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Due to the variety of benefits over traditional cutting techniques, the usage of laser cutting technology has risen substantially in recent years. The attributes of laser technology for leather cutting include adaptability, mass production, capability of cutting complicated patterns, ease of producing tailored components, and reduction in leather waste. In the present study, vegetable chrome-tanned buffalo leather specimens were cut using a 20 W laser diode with conventional and pulse width control in a photodiode-assisted laser cutting process. Emission rate, kerf width, carbonization, and material removal rate were considered as quality indicators. The higher power density associated with the pulse width approach reduces the interaction with the specimen, which results in a better emission rate and material removal rate, along with a lesser kerf width and carbonization. Using the MOORA approach, the optimal parameters of the present study were found to be a stand-off distance of 22 mm, a feed rate of 200 mm/min, a duty cycle of 75%, and a frequency of 20 kHz. The duty cycle can effectively control the pulse width at which the energy has been dissipated across the cutting zone. [ABSTRACT FROM AUTHOR]

Laser machining is a cutting-edge thermal energy-based industrial methodology that can be employed to replace the traditional mechanical machining practices in micro-domain applications. In this work, complex hexagonal shape profiles were cut on the surfaces of Nickel-based superalloy (Alloy 276) by fiber optics laser cutting system. Response surface methodology – Central Composite Design approaches were attempted for optimizing laser machining factors to obtain the better output responses. ANOVA was used to identify the significant machining factors which affect the cut quality characteristics. The desirability approach in multi-response optimization was deployed to achieve the minimal kerf width, low surface roughness, minimum heat affected zone while simultaneously increasing the material removal rate. To validate the predicted results obtained from the desirability index analysis, confirmation test was conducted based on a higher desirability index value. The result reveals that the error percentage is less than 5 for all the responses. The results of the confirmation test show that the proposed procedures are effective in improving laser machining parameters for obtaining the better responses. [ABSTRACT FROM AUTHOR]

This study investigates the influence of the stand-off distance (SoD), laser speed (LS) and laser power (LP) on kerf geometry (upper width Wu, down width Wd and kerf angle KA) and mean surface roughness (Ra) during CO2 laser cutting of 3D-Printed Polyethylene-Terephthalate-Glycol (PET-G) thin plates. A full factorial design is implemented, having two levels for SoD and three levels for LS and four levels for LP, resulting in twenty-four (24) cuts. The specimens were manufactured with the Fused Filament Fabrication (FFF) process and had a thickness of 4 mm. First, the Wu, Wd, and KA parameters were measured. Then, the specimens were cut into 24 smaller parts, and the Ra of the processed surfaces was measured. After analyzing the results using descriptive statistical analysis and contour plots corresponding to the two objectives of KA and Ra, a feed-forward and backpropagation neural network (FFBP-NN) was applied. After a series of subsequent training, it was found that the 3-10-2 NN architecture was quite efficient in explaining the variation in terms of the responses, thus having merit in practical applications related to laser cutting. The LC surfaces showed much better Ra (7.2-12 μm) than those in the literature for FFF parts surfaces without post-processing (10.3-30 μm). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this study, the holes of glass fiber reinforced polymer (GFRP) and multi-walled carbon nanotubes (MWCNTs) doped GFRP composite materials were drilled using abrasive water jet (AWJ), CO2 laser cutting, orbital drilling, and punching methods; the effects of these methods on hole quality were determined. The hole entry and exit dimensions were obtained equal and in the desired size by orbital drilling; thus, kerf formation was prevented due to the lateral and face milling of the end mill. The surface hardness change was not observed in the hole circles obtained with the orbital drilling and punching methods. However, epoxy hardening was observed in the hole circles obtained by laser cutting due to the heat effect of laser beam. In AWJ method, matrix-fiber integrity was disrupted, and delamination was observed due to the effect of water pressure and kinetic energy; consequently an increase in material thickness was observed and surface hardness decreased. It was determined that MWCNTs additive increased the surface hardness of composites and maintained its hardness and durability in post-cutting measurements. Splintering and burring were not seen in any method, but fiber carbonization was observed in the inner parts of the hole due to thermal effects in laser cutting. [ABSTRACT FROM AUTHOR]

A hybrid approach through combining genetic algorithm (GA) and adaptive neuro-fuzzy inference system (ANFIS) for modeling the correlation of laser beam cutting (LBC) parameters and enhancing the quality performance characteristics of machined Hastelloy C276 is emphasized. The LBC experiments are performed by considering gas pressure (GP), cutting speed (CS), pulse energy (PE) and stand-off distance (SOD) as input parameters. The output responses are material removal rate (MRR), kerf taper (KT) and surface roughness (Ra) for the present investigation. The optimal ANFIS training variables are obtained through GA. The training, testing errors, and statistical validation parameter results exposed that the ANFIS learned by GA is outperformed in forecasting LBC responses. In addition, to obtain the optimal combinations of LBC parameters, the multi-response optimization based on maximizing MRR and minimizing KT and Ra was performed using a trained ANFIS network coupled with a whale optimization algorithm (WOA). The responses such as MRR of 236.98 mg/min, KT of 1.135° and Ra of 1.109 µm are forecasted for the optimum cutting conditions: GP of 3 bar, CS of 319.8 mm/min, PE of 5.93 J and SOD of 2.97 mm, respectively. Furthermore, the WOA predicted results are validated by conducting confirmatory experiments. [ABSTRACT FROM AUTHOR]

In this work, two typical surface characteristics, i.e., mean surface roughness and angle of the kerf during laser processing of 3D-printed Polylactic Acid (PLA) plates with 4.00 mm in thickness, are investigated. A carbon dioxide laser was utilized to separate 27 work pieces of rectangular shape. The governing laser parameters, speed of cutting and laser power, were varied according to full factorial experimental methodology. An orthogonal array (OA) having nine combinations was implemented, and nine specimens were cut with the same set-up and the same parameters three times (27 replicates in total). The experimental results were analyzed using descriptive statistical analysis, i.e., histograms, box plots, interaction charts and optimized using analysis of means (ANOM) plots as well as ANOVA analysis. The data analysis indicated that laser speed is the dominant parameter for the kerf angle, whilst both the laser velocity and power are important for mean surface roughness of the cut surface for PLA 3D-printed parts. The spread of the data is smaller in Y direction, which indicates that the weaving phenomenon affects the laser cut performance. [ABSTRACT FROM AUTHOR]

This paper presents an experimental research that proposes to determine the influence of process parameters on CO2 laser cutting of 8 mm thick Hardox 400 steel, for which Kerf has a minimum value. The experimental research was conducted according to a complete factorial plan with laser power, assistant gas pressure and cutting speed as the input parameters, and cutting width as the dependable variable. The Design of Experiment (DOE) consisted of 27 references and was completed with four replicas to determine the variation of the Kerf average. Functional, linear and quadratic relations were determined, which describe the Kerf dependence on the cutting parameters in order to establish the most influential parameter. The results show that the independent parameter with the most significant influence was the laser power, with minimum Kerf obtained if the laser power and the assistant gas pressure were adjusted to average values. The interaction between laser power and auxiliary gas pressure at constant cutting speed was investigated to improve Kerf and reduce the laser processing cost. The study offers the right combination of process parameters that leads to a minimum value of the cutting width. [ABSTRACT FROM AUTHOR]

I believe that laser power, laser cutting speed, position and CO2 pressure with which to cut S235 steel material of different thicknesses have a great contribution to be able to set the best parameters for laser cutting that influences the kerf. I did an experiment to optimize laser cutting with a 4020-watt laser. Three new steps were established to estimate a cutting profile deviation response (KPD) by estimating the total cutting area of the laser cut, characterizing these steps due to the difference between the resulting cutting profile and a straight cut. We concluded that the deviation of the kerf improved by 23.2 for the 2 mm sheet thickness, by 41.8 for the 6 mm sheet thickness, by 13.8 for the 10 mm sheet thickness, by 25.4 for sheet thickness of 15 mm. [ABSTRACT FROM AUTHOR]

Plasma arc cutting (PAC) process is widely used in metal cutting industries and modern fabrication units. Precise cutting of high strength material is still a challenging task to the industries. PAC process uses thermal energy to melt the material through highly energized plasma gas. Mostly, "hard-to-cut" type materials is used to cut through this process to meet the demands. The present work proposes an experimental investigation of PAC process of hardox 400 and abrex 400. Both the materials are high strength and high abrasion resistance in nature. Experiments were conducted based on Taguchi's L 2 5 orthogonal array design. The cutting parameters analyzed were arc current, cutting speed, stand-off distance and supply gas pressure whereas material removal rate, kerf and surface roughness were selected as responses. Also, a prediction model was developed to estimate the responses using multiple regression analysis. A comparison between experimental and predicted result shows the accuracy of the model. Analysis of variance (ANOVA) was used to verify the effect of each parameter on the surface quality to be assessed. [ABSTRACT FROM AUTHOR]

This study supports the research in the field of laser cutting of steel sheets HARDOX400 (H400), a less well-known and analysed material. An H400 sheet with a thickness of 10 mm was used; a cutting plan was prepared according to Taguchi's method; the input parameters (laser power, assistant gas pressure and cutting speed) were varied according to a specific rule, producing nine pieces. The initial factorial experiment was replicated four times under the same conditions as the initial one. The values for the cutting width between the piece and the plate, the hardness, and the roughness of the 45 resulting pieces were measured. The results were interpreted for each measured parameter, and by using design of experiments (DOE) from the Statistics 7.0 software, we obtained the description of roughness (Ra) in terms of power and speed using Response Surface Method (RSM) for prediction and correlation formula. [ABSTRACT FROM AUTHOR]

The purification of laser keyhole and improving molten pool flow are important means to restrain the porosity of laser-MIG hybrid welding of aluminum alloy. In this paper, four kinds of kerf were prefabricated by four common gases (Argon, Nitrogen, Air, Oxygen), which are used for studying the effect of kerf remelted layer on weld porosity. The experimental results show that the porosity is affected by the composition and thickness of the remelted layer. The porosity of Argon-weld and Nitrogen-weld is low, and that of Air-weld and Oxygen-weld is high. It increased linearly with the thickness of remelted layer (d). Regardless of the types of kerf, when the d is less than 136 μm, the porosity is less than 2%. When the d is thin, the purification of laser keyhole avoids the adverse effect of remelted layer oxide on the molten pool and reduces the porosity. When the d is thick, the influence of oxygen on surface tension and molten pool flow driven by it starts to dominate. It makes the temperature coefficient of surface tension change from negative to positive, and the molten pool change from 'outward flow' to 'inward flow', which prevent bubbles from escaping and increasing the porosity. • The feasibility of the laser cutting-welding of aluminum alloy is proved. • The weld appearance is independent of the characteristics of kerf remelted layer. • When the oxide thickness is less than 136 μm, the weld porosity is less than 2%. • The purification of effect of laser keyhole reduces the weld porosity. • The influence of oxygen on the flow behavior is depended on oxide thickness. [ABSTRACT FROM AUTHOR]

In laser beam machining, the main concern is the machining quality as kerf width of the end product. It is essential for industrial applications to cut the workpiece with minimum kerf width. However, it is difficult to develop a precise functional relationship between input and output variables in laser machining. Therefore, an effort has been conducted to build up an intelligent fuzzy expert system (FES) model to predict the kerf width in CO2laser cutting. The employed input parameters were assisting gas pressure, laser power, cutting speed, and standoff distance. The fuzzy logic was performed on fuzzy toolbox in MATLAB R2009b by employing Mamdani technique. In total, 81 experiments were carried out and experimental results were used for training and testing of the developed fuzzy model. Relative error and goodness of fit were used to investigate the accuracy of the prediction ability and the values of 3.852% and 0.994, respectively, were found to be satisfactory. This paper will extend knowledge about the prediction of kerf width by using FES model. [ABSTRACT FROM PUBLISHER]

Abstract: Jet impingement onto a kerf is considered in relation to laser cutting process. Flow and temperature fields are predicted using the three-dimensional modeling. In the simulations influence of kerf wall wedge angle on the Nusselt number and the skin friction at the surface of the kerf wall is examined. The RNG k−ε model is incorporated to account for the turbulence. A control volume approach is introduced to discretize the governing flow equations. It is found that the kerf wall wedge angle has considerable influence on the Nusselt number and the skin friction. [Copyright &y& Elsevier]

Abstract: In laser cutting process, an assisting gas is used to improve the mass removal rate from the cutting kerf and protect the kerf surfaces from the high temperature exothermic reactions, such as oxidation reactions, during the cutting process. Therefore, heat transfer rates from the kerf wall and the skin friction along the kerf surface are important for quality cutting. In the present study, jet emerging from a conical convergent nozzle and impinging onto the kerf surface is investigated in relation to the laser cutting process. The flow field in the kerf, the heat transfer rates from the kerf wall, and the skin friction along the kerf surface are computed for four average jet velocities at the nozzle exit and two kerf wall wedge angles. The ratio of the stand-off-distance (distance between the nozzle exit and the kerf top surface) to nozzle diameter is selected as H/D=2.2., where H is the stand-off-distance and D is the nozzle exit diameter. The kerf wall temperature is kept at 1500K to resemble the laser cutting process. It is found that the Nusselt number increases sharply at the kerf inlet and decreases towards the kerf exit for the kerf wall angle of 0°. However, it increases gradually in this region for the kerf wedge angle of 4°. The skin friction decreases along the kerf surface. [ABSTRACT FROM AUTHOR]

• PP laser cutting was based on a thermal ablation mechanism, accompanied by the formation of by-products such as propene and benzene. • The width of kerf was reduced to ∼22 μm for high cutting speed (250 mm/s). • Under low cutting speed (50 mm/s) and high repetition rate (120 kHz), large HAZ (∼42 μm) was generated due to heat accumulation. • Under the optimal manufacturing parameters, the minimum width of kerf (21.26 ± 1.8 μm) and HAZ (16.92 ± 0.4 μm) were achieved. As a rapid, convincing, and scalability technology, laser micromachining has been widely reported for achieving high-quality processing of polymers. This paper presents a study on improving the cutting performance of polypropylene (PP) film with nanosecond laser emitting at 355 nm (ultraviolet light). Various repetition rates, cutting speeds and repeat times were applied to modify kerf properties, including cut width, heat-affected zone (HAZ) morphology, and cross-section depth. The narrowest kerf width of 21.26 ± 1.8 μm and heat-affected zone (HAZ) width of 16.92 ± 0.4 μm were obtained when repetition rate was 100 kHz, cutting speed was 250 mm/s and repeat times of 4. The laser-treated samples were studied by Scanning Electron Microscopy and Raman spectroscopy. Furthermore, Py-GC–MS and thermogravimetric analysis were employed to revealed thermal decomposition behavior. The morphological and composition analysis showed that swollen HAZ were produced after laser irradiation, with the residues after carbonization and the generation of gases such as propene, 1-butene, etc. These experimental results and developed mechanism provided some insights into the laser processing PP film. [ABSTRACT FROM AUTHOR]

Samples of 4130 steel were cut on a CO2 laser cutting system and the combined effects of power and feed rate on kerf width, surface roughness, striation frequency and the size of heat affected zone (HAZ) have been studied. Regression analysis was used to develop models that describe the effect of the independent process parameters on laser cut quality. For the range of operation conditions tested, it was observed that power had a major effect on kerf width and size of HAZ, while feed rate affects were secondary. On the other hand, surface roughness and striation frequency were affected most by feed rate. At low power levels, the smallest kerf width and HAZ are obtained and the effect of feed rate is moderate. Low feed rates gave good surface roughness and low striation frequency. For optimum cut quality, kerf width, HAZ and surface roughness are kept at a minimum. However, operating conditions that satisfy these requirements while maintaining high productivity could not be identified. [Copyright &y& Elsevier]

Carbon dioxide (CO2) laser cutting finds one of its most relevant applications in the processing of a wide variety of polymeric materials like thermoplastics and thermosetting plastics. Different types of polymeric materials like polypropylene (PP), polymethyl methacrylate (PMMA), low- and high-density polyethylene (LDPE, HDPE), are processed by laser for different household as well as commercial products in the industry. The reason is their easy availability and economical aspect in the market. The problems associated with laser cutting include heat-affected zone (HAZ) generated on the cut surface, kerf width (KW), surface roughness (SR), dross formation, and striations formation. Furthermore, other related problems include taper cutting for deep parts and high-power consumption. The primary purpose of this work is a comprehensive literature review in CO2 laser cutting of polymeric materials. The influence of parametric variation on the cut quality is also explained. Cut quality in terms of KW, SR, HAZ, dross formation, and striations formation is analyzed by optimizing cutting variables like laser power (PL), cutting speed (CS), assist gas pressure (Pg), pulse frequency, nozzle type and its diameter, and stand-off distance (SOD). The effects of the laser cutting on the properties of different thermoplastics/thermosetting materials are also reported. However, this topic requires further studies on exploring the range of polymeric materials, and their optimal parameters selection to improve the cut quality. Therefore, the research gaps and future research directions are also highlighted in the context of CO2 laser cutting for polymeric materials. [ABSTRACT FROM AUTHOR]

Recently, natural fiber-reinforced polymers (NFRPs) have become important materials in many engineering applications; thus, to employ these materials some final industrial processes are needed, such as cutting, trimming, and drilling. Because of the heterogeneous nature of NFRPs, which differs from homogeneous materials such as metals and polymers, several defects have emerged when processing the NFRPs through traditional cutting methods such as high surface roughness and material damage at cutting zone. In order to overcome these challenges, unconventional cutting methods were considered. Unconventional cutting methods did not take into account the effects of cutting forces, which are the main cause of cutting defects in traditional cutting processes. The most prominent unconventional cutting processes are abrasive waterjet (AWJM) and laser beam (LBM) cutting technologies, which are actually applied for cutting various NFRPs. In this study, previously significant studies on cutting NFRPs by AWJM and LBM are discussed. The surface roughness, kerf taper, and heat-affected zone (HAZ) represent the target output parameters that are influenced and controlled by the input parameters of each process. However, this topic requires further studies on widening the range of material thickness and input parameter values. [ABSTRACT FROM AUTHOR]

Stainless steel (SS 304) is commonly employed in industrial applications due to its considerable corrosion resistance, thermal resistance, and ductility. Most of its intended applications require the formation of complex profiles, which justify the use of wire electrical discharge machining (WEDM). However, its high thermal resistance imposes a limitation on acquiring adequate surface topography because of the high surface tension of the melt pool, which leads to the formation of spherical modules; ultimately, this compromises the surface quality. Furthermore, the stochastic nature of the process makes it difficult to optimize its performance, especially if more than one conflicting response is involved, such as high cutting speed with low surface roughness and kerf width. Therefore, this study aimed to comprehensively investigate the interaction of SS 304 and WEDM, with a prior focus on simultaneously optimizing all the conflicting responses using the Taguchi-based grey relational approach. Analysis of variance (ANOVA) revealed that the current was the most significant parameter for cutting speed and kerf, whereas roughness, voltage (45%), drum speed (25.8%), and nozzle offset distance (~21%) were major contributing factors. SEM micrographs showed that optimal settings not only ensured simultaneous optimization of the conflicting responses but also reduced the number and size of spherical modules. [ABSTRACT FROM AUTHOR]