Showing papers in "Materials and Manufacturing Processes in 2014"
TL;DR: In this paper, the machinability studies for titanium and nickel alloys are reviewed with reference to cutting tool materials, associated wear mechanisms, failure modes, and novel tooling techniques.
Abstract: Titanium and nickel alloys are the most commonly used in the demanding industries like aerospace, energy, petrochemical, and biomedical. These highly engineered alloys offer unique combination of heat resistance, corrosion resistance, toughness, high operating temperature, and strength-to-weight ratio. These alloys are termed as “Difficult to cut materials” because of their low machinability rating. They are difficult to machine because of properties like low thermal conductivity, high strength at elevated temperatures, and high chemical reactivity. Machining of titanium- and nickel-based alloys causes problems of surface integrity and selection of cutting tool materials that is always a challenge for manufacturers. In this work, machinability studies for titanium and nickel alloys are reviewed with reference to cutting tool materials, associated wear mechanisms, failure modes, and novel tooling techniques. It also discusses major surface integrity defects like carbide cracking, white layer formation, wor...
209 citations
TL;DR: In this paper, a new nanofluid is prepared and evaluated for lubricating property in machining process by applying it as MQL in turning by measuring cutting forces, cutting temperature, flank wear, roughness of machined surface, and examining chip morphology.
Abstract: Health and environmental concern on use of cutting fluids during manufacturing has led to development of minimum quantity lubrication (MQL) which requires specialized fluids having superior properties. In the present work, a new nanofluid is prepared and is evaluated for lubricating property. Its performance is evaluated in machining process by applying it as MQL in turning by measuring cutting forces, cutting temperature, flank wear, roughness of machined surface, and examining chip morphology. Newly prepared nanofluid showed improvement in the lubricating properties of base fluid and also showed superior performance compared to dry machining, flood cooling, and MQL application of conventional cutting fluid.
110 citations
TL;DR: In this paper, the surface modification of three different types of metal matrix composites (MMCs) 65vol%SiC/A356.2, 10vol% SiC-5vol%quartz/Al, and 30vol%SIC/A359 using powder-mixed electrical discharge machining was investigated.
Abstract: This article investigates the surface modification of three different types of metal matrix composites (MMCs) 65vol%SiC/A356.2, 10vol%SiC-5vol%quartz/Al, and 30vol%SiC/A359 using powder-mixed electrical discharge machining (PMEDM) process. Microhardness and surface integrity were evaluated after each trial, and contributing process parameters were identified. It was found that microhardness increased primarily with increase in the density of reinforced particles in the matrix. Each workpiece was examined by X-ray diffraction (XRD) followed by scanning electron microscope (SEM) for surface integrity and material deposition. The results show the significant amount of metal transfer from the copper electrode as compared to graphite.
110 citations
TL;DR: In this article, a review of the factors affecting shrinkage of molded parts in injection molding is presented, which is organized according to molding scale and by considering four branches of influence: material behaviors, processing parameters, mold and specimen design.
Abstract: Purpose: This paper reviews the factors affecting shrinkage of molded parts in injection molding. Methods: A selective screening of the papers published in the last 10 years was adopted. The review was organized according to molding scale (macro or micro) and by considering four branches of influence: material behaviors, processing parameters, mold, and specimen design. Results: Within the interval of confidence, at the macroscale, critical processing parameters were the temperatures, the packing parameters, cooling time, and injection speed; temperatures and packing parameters resulted critical factors at the microscale as well. Concerning the design aspects, the runner size and the ribs affect shrinkage at the macro and microscale, respectively. The analysis of the literature review has shown an absence of statistical approach for determining the material influences, a lack of information on shrinkage occur in powder-molded parts and the absence of data in specimen with dimensions below 10 µ. Conclusion...
105 citations
TL;DR: A review of research progress on aluminum-steel dissimilar welding is presented in this article, where current issues and recent developments in improving the intermetallic compound layer of weld joint are critically assessed.
Abstract: This paper presents a review of research progress on aluminum–steel dissimilar welding. Current issues and recent developments in improving the intermetallic compound layer of weld joint are critically assessed. Several welding factors that improve joint quality, such as welding method, weld and material preparations, as well as welding parameters, are also discussed. This study also examines recent developments in hybrid welding techniques and proposes a preheating method to enhance the weld joints of aluminum–steel dissimilar welding.
98 citations
TL;DR: In this article, the drilling behavior of unidirectional sisal-epoxy and sisal polypropylene composite laminates has been experimentally investigated, and the analysis of drilling force signals has been reported and the mapping of drilling for making holes to facilitate assembly of several components into an intricate part.
Abstract: Natural fiber composites have attracted global attention due to their lightweight, low-carbon footprint characteristics as well as good mechanical properties. Due to these distinct advantages, the application spectrum of these composites has grown at an unprecedented rate. These composites are used for making a wide variety of sophisticated engineering products; therefore, certain degree of machining operations is necessary for assembly purposes. Drilling is an indispensable machining operation that is frequently performed for making of holes to facilitate assembly of several components into an intricate part. In the present research endeavor, the drilling behavior of unidirectional sisal-epoxy and sisal-polypropylene composite laminates has been experimentally investigated. Chip formation characteristics in the context of both thermoset and thermoplastic natural fiber composite laminates have been discussed. Further, the analysis of drilling force signals has been reported and the mapping of drilling for...
97 citations
TL;DR: In this paper, the authors focused on optimizing process parameters in abrasive water-jet machining with the objective of minimizing surface roughness in brass-360, and the following process parameters were considered: abrasive flow rate, pump pressure, stand-off distance, and feed rate.
Abstract: This paper focuses on optimizing process parameters in abrasive water-jet machining with the objective of minimizing surface roughness in brass-360. The following process parameters were considered: abrasive flow rate, pump pressure, stand-off distance, and feed rate. The experiments were conducted using a Taguchi L27 orthogonal array. Response surface methodology was used to decide the optimal process parameters that minimized the surface roughness. Analysis of variance reflects the relative significance of process parameters and is used to find contribution of factors. Furthermore, a mathematical model was developed to correlate the machining performance. It was found that the pump pressure was the most significant parameter affecting the surface roughness. The optimal combination of process parameters are an abrasive flow rate = 75.37 g/min, pump pressure = 399 MPa, stand-off distance = 1 mm, and feed rate = 557 m/min. Finally, using a desirability function method, the optimal parameters for minimizing...
92 citations
TL;DR: In this paper, a state-of-the-art review on tool-based micromachining processes such as microturning, microdrilling, micromilling, micro-EDM and micro-ECM has been carried out.
Abstract: Technology development has led to the need of micro and miniaturized products in the field of automobile, aerospace, electronics, medical implants, biomedicine, robotics, and so on. Micromachining is the key technology to satisfy the need of the industry in terms of functionality and miniaturization in size. In this article, state-of-the-art review on tool-based micromachining processes such as microturning, microdrilling, micromilling, electric discharge micromachining (Micro-EDM), and electrochemical micromachining (Micro-ECM) has been carried out. The review begins with an overview of micromachining, classifications, and discussions about different aspects of tool-based micromachining processes. The research works carried out for the past 10 years are analyzed in terms of materials perspective, process parameters, size effects, performance characteristics, condition monitoring, product development, micro features generation, and fabrication of micro tools. A statistical analysis has been performed with...
87 citations
TL;DR: In this article, the influence of different EDM process variable peak current (I p ), duty factor (T au), and pulse-on duration (T on) on various performance characteristics such as material removal rate (MRR), surface roughness (SR), radial overcut (ROC), and surface crack density (SCD).
Abstract: Recently, electro-discharge machining (EDM) has become one of the preferred machining techniques for Ni-based super alloys. Although extensive research has been reported on EDM characteristics of Inconel 718, not much information is available on Inconel 825. Owing to the excellent resistance to corrosion, Inconel 825 finds particular application in highly corrosive environment. Therefore, the current investigation aims at studying the influence of different EDM process variable peak current (I p ), duty factor (T au), and pulse-on duration (T on) on various performance characteristics such as material removal rate (MRR), surface roughness (SR), radial overcut (ROC), and surface crack density (SCD). Experiments were designed and carried out using L9 orthogonal array. The most influencing factor for responses MRR, SR, and ROC was found to be I p with percentage contribution of 51.22%, 81.08%, and 54.78%, respectively, while it was T on for SCD with 39.54% contribution. Since EDM involves multiple performanc...
86 citations
TL;DR: In this article, the impact of four parameters (step down, feed rate, sheet thickness, and tool diameter) on surface roughness is analyzed using the response surface methodology with Box-Behnken design.
Abstract: As a critical product quality constraint, surface roughness is regarded as a weak point in incremental sheet forming (ISF). It is of great importance to identify the impact of forming parameters on the surface roughness and optimize the surface finish at the production stage. This paper proposes a systematic approach to modeling and optimizing surface roughness in ISF. The quantitative effects of four parameters (step down, feed rate, sheet thickness, and tool diameter) on surface roughness are analyzed using the response surface methodology with Box–Behnken design. The multi-objective function is used to evaluate the overall surface roughness in terms of the tool-sheet contact surface roughness, i.e., internal surface roughness and the noncontact surface roughness, i.e., external surface roughness. Additionally, the average surface roughness (R a) on each surface is measured along the tool-path step-down direction taking the impact of sheet roll marks into account. The optimal conditions for the minimiza...
72 citations
TL;DR: In this paper, a review of the literature on process aspect, modeling, and quality issues in twin-roll casting has been presented, where the role of process parameters on solidification during casting is reviewed.
Abstract: Since its invention by Sir Henry Bessemer in 1865, twin-roll casting (TRC) has been the subject of extensive research, not only to develop the technology but also to achieve an understanding of microstructural evolution. The present review confines itself to the literature on process aspect, modeling, and quality issues. Initially, the principles of the process are outlined. Modeling of fluid flow, heat transfer, and microstructural evolution, surface and internal defects in TRC of aluminum alloys are next discussed. The role of process parameters on solidification during casting is reviewed. The controls of grain structure by melt treatment are also discussed in brief.
TL;DR: In this article, a micro-hole was successfully drilled in stainless steel by electrochemical discharge machining with high-speed electrode using pure water as electrolyte using an experimental setup was established.
Abstract: Electrochemical discharge machining with high-speed micro-electrode is a micro-machining process based on the fundamental of electrochemical discharge principle The process has been applied in metal for drilling micro-holes Drilling of micro-holes in stainless steel is a challenge working A few qualitative conclusions are obtained by drilling micro-holes in stainless steel by electrochemical discharge machining with high-speed electrode using pure water as electrolyte An experimental setup was established A micro-hole was drilled in stainless steel successfully
TL;DR: An experimental work and investigation on electrical discharge machining (EDM) of Inconel 718 and 625 superalloys is presented in this article, where the significance of input parameters namely peak current, pulse-on time, and pulse-off time (T off) on the form tolerances were investigated.
Abstract: This article presents an experimental work and investigation on electrical discharge machining (EDM) of Inconel 718 and 625 superalloys. These superalloys are used for making parts like turbine blades, marine components, and nuclear reactor components. The precise components made up of superalloys which have cylindrical, square, and hexagonal machined features are required regular estimations of cylindricity, circularity, perpendicularity, and parallelism. In this work, EDM of the above said superalloys was carried out and form tolerances were analyzed. The significance of input parameters namely peak current, pulse-on time (T on), and pulse-off time (T off) on the form tolerances were investigated. In addition to these, the influence of individual parameters were also analyzed by analysis of variance (ANOVA) technique.
TL;DR: In this article, a machining of AA6061/10%SiC composite fabricated by mechanical stir casting process has been experimentally investigated using electrodischarge machining (EDM) process with tungsten-powder-mixed dielectric fluid (PMEDM).
Abstract: In this study, machining of AA6061/10%SiC composite fabricated by mechanical stir casting process has been experimentally investigated using electrodischarge machining (EDM) process with tungsten-powder-mixed dielectric fluid (PMEDM). Peak current, pulse on-time, pulse off-time, and gap voltage are selected as machining parameters. Mathematical relation has been established for response quality characteristics like surface roughness with and without tungsten powder dielectric fluid using Central Composite Rotatable Design (CCRD) through response surface methodology (RSM). Surface characteristics like microhardness, surface topography, and white recast layer have been evaluated through scanning electron microscope (SEM), electrodispersive X-ray spectroscopy (EDS), and micro-Vicker hardness. Results have also been compared with simple EDM of AA6061/10%SiC composite without powder-mixed dielectric fluid. The existence of tungsten powder in dielectric fluid increases surface quality owing to decrease in numbe...
TL;DR: In this article, the variation of surface roughness (SR) in a negative incremental sheet forming (ISF) process was systematically studied by means of four different process parameters, namely, the vertical step size, forming tool diameter, spindle speed, and feed rate.
Abstract: The features of the incremental sheet forming (ISF) process allow it to meet a wide array of customer preferences. In this paper, the variation of surface roughness (SR) in a negative ISF process was systematically studied. The variation was investigated by means of four different process parameters, namely, the vertical step size, forming tool diameter, spindle speed, and feed rate. By using Taguchi analysis with the help of design of experiment and analysis of variance (ANOVA), the effects of the above four process parameters have been studied to optimize parameter levels to realize minimum SR. The results illuminated which parameters have the greatest effect on SR variation, namely, tool size and vertical step size. The confirmation test also showed that the response tables and graphs from Taguchi analysis and ANOVA constitute effective and efficient methods for determining each design parameter's optimal level to produce the minimum value of the SR.
TL;DR: In this article, an investigation is carried out to find the influence of process parameters such as pulse current (I), pulse on time (T on), pulse duty factor (τ), and voltage (V) on the machining of Al(6351), 5-wt% silicon carbide (SiC), 5 -wt% boron carbide composite through electrical discharge machining.
Abstract: Metal matrix composites are found to have many applications in the materials and structural engineering field. In this work, an investigation is carried out to find the influence of process parameters such as pulse current (I), pulse on time (T on), pulse duty factor (τ), and voltage (V) on the machining of Al(6351)—5 wt% silicon carbide (SiC)—5 wt% boron carbide (B4C) hybrid composite through electrical discharge machining. The individual parameters were analyzed with an objective to minimize electrode wear ratio (EWR), surface roughness (SR), and power consumption (PC). The experimental result shows that the output responses were greatly influenced by pulse current, with a contribution of 33.08% to EWR, 76.65% to SR, and 48.08% to PC. The surface characteristics were also examined through scanning electron microscope and the presence of craters and recast layers was observed.
TL;DR: In this article, a method for manufacturing new generation of AMCs by adding 10Ce-TZP(tetragonal zirconia polycrystal)/Al2O3 nanoparticles to aluminum via powder metallurgy is devised.
Abstract: Aluminum matrix composites (AMCs) are candidate materials for total joint arthroplasty, dental prostheses, cutting tools, and biomedical gadgets owing to their strength, machinability, dimension accuracy, and wear resistance. A novel method for manufacturing new generation of AMCs by addition of 10Ce-TZP(tetragonal zirconia polycrystal)/Al2O3 nanoparticles to aluminum via powder metallurgy is devised. Aqueous combustion synthesis is used for dispersoid production and milling–compaction–sintering for AMC fabrication. Effects of 10Ce-TZP/Al2O3 content on hardness, erosion, and wear resistance are investigated. Scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and pin-on-disk analyses are used to explore worn interface, morphology, mechanism of abrasion, and resistance to wear. By addition of 7 wt% dispersoid, considerable increase in hardness and resistance to wear are achieved.
TL;DR: In this article, the authors applied ultrasonic vibration and magnetic field simultaneously/separately, and compared the machining performance by analyzing material removal rate and tool wear rate (TWR) while fabricating micro channels on nonmagnetic materials using micro-EDM milling.
Abstract: Micro-electric discharge milling (μ-EDM milling) is one of the micromachining processes which draw the attention of researchers in fabricating microcavities and microchannels. Improving the efficiency of this process remains challenging. There are publications that report the benefits of applying ultrasonic vibration to tool or workpiece and using magnetic fields to enhance debris removal. In almost all the literature, magnetic field and/or ultrasonic vibration were applied separately in micro-/macro-EDM. The aim of this study is to apply ultrasonic vibration and magnetic field simultaneously/separately, and compare the machining performance by analyzing material removal rate and tool wear rate (TWR) while fabricating microchannels on nonmagnetic materials using μ-EDM milling. From the results, it is recommended to use magnetic field or ultrasonic vibrations separately for achieving high MRR, but the combination of both gave poor results.
TL;DR: In this article, the effects of the grinding process on the porosity content, residual stress, microhardness, and adhesion and cohesion strength of the high-velocity oxy-fuel WC-10Co-4Cr coatings are investigated.
Abstract: In carbide cermet coatings, such as WC–Co–Cr, the surface roughness of the sprayed workpiece is much more than the acceptable values for various industrial demands. Thus, the surface of the carbide cermet coatings is to be ground appropriately to obtain suitable surface finish. However, the grinding may change the properties of coating. In this study, effects of the grinding process on the porosity content, residual stress, microhardness, and adhesion and cohesion strength of the high-velocity oxy-fuel WC–10Co–4Cr coatings are investigated. For this purpose, the grinding experiments have been performed on a surface grinder using a diamond wheel (resin bond) under different grinding parameters, such as table feed rate, cutting speed, and depth of cut. The investigations of residual stress state and adhesion properties were carried out using the X-ray diffraction and interfacial indentation test methods, respectively. The results indicated that the coating's porosity content increased after grinding due to ...
TL;DR: In this paper, the cutting forces induced during high-speed end milling of titanium alloy (Ti-6Al-4V ELI) as well as the surface quality of the milled surfaces were investigated.
Abstract: This study investigates the cutting forces induced during high-speed end milling of titanium alloy (Ti–6Al-4V ELI) as well as the surface quality of the milled surfaces. The high-speed machining was performed using carbide tool of coated and uncoated types at three cutting speeds of 200, 250, and 300 mm/min and two feed rates of 0.03 and 0.06 mm/tooth. Surface integrity was characterized in terms of surface roughness (Ra) and morphology. Cutting speed was found to be inversely proportional to the resultant cutting force at any cutting conditions. Cutting force in the X direction displayed higher sensitivity against cutting conditions. The results showed that feed rate is proportional to cutting force in X and Y directions regardless of tool type. Under the fixed feed rate condition, cutting force decreased at higher cutting speed for both tools. It was also found that uncoated tool induces less cutting force compared to coated one. High-speed end milling using uncoated tool provided better surface finish ...
TL;DR: In this paper, the influence of powder metallurgical (P/M) electrodes on the surface of mild steel in electric discharge machining was described, and an attempt has been made to deposit a uniform layer of tungsten and its carbide over the mild steel substrate using P/M green compact tools by electric discharge coating process.
Abstract: This paper describes the influence of powder metallurgical (P/M) electrodes on the surface of mild steel in electric discharge machining. An attempt has been made to deposit a uniform layer of tungsten and its carbide over the mild steel substrate using P/M green compact tools by electric discharge coating process. In this experimental work, W and Cu powders of 325 mesh size have been selected as electrode material and mild steel as workpiece material. A detailed investigation of process parameters, such as composition, compaction load, current, on-time, and off-time, which influence the material transfer rate (MTR), tool wear rate, roughness, and layer thickness, has been performed. Highest MTR of 281 mg/min and LT of 1262.99 µm have been achieved successfully. The hardness of deposited layer has been measured which proves that the deposited layer is 5–6 times harder than the substrate material.
TL;DR: In this paper, an attempt has been made to analyze the effect of EDM process on surface hardness of AISI 202 stainless steel with different tool electrodes such as brass and tungsten carbide.
Abstract: Since the recast layer affects the surface hardness of the workpiece in electrical discharge machining (EDM), it is very important to investigate the effect of the tool electrode on the machined surface. Owing to its importance in the locomotive structural elements, an attempt has been made to analyze the effect of EDM process on surface hardness of AISI 202 stainless steel with different tool electrodes such as brass and tungsten carbide. The investigation was carried out with various process parameters, and surface hardness values were computed using micro Vickers hardness tester. From the experimental results, it has been observed that the surface hardness of the workpiece increases with tungsten carbide tool electrode whereas it decreases with brass tool electrode due to the layer formation on the machined surface of the workpiece.
TL;DR: In this paper, the authors explore and subsequently establish wire electric discharge machining (WEDM) process as a superior, economical, and viable alternative for manufacturing the high-quality fine-pitched miniature gears through a comparative evaluation of process capabilities of WEDM and gear hobbing which is the most commonly used conventional process.
Abstract: With increasing emphasis on miniaturization, the demand for manufacturing the high-quality fine-pitched miniature gears is growing continuously. Inability of the conventional processes to manufacture high-quality miniature gears compels the need to explore a process which can economically manufacture precise and accurate gears required by the various miniature products used for different scientific, industrial, and domestic applications. This article reports on exploring and subsequently establishing wire electric discharge machining (WEDM) process as a superior, economical, and viable alternative for manufacturing the high-quality miniature gears through a comparative evaluation of process capabilities of WEDM and gear hobbing which is the most commonly used conventional process. The evaluation concentrated on those capabilities of these two processes which affect functional performance and service life of the miniature gears. This included microgeometry parameters (i.e., profile error and pitch error) a...
TL;DR: In this article, the authors used conductive powder-mixed dielectric in electrical discharge machining of Super Co 605 and optimization is carried out by means of Taguchi method.
Abstract: Experiments were performed using conductive powder-mixed dielectric in electrical discharge machining of Super Co 605 and optimization is carried out by means of Taguchi method. The process input parameters selected are flushing pressure, discharge voltage, pulse on-time, polarity, peak current, and pulse off-time to study the performance characteristics in the form of surface roughness, tool wear, and material removal rate. Experiments based on appropriate orthogonal array are conducted and significant parameters are identified. The optimum process conditions simultaneously leading to a better surface roughness, lower tool wear, and higher material removal rate are then demonstrated by confirmation testing. The experimental results confirm an improvement in surface roughness, tool wear, and material removal rate when Taguchi method is used.
TL;DR: In this paper, Ni-based powder (EWAC 1002 ET) is used to join the stainless steel and the characterization of joint has been carried out through microstructural analysis, X-ray diffraction analysis, tensile strength, elongation, and microhardness.
Abstract: In this paper, the microwave heating has fabricated joints of stainless steel (SS). Ni-based powder (EWAC 1002 ET) is used to join the stainless steel. The characterization of joint has been carried out through microstructural analysis, X-ray diffraction analysis, tensile strength, elongation, and microhardness. Microstructure analysis reveals that the joint is clearly visible. There are no cracks at the joints. Very small amount of porosity has been observed. Hardness decreases toward the joint. As the exposure time and percentage of nickel-based powder increase, tensile strength also increases. Tensile strength, elongation, and microhardness of joint are 323.16 MPa, 11.30%, and 145.3 Hv, respectively.
TL;DR: In this paper, a grey relational analysis and Taguchi methods were used to solve the EDM parameters optimization problems of Ti-6Al-4V material, where the tool electrode wear rate, workpiece material removal rate, and the workpiece surface roughness were selected to estimate the machining results.
Abstract: Ti–6Al–4V is widely used in manufacturing field for its exceptional merits, but it belongs to difficult-to-cut material. Electrical discharge machining (EDM) became an important machining method for this material. This paper aims to combine grey relational analysis and Taguchi methods to solve the EDM parameters optimization problems of Ti–6Al–4V material. Using tap water as working liquid is good for environment, because it is healthy and safe to the operators. The process parameters include peak current, open circuit voltage, lifting height, pulse width, and pulse intermission. The tool electrode wear rate, workpiece material removal rate, and the workpiece surface roughness are selected to estimate the machining results. Experiments were executed on orthogonal array and grey relational analysis, and then the results were verified through the contrast experiment. The results indicate that the workpiece material removal rate increased from 5.90 mm3/min to 6.02 mm3/min, the tool electrode wear rate reduce...
TL;DR: In this article, the authors applied the machining approach and other analysis techniques to investigate the material removal behavior during surface grinding of high-velocity oxy-fuel (HVOF) thermally sprayed WC-10Co-4Cr coating using a resin-bonded diamond wheel.
Abstract: The present study applies the machining approach and other analysis techniques to investigate the material removal behavior during surface grinding of high-velocity oxy-fuel (HVOF) thermally sprayed WC–10Co–4Cr coating using a resin-bonded diamond wheel. The basic grinding factors such as force ratio, specific material removal rate, maximum undeformed chip thickness, and specific grinding energy have been investigated and discussed. The mathematical models containing linear terms and interactions of the first-order have been used to investigate the effect of the grinding parameters on the grinding force. The results have shown that both tangential and normal grinding forces depend not only on the depth of cut, feed rate, and cutting speed, but also on the depth of cut and feed rate interaction. Scanning electron microscopy (SEM) examination of the ground surface has revealed that the mechanism of material removal presents both brittle fracture and ductile flow modes. Considering the effect of the process ...
TL;DR: In this article, a new approach for sidewall insulation of microtool by dip coating using liquid solution made of polymer and resin dissolved in isopropyl alcohol and use of acetone for opening the front end of the microtool was presented.
Abstract: This paper presents a new approach for sidewall insulation of microtool by dip coating using liquid solution made of polymer and resin dissolved in isopropyl alcohol and use of acetone for opening the front end of the microtool. This method can also be used to remove the previously applied coat completely so that the microtool can be reinsulated again for the reuse. To investigate the effectiveness of insulating film, in-situ fabricated tungsten microtool of 104 µm diameter was insulated with 4.5-µm thick film by proposed method. Microfeatures like microhole and microgroove were machined by electrochemical micromachining (EMM) using uninsulated microtool and insulated microtool on stainless steel. The machining accuracy of the microfeatures machined were compared in terms of overcut and taper angle generated on microfeatures. In this way, 33.78% reduction in radial overcut of microhole and 58.64% reduction in width overcut of microgroove were observed. Taper angle was reduced from 40.57° to 18.00° and 58....
TL;DR: In this article, the effect of input process variables on material removal rate (MRR) and kerf width (K w) during the cutting of borosilicate glass using self-developed tabletop traveling wire electrochemical spark machining (TW-ECSM) setup was investigated.
Abstract: Machining performance study of newly developed machining processes has always been a challenge to make them industrially viable. Traveling wire electrochemical spark machining (TW-ECSM) is a newly developed hybrid process in the area of nontraditional machining process which can be effectively utilized for difficult-to-cut electrically nonconductive very hard and brittle materials. Present paper discusses the investigations showing the effect of input process variables on material removal rate (MRR) and kerf width (K w) during the cutting of borosilicate glass using self-developed tabletop TW-ECSM setup. The experimental studies are conducted under varying applied voltage, pulse-on time, pulse-off time, electrolyte concentration, and wire feed velocity. The experimental results shows that MRR and K w increase with increase in applied voltage as well as pulse-on time, but these performance characteristics decrease with increase in pulse-off time. MRR and K w increase with increase in electrolyte concentrat...
TL;DR: In this article, the effect of tool type and size on the formability and surface integrity during the incremental sheet forming (ISF) process was investigated and compared with the experimental results.
Abstract: Incremental sheet forming (ISF) is a promising forming process perfectly suitable for manufacturing customized products with large plastic deformation by using a simple moving tool. Up to now, however, the effects of contact conditions at the sheet interface are not well understood. The aim of this work is to study the effect of tool type and size on the formability and surface integrity during the forming process. Experimental tests were carried out on aluminum sheets of 7075-O to create a straight groove with four different tools (ϕ 30,ϕ25.4,ϕ20 andϕ10mm). One tool tip was fitted with a roller ball (ϕ 25.4mm) while the other three were sliding tips. The contact force, friction and failure depth were evaluated. A finite element (FE) model of the process was set up in an explicit code LS-DYNA and the strain behavior and thickness distribution with different tools were evaluated and compared with the experimental results. This study provides important insights into the relatively high formability observed ...