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In the current scenario, industries face new challenges in cutting metal-based composites with good surface texture. The experimental investigation on laser cutting of magnesium AS2-Bimodal SiC composites is reported in the present work. Three bimodal compositions with varying proportions of micro-nano SiC reinforcement (75%-25%, 50%-50% and 25%-75%) were dispersed in AS21 alloy by stir-casting route. The comparison of quality characteristics such as surface roughness, kerf deviation and edge slope has been done to examine the behaviour of bimodal reinforcement with different laser cutting parameters. The experimental strategy was implemented based on the Taguchi L18 mixed design. The microstructure and cutting surface morphology has been analysed using OM, SEM and TEM. The results demonstrated that the AS21 composite with a bimodal structure of 75 vol.% micro-SiC and 25 vol.% nano-SiC showed better performance characteristics of CO2 laser cutting system due to uniform grain structure and homogeneous dispersion of nano-SiC reinforcement. [ABSTRACT FROM AUTHOR]

This study highlights the development of an intelligent thermo-structural model for precise prediction of responses such as the width of heat-affected zone (HAZ), equivalent stress and total deformation for laser beam machining (LBM) process while machining a novel Dual Phase 780 (DP780) workpiece. The numerical model is analyzed through response surface Box–Behnken design to study the consequences of input parameters such as voltage (V), current (I) and cutting speed (N) on the above-mentioned response parameters. The results achieved through the numerical model are validated by comparing them with experimental results. Furthermore, a careful parametric study along with line and surface plot analysis is conducted to evaluate both linear and quadratic relationships between the input and the response parameters, respectively. The results indicate that the HAZ can be reduced significantly through efficient laser processing with optimum input parameters. The process parameters are optimized by developing an objective function for each of the response parameters through regression analysis. An extremum model is used to obtain the ideal values of HAZ, equivalent stress and total deformation. These results are also validated by conducting a confirmative test using the numerical simulation model which is validated through experiments. [ABSTRACT FROM AUTHOR]

Balancing quality and productivity, especially deciding on the optimal matching strategy for multiple process parameters, is challenging in ultrashort laser processing. In this paper, an economical and new processing strategy was studied based on the laser scribing case. To reveal the temperature evolution under the combination of multiple process parameters in the laser scribing process, a two-temperature model involving a moving laser source was developed. The results indicated that the peak thermal equilibrium temperature between the electron and lattice increased with the increase in the laser fluence, and the temperature evolution at the initial position, influenced by subsequent pulses, was strongly associated with the overlap ratio. The thermal ablation effect was strongly enhanced with the increase in laser fluence. The groove morphology was controllable by selecting the overlap ratio at the same laser fluence. The removal volume per joule (i.e., energy utilization efficiency) and the removal volume per second (i.e., ablation efficiency) were introduced to analyze the ablation characteristics influenced by multiple process parameters. The law derived from statistical analysis is as follows; at the same laser fluence with the same overlap ratio, the energy utilization efficiency is insensitive to changes in the repetition rate, and the ablation efficiency increases as the repetition rate increases. As a result, a decision-making strategy for balancing quality and productivity was created. [ABSTRACT FROM AUTHOR]

This study investigates the laser beam machining mechanism, surface formation mechanisms, heat-affected zone, taper formation, and the dimensional deviation of the titanium alloy, based on the information available in literature. The heat induced by the laser beam melts and vaporises titanium alloy, which is removed by a high pressure-assisted gas. The machined titanium alloy surface is expected to have craters and resolidified materials which were contributed by the low thermal conductivity of the titanium alloy. Taper and circularity error can be minimised by optimising the laser parameter, but it cannot be avoided in the laser beam machining of titanium alloy. Laser beam machining induces a non-diffusion phase transformation, which slightly changes the surface mechanical properties of the titanium alloys. Laser beam machining is gaining popularity as a way to improve the surface finish quality and properties of titanium components manufactured by additive manufacturing processes. To enhance the machining efficacy of titanium alloys, several hybrid machining processes were proposed. [ABSTRACT FROM AUTHOR]

The innovative Green Ceramic Hybrid Machining (GCHM) process sequentially combines milling with a cutting tool (GCM, Green Ceramic Machining) and laser beam machining (GCLBM) of a ceramic material (black Y-TZP in this study) at the green stage mainly to increase productivity, avoid taper angle limitations of laser beam machining, and obtain micro-features. The study focuses on the reliability and the repeatability of the properties of sintered parts obtained by three manufacturing processes (GCM, GCLBM, GCHM) to assess the performance of hybridisation. It turns out that GCHM is a compromise of both milling and laser beam processes; it increases the repeatability of the surface quality and it slightly reduces (less than 7%) the flexural strength by comparison to milling for a similar reliability. The study also highlights that the surface quality of GCLBM processed parts relies on of the surface generated by the previous operation. Milling that surface at the previous step is therefore recommended, corresponding to the sequence adopted by GCHM. [ABSTRACT FROM AUTHOR]

Numerous industries, including footwear, handicrafts, and the automobile industry, utilize leather materials. The main goal of this study was to investigate the effect of input power of the diode laser in laser cutting on vegetable chrome tanned buffalo leather to enhance the cutting process. In the present investigation, carbonization, kerf width, and material removal rate (MRR) were taken as performance measures. The diode-based laser beam machining was designed and fabricated with 2.5 W, 5.5 W, and 20 W diode laser to cut vegetable chrome tanned leather. The high-intensity 20 W diode laser produced lower carbonization, lower kerf width, and higher material removal rate compared with the 2.5 W and 5.5 W diodes. This improved performance was due to the adjustable features associated with this diode laser actuation in the form of circular shape with adjustable diameter. A high power with a lower spot size under pulsed mode can produce higher power density. Since a higher power density can establish less interaction time, it produces lower carbonization. Due to the ability of the 20 W diode laser driver to control the beam shape and size, it could produce a lower kerf width and higher MRR. The optimal parameters for cutting chrome vegetable tanned cow leather were a standoff distance of 18 mm, feed rate of 200 mm/min, and duty cycle of 70%. [ABSTRACT FROM AUTHOR]

The process of unconventional machining is widely used to produce detailed, complex and accurate forms in materials such as titanium, stainless steel, high power temperature resistant alloys. It is used to remove materials using devices that are harder than the content itself. In the modern manufacturing system, to enhance the productivity of textile industries extensively using nontraditional machining system. Laser beam machining is one of them. The present paper is an attempt to review the usage of nontraditional machining especially laser beam machining.

Balancing quality and productivity, especially deciding on the optimal matching strategy for multiple process parameters, is challenging in ultrashort laser processing. In this paper, an economical and new processing strategy was studied based on the laser scribing case. To reveal the temperature evolution under the combination of multiple process parameters in the laser scribing process, a two-temperature model involving a moving laser source was developed. The results indicated that the peak thermal equilibrium temperature between the electron and lattice increased with the increase in the laser fluence, and the temperature evolution at the initial position, influenced by subsequent pulses, was strongly associated with the overlap ratio. The thermal ablation effect was strongly enhanced with the increase in laser fluence. The groove morphology was controllable by selecting the overlap ratio at the same laser fluence. The removal volume per joule (i.e., energy utilization efficiency) and the removal volume per second (i.e., ablation efficiency) were introduced to analyze the ablation characteristics influenced by multiple process parameters. The law derived from statistical analysis is as follows; at the same laser fluence with the same overlap ratio, the energy utilization efficiency is insensitive to changes in the repetition rate, and the ablation efficiency increases as the repetition rate increases. As a result, a decision-making strategy for balancing quality and productivity was created.

Laser beam machining of various materials has found wide applications in the industry due to its advantages of high-speed machining, no tool wear and no vibration, precision and accuracy, low cost of machining, etc. Investigations into the laser beam machining of uncommon alloy are still limited and more research is needed in this field. In this paper, an analysis of the laser beam machining of tungsten alloy was performed, for cutting and drilling machining processes. First, an experimental analysis of microhardness and microstructure on the laser-cut samples was performed, and then the numerical simulation of the laser beam drilling process and its experimental validation was carried out. The experiments were carried out on a tungsten alloy plate of two different thicknesses, 0.5 and 1 mm. No significant changes in the microhardness, nor in the microstructure characteristics in the heat-affected zone (HAZ), were observed for the cutting conditions considered. A two-dimensional axisymmetric mathematical model for the simulation of the laser beam drilling process is solved by a finite volume method. The model was validated by comparing numerical and experimental results in terms of the size of HAZ and the size and shape of the drilled hole. Experimental and numerical results showed that HAZ is larger in the 0.5-mm-thick plate than in the 1-mm-thick plate under the same drilling conditions. Good agreement was observed between the experimental and numerical results. The developed model improves the understanding of the physical phenomena of laser beam machining and allows the optimization of laser and process parameters. [ABSTRACT FROM AUTHOR]

Abstract Laser machining is a highly flexible non‐contact fabrication method used extensively across academia and industry. Whilst simulations based on fundamental understanding offer some insight into the processes, both the highly non‐linear interactions between laser light and matter and the variety of materials involved mean that theoretical modelling is not particularly applicable to practical experimentation. However, recent breakthroughs in machine learning have resulted in neural networks that are capable of accurate and rapid modelling of laser machining at a scale, speed, and precision well beyond those of existing theoretical approaches with applications including 3‐D surface visualisation and real‐time error correction. A perspective at the intersection of laser machining and machine learning is presented, followed by a discussion of future milestones and challenges for this field.

This study investigates the laser beam machining mechanism, surface formation mechanisms, heat-affected zone, taper formation, and the dimensional deviation of the titanium alloy, based on the information available in literature. The heat induced by the laser beam melts and vaporises titanium alloy, which is removed by a high pressure-assisted gas. The machined titanium alloy surface is expected to have craters and resolidified materials which were contributed by the low thermal conductivity of the titanium alloy. Taper and circularity error can be minimised by optimising the laser parameter, but it cannot be avoided in the laser beam machining of titanium alloy. Laser beam machining induces a non-diffusion phase transformation, which slightly changes the surface mechanical properties of the titanium alloys. Laser beam machining is gaining popularity as a way to improve the surface finish quality and properties of titanium components manufactured by additive manufacturing processes. To enhance the machining efficacy of titanium alloys, several hybrid machining processes were proposed.

The innovative Green Ceramic Hybrid Machining (GCHM) process sequentially combines milling with a cutting tool (GCM, Green Ceramic Machining) and laser beam machining (GCLBM) of a ceramic material (black Y-TZP in this study) at the green stage mainly to increase productivity, avoid taper angle limitations of laser beam machining, and obtain micro-features. The study focuses on the reliability and the repeatability of the properties of sintered parts obtained by three manufacturing processes (GCM, GCLBM, GCHM) to assess the performance of hybridisation. It turns out that GCHM is a compromise of both milling and laser beam processes; it increases the repeatability of the surface quality and it slightly reduces (less than 7%) the flexural strength by comparison to milling for a similar reliability. The study also highlights that the surface quality of GCLBM processed parts relies on of the surface generated by the previous operation. Milling that surface at the previous step is therefore recommended, corresponding to the sequence adopted by GCHM.

Numerous industries, including footwear, handicrafts, and the automobile industry, utilize leather materials. The main goal of this study was to investigate the effect of input power of the diode laser in laser cutting on vegetable chrome tanned buffalo leather to enhance the cutting process. In the present investigation, carbonization, kerf width, and material removal rate (MRR) were taken as performance measures. The diode-based laser beam machining was designed and fabricated with 2.5 W, 5.5 W, and 20 W diode laser to cut vegetable chrome tanned leather. The high-intensity 20 W diode laser produced lower carbonization, lower kerf width, and higher material removal rate compared with the 2.5 W and 5.5 W diodes. This improved performance was due to the adjustable features associated with this diode laser actuation in the form of circular shape with adjustable diameter. A high power with a lower spot size under pulsed mode can produce higher power density. Since a higher power density can establish less interaction time, it produces lower carbonization. Due to the ability of the 20 W diode laser driver to control the beam shape and size, it could produce a lower kerf width and higher MRR. The optimal parameters for cutting chrome vegetable tanned cow leather were a standoff distance of 18 mm, feed rate of 200 mm/min, and duty cycle of 70%.

Laser Beam machining (LBM) nowadays finds a wide acceptance for cutting various materials and cutting of polymer sheets is no exception. Greater reliability of process coupled with superior quality of finished product makes LBM widely used for cutting polymeric materials. Earlier researchers investigated the carbon dioxide laser cutting to a few thermoplastic polymers in thickness varying from 2mm to 10mm. Here, an approach is being made for grading the suitability of polymeric materials and to answer the problem of selection for LBM cutting as per their weightages obtained by using multi-decision making (MCDM) approach. An attempt has also been made to validate the result thus obtained with the experimental results obtained by previous researchers. The analysis encompasses the use of non-parametric linear-programming method of data envelopment analysis (DEA) for process efficiency assessment combined with technique for order preference by similarity to an ideal solution (TOPSIS) for selection of polymer sheets, which is based on the closeness values. The results of this uniquely blended analysis reflect that for 3mm thick polymer sheet is polypropelene (PP) to be highly preferable over polyethylene (PE) and polycarbonate (PC). While it turns out to be that polycarbonate (PC) to be highly preferable to other two polymers for 5mm thick polymer sheets. Hence the present research analysis fits very good for the polymer sheets of 3mm thickness while it deviates a little bit for the 5mm sheets.

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%).

Laser beam machining of various materials has found wide applications in the industry due to its advantages of high-speed machining, no tool wear and no vibration, precision and accuracy, low cost of machining, etc. Investigations into the laser beam machining of uncommon alloy are still limited and more research is needed in this field. In this paper, an analysis of the laser beam machining of tungsten alloy was performed, for cutting and drilling machining processes. First, an experimental analysis of microhardness and microstructure on the laser-cut samples was performed, and then the numerical simulation of the laser beam drilling process and its experimental validation was carried out. The experiments were carried out on a tungsten alloy plate of two different thicknesses, 0.5 and 1 mm. No significant changes in the microhardness, nor in the microstructure characteristics in the heat-affected zone (HAZ), were observed for the cutting conditions considered. A two-dimensional axisymmetric mathematical model for the simulation of the laser beam drilling process is solved by a finite volume method. The model was validated by comparing numerical and experimental results in terms of the size of HAZ and the size and shape of the drilled hole. Experimental and numerical results showed that HAZ is larger in the 0.5-mm-thick plate than in the 1-mm-thick plate under the same drilling conditions. Good agreement was observed between the experimental and numerical results. The developed model improves the understanding of the physical phenomena of laser beam machining and allows the optimization of laser and process parameters.

In modern industries, basalt and glass are the most commonly used fibers for the fabrication of various engineering components. Present work is focused on the fabrication of hybrid fiber reinforced plastic (FRP) composites, comprises of basalt and glass fibers. The aim of the work is to fabricate a composite justifying the current requirement of the era followed by the identification of the capabilities of fabricated composite by investigating its mechanical properties. Further, the machining of the fabricated composite has also been explored in order to limit the common problems in machining like fiber pull-out and delamination. From the results, it has been perceived that the fabricated composite can be machined flawlessly using laser beam machine subjected to the selection of input parameters. The proposed methodology seems helpful for researchers in fabricating the FRP composite and in identifying the range of input parameters suitable for machining. [ABSTRACT FROM AUTHOR]

Metal matrix composites (MMCs) are the new-generation advanced materials that have excellent mechanical properties, such as high specific strength, strong hardness, and strong resistance to wear and corrosion. All these qualities make MMCs suitable material in the manufacture of automobiles and aircraft. The machining of these materials is still difficult due to the abrasive nature of the reinforced particles and hardness of MMCs. The conventional machining of MMCs results in high tool wear and slow removal of materials, thereby increasing the overall machining cost. The nonconventional machining of these materials, on the contrary, ensures much better performance. This paper reviews various research works on the development of MMCs and the subsequent hybrid composites and evaluates their performances. Further, it discusses the influence of the process parameters of conventional and nonconventional machining on the performance of MMCs. At the end, it identifies the research gaps and future scopes for further investigations in this field.

Laser hardening is a process that modifies not only hardness, but also residual stresses near the surface. However, limited information is available on the effect of multi-cycle phase transformation on the hardness and residual stresses, which could be a possibility to achieve different material modifications. In this paper, the effects of multi-pass laser hardening on the material modifications of quenched and tempered as well as ferrite/pearlite AISI 4140 steel have been investigated. The multi-cycle phase transformation process has been carried out using a continuous wave laser with a rectangular beam shape using different schemes, without heat accumulation between each cycle. Results showed that material properties were modified with accumulation effects within the given pass up to 16 cycles. With increasing passes, it was found that the induced compressive residual stress at the surface decreased despite of the initial material state, while the hardness in the subsurface area and hardening depth increased differently, which depended on the initial heat treatment condition. These results indicated the possibility of tailoring the material hardness and surface residual stress by the given heat treatment condition, laser process and cycle number in the multi-pass laser hardening. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

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%). [ABSTRACT FROM AUTHOR]