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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.

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.

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.

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.

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...

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).

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.

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.

Micro-machining of dental ceramics namely as zirconium oxide is carried out through laser beam machining. Micro-channels of different sizes are fabricated under different laser parameters. The laser process performance is evaluated by considering the geometrical and quality responses associated with micro-channels. Laser intensity, pulse frequency, scanning speed and layer thickness per laser scan are opted as the influential controlling parameters. Geometrical characteristics of micro-channels include upper width (WU), lower width (WL), depth (D), taper angle of micro-channel’s sidewalls at right side (θR), and taper angle at left side (θR ). Quality of the machined micro-channels is evaluated by means of surface roughness (Ra of the bottom surface. Effects of each of the laser parameters on each of the geometrical and quality responses are studied in order to get the influential trends of laser parameters. SEM analysis is further performed to assess the micro-details of machining results. The results reveals that the shape and size of micro-channel are very sensitive to the variation in laser parameters. Two types of micro-channels shapes are obtained having V-shaped and U-shaped cross-sections. Furthermore, it is quite challenging to achieve the micro-channels with reasonable amount of lower width (WL).

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.

The present work intends to show a rapid prototyping experience carried out starting from a three-dimensional model realized with the Revit 2021® software of the never realized project of the “Due ville a Capri” by the Turin architect Aldo Morbelli. The scale model was realized through the application of two digital manufacturing techniques: additive, the Fused Deposition Modeling (FDM), used for the buildings and for the external built elements made of plastic and subtractive, the Laser Beam Machining (LBM), for the slope on which the two buildings stand, realized through the superimposition of cardboard layers.

Although continuous progress in technical advancement, the conventional machining process has became unsatisfactory in healthcare due to its disadvantages. This inadequacy has led researches to consider using the application of nontraditional machining that can machine extremely hard and brittle materials into complicated shapes in healthcare. Researches have proved that diverse NTM applications of Water Jet Machining (WJM), Ultrasonic Machining (USM), Laser Beam Machining (LBM), Wire Electrical Discharge Machining (WEDM) and Electrocautery are appropriated in manufacturing medical devices and implants for many different fields due to their several advantages. Tissue cutting operations are one of the fields where NTM technologies are widely used. In this review study, firstly, seven NTM technologies were investigated and represented with details to decide most suitable technologies for healthcare field. After this investigation, a literature study was conducted by focusing on WJM, LBM and Electrocautery device that are the most convenient using in tissue cutting operations in healthcare. For this review, 38 articles that have been studied after 2004 classified for the most popular 3 technology in this area, which are WJM, LBM and Electrocautery device.

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.

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.

Diamond is widely used in a series of industrial and scientific applications, including the micro-electro-mechanical systems, optical elements, ultra-precision machining tools, etc. Femtosecond laser beam machining is promising for high precision and high accuracy machining diamond material for its famous non-thermal machining regime. Initially, the laser ablation threshold was determined for the low and high laser fluence stage, respectively. Then, the ionization regime of femtosecond pulsed laser beam machining mono-crystalline diamond with different laser power was discussed. The influence of the ionization regime on laser machining also was analyzed basing on Raman analysis and laser machined surface topography. The laser ablation threshold was 0.29 J/cm2 for the low laser fluence stage and 2.35 J/cm2 for the high laser fluence stage, respectively. The calculation of the Keldysh parameter indicated that the multi-photon ionization prevailed in the low laser fluence stage while the tunneling ionization became dominant in the high laser fluence stage. The transition of the ionization regime from the multi-photon ionization to the tunneling ionization occurred around the laser fluence 3.2 J/cm2. Graphitization of diamond material was discovered on laser machined diamond surface by means of Raman analysis. Graphitization would be enhanced by the tunneling ionization regime in the high laser fluence stage. A strong surface cracking tendency was also observed in laser machining in the high fluence stage.

The aim of this work is to study the heating efficiency of refractory microstructures by excitation of surface plasmon polaritons in the far infrared that can be used for high-temperature applications. The work has designed metal grating couplers on molybdenum films to maximise the absorption of a 10.6 µm CO 2 laser light source. Molybdenum has been chosen since it is an industrial refractory metal combined with the fact that its optical properties in the far infrared are similar to gold but with stable high-temperature performance. Linear gratings have been used as plasmonic couplers on large area substrates produced by laser milling. Real-time absolute temperature measurements have been performed showing a 42% increase in the maximum achievable temperature from 702 to 985 K.

The research has been originated based on the persuasive applications of Lasers in Automotive, Aerospace, Electronic and Heavy manufacturing industries to machine a variety of metals and alloys. Among all machining processes, Laser Beam Machining has turned to be the best one since it furnishes quick material removal with an effectively controlled, non-contact, non-wearing tool, involves highly localized heat input to the work piece, reduces distortion, and offers no tool wear, diminishes tendency of cracking. This paper focuses on understanding the impact of laser process parameters on the final geometrical and surface nature of micro-channel features fabricated on Hastelloy C276. Ideal choice of process parameters is highly critical for successful material removal and high dimensional and surface quality for micro-sized die/mold applications. Full factorial plan is utilized to do the test outline. A few micro-channels have been fabricated as miniaturized scale shape holes varying different process parameters. The connection between process parameters and quality attributes has been examined with experimental modeling. The set up models were utilized for optimizing the process parameters using Genetic Algorithm.

Laser beam machining (LBM) is capable of almost force-free 2D and 3D machining of any kind of material without tool wear. This process is defined by many parameters, such as pulse energy, frequency, scanning velocity and number of scanning repetitions. Modern laser machines provide high energy at shorter pulse durations and have more precise positioning systems than machines of the past. These can easily fulfil today's continuous changing product requirements. For an overall understanding, an extensive amount of experimentation is required to display the interaction laws and dependencies between process parameters, as well as the resulting shapes and quality of the machined surface. By using an ultrashort pulse (USP) laser, a wide range of customer oriented applications in micrometer scale can be addressed, which leads to precise ablation with minimal thermal damage. This paper provides knowledge on the machining of copper micro features with high aspect ratio and a 532 nm wavelength laser beam. Aspect ratios up to 17 and slot widths smaller than 20 μm were performed with a beam radius ω0 smaller than 5 μm and pulse duration smaller than 12 ps. For desired slot geometries, necessary process parameters were developed and their physical limits are shown and discussed. The limits of minimum structure size have been analysed by observing the remaining material between slots at decreasing distances. Material debris deposits on the non-machined surface, as well as chemical changes of copper, were analysed using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). Special attention was given to the taper angle, which arises due to the Gaussian distribution of energy in the laser beam., Procedia CIRP, 68, ISSN:2212-8271, 19th CIRP Conference on Electro Physical and Chemical Machining

Metal cutting forms the basis of industry its relevance among products of everyday life due its high strength application in structural, aviation, aerospace , military ,naval purpose etc. Based on recent study it is found that many high strength steel are cut using lasers and it has given exceptional result as compared to other Non conventional machining process it is important to know how the cutting is affecting the material properties and which parameters are responsible for such change. The various parameters and their effects are shown in the given study which is analyzed by different researchers along the course of time. The material and thickness and different optimization techniques by different researchers is also shown

We investigated terahertz (THz) transmission of square-particle and rod structured TbFeO3 metamaterials. Mie-type resonances were excited in TbFeO3-based metamaterials. And their dependence on shape and orientation angle was studied. Dielectric TbFeO3 ceramic wafers, which were prepared by 3-D direct writing technology and traditional solid-state sintering method, were processed into square-particle and rod structured metamaterials using laser beam machining. With variation of orientation angle, square-particle structured metamaterial showed angle-independence, while rod structured metamaterial showed complicated behaviors: angle-dependence at lower frequencies and angle-independence at higher frequencies. Circular magnetic and electric field distributions surrounding the incident electromagnetic fields endowed resonances insensitivity to orientation angle. And angle-dependence of rod-shaped metamaterial at lower frequencies were caused by the central symmetry breaking.

Leather is a robust, durable and stretchy material created by tanning animal rawhide and skins. It is used to make variety of articles including footwear, bags, fashion accessories, furniture etc. The conventional method of cutting leather is a tiresome process. Laser diode technology offers advantages in cutting intricate geometries, stable cutting quality and potential to make the most use of leather product effectively. In this study, the machinability of leather using diode based laser beam machining and surface quality of the leather product have also been examined. The goal is to acquire the thermal effect caused by the laser at the cut contour edges. Buffalo leather has been taken as specimens in the present study. While cutting leather, it has been. proposed that diode based Laser Beam Machining minimize carbonization layer more than traditional machining.

For terahertz systems, rectangular waveguide is an ideal low loss medium for interconnectivity and the construction of passive circuits. A drawback when manufacturing waveguides at submillimeter wavelengths is the demanding tolerances due to small dimensions. For example, a WR-3 waveguide (operating between 220 and 325 GHz) has a cross-sectional dimension of just 864 by 432 µm, and higher frequency waveguides get proportionally smaller. An additional challenge is that whether using waveguide for passive circuits such as filters, there are additional structures inside the waveguide which are significantly smaller than the waveguide itself. Traditionally, computer numerical control (CNC) milling has been used for waveguides, however at terahertz frequencies this is difficult to utilise. Emerging technologies for terahertz waveguides are compared with conventional CNC solutions. The technologies include the photolithography-based polymer etching of waveguides using SU-8 photoresist, and the laser machining of metal. Both have shown promise, and good quality terahertz passive components have been fabricated and measured.

Pulsed laser equipment can be used to generate elastic waves through the instantaneous reaction of thermal expansion or ablation of the material; however, we cannot control the waveform generated by the laser in the same manner that we can when piezoelectric transducers are used as exciters. This study investigates the generation of narrowband tone-burst waves using a fiber laser of the type that is widely used in laser beam machining. Fiber lasers can emit laser pulses with a high repetition rate on the order of MHz, and the laser pulses can be modulated to a burst train by external signals. As a consequence of the burst laser emission, a narrowband tone-burst elastic wave is generated. We experimentally confirmed that the elastic waves agreed well with the modulation signals in time domain waveforms and their frequency spectra, and that waveforms can be controlled by the generation technique. We also apply the generation technique to defect imaging with a scanning laser source. In the experiments, with small laser emission energy, we were not able to obtain defect images from the signal amplitude due to low signal-to-noise ratio, whereas using frequency spectrum peaks of the tone-burst signals gave clear defect images, which indicates that the signal-to-noise ratio is improved in the frequency domain by using this technique for the generation of narrowband elastic waves. Moreover, even for defect imaging at a single receiving point, defect images were enhanced by taking an average of distributions of frequency spectrum peaks at different frequencies.

We demonstrate a novel femtosecond laser beam machining method which is proposed to achieve better quality micro-machining. The fused silica sheet coated with aluminum film was prepared by Pulsed Laser Deposition (PLD) in the high vacuum chamber (below 5 × 10−4 Pa). After femtosecond laser ablation, the aluminum film on fused silica sheet was cleaned by hydrochloric acid solution (HCl) in a solution of 10% until the aluminum film was absolutely reacted, finally the micro-hole array was formed on the silica. The existing of a thin film is found to be effective for improving the quality of micro-machining. The micro-hole arrays fabricated by the new method were quite good in roundness and the morphology of single hole was relatively good, and the edges of the holes were with no cracks and recast layer. In addition, the effect of the fluence of femtosecond laser and the average diameter of the micro-hole array on the fused silica sheet was investigated. Finally, we examined the diffraction characteristic of the micro-hole array to reflect the overall morphology of holes.

This paper describes a state of the art in micro-structuring high strength metallic materials. Tungsten micro pin arrays in a variety of shapes are fabricated using a micro carving technology, which combines laser beam machining and electrochemical etching processes. First, micro pin arrays were rough-shaped by laser beam machining along a pre-defined scanning path to control their structural shape. The micro pin array in this stage had near-conical shape of structures due to a recast layer. Next, the genuine shape of micro pin arrays came to the surface via electrochemical etching process to elute the recast layer into electrolyte. Quantitative elemental analysis with energy-dispersive spectroscopy (EDS) was implemented to characterize the formation of recast layer on a micro pin structure after the laser beam machining process. The atomic percentage EDS maps indicated that higher percentage of tungsten was detected on the core micro pin structure, whereas relatively large percentage of oxygen was found on the recast layer (O 9%, W 91% in the center area, and O 53%, W 47% in the outer area).

In the last few years, commercially available ultrashort pulsed (usp) laser systems have reached average powers of several 100 W, which makes them also interesting for enhancing traditional applications. For example, laser drilling, a conventionally melt-dominated process, would benefit from the advantages of an usp ablation process. Due to the small processing area in laser drilling, substantial heat accumulates already at a few Watts of average power. This heat accumulation creates melt but also increases the mean ablation rate at least 1 order of magnitude and could lead to a productive drilling process. In this study, the increase of the mean ablation rate in percussion drilling due to heat accumulation is examined for various metals and sample thicknesses for high average powers of up to 300 W and a pulse energy in the milliJoule range. Those investigations have not yet been performed in such detail. It is shown that by doubling the pulse energy the drilling time can be decreased by 2 orders of magnitude due to heat accumulation. This behavior is valid for various metals like steel or aluminum, despite their varying material parameters. By analyzing the influence of different repetition rates and focal diameters, it is shown that the predominant parameter to characterize the heat accumulation is the average power. No significant difference is observed if the average power starting from 20 W is set up by a high pulse energy or repetition rate. Stainless steel has a different behavior compared to the other investigated metals when the pulse duration is changed from 2 to 20 ps, which is caused by a modified plasma generation. For stainless steel, the drilling time is found to be describable with one empirical formula for the entire range of examined average power and sample thickness.In the last few years, commercially available ultrashort pulsed (usp) laser systems have reached average powers of several 100 W, which makes them also interesting for enhancing traditional applications. For example, laser drilling, a conventionally melt-dominated process, would benefit from the advantages of an usp ablation process. Due to the small processing area in laser drilling, substantial heat accumulates already at a few Watts of average power. This heat accumulation creates melt but also increases the mean ablation rate at least 1 order of magnitude and could lead to a productive drilling process. In this study, the increase of the mean ablation rate in percussion drilling due to heat accumulation is examined for various metals and sample thicknesses for high average powers of up to 300 W and a pulse energy in the milliJoule range. Those investigations have not yet been performed in such detail. It is shown that by doubling the pulse energy the drilling time can be decreased by 2 orders of magni...

One of the emerging technologies in the world of micromachining is that of the usage of short and ultrashort laser pulses. Many manufacturing industries have been revolutionized by the employability of laser beam micromachining (LBMM) process for a number of micro-engineering applications. Short and ultrashort laser pulses houses tremendous amount of thermal energy that can be used for the fabrication of micro-features using a wide range of engineering materials. To further extend the capability of the process, the laser is integrated with other standalone micromachining processes such as micro-milling, micro-grinding, electrochemical micromachining, water jet micromachining, etc., and giving rise to hybrid micromachining setup in the form of laser-assisted micromachining process. This chapter begins with a short introduction on laser beam machining. Laser beam micromachining has been discussed next in the subsequent section. The next section elucidates on few applications of the laser-assisted micromachining process. The chapter finally terminates with the concluding remarks.

Optimization of non-conventional machining (NCM) processes viz. AJM, AWJM, EDM, WEDM, ECM, ECMM, LBM, PAC, etc. has always been an open research area for researchers. In recent manufacturing environment, almost all the NCM processes consist of a number of input and output to be considered together. The purpose of the present article is to highlight the application of a multi-criteria decision making (MCDM) based method called Technique of Order Preference by Similarity of Ideal Solution (TOPSIS) in optimization of some modern manufacturing processes (MMPs). In the present paper, seven different MMPs namely Electro Chemical Honing (ECH), Abrasive Water Jet Machining (AWJM), Abrasive Jet Machining (AJM), Laser Beam Machining (LBM), Plasma Arc Cutting (PAC), Laser Cutting (LC) and Electric Discharge Machining (EDM) were exemplified. The multiple outcomes of all the illustrated MMPs have been optimized simultaneously by using TOPSIS method. It is a simple, systematic, and logical technique which can be employed to obtain the best parametric combination of cutting parameters. It was observed that the results attained by using TOPSIS method were almost tie with those derived by past researchers. This proves the applicability and adaptability of the TOPSIS method while solving different MCDM-based problems in a real manufacturing system.

Nd: YLF laser beam machining (LBM) process has a great potential to manufacture intricate shaped microproducts with its unique characteristics. Continuous improvement (CI) effort for LBM process is usually realised by response surface methodology, which is an important tool in Design of Six Sigma. However, when determining the optimal machining parameters in CI for LBM process, model parameter uncertainty is typically neglected. Performing worst case analysis in CI, this paper presents a new loss function method that takes model parameter uncertainty into account via Bayesian credible region. Unlike existing CI methods in LBM process, the proposed Bayesian probabilistic approach is based on seemingly unrelated regression which can produce more precise estimations of the model parameters than ordinary least squares in correlated multiple responses problems. An Nd: YLF laser beam micro-drilling process is used to demonstrate the effectiveness of the proposed approach. The comparison results show that micro-...

Thanks to the favourable combination of outstanding mechanical, thermal and chemical properties, engineering ceramics find widespread applications in the modern industry. Nevertheless, their extensive use is still hindered by the implementation of a labour and cost intensive manufacturing chain. Electro, chemical and physical shaping techniques, like electrical discharge machining, additive manufacturing and laser beam machining, have recently been investigated to offer efficient alternatives. This work provides a comprehensive overview of the current technological trends and main perspectives on electro, chemical and physical shaping of engineering ceramics with a focus on experimental works. The literature data trace back to the 80s.

With the development and advancements in the material research, increasing number of new materials with micro and nano has been developed to meet the expectations of the micro and nano industries. Although the material database has grown tremendously, machining of the new materials with the traditional has posed a major challenge, thereby restricting their applications to their applicability to the nano and micro industries. To overcome such challenges, new micro and nano machining techniques have been researched and developed. The new machining techniques are referred to as unconventional machining process and are being used increasingly because of a number of associated advantages. Owing to the importance of micro and nano machining techniques, the present chapter discusses important micro machining processes such as electrical discharge machining (EDM), electrochemical machining (ECM), abrasive water-jet machining (AWJM), and laser beam machining (LBM). A brief section on recent trends in nano-machining has also been presented at the end of the chapter.

In this paper, we report an X-band 3D printed two-way rectangular waveguide power divider made up of electroless plated non-conductive material. In contrast to conventional metal machining fabrication processes, such as computerized numerically controlled (CNC) milling and laser beam machining (LBM), it is verified that 3D printing methods can be used to fabricate rectangular waveguide power dividers with low cost and low weight in short time.

The utilization of laser technology on machining leather has grown significantly during recent years due to number of advantages such as flexibility, high production speed, possibility to cut complex geometries, easier cutting over conventional cutting methods of slitting knifes, die press techniques and manual cutting . In the present work, an endeavor has been proposed to analyze the machinability of leather using CO2-based laser beam machining (LBM) process. Buffalo leather has been taken as specimens in the present study. It has been inferred that LBM can produce less dross compared to conventional machining while cutting leather.

The backscattered light originated when machining with femtosecond laser pulses can be used to accurately measure the processed surface position through an interferometer, as recently demonstrated by our group, in a setup that uses the same laser beam for ablation and inspection. The present work explores the characteristics of the laser light reflected by the target and its interaction with the resulting plasma to better understand its propagation physics and to improve the dynamic focusing system. The origin of this returning radiation was studied and has been traced, mainly, from the peripheral area of the focal spot (doughnut-like). By means of a Mach-Zehnder setup, the interferometric pattern was measured and analyzed aiming to access the influences of the plasma on the laser beam properties, and therefore on the retrieved information. Finally, the wavefront of the laser that creates and propagates through the plasma was characterized using a Shack-Hartmann sensor.

The impact of teaching material design for multidisciplinary learning on learning achievement with science and technological university students was examined. The participants were students enrolling in an elective general education course, named Technology and Life Application, at a technological university. The experiment lasted for one semester with a total of 16 weeks. The results revealed that the teaching material design for the four topics, including ultrasonic machining, abrasive jet machining, investment casting, and precision welding machining, significantly enhanced students’ learning achievement. However, the teaching material design for the topics of laser beam machining and electrical discharge machining did not have a significant effect on learning achievement. Therefore, the contents of the teaching materials for the topics of laser beam machining and electrical discharge machining required revisions.

Electrothermal cutting processes employ a combination of electrical energy and heat to achieve material removal process. Many materials will burn when subjected to heat. By bringing materials into melting and vaporisation state, material cutting can be achieved. Electrothermal machining is an advanced machining process which is contact-less and hence does not require the physical contact of the tool and the workpiece making cutting forces negligible. There are different types of electrothermal machining processes such as electrical discharged machining, electron beam machining and laser beam machining, which are explained in this chapter. This advanced machining process however uses thermal energy to achieve the desired cutting process but does not create heat damage to the material when compared to the similar conventional cutting processes. The principles of operation of each of these processes are explained in this chapter with their advantages, limitations and areas of application. Some research works in this field are also presented.

Non-conventional manufacturing techniques are most widely used in industries in order to achieve high accuracy and desirable product quality. Therefore, the selection of an appropriate machining parameter has become a crucial job before starting the operation. Several optimization methods are available to resolve the upstairs situation. The current study explores a novel technique namely multi-objective optimization on the basis of ratio analysis (MOORA) to solve different multi-objective problems that are encountered in the real-time manufacturing industries. This study focuses on the application of MOORA method for solving some non-conventional machining processes that have multiple criteria problems. Wire-Electric Discharge Machining (WEDM), Plasma Arc Cutting (PAC), Electro Chemical Micro Machining (ECMM), Electro Chemical Machining (ECM), Abrasive Jet Machining (AJM), Abrasive Water Jet Machining (AWJM), Ultrasonic Machining (USM), Laser Beam Machining (LBM) and Laser cutting process are the major attentions in the current study. Total nine NTM multi-criteria problems which include selection of proper machining parameters have been studied. The optimal settings of input variables obtained by using MOORA method nearly tie with those derived by the earlier investigators.

Transparent superhydrophobic surfaces have great potential for application to self-cleaning transparent windows. We suggest a fabrication method that combines laser beam machining and polymer casting. A UV nanosecond pulsed laser was used to machine arrays of holes into molds composed of 6061 aluminum alloy. Then, polydimethylsiloxane was cast into the laser-machined molds. To study the effects of the array geometry on superhydrophobicity and transparency, a series of micropillar arrays with different step sizes were fabricated. As a result, the critical step size at which the surfaces changed from hydrophobic to superhydrophobic was found to be approximately 80 μm. Cone-shaped micropillar arrays with 80 μm step size showed 175° maximum water droplet contact angle and were highly transparent throughout the 300–1000 nm spectral region. Sliding angle was observed to confirm the surfaces’ self-cleaning ability. This work opens up the possibility of mass production of superhydrophobic, transparent, self-cleaning surfaces.

This study presents the investigation results of micro-channel fabrication in nickel-based super alloy (Inconel 718) by Nd:YAG laser beam machining. The effects of laser parameters on the machining performance characteristics over dimensional sizes are evaluated. Three number of laser parameters have been reserved as predictors to the naming of laser intensity, pulse frequency, and laser scanning speed. The channel’s top width, bottom width, depth, and taperness are considered as the process responses. Micrographs by SEM have been organized to study and measure the micro-sized dimensions of fabricated channels. The results showed that the selection of channel size is critical to achieve desired machining results. Wider-sized channels (for example 200 × 100 μm and 1000 × 500 μm) can more confidently be machined than narrower-sized channels (50 × 50 μm). The possible reasons behind the failure of narrow-sized micro-channel fabrication are identified. The appropriate combination of parameters that can yield the better results for 100 × 100 μm channel size are the laser intensity of 92.7 %, repetition rate of 30 kHz, and scan speed of 300 mm/s. At this combination, the channel geometries of wider-sized channels are more close to the designed geometries as compared to narrow-sized channels. Microstructures of the machined channels are also studied showing the recast layer with lamellar grain structure and phase transformation near the edges of micro-channels. The channel edges and their adjacent areas show variation in hardness relative to bulk material. This has been validated via micro-hardness profiles of the close vicinity of machined micro-channels.

The laser beam drilling is generally included in the larger group of laser beam machining methods based on the material removal. The problem addressed in this paper referred to the laser beam drilling of test pieces made of Plexiglas. Some theoretical aspects were highlighted by analyzing the physical effects developed in Plexiglas by the laser beam action. Experimental research was developed in order to highlight the influence exerted by the duration of the CO2 laser beam action on the Plexiglas in obtaining blind and through-holes. Empirical mathematical models and graphical representations allowed formulation of some remarks concerning the results of experimental research.

In laser beam machining with oxygen gas, striations are formed on the cut surface due to the cyclic oxidization reaction, which is affected by the cutting conditions and the thermal properties of the workpiece. The formation of striations causes an increase in surface roughness. In order to reduce the surface roughness, we propose controlling the formation of striations by utilizing multi-DOF oscillation of the focus position of the laser. In this paper, we construct a laser machining system in which positioning control of the focus position is achieved by driving the focal lens. The effect of orbital oscillation of the laser focus position parallel to the top surface of the workpiece and vertical oscillation perpendicular to this surface on the formation of striations was evaluated by performing laser cutting tests on thick mild steel plates. The experimental results show that control of the formation of striations can be realized by choosing the appropriate oscillation conditions. The surface roughness with oscillation was less than half that without oscillation.

Under liquid laser beam machining (UL-LBM) is the advanced machining process where laser beamis used for material removal in presence of liquid. It can be applied to different materials like metals, polymers,ceramics, and alloys for different operations such as drilling, cutting and micromachining. The mechanism of UL-LBM mainly includes transmission (absorption) of light in liquids, liquid heating, vaporization, bubble formation, growth and collapse, material heating, melting and/vaporization and explosive removal. It is suitable for fabrication of high quality miniature parts that are made from variety of advanced materials. The present study reviews the effect of different UL-LBM process input parameters on the output responses and comparison of this process performance with conventional laser beam machining (LBM) to demonstrate the advantages.

In the last decades a strong increase of use in Carbon Fibre Reinforced Polymers (CFRPs) in the production of structures and components occurred. In particular in the automotive and aeronautical sectors several manufacturers already replaced light alloy or high strength steel parts with composites but the use of composite materials is rapidly growing also in other industrial sectors. Composites offer great advantages not only in term of specific proprieties but also in term of “functionalization” of the products by means of the lay-up sequence optimization and consequently providing heterogeneous improved proprieties in the different three-dimensional directions. CFRPs with epoxy resin matrix, among the polymer composites, offer the highest mechanical proprieties in particular when combined with autoclave technology that represents the top standard. On the other side the production of composite materials parts, and particularly the autoclave processing, is still very far respect to conventional metal forming processes in term of production rates. For this reason a considerable effort is oriented towards research and development of the so called “out of autoclave” processing where a trade-off between mechanical proprieties and production rates are investigated. A real optimization of the whole process requires robust and efficient technologies also during those phases able to guarantee high production rates. Laser processing represents a typical technology able to guarantee high flexibility joined with high automation and high production rate not only for small but also for large series manufacturing. For all these reasons, a solid state continuous wave Laser has been used for machining thin sheets made by woven carbon fibre/epoxy resin Pre-preg of 160 g/mm2 (HR 3K 200 TEX carbon fibre with a 50% fibres in the warp and 50% in the weft directions). The aim was to investigate the interaction mechanism for removing the resin without damaging the fibres. Preliminary results in terms of process feasibility area were presented and discussed.

Laser beam machining (LBM) is widely used as thermal energy based non-contact type advance machining process which can be applied for almost whole range of materials. It is suitable for geometrically complex profile cutting in the metals used in manufacturing engineering.

Stringent quality requirements, increased global competitiveness, and strict environmental regulations have led to the development of advanced processes for gear manufacturing. Researchers and engineers are constantly striving to find novel solutions to improve quality, productivity, and sustainability in gear manufacturing processes either by enhancing capabilities and optimization of the existing processes or developing new advanced processes. This chapter provides a detailed discussion on the basic principles, advantages, capabilities, and applications, of recently developed advanced manufacturing processes for gears. These include laser beam machining, abrasive water jet machining, spark erosion machining, additive layer manufacturing, micrometal injection molding, injection compression molding, and Lithographie, Galvanoformung and Abformung (English translation is lithography, electroplating, and molding), etc. and then also advances in the conventional processes of gear manufacturing. It also includes a section on sustainable manufacturing of gears.

Laser beam machining (LBM) is a widely used thermal advance machining process capable of high accuracy machining of almost any material with complex geometries. CO 2 and Nd:YAG lasers are mostly used for industrial purposes. Drilling, cutting, grooving, turning and milling are the applications of LBM with different material removal mechanisms. Modeling and simulation of the LBM process is indispensable for optimization purposes. Modeling can be done by implementing analytical, numerical, experimental and artificial intelligence-based methods. This paper provides a review of the various methods used for modeling and simulation of the laser beam machining process as well as key researches done in this field so far.

Recently, the world's evolving experimental design and research work on the creation of technological methods and systems of layered laser synthesis products of machine parts. These systems allow to accelerate the introduction of new technology at all stages of product design to create its original layout in full size. There are currently variety of methods sintering of metal powders.This paper presents experimental data which show the effects of the strategy of forming a sintered layer in the synthesis of products by SLS.