drill bits were used for the investigation: standard twist, core, step cone and candle stick drill. Three speed and feed rates were used for the investigation. Our objective was to find the minimum thrust force during the drilling of pure and chemically treated Kevlar reinforced composite using four different drill bits. Optimization of drilling process parameters was performed using the Taguchi method of L9 Orthogonal Array. We found that among the four drills core and candle stick drills produce a minimum thrust force compared with the twist and step cone drills. Thrust force values produced by a chemically treated specimen is lower than that of a pure composite specimen irrespective of the drill bits used. Chemically treated specimens of the core and candle stick varieties are suitable for lower thrust force and delamination free holes under specified experimental conditions. The significance of feed rate is more important for thrust force during the drilling of composite specimens irrespective of drills.

International audience; The building sector has been showing great interest in incorporating technologically advanced materials with lightweight, ecofriendly, high strength, and stiffness properties in flooring, roofing, and partition walls, etc. In addition to the mechanical properties, these materials should have good thermal properties as well. In response to these requirements, an attempt has been made to study the thermal behavior of green composite sandwich made of flax and agglomerated cork. Composite sandwiches were fabricated by using flax as skin reinforcement and agglomerated cork as core with different densities as 240, 280, and 340 kg m−3 using vacuum bagging method. Glass was also used as skin reinforcement for manufacturing composite sandwiches for comparison purpose. Experiments were conducted to predict thermal properties, viz. thermal conductivity, thermal expansion, flammability, and thermal stability. The experimental results show that the lowest thermal conductivity of 0.03 W m−1 K−1 was observed in flax-based composite sandwich having core density of 240 kg m−3; the lowest thermal expansion of 29.2 × 10−5 °C−1 was observed in glass-based composite sandwich having core density of 340 kg m−3; the highest value of time to ignition was 12 s, and minimum propagation rate was 0.25 mm s−1 in flax-based composite sandwich having core density of 340 kg m−3; The highest initial degradation temperature was 362 °C for glass-based skin and 263 °C for cork having density of 240 kg m−3.

In recent years, material scientists have been focusing on the utilization of materials from natural resources due to environmental concerns. In the same context, the aim of this work is to evaluate impact response, sound absorption behavior, and vibration damping characteristics of natural-based composite sandwich made of flax as skin reinforcement and agglomerated cork as core. Vacuum bagging method was used for manufacturing composite sandwiches with different cork densities of 240, 280, and 340 kg/m3. Composite sandwiches have also been manufactured by using glass as skin reinforcement for comparison. Low velocity impact test was conducted and found that glass fiber reinforced composite sandwich required 73–77% more energy to perforate when compared to the flax fiber reinforced composite sandwich irrespective of core density. Flax fiber reinforced composite sandwich has 45–96% higher sound absorption capacity and 27–32% higher vibration damping ratio than glass fiber reinforced composite sandwich irrespective of core density. This is due to multiscale structure and cellular nature of the flax fiber and the cork materials, respectively. These enhancements in sound and vibration are accomplished with just little forfeits in perforation energy. This study recommends that, if optimized, the natural-based composite sandwich could be an ecologically appealing answer for automobile and construction applications, where impact behavior is important, along with sound and vibration properties.

During trimming of edges of carbon fiber-reinforced polymer composite parts, issues such as resin degradation, delamination, and poor surface finish at the trimmed edges, and increased tool wear in cutting tools used is common. Therefore, it is essential to carry out investigations on edge trimming of carbon fiber-reinforced polymer to find the effect of cutting forces generated and the cutting tool temperature induced at different high speeds and feeds conditions. In this work, two different-coated router tools of titanium aluminum nitride-coated and diamond-like carbon-coated routers were used for investigating the effect of these coatings on cutting force and cutting tool temperature which affect the surface quality of trimmed carbon fiber-reinforced polymer. From the investigation, it was found that the diamond-like carbon-coated router tool has generated lower cutting forces, cutting tool temperatures, and, in turn, better surface finish even at high-speed conditions when compared to other tools. Due to the complex geometry of the router tool, online tool wear monitoring by acoustic emission technique was employed. Acoustic emission signals were taken as the measuring index of tool wear which shows good correlation with direct tool wear measurements. From the experiments, it was found that the tool performance of the diamond-like carbon-coated router is superior when compared to other tools. In addition, for edge trimming of carbon fiber-reinforced polymer composite parts, the diamond-like carbon router tool performed without much disturbance for a length of machining of around 5.9 m which is about 46% of increase in length of machining when compared to uncoated router tool.

This work presents the results of an optimization study of trimming carbon fiber composite by technique of order preference by similarity to ideal solution (TOPSIS). Edge trimming was conducted at different levels of cutting speed, feed speed, and radial depth of cut using a 2 k factorial design. The effects of cutting parameters on tool wear, surface roughness and tool temperature were analyzed and discussed. Data generalization was performed by training multiple neural network structures (NN) where the input vector of the neural networks contained sensor data in addition to typical process parameters. TOPSIS was used to select the optimal cutting conditions that could generate minimum tool wear, surface roughness, and tool temperature simultaneously while maintaining high production rates. The results show that the NN models offer better results when sensor data is fused in the input vector. TOPSIS optimum conditions were confirmed by validation experiments and were found to be accurate.

In the current investigation, it was focused mainly to compare and evaluate the analytical and experimental trials on the cutting temperature in machining the titanium alloy using micro-hole textured cutting inserts. Initially, the main input parameters such as cutting speed, depth of cut, and feed rate have been used to evaluate the performances. Box–Behnken technique of response surface methodology was used to perform machining experiments. Secondly, with the help of width of cut and thickness of the chip formed at each trial, the analytical calculation of cutting temperature at the two-deformation zone, namely primary and secondary of the orthogonal cutting, has been done. The efficacy of the input parameters on cutting temperatures has been also compared with the analytical calculation. Importance of the cutting parameters was studied with the help of mean effective plots. Results also revealed that the deviation of cutting temperature between the numerical and experimental investigation was only 13%. This depicts the analytical formulation which was much close relation to that of machined trials of cutting temperatures. Further, the cutting temperatures are found to be minimized at lower feed rates and cutting speed using the observation of mean effect plots.

The machining of composite components finds lot of challenges due to the abrasive nature of the fibres used. The problems such as delamination, fibre pull-out and resin degradation which may be encountered during machining of workpiece and deciding its quality characteristics. Also, the tool wear is a major concern which has to be considered in controlling tooling cost and impact final product cost. Therefore, it is necessary to appropriately select the suitable cutting tool which is expected to cause minimum damages to workpieces. This chapter discusses the cutting tools used when machining (mainly drilling and milling) polymer matrix composites (PMC). The chapter will also discuss cutting conditions, cutting tool materials, cutting tool geometry and coatings. The machinability characteristics due to the effect of cutting parameters and tool materials/geometries during drilling various composite materials will be compared. High speed edge trimming of carbon fibre reinforced polymer (CFRP) materials using fluted and router tools is also discussed to determine the effect of tool geometry and tool coating materials on surface roughness of machined surfaces and the tool wear. This chapter also discusses the cutting tools for machining of metal matrix composites (MMC) and ceramic matrix composites (CMC).

This research work was carried out to find a suitably treated electrode for the required machining output response like MRR and TWR. The experimental design was formed using Box–Behnken design. Experiments were conducted to machine 500 µm holes on titanium (Ti-6Al-4V) alloy using copper electrodes. Input parameters selected were input current (Ip), pulse-on time (Ton), and pulse-off time (Toff). Material removal rate and tool wear rate were analyzed using contour plots. Based on these experimental data, the grey relational analysis technique was applied to find the optimal parameters for achieving maximum MRR and minimum TWR. Optimal parametric values obtained were input current (Ip) 4.0 A, pulse on time (Ton) 2.0 µs and pulse off time (Toff) 6.4 µs. The achieved optimized parameters were further used to conduct experiments with cryogenic treated and coated electrodes. Electrodes were coated with conductive materials (silver, nickel, and zinc) and non-conductive material (epoxy). The experimental results showed each type of electrode enhances a particular machining characteristic such as silver-coated electrode produced a higher value of MRR, epoxy-coated electrode achieved minimum TWR. It is observed from the results that this work can be applied to identify the suitable electrode for producing the desired machining output characteristics.

A novel approach of a gas pressure infiltration technique is presented for the synthesis of Co-Continuous Ceramic Composite (C4). SiC foams of varying pore sizes were infiltrated with aluminium AA5083. Optical examination revealed that the SiC foams contained open cells with a network of triangular voids. The number of pores-per-inch (PPI) in the foams was found to depend on the strut thickness and pore diameter. The compressive strengths of two foam configurations, 10 and 20 PPI, were estimated to lie between 1–2 MPa. After infiltration, the compressive yield strength of the resulting C4 was observed to increase to 126 MPa and 120 MPa, respectively, for the 10 and 20 PPI C4. Additionally, the infiltration of ceramic foam with the AA5083 alloy resulted in an increase in strength of 58–100 times when compared with plain ceramic foam. The failure modes of the composites in compression were analyzed by crack propagation and determining the type of failure. The study revealed that shear failure and vertical splitting were the predominant mechanisms of compression failure, and that the fabricated C4 is advantageous in mechanical properties compared to the plain ceramic foam. This study, therefore, suggests the use of C4 composites in armour applications.

Light weight and high strength materials like carbon fiber reinforce plastics (CFRP), Titanium alloys (Ti) and stacks (CFRP/Ti, CFRP/Al, CFRP/Al/Ti) are being extensively used in commercial aircraft. Drilling process on the aircraft components was carried out to facilitate the assembly process. Drilling operations are made under dry condition which leads to tool wear and poor hole quality. In this paper study on drilling of CFRP/Ti6Al4V stacks under minimum quantity lubrication (MQL) using LRT 30 oil with varying flow rate, spindle speed and feed rate have been carried out using three modified drill tool made of solid carbide (K 20) coated with TiAlN. The recital of the tools were evaluated based on hole quality, burr height, thrust force, chip formation and tool wear. It was found that TG1 tool performance was better by producing minimum burr height while drilling Ti. TG2 recital was better by producing minimum force and better hole quality.

The present study aims in analyzing the mechanical behavior of natural fiber (abaca) reinforced polymeric composites under dynamic conditions. It is evident from the past research reports that natural fiber offers desirable physico-mechanical properties to the added polymers. In the present research work, abaca fiber is utilized for the preparation of composites due to its promising mechanical properties and resistance to salt water corrosion, its lignin content is 15% and grows up to 3 m. Abaca is extracted from leaf sheath of Manila hemp plant, it is a kind of banana family. Influence of temperature on the mechanical behavior of natural fibers needs to be identified to ensure its usage for high performance applications. Pure and chemically treated abaca fiber based vinyl ester composites are subjected to dynamic mechanical analysis (DMA). The reason for the chemical treatment of abaca fiber is to enhance its interfacial bonding with base matrix. Fourier transform infrared spectroscopy (FT-IR) analysis signifies the morphological changes in abaca fiber after chemical treatment. Storage modulus (E') and damping characteristics of abaca fiber reinforced vinyl ester composites are comparatively higher than in neat polymer. In addition, surface treatment of fiber demonstrates significant enhancement in storage modulus compound compared to pure and raw fiber reinforced polymer due to strong physical interaction between fiber and matrix.

Wire electric discharge grinding has been developed to generate cylindrical profiles on hard-to-machine microparts. The outcome of the part is influenced by the process conditions and the rotational speed of the spindle. This paper investigates the effects of machining parameters on material removal rate (MRR), surface roughness and circularity during wire electrical discharge grinding process of tungsten carbide workpiece. Experiments have been carried out by varying process conditions such as peak current, open circuit voltage, pulse off time, servo voltage and number of passes. Pulse current has the highest significance to obtain maximum MRR. To obtain the best surface quality, pulse current, number of passes and pulse off time are identified as the most significant parameters. Using the technique of order preference by similarity to ideal solution, the optimal conditions estimated are pulse current (38 A), open circuit voltage (60 V) and pulse off time (24 µs) for finish machining.

The scope this research work is to develop and study the finite element analysis of GFRP composite laminates with combined bolted and bonded joint. Polymer matrix composite materials are widely used due to the reason of high strength to weight ratio. Design techniques for fastened joints have received valuable attention due to the different nature of the stress field in the proximity of the joint, the different of failure modes that can occur. A foremost goal of bolted joint research is to limit the effect of several bolting parameters on the bearing strength of the joints. These parameters such as: (a) joint geometry (b) joint configuration (c) loading condition (d) fastening parameters and (e) material parameters. The scope of the project is to examine the influence of certain factors on the strength of bolted joints in [0/90]4s GFRP composites. These features include the tightening torque (T= 15, 20, 25 & 30 Nm). The mechanical properties (Tensile & Compressive) of GFRP laminates have been examined experimentally and theoretically. From the investigational study, it is found that bolted joint and bolted - bonded joint with 6 mm diameter, 25 Nm tightening torque has the extreme strength. Most of the test specimens failed in (a) Bearing failure (b) Net tension failure (c) Shear out failure (d) Cleavage tension failure.

Custom 465 steel is a martensitic, age-hardenable alloy having a superior combination of strength and corrosion cracking resistance, which are commonly used in aerospace industries. When machining Custom 465 steel, tool-work interface temperature and tool wear are the major parameters which influences the machinability factors at a greater extend. Even though, researchers have performed many operations based on this subject, no significant data’s were available regarding the Custom 465 steel. A dry machining operation known for its ecological desirable and cost effective process was implemented to experimentally investigate the tool wear and tool-work interface temperature when machining Custom 465 steel using uncoated, TiAlN and TiCN coated carbide cutting tool inserts with a cutting speed of 100 m/min and 200 m/min and also the effects of cutting speed on tool wear and tool-work interface temperature were also determined. The highest tool life of 6.15 minutes was recorded for TiAlN coated insert at a cutting speed of 2000 rotations per minute (rpm), feed rate of 200 mm/min and depth of cut of 0.5 mm. The maximum tool wear recorded for TiAlN coated insert was 0.25 mm and the maximum temperature on the tool-work impact was 142.43 degrees. In all cutting speeds, TiAlN coated insert outperformed uncoated and TiCN coated insert in term of tool life and temperature. For a cutting speed of 2000 rpm and above uncoated inserts are not suitable to be used for machining Custom 465 steel due to the rapid wear of cutting edge.

The main objective of this paper is to study the effect of water absorption on the flexural strength of new green sandwich composite material made of flax as skin reinforcement and agglomerated cork as core. In this work, three different types of skin reinforcements and three different densities of agglomerated cork core have been used for the manufacturing of sandwich composites. The manufactured sandwich composites were subjected to three-point bending tests under both dry and wet conditions. The three-point bending results confirmed a decrease in the specific flexural strength by 14-42 % in wet samples due to water absorption. Also, the increase in core density leads to an increase in flexural strength both in dry and wet conditions. During testing under dry conditions, the specific flexural strength of flax reinforced sandwich composite was found to be superior because of the higher strength to weight ratio factor of flax fiber when compared to a glass reinforced sandwich composite and glass/flax reinforced hybrid sandwich composite. Due to the hydrophilic nature of flax fibers, flax reinforced sandwich composite has a reduced specific flexural strength in wet conditions when compared to glass reinforced sandwich composite and glass/flax reinforced hybrid sandwich composite.

The primary objective of this work is to compare the effect of tool material during trepanning of woven CFRP composites. Composites are commonly used, especially, for their lightweight, stiffness, and strength. Trepanning is a machining operation especially performed for creating an effective hole in CFRP composites. The experiment is performed with two trepanning tools [polycrystalline diamond (PCD) and solid carbide tool (SC)] at different feed and spindle speed. The measured parameters such as thrust force and torque of the tool are measured using dynamometer, and the acoustic emission signal is obtained using AE sensor for analysis. The acoustic emission (AE) indicates the crack propagation occurred during trepanning of CFRP composites. The voltage obtained is high when the shearing of last ply occurs (post-delamination occurs). It is found that the PCD tool material has higher magnitude of thrust force compared to carbide tool material. The delamination factor obtained indicates that the increasing feed increases the delamination factor. The delamination factor is less with the usage of PCD tool at low feed compared to the solid carbide tool. It is found that, the delamination factor can be controlled by using suitable tool material and machining parameters such as spindle speed and feed. Thus, the amount of delamination is found to be small with PCD tool compared to the solid carbide and less feed and high spindle speed is recommended for good dimensional accuracy of hole.

In recent decades, the noticeable amount of research has been carried out in the role of non-metallic inclusions and their relationship to the machinability of various steels. This paper compares the performances of EN alloy steels for varied machinability aspects throughout the machining under dry cutting condition. Cutting speed, feed, and depth of cut were the major ruling parameters affecting the machinability of materials. The present works review the machining of different alloy steels and the role of non-metallic inclusions in them. More precisely, the effects of composition and morphology of inclusions on machinability factors such as cutting force and chip size and shape are discussed and summarized. EN 1A Pb&Te alloy steel provides lower cutting force, and good curl or breakdown chips thus provides the better machinability.

In this work experimental and numerical result of high speed orthogonal machining of Ti-6AL-4V titanium alloy is presented. High speed orthogonal turning is carried in a lathe using uncoated carbide inserts under dry cutting conditions. Experimental study is carried out by focusing on the measurement of cutting force and cutting temperature. The experimentation is supplemented by simulations from 2D finite element model (FEM) using Third Wave AdvantEdge software. The measured cutting forces and temperature are compared with FEA results. The major factors affecting the machinability of titanium alloy such as spindle speed, feed and cutting tool rake angles are investigated. Numerical results agree with the experimental results at higher speeds and feed levels. These results can be used for further study in high speed turning of titanium alloys.

This present study aims to investigate the dry sliding wear behaviour of tungsten disulfide (WS2) particle reinforced bronze matrix composite against surface hardened steel and to discover the optimum wear parameter values such as applied load, sliding distance, sliding velocity and volume fraction of reinforcement to reduce the specific wear rate. The composite specimens were fabricated by liquid metallurgy route by varying the volume fraction of solid lubricant particles and prepared as per American Society for Testing of Materials (ASTM) G99-95. The experiments were carried out based on Taguchi design of experiments technique with L27 orthogonal array. The wear tests were conducted in pin-on disc wear testing machine for different loads - 20N, 40N and 60N, sliding velocities - 2.09m/s, 2.62 m/s and 3.14m/s and sliding distances of 600m, 1200m and 1800m in unlubricated conditions. The significant influence of wear parameters on sliding wear, interactions and optimum combination of wear parameter values to minimize the wear rate were obtained by signal-to-noise (S/N) ratio and analysis of variance (ANOVA). The results demonstrated that inclusion of tungsten disulfide particles decreased the wear rate of bronze and also the increases in amount of secondary phase increase the wear resistance of composites. The effect of solid lubricant particle on interfacial temperature was also studied and reported. It was found that percentage of solid lubricant and load are the most significant factors influencing the friction and wear properties of composites. The results revealed that, WS2 particle reinforced bronze matrix composites were the potential component can be replaced for pure bronze products in wear resistance applications.

Carbon Fiber Reinforced Plastic (CFRP) and Titanium Alloy (Ti6Al4V) stack, extensively used in aerospace structural components are assembled by fasteners and the holes are made using drilling process. Drilling of stack in one shot is a complicated process due to dissimilarity in the material properties. It is vital to have optimal machining condition and tool geometry for better hole quality and tool life. In this study the tool wear and hole quality were analysed by experimental analysis using three modified twist drills and online tool condition monitoring using Acoustics Emission (AE) sensor. Helix angle and point angle influence tool performance and cutting force. It was found that a tool geometry (TG1) with high helix angle of 35°with low point angle 130° results in reduction in thrust force of 150-500 N range but the TG2 also perform almost similar to TG1, but when compared with the AErms voltage generated during drilling it was found that progressive rise in voltage in TG1 is less with respect to TG2 which can be attributed to tool life. In process wear monitoring was done using crest factor as monitoring index. AErms voltage were measured and correlated with the performance of the drills.

Titanium alloys are categorized as light weight materials posse greater strength and toughness and are usually known to create major challenges during conventional and non-conventional machining. In general, these alloys are referred as difficult to machine materials. Titanium alloy (Ti-6Al-4V) suffers poor machinability for most cutting processes, especially the generation of micro-holes using traditional machining methods. Electrical Discharge Machining (EDM) is suitable for machining titanium alloys, although selection of machining parameters for higher machining rate and accuracy is a challenging task in machining micro-holes. Discharge current, pulse ON time and Flushing pressure were considered as the major influencing machining parameters and Material Removal Rate (MRR), Tool Wear Rate (TWR) and Hole Taper were considered as the performance criteria. It is observed that machining performances are affected mostly by the peak current and pulse-on time during micro-electro discharge machining of titanium alloy. Mathematical models have been developed using multiple regression analysis, to establish the relationship between various significant process parameters and micro-EDM performance criteria. Also, studies have been made to examine the influence of various process parameters on the quality of the machined micro-hole.

Ti-6Al-4V alloy is well known for its difficulty in machining due to its ultimate hardness. The temperature generated at the tool-chip interface is typically high which results in poor surface finish and rapid tool wear. The current focus of work was to analyze the influence of response parameters such as cutting speed, feed rate and depth of cut on the surface roughness on the non-textured and textured cutting inserts. Response Surface Methodology (RSM) was utilized to generate the analytical relation between the process parameters and their interaction with the responses namely surface roughness. Analysis of Variance (ANOVA) was implemented to correlate with the significant factors and the correctness of the model. The machining was done experimentally using the textured and non-textured tools and the surface roughness was measured to analyze the influence of process parameters. It was found that the surface roughness was immensely reduced while using microtextured cutting tools.

Although minimum quantity lubrication (MQL) has been proved beneficial for the machinability improvement of metallic materials, it is still not well understood whether or not to use the MQL when machining the composite-titanium stacks and whether the MQL can achieve a comparable effect as it operates in the metal cutting processes. The current work is aimed at revealing the underlying mechanisms of the MQL drilling on the CFRP/Ti6Al4V stacks. Both the MQL and dry conditions were examined using the TiAlN-coated and diamond-coated carbide drills to quantify how the MQL operates when compared with the conventional dry machining. The effects of the MQL environment on the machinability of the composite-titanium stacks were quantified in terms of drilling thrust forces, delamination damage of the composite phase and tool wear signatures. A particular emphasis is put on the wettability testing of cut stack hole surfaces versus the minimum quantity lubricants in terms of the contact angle. The results indicate that the machined composite surface shows a strong ability to absorb the lubricants under the MQL condition and fails to form a protective oil film at the drill-chip interface, resulting in an increase of thrust forces and delamination damage. Moreover, the MQL environment cannot prevent the drill bits from premature failures during the machining of CFRP/Ti6Al4V. It is indicated that the MQL fails to yield a comparable beneficial role as it operates in the machining of individual metal alloys in terms of the examined drilling responses.

This paper presents an experimental study on the diametrical overcut and taper obtained during the machining of micro holes by electro-discharge machining (EDM). Many trials were taken by machining a 2.0 mm electrolytic copper rod to 0.50 mm under various conditions to analyse the effect of process parameters by wire electric discharge grinding process (WEDG). The optimum process parameters were determined by Taguchi’s method. Then a set of electrodes were produced with the determined optimum process parameters and were used to machine micro holes on Ti-6Al-4V alloy. The diameters of the holes were measured and the effects of various parameters were analysed for the variation in taper and diametrical overcut. The experimental results were analysed using analysis of variance approach.

Drilling is a widely used machining process for various components pertaining to industries such as aerospace, automobile etc. Ti6Al4V is very often used for high stressed components like aircraft structure because of its excellent strength to weight ratio. Tool geometry plays a vital role in effective drilling. It is very difficult to develop a modified geometry in order to achieve better hole quality and improved tool life and validating its outcome experimentally is very expensive. The current paper presents the concept of drilling simulation process using commercial finite element software, Abaqus/Explicit. Five major drill bit geometry such as point angle, helix angle, clearance diameter, and web thickness were varied The proposed simulation model for drilling process was based on Eulierian formulation with explicit interaction. The results of simulation were compared with that of experimental drilling. The simulated result has a good correlation with the experimental result. The change in reference point to chisel tip in the simulation yielded better results as compared to when the reference point is taken at top surface of the tool.

In this study the process of Wire Electric Discharge Grinding was carried out with a precise, flexible and corrosion resistant submerged rotary spindle which was designed, fabricated and installed in a five axis CNC Wire Electric Discharge Machining in order to produce free form surfaces on micro rods. The tungsten was taken as a work material since it is hard to machine through conventional process. Based on the literature survey the following four factors such as the spindle speed, pulse off time, peak current and wire speed are considered for obtaining high diametrical accuracy. By Taguchi parametric design the array was designed and experimental trials were taken by machining an Ø2.0mm tungsten (W) pin to Ø0.40mm under various set of parameter combinations. The S/N ratio analysis was carried out to find the optimum machining parameters and significant parameters affecting the diametrical accuracy. The analysis of variance was used to analytically verify the significant parameters. Finally it is concluded experimentally and statically that the significant parameters affecting the diameter accuracy are spindle speed and pulse off time.