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ABSTRACTThe operation of laser marking occurs due to oxidation on the metallic surface at a high temperature, which finds applications in many organisations due to its cleanness and high handling speed with the negligible human association. The generated marked objects are permanent in nature, generally utilised for product identity. From the perspective of laser marking, the general requirement of laser marking is mark clarity or marking quality with minimal effect on the workpiece surface. The paper deals with producing good-quality laser-marked surface by the utilisation of process parameters such as transverse feed, average laser power and scanning speed, which seem to have a significant effect on the surface of designed materials for the development of laser marking qualities. The diode-pumped pulsed fibre laser was utilised for the purpose of marking on the surface in a single pass within the minimum possible time. Experimental studies revealed that decrease in transverse feed from 8 μm to 2 μm/laser stroke had a projection towards the increase in mark intensity which could be reached up to 0.95 on the application of the lower value of transverse feed, i.e., 2 μm/laser stroke upon using a proper set of process parameters. .

The present article deals with the generation of micro-grooves on 316L stainless steel (SS) by a nanosecond pulsed fiber laser system. Fabrication of micro-grooves on 316L SS has immensely contributed to the biomedical and automotive industries through improving the mechanical, lubrication, and corrosion resistance properties. In the present work, the considered process parameters are the preheating temperature (100°C and 200°C), along with the room temperature (24°C), cutting speed, sawing angle, pulse frequency, and laser power. The ranges of cutting speed and sawing angle are 0.1–1.1 mm s−1and 0.1°–1°, respectively. Besides, pulse frequency and laser power vary from 55 kHz to 85 kHz and from 15 W to 45 W, respectively. The constant parameters are the pulse width of 99% and assist air pressure of 6 kgf cm−2. The variable parameters for the analysis are cut width and heat-affected zone (HAZ) width. The article aims to showcase a comprehensive study of fiber laser process parameters at different temperatures (preheated condition and room temperature) with variable sawing angles to produce better process control and bring about each considered process parameter’s critical value. The experimental results show that higher dimensions of cut width and HAZ width are observed at 200°C with the increment of sawing angle and laser power, compared to other temperatures. With the increment of cutting speed and laser power, the HAZ width tends to rise sharply. A significant drop in cut width and HAZ width dimensions is observed with the increment in pulse frequency for any temperature.

Laser marking is one of the operations performed by laser with an aim to identify products, components, etc., so that they can be easily traced with information. The multi diode pumped fibre laser with ytterbium doped as a lasing medium, was used to mark a circular shaped image. The paper aimed to study the influence of process parameters such as laser power, pulse frequency, scanning speed, duty cycle and transverse feed on responses such as mark intensity, circularity and surface roughness value (Ra, μm). The range of process parameters involved were transverse feed of 4-14 μm per laser stroke, laser power of 7.5-17.5 W, pulse frequency of 50-60 kHz, duty cycle of 20-40% and scanning speed of 5-25 mm/s. Experimental work was carried out without the supply of assist gas pressure and laser marking process was done by scanning the fibre laser for single pass. Experimental results revealed that for better value of mark intensity, circularity and surface roughness value (Ra) of circular shaped marked image, the process parameters such as laser power of 12.5 watt (W), pulse frequency of 50 kHz, duty cycle of 30% and scanning speed of 5 mm/s should be selected.

Microchannel cutting on electrically nonconducting materials with electrochemical discharge machining (ECDM) process has drawn a momentous attention in manufacturing field as compared to other existing nontraditional machining processes. In the present research work, an effort has been accomplished to investigate the effects of process parameters, namely, applied voltage (V), electrolyte concentrations(wt%), pulse frequency, and duty ratio on different performance characteristics of ECDM viz., material removal rate (MRR), overcut (OC) and heat-affected zone (HAZ) area during microchannel cutting on glass. Also, the comparative performance studies during microchannel cutting have been done by using mixed electrolyte of NaOH and KOH and different tool polarities. Overcut is measured as lower (42.26 μm) when aqueous KOH electrolyte is used and as higher (133.44 μm) for aqueous NaOH electrolyte. HAZ enlarges with enrichment in concentration for both types of electrolyte. It is observed that polarity has a vital role on various machining characteristics. As compared to direct polarity, MRR is found very low (3.2 mg/h) in reverse polarity of tool. Overcut is found low in KOH electrolyte for both types of tool polarity (i.e., 64.68 μm for direct polarity and 42.27 μm for reverse polarity). The process parameters influence on the surface texture of microchannels. Microcrack is noticed for direct polarity of tool.

ABSTRACTDeveloping tools for ultrasonic machining processes is one of the most challenging tasks, because the shape of the machined surface of the workpiece is a replica of the tool surface. In this research, using reverse engineering (RE), the tool has been designed and fabricated for the ultrasonic machining (USM) process. Zirconia is a very hard and brittle bio-ceramic material and is highly biocompatible. Nowadays, zirconia material is used for producing the acetabular cup for hip joint. In this research work, an attempt has been made to apply the RE for developing the CAD model of a USM tool from the existing hemispherical shape cavity on a zirconia workpiece. Experimental analysis has been undertaken for generating the hemispherical shape cavity on zirconia bio-ceramics with the help of these developed tools. Through a number of graphical plots, comparisons of diametrical deviation and circularity error have been made using RE and without RE. Comparisons have also been made for justifying the accuracy of the tool development by RE with respect to the initial existing hemispherical shape cavity and developed tool for USM.

Micro-electro-discharge machining (micro-EDM) process has great potential to machine difficult-to-cut and electrically conducting materials like aluminium, nickel, titanium and their alloys etc. This present research work intends to investigate during micro-holes drilling on pure aluminium by means of vibration at workpiece in electro-discharge machining process. The influences of different process variants such as polarity, peak current, direction of flushing and pulse on-time have been studied using experimental results, which were obtained based on L18orthogonal array of Taguchi method and the suitable parametric combinations for optimum machining criteria have been searched out. Also, the effects of vibration on different machining performances, as well as surface quality and accuracy of the micro-holes have been investigated with a rotary vibrator, which has been indigenously designed and developed. The performance characteristics such as metal removal rate (MRR), tool wear rate (TWR) and roundness have been found to be improved on account of influence of the vibration of workpiece.

Electrochemical discharge machining (ECDM) process has great potential to machine hard, brittle and electrically non-conducting materials in micron range. The objective of this paper is to investigate into electrochemical discharge micro-machining on electrically semi-conductor type silicon carbide (SiC) material so as to study the effects of applied voltage, electrolyte concentration and inter-electrode gap on material removal rate (MRR) and radial overcut (ROC) of micro-drilled hole. Experiments were conducted based on L9 array of Taguchi method with stainless steel µ-tool of 300µm diameter using NaOH electrolyte. An attempt has been made to find out the single as well as multi-objective optimal parametric combinations for maximum MRR and minimum ROC. The single-objective parametric combinations were selected as 45V/20wt%/20mm and 25V/20wt%/40mm for maximum MRR and minimum ROC respectively whereas multi-objective optimal parametric combinations was found as 25V/20wt%/40mm. Further mathematical models have been developed between the above machining parameters and characteristics.

An attempt has been made to apply the Taguchi parameter design method and multi-response optimization using desirability analysis for optimizing the cutting conditions (cutting speed, feed rate and depth of cut) on machining forces while finish turning of AISI 4340 steel using developed yttria based zirconia toughened alumina inserts. These zirconia toughened alumina inserts were prepared through wet chemical co-precipitation route followed by powder metallurgy process. The L9(4) orthogonal array of the Taguchi experiment is selected for three major parameters, and based on the mean response and signal-to-noise ratio of measured machining forces, the optimal cutting condition arrived for feed force is A1, B1and C3(cutting speed: 150 m/min, depth of cut: 0.5 mm and feed rate: 0.28 mm/rev) and for thrust and cutting forces is A3, B1and C1(cutting speed: 350 m/min, depth of cut: 0.5 mm and feed rate: 0.18 mm/rev) considering the smaller-the-better approach. Multi-response optimization using desirability function has been applied to minimize each response, that is, machining forces, simultaneously by setting a goal of highest cutting speed and feed rate criteria. From this study, it can be concluded that the optimum parameters can be set at cutting speed of 350 m/min, depth of cut of 0.5 mm and feed rate of 0.25 mm/rev for minimizing the forces with 78% desirability level.

The essence of the “ratio data” in cellular manufacturing system has rarely been correctly emphasized since past few decades of research and study. This article is an attempt to deal with cell formation problem which exploits machine utilization percentage and eliminates the “fuzziness” on the subject of ratio data. In the course of this study, a distinctive technique is adopted based on multi-criteria decision technique with significant modifications which is experimented on test data and compared with published methodology. To verify the grouping result, a novel performance measure is proposed and elaborated analytically to establish its superiority and robustness over the earlier efficiency measures published in the past literature of cellular manufacturing system. The novelty of this research remains in eradicating ambiguities on the subject of “ratio data,” imposing appropriate rules while generating the test problems, catering a unique multi-criteria decision technique–based approach and a novel performance measure for the aforesaid problem.

Simple microgrooves can be fabricated easily, whereas fabrication of varied cross-sectional microgrooves on metallic surfaces is still a challenging task by present traditional as well as non-traditional methods. An application of electrochemical micromachining (ECμM) for machining various cross-sectional microgrooves on SS has been proposed in this paper. Influences of process parameters on width overcut have been investigated, and experimental findings have been applied to devise guidelines to fabricate various cross-sectional microgrooves. Disc microtool with longitudinal vibration has been utilised in layered machining of microgrooves. Duty ratio has been varied from 30% to 60% along depth of microgroove with other identical process parameters. The guidelines for straight, reverse tapered, barrel-shaped, double stepped, spherical based, and microgroove with internal pocket have been developed, and fabrications of these microgrooves have been demonstrated successfully. The experimental findings may be useful for planning and machining various cross-sections of microgrooves for different applications.

Ultrasonic micromachining (USMM) has immense potential for micro-machining on quartz which is used in different field of applications such as optics, metrology and micro electro mechanical system (MEMS) etc. In this paper the influences of process parameters such as power rating, abrasive slurry concentration and tool feed rate on material removal rate (MRR), overcut and taper angle of the micro hole on quartz by USMM have been investigated. Stainless steel of grade 304 has been selected as the micro-tool material for ultrasonic micro drilling on quartz. The higher value of MRR of 0.4235 mm/min has been obtained at power rating of 400 W, abrasive slurry concentration of 40% and tool feed rate of 1.2 mm/min. The lower value of overcut of 55 µm and taper angle of 0.600 of micro hole have been obtained at abrasive slurry concentration of 20%, power rating of 300 W and tool feed rate of 1 mm/min.

Modern industrial field of micro-machining has an attractive attention to increase the machinability of electrically non-conducting materials. Electrochemical discharge micro-machining process has the ability to machine high strength non-conducting brittle materials like glass. This paper shows a development of second-order correlation between the various machining criteria and different process parameters such as applied voltage, electrolyte concentration and inter-electrode gap (IEG). The analysis of variance (ANOVA) has been performed to find out the adequacy of the developed models. The research paper includes the effects of various process parameters on material removal rate (MRR), overcut (OC), heat affected zone (HAZ) and machining depth (MD) during micro-channel generation on glass. This paper also represents the single as well as multi-objective optimised results to determine the suitable parametric combination for maximum MRR and machining depth and minimum overcut and HAZ area using response surface methodology (RSM) and genetic algorithm (GA).

A back propagation neural network model has been adopted for the flank wear prediction of zirconia toughened alumina (ZTA) insert in turning operation. The experiments are performed on AISI 4340 steel using developed yttria based ZTA inserts. These inserts are prepared through wet chemical co-precipitation route followed by powder metallurgy process. Machining conditions such as cutting speed, feed rate and depth of cut are selected as input to the neural network model and flank wear of the inserts corresponding to these conditions has been chosen as the output of the network. The experimentally measured values are used to train the feed forward back propagation artificial neural network for prediction of those conditions. The convergence of the mean square error both in training and testing come out very well. The performance of the trained neural network has been validated with experimental data. The results demonstrate that the machining model is suitable and the optimization strategy satisfies practical requirements.

Microgrooves are one of the basic microfeatures fabricated on different microproducts, used to integrate micro systems in various fields. Service life and product functioning of microproducts are directly influenced by shape, size, and surface quality of microgrooves fabricated on it. Hence, these are the important criteria to be considered while fabricating microgrooves on micro devices. This article presents the experimental study into fabrication of microgrooves on stainless steel by electrochemical micromachining. The influence of electrochemical micromachining process parameters like applied voltage, pulse frequency, duty ratio, electrolyte concentration, and microtool scanning speed on machining accuracy, that is, width overcut, length overcut and depth overcut, material removal rate, linearity of microgroove, depth profile, and surface finish were investigated during microgroove generation. From the experimental results, optimal parameters obtained were applied voltage of 2.6 V, pulse frequency of 8 MHz, 30% duty ratio, electrolyte concentration of 0.15 M H2SO4, and microtool scanning speed of 93.75 μm/s for machining of accurate microgroove, with best surface finish. Finally, microfeatures like “C”-shaped microgroove of rectangular cross section and multiple microgrooves as required in micro thermal devices have been machined with optimal parametric settings. This study will be useful for machining of need-based microgrooves on microproducts like micro actuators, micro pumps, micro coolers, and micromixers.

Abrasive water jet cutting (AWJC) is a rapidly developing technology that is used in industry for cutting of ceramic materials. Dense Si3N4, is one of the very hard ceramic materials, used for both room and high-temperature structural application, was machined by abrasive water jet machining technique. The selection of optimum values of important process parameters of AWJC processes such as water pressure, abrasive flow rate, traverse speed and standoff distance can be done based on parametric study and then optimisation of non-linear functions using Grey-Taguchi method has been introduced for determining optimal AWJC process parametric combinations.

Electrochemical Discharge micro-machining process appears better utility with greater effectiveness in the modern micro-machining industrial field. Electrochemical discharge micro-machining process is involved to generate micro-channel as well as curve profile on glass for utilization as micro-fluidic device. This paper shows second order mathematical modeling of correlation between the machining criteria such as machining rate as a form of material removal rate (MRR), overcut (OC), machining depth (MD) with various process parameters like applied voltage (V), electrolyte concentration (wt %) and inter-electrode gap (IEG) (mm). The analysis of variance (ANOVA) has been performed to find out the adequacy of the developed models.This paper also shows the multi objective optimization to achieve the optimal parametric combination for maximum MRR, MD and minimum OC using response surface methodology (RSM). Keywords: μ-ECDM, MRR, OC, MD, RSM, ANOVA, Glass.

The present paper addresses an investigation on the effect of process parameters during Nd:YAG laser micro-turning operation of different grade of alumina (Al2O3) ceramic materials. Considering different levels of various process parameters i.e. laser beam average power, pulse frequency, workpiece rotational speed and Y feed rate, Taguchi method based experimental design has been used to construct the set of experiments. The same set of experiments has been utilized to machine 10 mm diameter cylindrical workpiece made of different grades of Alumina ceramics i.e. K60 and K80. Surface roughness (Ra) and micro-turning depth deviation were considered as the process characteristics. Analysis of variance (ANOVA) test was performed for each grade of alumina ceramic to find out the significant process parameters during laser micro-turning process. The optimum process parameters settings for individual responses were obtained by analyzing the signal-to-noise (S/N) ratio. Mathematical models, which correlate the response and process variables, have been developed for all the grades of ceramics. Multi-objective optimization i.e. simultaneous minimization of surface roughness (Ra) and micro-turning depth deviation has been done through combined approach of Taguchi methodology and Grey Relational Analysis.

This article portrays a chronological review of the influence of artificial neural network in group technology applications in the vicinity of cellular manufacturing systems. The research trend is identified and the evolvement is captured through a critical analysis of the literature accessible from the very beginning of its practice in the early 90s till the 2012. Analysis of the diverse ANN approaches, spotted research pattern, comparison of the clustering efficiencies, the solutions obtained and the tools used make this study exclusive in its class.

Laser marking process has excellent features over other marking processes due to its high-speed and precise process with excellent reproducibility and flexibility. Ceramic is a difficult material to be processed by conventional marking techniques due to its high hardness and brittleness. This paper presents the analysis of Nd: YAG laser marking process parameters like pulse frequency, lamp current, laser scanning speed on various laser marking characteristics like mark width, mark depth and mark intensity on alumina ceramic. Analysis shows that mark depth, mark width and mark intensity depends on the interaction process of the laser beam and the material, which further relies on the process parameters. Moreover pulse frequency has a major role in the vaporization of the material, which in turn affects the mark efficiency. An increase in the pulse frequency results in minimum mark width and mark depth. In addition to it, lamp current controls the laser power output and the scanning speed plays an important role in the overlapping of the laser spot. From the analysis it has been found that high lamp current is necessary to achieve maximum mark width and mark depth. Analysis based on optical photographs has also been performed.

The present paper investigates the laser micro–turning operation on cylindrical aluminium oxide (Al

Laser beam machining (LBM) is the most exciting thermal energy based non-contact type advanced material machining method to process almost whole range of materials. The laser microturning of ceramics are highly demanded in the present industries because of its wide and potential uses in various engineering fields such as automobile, electronics, aerospace, biomedical applications etc. The present paper addresses the basic experimental study of Nd:YAG laser microturning of advanced engineering cylindrical shaped ceramic material to explore the desired laser output responses i.e. depth of cut and surface roughness by varying laser micro-turning process parameters such as lamp current, pulse frequency and rotational speed of workpiece etc.

The electrochemical discharge machining (ECDM) process has become a promising area in the field of non-conventional machining processes, as it has a great potential to machine electrically non-conducting materials such as glass and ceramics. However, when it is applied as a micromachining process, its performance characteristics are influenced by various control factors such as the applied voltage, electrolyte concentration, and interelectrode gap, the characteristics of the power circuit, etc., as a result of variation in the sparking intensity. The objective of the present research work is to find out the most suitable power circuit for the ECDM process during its application in the microdrilling of glass. The influences of various power circuit configurations on the material removal rate (MRR), the tool wear rate (TWR), the radial overcut (ROC), and the heat-affected zone (HAZ) have been investigated using an NaOH salt solution as electrolyte. The individual effects of the inductance L, resistance R, and capacitance Cof the power circuit on machining performance have been studied experimentally in order to find their optimal values. Experiments have been carried out to search for the pairwise effect of power circuit variables by considering their optimal values according to a Taguchi L9orthogonal array. Maximum MRR and minimum TWR can be achieved at LC/60V/20 wt %/20 mm and RL/50 V/30 wt %/40 mm respectively. Minimum ROC and minimum HAZ thickness have been obtained at RC/50 V/10 wt %/40 mm. Thus, from the point of view of the accuracy and quality of the machined hole, an RC circuit has been found to be most suitable for the micromachining of electrically non-conducting materials by the electrochemical discharge machining process.

Laser Assisted Electrochemical Machining (LAECM) has proven its advantages and applications over almost all the range of conductive materials. It offers its adroitness to generate simple shapes to complex shapes from macro to micro machining. Laser assisted ECM is a hybrid approach of machining which has been manifested to obtain improved results in terms of surface integrity, thermal damage, geometrical tolerance and material removal rate. Laser assisted Electrochemical Machining (LAECM) is a hybrid machining process in which laser enhances the electrochemical dissolution process by increasing the temperature and hence the current density of the electrolyte. Laser helps to remove material from the particular machining zone and stray machining effect is reduced and thus improves the precision and efficiency of LAECM, also productivity. New route of laser assisted hybrid machining processes has been built in the past decade by few of the researchers to reduce the intrinsic problems of ECM. This paper reviews on the investigation into LAECM process. The article also highlights various possibilities and applications of LAECM process. There are various challenges in LAECM process which have been also discussed in this paper.

In hybrid electrochemical discharge machining (ECDM) process machining of electrically conducting and non-conducting materials takes place in an alkaline electrolyte with the introduction of a tool electrode and an auxiliary electrode. In this paper an alternative of ECDM process, Electrochemical Discharge Turning (ECDT), is proposed to machine a cylindrical job which rotates continuously against a stationary or moving tool electrode. The material removal mechanism of ECDT process is similar to ECDM process, but ECDT employs ECDM components with rotary cylindrical workpiece immersed in an electrolytic solution. The present paper highlights the design and development of ECDT set-up which can be applied for turning operation. The proposed ECDT set up can also be utilized for making grooves of different shapes and sizes on cylindrical parts of electrically non-conducting materials.

The sequential micro-machining (SMM) is an emerging technique highly recommended for the manufacture of micro parts and also for generating micro features on parts. The review incorporates various traditional as well as non-traditional machining processes used in sequential manner. This paper focuses on recent trends in sequential micro machining combining diverse machining processes such as electrical discharge machining (EDM), laser beam machining (LBM), electrochemical machining (ECM), ultrasonic machining (USM), electrochemical discharge machining (ECDM), micro milling, micro grinding, electro-polishing, etc. The basic concepts, working principle, classification, mechanism of operation, the rationale behind the sequencing of individual machining processes etc. are described elaborately.

Quartz has been broadly applied in industries including electronics, optics, micro electromechanical system (MEMS), biomedical. Micro ultrasonic machining (Micro USM), is a non traditional micro machining technique, extensively used to produce micro features and parts on quartz, silicon, ceramics and glass. A micro tool of stainless steel having diameter 330um has been develop for generating micro hole on quartz. Experiments have been done by using different types of abrasives like boron carbide, silicon carbide and aluminum oxide of average grain size 14 um. Experiments have been performed under different parametric setting of tool feed rate and power rating. The range of tool feed rate is 0.8 to 1.1 mm/min. The range of power rating is 200 to 500 W. Micro hole has been generated on quartz. Overcut and taper angle has been considered as response of micro ultrasonic drilling. In the present research effect of tool feed rate and power rating on taper angle and overcut has been investigated while using different type of abrasives.

Wire electrochemical machining (WECM) is a recently introduced fabrication process which is yet to be fully investigated. Preliminary studies have shown that it offers superior feasibility and capability concerning the fabrication of various microfeatures. More extensive investigations are needed to discover any associated problems with the process and to extend its applicability and efficiency by determining its limitations in order to make this process a successful fabrication technique not only in microdomains but also for macro fabrications as well. Here we begin with a detailed overview of the fundamental and technological aspects of the WECM process. We then discuss its mass transfer strategies and kinematics, which are equally important as associated operating parameters, as well as the apparatus, materials, and machining conditions, challenges, and applications. Finally, we note recent advances to guide upcoming research attempts and future investigations aimed at making this anodic dissolution process proficient and established.