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Purpose The purpose of this study is to obtain strong materials with multiwall carbon nanotubes (MWCNTs) doped and investigate laser cut of MWCNTs also find the effect of the laser cutting parameters on composite materials. Design/methodology/approach The laminated composite plates were manufactured by using a vacuum infusion process. The mechanical properties of the composite materials produced were determined according to American Society for Testing and Materials (ASTM) D3039M, ASTM D3171, ASTM D 792 and ASTM D2583. A 130 Watts carbondioxide (CO2) laser cutting machine was used for drilling the two different composite plates with a thickness of 1.6–1.5 mm. Three variables were considered as process parameters including laser power (in three levels of 84.50, 104.00 and 127.40 W), cutting speed (in three levels of 4, 6, 8 mm/s) and 14 mm fixed focal position. Findings The fibers could not be cut due to insufficient melting in the experiments performed using 84.50 and 104.00 W laser power but the cutting was successfully completed when the laser power was 127.40 W. However, as the cutting speed increased, the contact time of the laser beam with the material decreased, so the kerf decreased, but the increased laser power created a thermal effect, causing an increase in hardness around the cutting surface. This increase was lower in MWCNTs doped composites compared to pure composites. It has been found that the addition of nanoparticles to layered glass fiber composite materials played an effective role in the strength of the material and affected the CO2 laser cutting quality. Originality/value This study is a unique study in which the CO2 laser cutting method of MWCNT-doped composite materials was investigated and the machinability without cutting errors, such as delamination, splitting, distortion and burring using the most suitable laser cutting parameters was revealed.

This study aims to investigate the effect of ampere and cutting speed on kerf width (KW) in order to optimize cutting quality of 10 mm Aluminum (Al) surfaces using Plasma Arc Machining (PAM). PAM is an alternative, fast, cheap and technique compared to other techniques like Laser Beam Machining and Abrasive Water Jet Machining. Ampere and cutting speed values are considered to obtain the influence of these parameters on cutting quality. The experimental approach is used to operate 27 specimens through cutting. They are divided into three groups. Different Cutting speeds and 9 different ampere values were used to every group. Cutting path design included straight line, acute angles, square angles, obtuse angles, and curved line. KW measurements were investigated, recorded and evaluated. All specimens results were compared, discussed and represented graphically in order to determine the values of parameters we must use to get the optimum cutting quality. The following are the major results. Some of the recorded values allowed for lower KW using medium amps and cutting speeds and led to higher cutting quality. Also, the use of high cutting speeds at the starting point of cutting KW (key hole) led to minimum cutting width, but the increase in amps had the greatest effect and increased the KW. Also, using fewer amps at the straight line of the cutting path resulted in a lower KW. When increasing the cutting speed, the KW became at the minimal. As for using higher ampere that produce a KW at the maximum sampling level and to obtain appropriate cutting quality, this requires the use of higher cutting speeds with fewer amps to allow a KW at the minimum. This turns out that the relationship is direct between each of the amps and the width of the cut. This means that the more the amps, the more the kerf width; and the less the amps, the kerf width, hence the cut quality. As the KW decreased through using fewer amps at the right angle, the KW increased with the increase in amps at the same cutting speeds used for the right angle and in the middle of the curve along the cutting path. In addition, the KW quality at the obtuse and the right angles was significantly lower than the KW quality in the case of the acute angle and the angle that corresponds to the diagonal line with the curve. But, when reducing the ampere, the KW decreased and the cutting quality increased. On the other hand, the cutting was bad at the acute angle and at the angle that corresponds to the diagonal line with the curve, so it should be avoided when designing the cutting path with a plasma arc. Also, using high cutting speeds at acute angle with fewer amps produced lower KW and higher quality. Even all the cutting speeds and amps used at the acute angle produced a KW at the maximum, contrary to the cut at the right angle where the cut width was lower and at the minimum. In addition, the use of a lower speed and a lower ampere allowed a lower cut width at the end of the curve of the cutting path. It turned out that the relationship is inversely between the cutting speed and the KW. The higher the speed, the lower the KW and the higher the cutting quality, the lower the cutting speed, the greater the cutting width and the lower the cutting quality. Also, the thickness of 10 mm Al prevented melting of the cutting edges during operating and the higher thickness helped to keep the Heat Input to work, differently from thin thicknesses. The difficulty of controlling the cutting of thin thicknesses of Al was also shown because the surface retains the heat generated from operating and melting. The lowest reading was 2,217 mm at the right angle as a result of using the 190 ampere values with the cutting speed of 1100 mm /min, arc voltage 130 volt and gass pressure 4.2 bar. This is the optimum value to obtain the minimum KW and higher cutting quality.

The research work is related to nickel titanium composite that has been increased due its admirable substance properties. The present research concluded that the nickel and titanium is reinforced with boron carbide prepared by metallurgy method. The synthesized composite is processed under different testing for evaluation of substance properties. Subsequently, the accumulation of boron carbide, the substance properties has been greatly improved. Non-traditional machining processes like Spark Erosion Machining (SEM) and Laser Beam Machining (LBM) are carried out to evaluate the machining behaviors such as. In each non-traditional machining process, the prominent factors effect is examined through variance analysis. In EDM process, the current is offered the utmost effects (83.28%) on MSR. In LBM process, the cutting speed is top most effects (90.27%) on material subtraction rate followed by gas pressure (6.21%).

The required shape and size was obtained through machining process. In recent years, Unconventional machining processes are contributing large effect in metal manufacturing industries. It was used to machine very hard material with good dimensional accuracy and surface finish. In this work, the synthesized cupronickel Metal Matrix Composite (MMC) was machined through various unconventional machining processes such as Spark Erosion Machining (SEM) and Laser Beam Machining (LBM). In SEM process, the different input actors were used such as voltage, current and pulse on time. In LBM process, the various input factors have been considered such as cutting speed, laser power and Standoff Distance (SOD). The Material Removal Rate (MRR) was analyzed with their effect of parameters. The parameter contribution was found through variance analysis.

The machining of Nickel Aluminum Bronze (NAB) via traditional machining methods creates many problems which include wear of the tool, the appalling surface of the finished product, large dimensional deviation, and excessive heat-affected area. These issues can be mitigated by non-traditional techniques such as electrochemical micromachining, electric discharge machining, laser beam machining, and plasma arc machining. Electrochemical micromachining (ECMM) works under the principle of anodic dissolution. Difficult to machine materials can be easily machined by ECMM technique. The micro-domain applications of NAB are found in perforated orifice and pharmaceutical industries. In this study, micro-drilling on NAB alloy was conducted using the ECMM process. The influence of two different electrolytes such as sodium chloride (non-passivating) and sodium nitrate (passivating) while micromachining NAB alloy was analyzed. The response surface methodology (RSM) approach was proposed to obtain the maximum material removal rate (MRR). The output response MRR was analyzed using desirability analysis. The NAB alloy machined with sodium chloride electrolyte was found to have 2.20 times higher MRR than the component machined with sodium nitrate solution.

Laser Beam Machining (LBM) is an unconventional process where the laser beam is directed to the work piece where the thermal energy is utilized to remove the material. Laser Beam Machining (LBM) is best suited for machining tough to cut material like leather as it provides several advantages like high precision, and no tool wear as there is no contact between work piece and nozzle. Leather seals are used in oil hydraulic systems. The laser beam machining was carried out for leather with different levels of process parameters like Power (P), Transverse Speed (Sp), Standoff Distance (SOD) and Gas Pressure (G.Pr) and its effect on various response parameters such as MRR, Conicity, Overcut and Circularity are studied. From the results obtained, out of two trials conducted on leather the second trial has high MRR, better overcut and circularity because of the fact that second trial has lesser SOD so the intensity is more and beam divergence is less compared to trial one. The most influential parameter for leather is transverse speed because the heat transfer on the workpiece gets changed with respect to time available for the heat to spread.

Generation of micro-scaled features over super alloys are very convolute process. However, many advanced machining tactics are extant to compete against the materials response during the genesis of geometrical features. Out of those, the most prominent approach having less arduousness is machining with laser. Although as an idiosyncratic process laser beam machining (LBM) holds many superiorities, but it has certain paucities like it ingest much machining cost during the process. Therefore, the knowledge of laser related process variables and their effects during machining of hole feature upon super alloy sheet is always essence to obtain requisite traits and preserve the cost-effectiveness. This paper holds preliminary machining analysis with the bolster of methodology like Finite Element Method (FEM) to scrutinize some of the captious responses like temperature disparities, heat flux, and structural analysis during the course of the electrolyte supported laser beam trepanning machining (ES-LBTM) by considering temperature fields for structural analysis. In this research, thermal analysis were performed on 3D work model of Fe-Cr-Ni based super alloy (duplex stainless steel i.e. DSS) with an assist of laser as a source. It also reports material removal rate (MRR) response from the experimentation followed by particle-swarm optimization (PSO). Moreover, to scrutinize the structural deformation and the temperature distribution at the scope of machined surface during ES-LBTM, a 3D physical model was established using ANSYS to ascertain the influence of one of the imperative laser process parameter such as laser power with three distinctive levels during the generation of hole feature.

Laser beam machining (LBM) is the most widely used machining process and can be applied to almost all metallic and non-metallic range of materials. In this paper, the effect of process parameters such as cutting speed, laser power, frequency, duty cycle and gas pressure have been investigated on hard die steel plate (EN-31, 10 mm thick) to determine the impact on taper angle, surface roughness (Ra) and Heat Affected Zone (HAZ). Second-order mathematical models have been developed using Response Surface Methodology (RSM) and compared with the experimental results. It has been observed from the main effect plot that cutting speed, laser power and frequency have a major impact on the taper angle. For getting better surface roughness, all the process parameters have been set to its mean value. Cutting speed, power and gas pressure were the significant parameters to control the HAZ. The bottom edge has been observed with larger HAZ than the top edge for all holes. Optimized parameters have been identified and industry desirable results were obtained for all the responses. A scanning electron microscope has been used to notice the striation pattern and surface damage on the top surface of the hole.

Fabricating micro-scale features in ceramic materials, such as alumina (Al2O3), is challenging because of their high hardness and brittleness. Laser-assisted machining, in which a laser beam is a heat source for pre-softening the local area on a workpiece, is an effective hybrid method for machining ceramics. The study identified the effects of carbon dioxide (CO2) laser-assisted micro-grinding (LAMG) with a wire electrical discharge grinding polycrystalline diamond tool on Al2O3. Comprehensive investigations have been conducted on the effects of laser beam machining itself and the effect of machining parameters, such as laser beam power, axial depth of cut, and feed rate. The average grinding force was found to decrease by 46% in the thrust direction and 44% in the feed direction, and surface roughness decreased by 17% with LAMG. Moreover, machining at a higher feed rate was possible without tool fracture. The results indicate that the CO2 laser heating of Al2O3 has significant advantages over conventional methods regarding machinability and channel geometry. Finally, an improved LAMG process to prevent edge cracks by revising the machining conditions is proposed.

Laser beam machining (LBM) is a non-contact type advance machining process and can be applied to almost all metallic and non-metallic range of materials. The effect of process parameters such as fe...

The use of unconventional machining technique for Aluminum based Metal Matrix Composites [MMCs] are generated considerable interest in machining. In the aviation industry, in order to obtain a high precision, a good surface finishing and high working speed, the processing of these hard materials is done with the help of the fiber beam laser). The objective is to determine the mechanical properties of the hybrid composite and further investigate its machinability. The aerospace industry uses the laser machining for its machining process like drilling the cooling holes etc. Standard frequency and variation in other parameters such as pulse width, power, and time will occur the impact in the laser beams composites like diameter and roundness of the hole. Especially, the increase in the variation of power and time plays a vital role in the diameter and roundness of the hole.

Machining of microwave processed nano-Hydroxyapatite (HA) reinforced ultra-high molecular weight polyethylene (UHMWPE) is challenging due to enhanced mechanical strength. The present research work aims to find possibility of machining on microwave processed UHMWPE/nano-HA composite using laser beam machining (LBM) method. The weight fractions of nano-HA in UHMWPE were 10%, 15% and 20%. The surface roughness of UHMWPE increased 3.64 times with 20% nano-HA addition. The heat-affected zone (HAZ) and defect factor decreased 64.32% and 35.75%, respectively with 20% nano-HA addition.

The aim of this study is to predict the hole accuracy which drilled by laser beam machining using Response Surface Methodology (RSM) within Minitab 17. ANOVA program and compare the results with the experimental values which performed under different cutting conditions Cutting speed (2, 2.5, 3, 3.5, 4 m/min ) with power ( 600, 700, 800, 900, 1000 watt ) and gas pressure assist ( 2, 3 ,4, 5,6 bar ) so another parameters that using during operation remain constant. Experiments were conducted to predict the hole accuracy, the estimated result shows that there is good agreement between average experiments values and predicted values of hole accuracy (95.96%).

We present a novel method of realizing instant hydrophobic and long-lasting superhydrophilic states on stainless steel (SS) surfaces by micropatterning and thermally-induced surface layers (TISL). Heat treatment of SS surfaces in the air for 6 h yields hydrophobic TISLs at 140 °C and hydrophilic TISLs at 300 °C. The result of X-ray photoelectron spectroscopy reveals the correlation of chromium depletion with the hydrophilic TISLs, as well as surface oxidation with the hydrophobic TISLs. We fabricated superhydrophilic SS surfaces holding the wettability over 40 days, and hydrophobic SS surfaces realized in an hour-scale period via the fabrication process comprised of laser beam machining, electrochemical etching, and heat treatment in serial.

In the machining of silicon compound ceramic materials via laser beam, processing in water has been found to enhance machining quality, while processing in air has limitations such as the generation of a recast layer, heat affected zone, and thermal crack. However, few studies have investigated the effects of water on the ablation rate of silicon compound ceramics. In this research, the ablation behavior and machining principles of the laser beam machining of silicon compound ceramics in water are investigated. The research concluded that the increase in temperature induced by laser irradiation promotes hydrothermal reaction between the silicon compound ceramics and water. The hydrothermal reaction assists in the removal of the oxide layer at the machined area and enhances the efficiency of the process in water. The effects of water on ablation are confirmed for various machining parameters such as the flow rate of sprayed water on the workpiece and laser conditions. Finally, the various micro-structures were fabricated on the silicon compound ceramics to evaluate the processability.

Wall attachment mechanisms for robot have attracted great attention. In this study, we present a novel fabrication method for flexible micro-pin array adapting to various surface profiles. The fabrication process was composed of three steps. First, the stainless steel (AISI304) micro-pin array was fabricated by using laser beam machining. In this process, laser beam machining was adopted because it is valuable for machining stainless steel. Dross and recast layers that were generated during laser machining were used as a material of micro-pin. Second, to eliminate unnecessary area without micro-pin, electrochemical etching was carried out. In this step, paraffin wax was coated to protect micro-pin array. It was eliminated by using heat and ultrasonic wave vibration after finishing electrochemical etching. Lastly, Polydimethylsiloxane (PDMS) as a flexible base was formed to etched micro-pin array. As a result, flexible based micro-pin array was fabricated. To verify attachment application on the wall, interlocking force between flexible micro-pin array and curved rough surface was measured (39.71 mN).

Liquid-assisted laser beam machining (LA-LBM) process is used as an alternative to existing laser beam machining (LBM) process to address the problems associated with the extreme heat of the laser. In this research, the thermal effects of laser and hydrodynamics effects of the liquid medium in the LA-LBM process are investigated to understand the complex interactions involved in the material removal during LA-LBM process. The study utilizes the versatile multiscale modeling approach by coupling the molecular and continuum domains. The research investigates the role of the water layer in the LA-LBM process along with the material transformations taking place in the water layer in the vicinity of the machined zone. The results of the study augment our existing knowledge of the complex mechanisms involved in the LA-LBM process. Investigation on cavity depth revealed the increase in material removal with the increase in laser heat. The change in water layer thickness revealed the reduction in the radius of the heat-affected zone while further explaining the nodal temperature distribution profile and electron temperature distribution in the water layer.

In the present work, basalt and glass layered hybrid composite has been fabricated and thereafter its various mechanical properties have been tested. It has been observed that this hybrid fiber composite has better mechanical properties as compared to basalt fiber reinforced plastic (BFRP) and glass fiber reinforced plastic (GFRP). Conventional machining methods have various limitations viz. fiber pullout, burr formation, etc., which results in poor cut surface quality and degraded mechanical performance. Laser beam machining can be one of the alternatives because it requires low specific energy and supports non-contact machining. However, in order to achieve better cut quality with high precision and accuracy during laser beam machining, selection of favourable range and levels of cutting parameters is quite pertinent. In the present study, Response surface methodology has been used to develop the mathematical models of kerf deviations in terms of input cutting viz. lamp current, pulse frequency, cutting speed, pulse width and compressed air pressure. Well correlation between the predicted and experimental values validates the proposed methodology of ascertaining favourable process parameters during laser machining of basalt – glass hybrid composite. Validation experimental results shows the lowest Top Kerf Deviation (TKD) and Bottom Kerf Deviation (BKD) have been achieved.

—To determine the cracking susceptibility for amorphous metal alloys (AMAs) or metallic glasses, a method based on the determining the dependence of the relative crack resistance (χ) on the load applied to intender of PMT-3 microhardness tester is proposed. In the method, the relative crack resistance at a load of 160 g is set equal to unit. At lower loads, crack resistance has been determined as the average of 10 measurements. In this article, we also have proposed a method for determining the heating temperature of AMA ribbons during laser beam machining that is based on a comparison of the dependence of the relative crack resistance of AMAs on load applied to indenter for samples annealed in the furnace and after laser irradiation. It has been found that cracks begin to appear in the samples after a ten-minute annealing at Т = 773 K. Fatigue tests of samples under a load varying from a maximum value of 750 MPa to a minimum of 400 MPa under a condition of repeated stress cycle with a frequency of 2 Hz have been carried out using a specially designed setup. In the domain exposed to laser radiation, four characteristic areas can be distinguished on the sample surface: internal reflow zone; dendritic growth area; area with unfinished growth of dendrites, area not exposed to radiation. In these areas, the relative crack resistance (χ) determined via the critical stress intensity factor of the first kind K1c monotonically decreases from 1 in the center to 0 at the periphery. It has been established that the laser action does not affect fatigue, the fatigue limit of the samples remains the same and is equal to 428 MPa. The characteristic features of the destruction are revealed. Cracks that propagate with branching in the reflow zone and after passing through its boundary develop rectilinearly have been found.

Laser beam machining of Y-TZP engineering ceramic material is carried out in green stage to increase the material removal rate. The generation of hot spots may cause local sintering of the ceramic material leading to a decrease of the mechanical properties of the final sintered component. This paper presents the implementation of alternative laser beam paths to reduce the hot spots occurrence. A thermal finite element model has been developed to support the experimental analysis as well as the prediction of local sintering. The experimental validation of the newly developed toolpath strategies confirmed the reduction of local sintering.

The research work and applications of aluminium based Metal Matrix Composite (MMC) has been increased. It has more attractive material properties like strength, ductility, corrosion and wear resistance. The current work reports the Titanium Carbide (TiC) and Vanadium Carbide (VC) reinforced aluminium scandium MMC is formulated through metallurgy technique. The synthesized MMC is under various materials testing for evaluating the properties. After addition of TiC and VC, the material properties have been increased. Hence, Unconventional machining techniques such as Spark Erosion or Electrical Discharge Machining (EDM), Abrasive Water Jet Machining (AWJM) and Laser Beam Machining (LBM) have been carried out. In each machining processes, the influential parameter effect is determined through the Analysis of Variance (ANOVA). The orthogonal array (L9) based Taguchi approach is employed to find the optimal parameter for Material Deletion Rate (MDR).

In today’s market utilization of suitable machine for machining of composites for the application of aircraft and automotive parts was crucial one, because of their high strength with low weight ratio. Also, the profile such as micro elliptical shape was machined to reduce stress concentration of the area which is in contact with loads. Since the regular circular profile has affected high amount stress concentration than that of elliptical profile for the same loading conditions, an attempt was made in machining of micro elliptical profile on the Al 7475 composite material by using the laser beam machining (LBM). For betterment of profile (dimension and good surface) an analyze was done on the parameters such as scanning speed and laser power of the LBM, The dimensional stability as well as surface qualities were determined and the suitable parameter was suggested for the future work in Al 7475 composite with LBM.

Bolt connections are the most prevalent technical solution to join several devices. To meet high requirements on lightweight constructions and safety-relevant technologies bolt connections require additional security elements or surface modifications to increase static friction without damaging the workpiece surface significantly. One possible solution is the micro structuring of the connection element surface within the conventional forming process chain. For the manufacturing of micro structured connection elements a micro structured forming tool is needed. Therefore, the forming tool has to feature a negative geometry of the connection element surface micro geometry. Requirements on forming tool materials are high hardness in combination with high wear resistance and good toughness. Suitable technologies to manufacture such micro structured metal dies are laser beam machining (LBM), electrochemical machining (ECM) and electrical discharge machining (EDM), respectively. In this study the micro forming process of high static friction connection elements is investigated. The manufactured connection element surfaces are analyzed after the forming experiments and the results are associated with the surfaces of the metal dies. Therefore the surfaces of the utilized metals dies are compared with each other and with a grinded reference surface and characteristic parameters are analyzed. The comparison is based on the resulting surface roughness parameters and surface conditions before and after lubricated forming experiments. At least wear of the metal dies after multiple forming operations is analyzed. As one result, ECM manufactured metal dies have shown a high degree of replication in combination with high wear resistance.

The material removed from the surface of the material in the laser beam machining is basically depends on the parameters like laser power, cutting speed, pressure of the gas and pulse width. Among all the parameters laser power and cutting speed plays vital role in the case of surface finish, shape and size of the final machining condition. Here, an attempt was made to find the optimum parameters to make the elliptical profile in the aluminium based composite material. For that, dimensions and mathematical characters like area, perimeter were selected as the output responses. L9 orthogonal array with Taguchi method was selected to conduct experiments and to study the effect parameters on the responses. For utilizing the better parameters in future analysis for making micro elliptical profile on the aluminium based composite, an ideal multi objective optimization method TOPSIS was utilized in this work.

Process optimization is an essential step to attain the machinability indicators as desired and suitable to the requirement. Whether its conventional or advanced manufacturing, statistical and/or soft computing based optimization has been attempted since a long to for the required process productivity, product quality, and sustainability. In this paper, single and multi-performance optimization of laser beam machining parameters is discussed for productivity and surface quality of miniature gears of stainless steel. A statistical optimization technique, desirability analysis has been used for optimization. Confirmation experiments have been conducted to verify the prediction of optimization. Further, a detailed surface integrity analysis of miniature gears machined at optimum laser parameters have been investigated for heat affected zone, surface defects, and hardness. Desirability technique has been found effective to optimize laser parameters in order to produce quality miniature gears. This investigation identified the potential of laser beam cutting for fabrication of quality miniature gears at high process productivity.

Zirconia toughened alumina (ZTA) is employed to make components for aerospace, chemical, biomedical and cutting tool industries due to its excellent hardness, fracture toughness and strength. Improved properties of ZTA make it difficult-to-cut ceramic composite. Achieving a better surface quality in machining of ceramic composites has been very challenging due to the presence of surface cracks. Recent researchers have revealed that laser beam machining can overcome the machining limitations of ceramic composites. The present study tries to optimize the surface roughness of laser cut holes in ZTA plate using artificial intelligence tool. The optimum result shows an improvement of 17.5% in surface finish as compared with surface finish obtained at non-optimal parameters levels. The predicted optimum results have been tested by confirmation experiments.

Particularly in the aerospace industry and its applications, recast layers and microcracks in base materials are considered to be undesirable side effects of the laser beam machining process, and can have a significant influence on the resulting material behavior and its properties. The paper deals with the evaluation of the affected areas of the Inconel 718 nickel-base superalloy after its drilling by a laser beam. In addition, measurements and analyses of the mechanical properties were performed to investigate how these material properties were affected. It is supposed that the mechanical properties of the base material will be negatively affected by this accompanying machining process phenomenon. As a verification method of the final mechanical properties of the material, static uniaxial tension tests were performed on experimental flat shape samples made of the same material (Inconel 718) and three different thicknesses (0.5/1.0/1.6 mm) which best represented the practical needs of aerospace sheet metal applications. There was one hole that was drilled with an angle of under 70 degrees in the middle of the sample length. Additionally, there were several sets of samples for each material thickness that were drilled by both conventional and nonconventional methods to emphasize the effect of the recast layer on the base material. In total, 192 samples were evaluated within the experiment. Moreover, different tensile testing temperatures (room as 23 degrees C and elevated as 550 degrees C) were determined for all the circumstances of the individual experiments to simulate real operation load material behavior. As a result, the dependencies between the amount of the recast layer and the length of the microcracks observed after the material was machined by laser beam, and the decrease in the mechanical properties of the base material, were determined. Web of Science 14 11 art. no. 3052

The aim of this study was to investigate the effect of microslits formed by Nd:YVO4 laser beam machining on the bond strength between two types of zirconia, yttria-partially stabilized zirconia (Y-TZP) and ceria-partially stabilized zirconia/alumina nanocomposite (Ce-TZP/A), and porcelain or two types of resin. Zirconia disks were divided into three groups: 1) non-treated (NT); 2) blasted with alumina particles (AB); 3) microslits fabricated on a zirconia surface by laser beam machining (MS). After veneering porcelain or resins on zirconia specimens, halves of the resin specimens were thermocycled up to 20,000 cycles. The shear bond strength between porcelain and both types of zirconia was not improved by the microslits. Before and after thermocycling, the bond strength between an indirect composite resin or acrylic resin and Y-TZP with microslits was the highest. It was concluded that the microslits on Y-TZP enabled micromechanical interlocking and improved the bond strength and durability of the resins.

The synchronized laser and shaped tube electrochemical machining (Laser-STEM), a hybrid machining process that combined the advantages of electrochemical machining (ECM) and laser beam machining (LBM), has been proposed and studied. The mechanisms of Laser-STEM were studied theoretically and experimentally. Mathematical model has been developed to study the effects of laser-induced thermal effects on the electrochemical dissolution rate. The influences of electrolyte concentration and laser power on the laser attenuation coefficient have been studied. Results showed that the side gap could be decreased by 62.7% and the feeding rate could be raised by 108% when utilizing Laser-STEM with a proper laser power for drilling small holes, compared with that without laser assistance. Moreover, the performance of Laser-STEM has been investigated, in terms of laser power and pulsed voltage. Experimental results showed that the machining efficiency increased with higher laser power, pulse voltage, and feeding rate, and the precision could be improved with the higher laser power and feeding rate and a smaller pulsed voltage. Finally, small holes with a diameter of 1.25 mm and free of recast layer have been fabricated on the aluminum alloy workpiece of 5 mm in thickness.

Achieving the maximum material removal rate (MRRmax) is not always desired in machining especially during laser milling. Actual volume of the material removed during laser beam machining (LBM) is not always precisely equal to the designed volume. Dimensional accuracy of the laser milled feature requires the controlled layer of the substrate removal after each scanning cycle so that the cumulative material removal after full length of canning cycle conforms to the designed depth or geometry. In this research, laser milling of aluminum alloy has been carried out. Percentage of material removal rate (MRR%) and the roughness of the machined surface (SR) are taken as the response indicators. Optimal parametric combinations resulting in MRR% close to 100% with minimum SR have been pursued. Strength of the effects of five significant variables (in terms of one-way, square, and two-way interactions) is also identified. Furthermore, mathematical models are developed to predict the machining responses prior to proceed for actual machining. The research outcomes may be utilized to perform laser milling of AA 2024 (aluminum alloy used in various fields including aerospace industry) with precise control over MRR which ultimately will strengthen the dimensional accuracy of the machined profiles.

Zirconia Toughened Alumina (ZTA) ceramic is used to make distinct components of aerospace, military and biomedical industries which require suitable machining method free of mechanical forces. Recent researchers reveal that Laser Beam Machining has diverse potential to overcome machining difficulty of structural ceramics. But to enhance the durability and performance of these components, study of material properties became essential after laser machining because this process involves intense heat or thermal energy. Present study investigates the material characteristics of laser trepanned ZTA plate with the aim to explore the effects of process parameters on recast layer thickness, microcrack width and microhardness. The outcome of study may be helpful in setting the processing regime for laser trepanning of ZTA ceramic which may furnish the products with minimum recast layer thickness and microcrack width along with minimum change in microhardness. The experimental results show that lower pulse width or trepanning speed, and higher air pressure reduce the recast layer thickness and microcrack width.

Nickel alloys including Inconel 718 are considered as challenging materials for machining. Laser beam machining could be a promising choice to deal with such materials for simple to complex machini...

Copper is one of the best light metal based on their properties and usefulness in the field of precision parts.Emergence of advanced engineering materials, unusual size and intricate shape of jobleads towards the use of non-conventional machining processes. Laser beam machining (LBM) is one of them which is non-contact and optical-thermal process used for machining almost all range of engineering materials. Artificial neural network is used to develop a prediction model representing complex relationship between the input (process) parameters and output parameters (responses). In this present paper, micro-drilling has been performed on 0.2 mm thickcopper sheet by Nd:YVO4 laser of 12 kW. Design of experiment is performed by Taguchi's L9 orthogonal array. Here, hole taper and HAZ width have been observed varying the process parameters like laser beam power, pulse frequency, scanning speed and number of pass. Experimental results are analyzed by S/N ratio and verified by confirmation experiment. A feed forward back propagation ANN model is also developed to predict the responses at any combination of process parameters within the limit.

Standardized multilayer microperforated panel fabricated by laser beam machining of the spring steel was proposed for noise reduction in this study. Geometric parameters of the standardized multilayer microperforated panel, which include diameter of the hole, thickness of the panel, distance between the neighbor holes, and length of the cavity, were optimized for the better sound absorption performance. Sound absorption coefficient of the standardized multilayer microperforated panel was theoretically modeled based on the Maa's theory. The optimization of geometric parameters of the standardized multilayer microperforated panel was obtained by the Cuckoo search algorithm, and the finite dimension of 30 mm was treated as the additional constraint condition. Preliminary verification of the obtained optimal parameters was conducted through the constructed finite element simulation model. Actual sound absorption coefficients of the standardized multilayer microperforated panels with layer number of 1 to 4 were measured by standing wave method, which were consistent with theoretical data and simulation data, and the corresponding average values in the frequency range of 100â–“6000 Hz were 57.45%, 70.85%, 71.99%, and 72.28%, respectively. By theoretical modeling, parameter optimization, simulation, and experimental validation, an effective method was proposed to develop practical sound absorbers, which would promote their applications in noise reduction.

Depth of fabrication is an essential characteristic of micro-channels. The laser beam machining process is one of the most suitable processes to fabricate micro-channels. This process has an excellent potential for the fabrication of microfluidic devices which are instrumental for various biomedical applications such as electrophoresis, chromatography, blood protein studies, DNA analysis, etc. In this research work, an attempt has been made to fabricate micro-channels on a thick Polymethyl methacrylate (PMMA) plate at submerged condition by utilizing laser transmission micro-machining process. The laser transmission micromachining operation is conducted here at submerged condition to reduce the adverse thermal effect during machining. Nanosecond pulsed Nd: YAG laser with wavelength in near infrared region has been used here. The depth of micro-channel and heat affected zone (HAZ) width has been taken into account as machining responses. Total 3 sets of experiments which contain 31 experiments in each set have been conducted for three different laser beam pass with the aid of response surface methodology (RSM). The effects of varying laser beam pass on the depth and HAZ width has been studied.

Carbon fiber reinforced polymer (CFRP) composites gained wide acceptance in aerospace, automotive and marine industries due to their superior properties. It became the major structural material that substitutes metals in many weight-critical components such as the new A350 and the B787 aircrafts, with composite content to exceed the 50%. Although CFRP structures are manufactured to near-net-shape, edge trimming, drilling, sawing, milling, and grinding operations are unavoidable. Being anisotropic, inhomogeneous and highly abrasive, their conventional machining is normally associated with delamination, fibers pull-out, inadequate surface quality, and tool wear. Other nontraditional processes which include abrasive water jet machining (AWJM), ultrasonic machining (USM), and electrodischarge machining (EDM) offer substitute to the conventional methods. Laser beam machining (LBM) is an emerging technology offering an excellent alternative for machining CFRP composites. This paper reviews the research work carried out in the area of LBM of CFRP materials. It reports the experimental and theoretical studies covering the process accuracy in terms kerf width, kerf depth and edge quality, and the thermal characteristics in terms of heat-affected zone (HAZ). Minimizing the kerf taper, increasing kerf depth, and eliminating the HAZ in the polymer matrix are considered the major obstacles of CFRP industrial applications. Methods of improving the machining productivity by reducing the machining time and increasing the material removal rate (MRR) and kerf depth are reviewed. Several mathematical and statistical modeling and optimization techniques have been critically examined. The concept of specific energy and its impact on HAZ and kerf width is introduced. The relationship between laser type and HAZ is discussed. The current work furthermore outlines the possible trends for future research.

Chemo mechanical laser beam assisted finishing is the process of a conceptual combination of a fundamental cognitive process. In this process, three basic concepts are synthesized to obtain a smooth surface of silicon carbide. Three different chemicals of H2SO4 , HCl, and HF with a 50% solution with purified water were used. Continuous mode CO2 power from 250W-300W was used to melt the surface after acid was applied. The smooth surface was evaluated using morphology, including pore pattern, pore depth, and pore width was studied under a scanning electron microscope, and the surface roughness, wear-resistance, and hardness were analyzed using a non-contact surface profilometer, scratch tester TR-101, and Digital Rockwell hardness device respectively. The results were statistically analyzed using Design expert software analysis of variance (ANOVA). The results showed a significant change in the pore pattern, crystal structure, surface roughness, wear-resistance, and hardness. This result was verified by scanning electron microscope, optical microscope, Non-contact profilometer, and scratch tester TR-101machine. The hardness of the smooth surface was increased as well as surface roughness and the coefficient of friction also improved as compared to substrate silicon carbide.

The applications of new synthesized metals are using in different fields. In present research deals with zirconium carbide (ZrC) based titanium metal matrix which is formed through stir casting route. ZrC is mixed to the titanium with 3, 5 and 7 weight percentages. The substance properties have been measured for the stir casted samples. Based on the comparison of substance properties, titanium composite with 7% of ZrC has been considered for this research. The synthesized titanium composite is processed under laser beam machining process (LBM). The response factors such as material deduction rate (MDR) and surface roughness (SR) are measured. The effects of response factors with the control factors have been studied through variance analysis.

In the field of micro processing of materials, laser has great importance as a source of heat and for its ability to deliver a coherent beam. The use of 50-watt average power for through-hole is impossible to achieve good quality drilling of the metal sheet upto 2 mm thickness. But the use of unique parameter sawing angle and constant focal point distance plays a significant role on hole diameter and circularity in laser trepan drilling. In the present research study, laser trepan drilling is investigated through multi diode pulsed fiber laser beam machining. Experimental analysis based on central composite design (CCD) of response surface methodology (RSM) has been fulfilled to find out the mathematical model. A study of the effect of sawing angle with other process parameters such as cutting speed, power, duty cycle, and pulse frequency on overcut bottom diameter and circularity at bottom for a monel k-500 has been conducted. Experimental validation of the proposed model shows that desired hole quality can be obtained by optimization of controllable of suitable process parameters.

Shape-memory alloys (SMAs) have received a great deal of interest due to their excellent properties, which make them significant for various applications. Despite its unique properties, the processing of these alloys is often challenging as it endures a solid-state transition. This chapter thus aims to explore non-conventional machining techniques such as laser beam machining (LBM), electrical discharge machining (EDM) and its associated techniques for the processing of these alloys without altering their intrinsic properties. Both the techniques are discussed in terms of their working mechanism and contribution to the processing of SMA alloys. In addition, the use of EDM processed SMA alloys in various actuators, in particular micromanipulator, micro-positioning stage and tunable coil, is also discussed. Finally, it concludes by discussing the main outcomes of the chapter.

Leather is a sturdy material renowned for its fashion, style and versatility. High quality cutting and simple adjustment of cutting geometry are provided by laser cutting of leather. Diode lasers can process leather rapidly and efficiently. An endeavor to investigate the machining of buffalo leather using power diode laser cutting technique was suggested in the proposed approach. Laser cutting attempts were performed on buffalo leather samples with thickness of 2 mm. This work explores the much effective utilization of power diode laser cutting method of leather to distinguish its advantages and disadvantages. It also provides discrimination between laser cutting and traditional cutting of leather.

The applications of super hard material have been increased in aerospace, marine and automobile industries. In the present, the investigation deals with rhenium diboride (ReB2)-based molybdenum metal matrix which is fabricated through stir casting method. Rhenium diboride is mixed to the molybdenum with various weight percentages such as 3, 5 and 8%. The material properties are evaluated for the sample specimens. Based on the comparison of material properties, molybdenum with 8% of rhenium diboride has been considered for these experimental investigations. Due to high hardness and strength, conventional machining methods are not suitable. Among all the unconventional machining processes, the laser beam machining process is the most suitable for high hardness materials. Various input and output parameters are considered. The responses such as the material removal rate (MRR) and surface roughness (SR) are measured. The effects and contribution of parameters are confirmed through analysis of variance (ANOVA) and Pareto charts.

Laser Beam Machining (LBM) is one of the versatile non-traditional manufacturing processes. Material removal in LBM is based on high heat flux generated by laser beam which melts and vaporizes the workpiece material in the focused point. Laser Beam Machining process can shape almost all range of engineering materials from metallic alloys to non-metallic alloys as well as composite materials. But one of the main limitations of laser beam machining is the machining of reflective materials. When laser beam is focused on the reflective surface, part of the energy is reflected by the surface and the remaining is absorbed. In this study, an attempt has been made to increase the absorptivity of the reflective material by coating anti-reflective coating on the surface of the material. Glass has been used as reflective material in this study because of its extensive applications in the micro-opto-electro-mechanical systems. The optimal machining depends on both laser parameters and properties of the workpiece material. There are number of laser parameters that can be varied in the laser machining process. It is difficult to find optimal laser parameters due to mutual interaction of laser parameters. A statistical study based on design of experiment (DoE) has been made to study the effect of anti-reflective coating and parameters like laser power, laser scanning speed, angle of inclination of the workpiece on depth of the slot, width of the slot, aspect ratio and material removal rate (MRR) in the laser machining process using 2k factorial design and ANOVA. On an average 4 times increase in depth of the slot, 2 times increase in width of the slot and 7 times increase in the MRR was observed in the glass work samples with anti-reflective coating when compared to glass work samples without anti-reflective coating.

Micromachining has gained considerable interest across a wide range of applications. It ensures the production of microfeatures such as microchannels, micropockets, etc. Typically, the manufacturing of microchannels in bioceramics is a demanding task. The ubiquitous technologies, laser beam machining (LBM) and rotary ultrasonic machining (RUM), have tremendous potential. However, again, these machining methods do have inherent problems. LBM has issues concerning thermal damage, high surface roughness, and vulnerable dimensional accuracy. Likewise, RUM is associated with high machining costs and low material-removal rates. To overcome their limits, a synthesis of LBM and RUM processes known as laser rotary ultrasonic machining (LRUM) has been conceived. The bioceramic known as biolox forte was utilized in this investigation. The approach encompasses the exploratory study of the effects of fundamental input process parameters of LBM and RUM on the surface quality, machining time, and dimensional accuracy of the manufactured microchannels. The performance of LRUM was analyzed and the mechanism of LRUM tool wear was also investigated. The results revealed that the surface roughness, depth error, and width error is decreased by 88%, 70%, and 80% respectively in the LRUM process. Moreover, the machining time of LRUM is reduced by 85%.

Electro-spark deposition (ESD) and laser beam machining (LBM) are the technologies using the concentrated energy flux. This paper deals with the issue of the impact of laser modification on the morphology and mechanical properties of carbide/copper coatings produced by electro-spark treatment. The coatings were applied to C45 carbon steel samples using the EIL-8A device. The following three types of electrodes made using the powder metallurgy (PM) hot pressing technique, from copper and tungsten carbide powders of different percentage compositions, were used for the coatings: 25% WC and 75% Cu, 50% WC and 50% Cu, and 75% WC and 25% Cu. Laser modification of the surface layers was performed with an Nd:YAG laser. The research focused on the analysis of the morphology of coatings applied by electro-spark technology before and after laser processing. The analysis of the morphology of electro-spark coatings revealed that the coatings had microcracks and pores. The laser beam machining of ESD coatings led to the homogenization of chemical composition, fragmentation of the structure, and elimination of microcracks. In addition, measurements of porosity, microhardness, adhesion, and analysis of XRD phase composition of the electro-spark coatings were performed. Laser processing proved to have a positive effect on improving the adhesion of coatings and reducing their porosity. This paper also presents a simulation model of heat transfer processes for the case of laser radiation impact on a WC-Cu coating. The developed numerical model, describing the influence of laser treatment on the distribution of temperature fields in the heated material (at a given depth) is of significant importance in the development of treatment technologies. Laser-modified ESD coatings perform anti-wear and protective functions, which enable their potential application in means of transport such as rolling stock.

The application of metal matrix has been increased in manufacturing industries. The demand of advanced metal matrix in aerospace and nuclear plant has gradually increased. The stellite is one of super alloys which consist of cobalt and chromium. In present article deals with the machining performance of tantalum carbide (TaCx) based stellite metal matrix composite. The various unconventional machining processes such as Ultra Sonic Machining (USM) and Laser Beam Machining (LBM) processes are used to machine the metal matrix composite. The various control and response parameters are considered for the experimental investigation. The abrasive wear resistance is also discussed.

This chapter introduces the machining methods for metallic materials for medical applications. Conventional cutting methods, including turning, milling, drilling, and grinding, are still the most widely used in the manufacture of components for medical devices, and almost all such metallic components can be manufactured using a combination of these processes. Unconventional cutting methods, including water-jet machining, electrical discharge machining, electrochemical machining, and laser beam machining, are the alternative options which are often used when a workpiece cannot be further shaped or refined by conventional machining. The computerized numerical control (CNC) technique has been extensively used on different machine tools, and the components for medical devices can be shaped with high accuracy and fine surface finishing by application of multiaxis CNC machines.

Nonconventional or advanced machining processes such as electric discharge machining, electrochemical machining, abrasive water jet machining, and laser beam machining have been widely used as a viable alternate to the conventional processes to manufacture high-quality engineered parts having certain typical features. In spite of their special features, wider acceptance, and use, they suffer from certain inherent limitations with regard to sustainability such as high consumption of energy and resources; generation of toxic liquid, gases, and solid wastes; risk for health and safety; air pollution; generation of waste and its disposal problems; and workpiece contamination and thermal damage to the parts being produced. It is found that these factors all adversely affect the environment to a certain extent. Innovative sustainable techniques such as dry, near-dry, and green electric discharge machining; green and hybrid electrochemical machining; ice-jet machining; and eco- and underwater laser beam machining, etc. have been developed to address sustainability challenges and greatly benefited with improvements in quality, productivity, and sustainability. This review article first introduces four major nonconventional machining processes, discusses their inherent sustainability issues and challenges, and presents state-of-the-art review of the work conducted using sustainable innovative techniques and strategies with an aim to encourage academics, researchers, and engineers for research and developments in order to establish the field further. The literature review offered in this article is based on over 80 articles published from 1975 to 2017. Finally, the article ends up with concluding remarks and recommending possible avenues to stimulate future research.

Development of future aero engine components based on new design strategies utilising topological optimisation and additive manufacturing has in the past years become a reality. This allows for designs that involve geometries of "free form" surfaces and material combinations that could be difficult to machine using conventional milling. Hence, alternative manufacturing routes using non-conventional high energy methods are interesting to explore. In this investigation, the three high energy machining methods abrasive water jet machining (AWJM), electrical discharge machining (EDM) and laser beam machining (LBM) have been compared in terms of surface integrity to the reference, a ball nosed end milled surface. The results showed great influence on the surface integrity from the different machining methods. It was concluded that AWJM resulted in the highest quality regarding surface integrity properties with compressive residual stresses in the surface region and a low surface roughness with texture from the abrasive erosion. Further, it was shown that EDM resulted in shallow tensile residual stresses in the surface and an isotropic surface texture with higher surface roughness. However, even though both methods could be considered as possible alternatives to conventional milling they require post processing. The reason is that the surfaces need to be cleaned from either abrasive medium from AWJM or recast layer from EDM. It was further concluded that LBM should not be considered as an alternative in this case due to the deep detrimental impact from the machining process.Keywords First Online: 05 October 2018