Explore the vast range of titles available.

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.

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.

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.

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.

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.

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.

The problems of standardization of the shaft surface roughness for armored rubber cuffs are considered. It is revealed that a decrease in the shaft surface roughness leads to increased leakage, and with its increase, the wear of the cuff increases sharply. It is shown that the relative length of the profile bearing affects the cuff wear. In order to increase the durability of the sealing unit, it is recommended to standardize the surface roughness not only within a given range, but also to take into account the location of irregularities and the relative profile bearing length, which can be provided by surface-plastic deformation using rollers or balls.

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.

The purpose of this paper is to identify based on the composite central factorial experiment, the mathematical model between the arithmetic mean deviation of the surface profile and the cutting process parameters (cutting speed, cutting depth and feed per tooth), which describes the studied system in any point of the chosen experimental domain. The coefficients of these equations represent the influence of the variables on the response. The analysis of the variance ANOVA is focused on estimating the different types of variability of the response and the estimations made with the Fisher test. This test analyses the coefficients significance of the regression equation, by comparing the ratio of two variants. The Fisher test indicate the probability to be a statistical difference between them or not. In any case, the experimental results are associated with experimental errors. It is essential to find the prediction accuracy of the coefficient's values, and not only their absolute value. In the end, will be determined the arithmetic mean deviation of the surface profile Ra, based on the mathematical model, and will be compared with the experimental results.

Surface temperature and heat flux were measured in a single cylinder SI engine piston when uncoated and with two different surface coatings: a metal TBC and YSZ. Average heat flux into the piston substrate was 33 % higher with the metal TBC and unchanged with the YSZ relative to the uncoated surface. The increase with the metal TBC was attributed to its surface roughness. However, the metal TBC and YSZ reduced peak heat flux into the substrate surface by 69 % and 77 %, respectively.