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A main topic in mass production of machine parts is how to increase the productivity to produce more parts in a given time while maintaining the prescribed surface quality on the machined surfaces. Novel machining procedures have been introduced to achieve this goal; however, the further development of already established and wide-spread procedures can offer simply accessible solutions. Tangential turning is a rediscovered variant of the traditional turning procedure, where a specially designed cutting tool ensures chip removal with a feed tangential to the workpiece. This process results in low surface roughness even at higher feed rates. In this paper, the achievable surface roughness is analyzed by analytical and experimental steps. In the mathematical analysis, the theoretical surface roughness is determined using the constructive geometric modelling method. The worked-out equations are validated in cutting experiments on 42CrMo4 grade steel workpieces. The theoretical and experimental analyses show that the strictly prescribed surface roughness can be achieved with high feed rates by the application of tangential turning.

The major objective of this research was to evaluate the efficacy of biodiesel infused with CuO nanopowder as a fluid used for cutting in the framework of metal cutting processes. The transesterification process utilizing corn oil as the feedstock synthesized Biodiesel. Subsequently, the resulting biodiesel was blended with CuO nanopowder at a concentration of 100 parts per million (ppm). The aluminium work piece was firmly attached to a computer numerical control (CNC) machine, and a metal cutting process was carried out using biodiesel as the cutting fluid. The research included the evaluation of many attributes, including Arithmetic mean roughness (Ra), Root mean square roughness (Rq) and Ten Point height roughness (Rz), using the Talysurf apparatus. The results suggest that there is a positive relationship between the depth of cut and cutting time, as well as a negative relationship between the depth of cut and roughness values. Based on the results obtained, it can be deduced that the biodiesel produced has promising characteristics for use as efficient cutting fluids in the metal cutting procedure.

Exterior car-body parts are made of steel or aluminum sheets. Their formability and appearance after painting depends not only on the mechanical properties but also on their surface texture. The surface roughness characteristics, the roughness average Ra and the peak count Pc per centimeter depend on the texture of rolling mill’s finishing rollers, their wear and the degree of removal by the rolling mill. The research was carried out on heat-treated finishing rollers on the surface of which a controlled texture was created by changing the electro-discharge texturing (EDT) parameters. Parameters and the number of electro-discharge texturing experiments were optimized using full four-factor experiment techniques at the upper and lower levels of the parameters in the form of 24. The significance of the impact of individual EDT parameters and their interactions was identified based on the variance results. The ANOVA variance analysis results confirmed that the roughness Ra and the peak count Pc depend primarily on peak current (Ip), discharge peak voltage (Up), pulse on time (Pont) and pulse off time (Pofft). Optimization of the effect of the above parameters on the target roughness RaT,FR values and the peak count PcT,FR of finishing rollers was performed by the response surface methodology (RSM). Obtained regression models describe relationships between the input parameters of the electro-discharge texturing of finishing rollers and the output characteristics of the RaT,FR and the PcT,FR texture to a very high degree. The reliability of the electro-discharge texturing process of working rollers was assessed using the process capability index Cpk.

CO 2 laser cutting is an advanced processing technology, which can, according to the computer-aided design graphics, cut a variety of shapes in the surfaces of many polymer sheets. This work aims to analyze the effect of laser power, scanning speed, and processing times on the surface roughness of polymethyl-methacrylate microchannels with CO 2 laser LCJG-1290 cutting process. There are several experiments designed by us, and the results were analyzed by orthogonal experimental method. Finally, optimal power, scanning speed, and processing times were obtained, and in the optimal case, the arithmetical mean roughness (Ra) can reach as small as 110 nm.

This study investigated the AISI 1040 steel turning in dry environment with four cutting inserts of different corner radii coated by CVD method. Experimental investigations were performed for different levels of cutting speeds, feeds and depths of cut using a randomized full factorial design. Quality characteristics of the workpiece machined surface were measured (arithmetical mean roughness) as well as the cutting inserts tool life characteristics (average width of flank wear). Machining times and chip volume were calculated, and based on this, chip quantity in time (material removal rate). The response surface approach and analysis of variance were used to determine the effects of input process parameters on the response variables. Based on the derived regression models, multi-objective optimization of output process parameters was performed using genetic algorithm. The objective function was simultaneous minimization of flank wear, minimization of surface roughness and maximization of material removal rate. The parameters of the genetic algorithm (crossover ratio, crossover fraction, mutation rate, Pareto front population fraction) were varied to obtain the optimal values of the objective function. Additionally, a sensitivity analysis was performed, which showed that the selected values of genetic algorithm parameters gave the best (minimum) value of objective function. Instead of the usual approach of obtaining only one combination of optimal parameters as a final solution, the basic idea was to obtain multiple combinations of optimal input process parameters depending on the importance of each output process parameter, i.e. requirements of production. Accordingly, the results of multi-objective optimization showed that there are a large number of Pareto optimal solutions. To validate the optimal input and output process values, confirmation experiments were conducted for selected trials of Pareto optimal results obtained from multi-objective optimization. A mean error percentage of 1.478% and 1.146% for flank wear and arithmetical mean roughness, respectively, proves that the predicted optimum values are confirmed by experimental results.

Japan has many concrete irrigation channels with total length of about 400,000 km. Most of these channels are now too old for continued use. It would be too costly to reconstruct these channels. The concrete surfaces of the channels have been abraded by the flow of water and sand. The roughness of the concrete surface causes a decline in the water flow function. Over the years, considerable attention has been paid to the measurement of the arithmetic mean roughness. However, a method that can measure roughness underwater has not yet been developed. The purpose is to develop a sensor able to measure roughness underwater. We propose a method using underwater ultrasonic waves. We used 200 kHz frequency sensor. We measured the reflected waves and analyzed the peak to peak. We examined four experiments. The propagation loss became larger as the distance was reduced. The theoretical value and the measured value showed good agreement. The dispersion of measured values stabilized within 0.5% using a 10-point moving average. The measurement range was considered and found to be 300 mm. Its application to measure roughness was considered by testing the relationship between the measured value and the arithmetic mean roughness as measured by another method. The measured value decreased as the arithmetic mean roughness increased. The determination coefficient R2 at a distance of 500 mm was 0.91. The R2 at a distance of 1000 mm was 0.79. The results of these experiments show that the underwater ultrasonic wave sensor is an effective tool for underwater.

This paper focused on the maintenance or repair of holes made using hybrid Mg–Al–Mg components by drilling, using two sustainable cooling techniques (dry machining and cold compressed air) and taking surface roughness on the inside of the holes as the response variable. The novelty of the work is in proving that the repair operations of the multi-material components (magnesium–aluminum–magnesium) and the parts made of aluminum and magnesium (separately) but assembled to form a higher component can be done simultaneously, thus reducing the time and cost of the assembly and disassembly of this type of component. The study is based on a design of experiments (DOE) defined as a product of a full factorial 23 and a block of two factors (3 × 2). Based on our findings, we propose that the analyzed operations are feasible under sustainable conditions and, in particular, under dry machining. Also, the results depend on the machining order.

In this work, the dry turning of Inconel 601 alloy in a dry environment with PVD-coated cutting inserts was studied. Turning was performed at various cutting speeds, feeds, insert shapes, corner radii, rake angles, and approach angles. After machining, arithmetic mean surface roughness (Ra) and flank wear (VB) were measured, and the material removal rate was also calculated (MRR). An analysis of variance (ANOVA) was performed to determine the effects of the turning input parameters. For the measured values, the turning process was modeled using an artificial neural network (ANN). Based on the obtained model, the process parameters were optimized using a genetic algorithm (GA). The objective function was to simultaneously minimize Ra and VB and maximize MRR. The accuracy of the model and the optimal values were further validated by confirmation experiments. The maximum percentage errors, which are less than 2%, indicate the possibility of practical implementation of the hybrid approach for modeling and optimization of dry turning of Inconel 601 alloy.

Multimaterial hybrid compounds formed from lightweight structural materials have been acquiring great importance in recent years in the aeronautical and automotive sectors, where they are replacing traditional materials to reduce the mass of vehicles; this will enable either an increase in the action ratio or a reduction in the fuel consumption of vehicles and, in short, will lead to savings in transport costs and a reduction in polluting emissions. Besides, the implementation of production and consumption models based on the circular economy is becoming more and more important, where the repair and, for this purpose, the use of recyclable materials, is crucial. In this context, the analysis of a repair process is carried out by re-drilling Mg-Al-Mg multimaterial components using experimental design (DoE) based on Taguchi methodology, an analysis of variance (ANOVA) and descriptive statistics. The study concludes which are the significant factors and interactions of the process, comparing the results with previous similar studies, and establishing bases to determine the optimum thicknesses of hybrid magnesium-based component plates of drilled parts in the aeronautical industry, guaranteeing surface roughness requirements in repair and maintenance operations throughout their lifetime.

The behavior of gas flow in fractures is crucial for evaluating shale gas production. This study focused on the coupling relationships between effective stress, surface roughness, and gas flow behavior in shale fractures. Three fractured shale specimens were generated using Brazilian splitting tests. The fracture surfaces were then scanned using a 3D profilometer to quantify surface roughness in two and three dimensions. Gas flow tests were conducted on the fractured shale specimens under varying effective stresses (1–15 MPa). The results showed that the Spc (arithmetic mean curvature of crest points) had little effect on nonlinear flow at low effective stress (1–5 MPa) but it became more pronounced at high effective stress (10–15 MPa) due to fracture channel narrowing. Then, the inertial force effect regulated by effective stress and roughness was enhanced as the Reynolds number increased. A friction coefficient model based on the nonlinear effect factor and Reynolds number is proposed and it fits the experimental data well. Furthermore, that effective stress plays a dominant role in permeability loss compared to fracture surface roughness and fluid properties, and exponential function better describes fractured shale permeability under effective stress than power function. Finally, during fracture closure under effective stress, Ra (arithmetic mean roughness) correlated positively with the self-supporting effect of fracture surfaces. As Spc increased, fracture surface peaks became sharper and more easily damaged due to excessive extrusion between contact surfaces.