3D Roughness Parameters Research Articles

Correlation between surface roughness parameters and contact stress of gear

To reveal the relationship between rough tooth surface microstructure characteristics and contact performance, contact analysis is carried out based on the measured surface topography of the tooth surface of ultrasonic grinding by utilizing the elastic-plastic contact mechanics and statistical correlation analysis theory. Simple correlation analysis and partial correlation analysis are adopted for the gear three-dimensional surface roughness parameters and the maximum Mises stress and maximum shear stress. Then, the method of stepwise regression analysis and path analysis is used to construct the best fitting linear model of 3D roughness parameters and the maximum Mises stress and maximum shear stress, and the parameters’ decision coefficient is obtained. The research shows: (1) the rank of comprehensive influence factors of the maximum Mises stress is as follows: arithmetical mean height ( Sa), peak material portion ( Smr1), maximum peak height ( Sp), reduced peak height ( Spk), and minimum curvature radius and height ratio ( K), where Smr1, Spk, and K are negatively correlated with the maximum Mises stress; (2) the comprehensive influence variables of the maximum shear stress are in the order of Sa, Spk, and Vmp, among which Spk and Vmp are inversely related to the maximum shear stress.

Stability analysis of anchored slopes based on a peak shear-strength criterion of rock joints

A new three-dimensional shear-strength criterion (3DSSC) considering the three-dimensional (3D) roughness of rock joints and the internal friction angle of rock masses is discussed. Two methods for transforming the parameters of the 3DSSC into the linear Mohr–Coulomb failure criterion parameters are proposed. The calculation method of the anti-sliding safety coefficient of a rock slope controlled by a single anchored rock joint is derived, and anchoring parameter analysis is carried out. Compared with the equivalent linear fitting method and tangent equivalent method for obtaining the Mohr–Coulomb shear-strength parameters, the 3DSSC can be directly applied to calculate the rock slope stability controlled by a single rock joint. The change in the characteristics of the anti-sliding safety coefficient of the slope with the changes in the 3D roughness parameters, shear rate, and internal friction angle are discussed. The sensitivity of these factors to the slope stability is analyzed. It is suggested that for rock slopes with high roughness and a small internal friction angle, the weakening effect of the anchoring force angle on the anti-sliding stability of the slope should be taken into account.

Evaluation of Surface Roughness and Defect Formation after The Machining of Sintered Aluminum Alloy AlSi10Mg.

This article presents selected issues related to the workpiece surface quality after machining by the laser sintering of AlSi10MG alloy powder. The surfaces of the workpiece were prepared and machined by longitudinal turning with tools made of sintered carbides. The occurrence of breaches on the machined material surface was found, which negatively influence the values of 3D surface roughness parameters. The occurring phenomena were analyzed and proposals for their explanation were made. Guidelines for the machining of workpieces achieved by the laser sintering of powders were developed. The lowest value of the 3D roughness parameters was obtained for f = 0.06 mm/rev, ap = 0.5–1.0 mm, and for the nose radius of cutting insert rε = 0.8 mm. The results of research on the effect of cutting parameters on the values of parameters describing the surface quality are presented. Topography measurements and 3D surface roughness parameters are presented, as well as the results of a microscopic 3D surface analysis. Taguchi’s method was used in the research methodology.

How to Select 2D and 3D Roughness Parameters at Their Relevant Scales by the Analysis of Covariance.

In this paper, a multi-scale methodology is proposed to model and characterize the effect of two lubricants on changes in surface morphology during a running-in test. The test concerns two steels samples, mounted on a twin-disc tribometer to test each of lubricants A and B for a period of 42 h. The changes are characterized by the standardized roughness parameters given in ISO 25178. A technique involving replication is used to monitor wear during the test. Using all these replication measurements, a multi-scale methodology is applied. These selected models highlighted the relevant parameters for quantifying wear during lifespan, and also showed that lubricant A was better able to preserve surface integrity during wear than lubricant B.

Porous Coatings Containing Copper and Phosphorus Obtained by Plasma Electrolytic Oxidation of Titanium

To fabricate porous copper coatings on titanium, we used the process of plasma electrolytic oxidation (PEO) with voltage control. For all experiments, the three-phase step-up transformer with six-diode Graetz bridge was used. The voltage and the amount of salt used in the electrolyte were determined so as to obtain porous coatings. Within the framework of this study, the PEO process was carried out at a voltage of 450 VRMS in four electrolytes containing the salt as copper(II) nitrate(V) trihydrate. Moreover, we showed that the content of salt in the electrolyte needed to obtain a porous PEO coating was in the range 300–600 g/dm3. After exceeding this amount of salts in the electrolyte, some inclusions on the sample surface were observed. It is worth noting that this limitation of the amount of salts in the electrolyte was not connected with the maximum solubility of copper(II) nitrate(V) trihydrate in the concentrated (85%) orthophosphoric acid. To characterize the obtained coatings, numerous techniques were used. In this work, we used scanning electron microscopy (SEM) coupled with electron-dispersive X-ray spectroscopy (EDS), conducted surface analysis using confocal laser scanning microscopy (CLSM), and studied the surface layer chemical composition of the obtained coatings by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), glow discharge of optical emission spectroscopy (GDOES), and biological tests. It was found that the higher the concentration of Cu(NO3)2∙3H2O in the electrolyte, the higher the roughness of the coatings, which may be described by 3D roughness parameters, such as Sa (1.17–1.90 μm) and Sp (7.62–13.91 μm). The thicknesses of PEO coatings obtained in the electrolyte with 300–600 g/dm3 Cu(NO3) 2∙3H2O were in the range 7.8 to 10 μm. The Cu/P ratio of the whole volume of coating measured by EDS was in the range 0.05–0.12, while the range for the top layer (measured using XPS) was 0.17–0.24. The atomic concentration of copper (0.54–0.72 at%) resulted in antibacterial and fungicidal properties in the fabricated coatings, which can be dedicated to biocompatible applications.

The influence of grinding conditions on surface roughness parameters of 20MnCr5 steel vacuum-carburised by single-piece flow method

The purpose of the experimental tests described in the article was to determine the effect of selected abrasive machining conditions on the value of surface roughness of 20MnCr5 steel samples. The samples were subjected to vacuum carburising (LPC) using the ‘single-piece flow’ method and high-pressure gas quenching (HPGQ) in a 4D Quenching chamber to obtain an effective case depth (ECD) of 0.4 mm. Next, the samples were ground with a Norton Vortex corundum grinding wheel. Cooling and lubricating fluid was delivered to the grinding zone using the flooding method (WET) and with the minimum quantity lubrication method (MQL). The samples were ground in one pass of the grinding wheel using two grinding depths – ae = 0.01 mm and ae = 0.02 mm. For each grinding test, surface roughness measurements were made using a stationary laboratory profilometer T8000 from Hommel Werke. These measurements enabled the determination of the 2D and 3D roughness parameters. Analysis of the measurement results showed that for the adopted test conditions, the use of the MQL method resulted in a decrease in surface roughness compared to the surface ground using the WET method. This property applies to both tested grinding depths.

Surface Quality Assessment after Milling AZ91D Magnesium Alloy Using PCD Tool.

Surface roughness is among the key indicators describing the quality of machined surfaces. Although it is an aggregate of several factors, the condition of the surface is largely determined by the type of tool and the operational parameters of machining. This study sought to examine the effect that particular machining parameters have on the quality of the surface. The investigated operation was the high-speed dry milling of a magnesium alloy with a polycrystalline diamond (PCD) cutting tool dedicated for light metal applications. Magnesium alloys have low density, and thus are commonly used in the aerospace or automotive industries. The state of the Mg surfaces was assessed using the 2D surface roughness parameters, measured on the lateral and the end face of the specimens, and the end-face 3D area roughness parameters. The description of the surfaces was complemented with the surface topography maps and the Abbott–Firestone curves of the specimens. Most 2D roughness parameters were to a limited extent affected by the changes in the cutting speed and the axial depth of cut, therefore, the results from the measurements were subjected to statistical analysis. From the data comparison, it emerged that PCD-tipped tools are resilient to changes in the cutting parameters and produce a high-quality surface finish.

Characterization and Parametric Optimization of Micro-hole Surfaces in Micro-EDM Drilling on Inconel 718 Superalloy Using Genetic Algorithm

Drilling of cooling holes in turbine blades on difficult to machine materials like Inconel 718 has been one of the significant applications of micro-EDM. Owing to the difficulties in the contact measurement techniques, the actual side wall characteristics of micro-holes were not explored in detail. In this study, optical non-contact 3D profilometry is used to characterize the side wall surface. The 3D roughness parameter, Sa, has been introduced to measure the side wall surface quality of the holes drilled using micro-EDM. Along with side wall roughness, all the significant responses in the micro-hole manufacturing like material removal rate, overcut, and taper angle were also taken as the responses. The voltage, feed rate, and electrode rotation speed were chosen as the factors. The Box–Behnken design for three factors was used as the experimental design to conduct the study. The analysis showed that voltage was the most significant factor influencing all the responses within the design space. Multi-objective optimization of the process parameters was carried out by the method of sum of weighted objectives using genetic algorithm. A machining strategy was proposed combining both response surface methodology and genetic algorithm to formulate an optimum cutting condition which was able to reduce the inner side wall surface roughness to 1.3587 $$\upmu $$ m. The predicted responses were validated experimentally and the maximum relative error obtained was less than 10%.

Is Deterioration of Surface Properties of Resin Composites Affected by Filler Size?

Purpose To investigate the effect of filler size on surface gloss and roughness of resin composites using a glossmeter and 3D noncontact surface topography, respectively, before and after tooth-brushing abrasion. Materials and Methods Seven model resin composites and one commercial were tested in the study. All materials were first polished, and then the surface gloss and 2D and 3D roughness parameters were recorded. Materials are then subjected to abrasion in a tooth-brushing simulator. Roughness parameters were recorded after 10,000 cycles, and after 20,000 cycles, both roughness and gloss were recorded. One-way ANOVA and Bonferroni post hoc test (p < 0.05) were used to analyze data. Conclusion Filler size is strongly correlated to gloss and surface roughness retention.

Image Data-Based Surface Texture Characterization and Prediction Using Machine Learning Approaches for Additive Manufacturing

Abstract The increase in the use of metal additive manufacturing (AM) processes in major industries like aerospace, defense, and electronics indicates the need for maintaining a tight quality control. A quick, low-cost, and reliable online surface texture measurement and verification system are required to improve its industrial adoption. In this paper, a comprehensive investigation of the surface characteristics of Ti-6Al-4V selective laser melted (SLM) parts using image texture parameters is discussed. The image texture parameters extracted from the surface images using first-order and second-order statistical methods, and measured 3D surface roughness parameters are used for characterizing the SLM surfaces. A comparative study of roughness prediction models developed using various machine learning approaches is also presented. Among the models, the Gaussian process regression (GPR) model gives an accurate prediction of roughness values with an R2 value of more than 0.9. The test data results of all models are presented.

Surface integrity factors influencing fatigue crack nucleation of laser powder bed fusion Ti6Al4V alloy

The quality of the surface influences remarkably the fatigue life of additive manufactured components. This work proposes to study the influence of surface integrity on the bending fatigue life of Ti6Al4V manufactured by laser powder bed fusion. Rectangular specimens were manufactured horizontally and the last printed layer had laser track scanning directions (α=30°,60°,90°) in relation to the specimen length. The top surface 3D-roughness average was similar for all the specimens. The specimens were studied under as-built and heat-treated conditions. A correlation between laser track scanning direction, 2D-roughness parameters, and fatigue life for as-built specimens was found. The as-built specimens with 90° and 30° direction showed the shortest and the longest fatigue life, respectively. Heat-treated specimens showed a shorter fatigue life independently of the surface roughness. This could be explained by other surface integrity factors influencing fatigue performance of the material, such as the presence of subsurface porosity and surface oxygen enrichment.

Influence of bearing raceway surface topography on the level of generated vibration as an example of operational heredity

In this paper, an influence of surface topography of ball rolling bearing raceways of the vibration values has been examined. Experiments have been preferment using series of bearing types 6304. Surface topography of bearing raceways has been measured using a stylus profilometer Talysurf PGI 1230. The 2D and 3D roughness and waviness parameters have been analyzed. The vibration measurements of ball rolling bearings have been carried out using a measuring device ―Anderonmeter‖. The concept of technological heredity and operational (exploitation) heredity in the aspect of production and operation of rolling bearings has been presented. Based on experimental study, an operation heredity analysis of ball bearings has been carried out. It has shown that the condition of surface texture of rolling bearing raceways directly affects the values of vibration generated by bearing units.

Properties of the Surface Layer After Trochoidal Milling and Brushing: Experimental Study and Artificial Neural Network Simulation

The aim of this study was to investigate the effect of milling and brushing cutting data settings on the surface geometry and energy parameters of two Mg alloy substrates: AZ91D and AZ31. In milling, the cutting speed and the trochoidal step were modified (vc = 400–1200 m/min and str = 5–30%) to investigate how they affect selected 2D (Rz, Rku, Rsk, RSm, Ra) and 3D (Sa, Sz, Sku, Ssk) roughness parameters. The brushing treatment was carried out at constant parameters: n = 5000 rev/min, vf = 300 mm/min, ap = 0.5 mm. The surface roughness of specimens was assessed with the Ra, Rz, and RSm parameters. The effects of the two treatments on the workpiece surface were analyzed comparatively. It was found that the roughness properties of the machined surface may be improved by the application of a carbide milling cutter and ceramic brush. The use of different machining data was also shown to impact the surface free energy and its polar component of Mg alloy specimens. Complementary to the results from the experimental part of the study, the investigated machining processes were modelled by means of statistical artificial neural networks (the radial basis function and multi-layered perceptron). The artificial neural networks (ANNs) were shown to perform well as a tool for the prediction of Mg alloy surface roughness parameters and the maximum height of the profile (Rz) after milling and brushing.

A New Criterion for Peak Shear Strength of Rock Joints with a 3D Roughness Parameter

With the help of 3D printing and 3D laser scanning techniques, cement mortar joint samples with a certain surface morphology were prepared. Shear tests of 20 sets of matching joint samples and 8 sets of joint samples with different percentages of cavity area were performed under constant normal load and uniform shear displacement. The results show that the distribution characteristics of the equivalent height difference based on the new roughness description were in accordance with the distribution of the wearing area after shearing, and the effect of cavities on the peak shear strength is essentially due to the influence of the cavities on the roughness of the joint surface. The relationships between the peak shear strength and the two roughness parameters were discussed, and a new criterion for predicting the peak shear strength of rock joints was proposed. It was noted that the roughness parameter system adopted in this paper, which can describe the peak shear strength, was reasonable. The roughness anisotropy of the five joint surfaces was discussed, and a corresponding quantification parameter AAHD accounting for the roughness anisotropy was proposed. The roughness of the joint surface has a positive size effect, a negative size effect and no size effect in a certain direction. However, no matter the direction, the roughness parameters will gradually stabilize as the research scale increases. A similar relationship between the roughness anisotropy parameters and research scales was also observed. To check the applicability of the proposed criterion for estimating the peak shear strength of natural rock joints, 12 sets of rock joints with the same surface morphology were produced based on a numerically controlled engraving technique. Under the same loading conditions as those in the shear tests of the cement mortar replication joints, the peak shear strengths of the rock joints were tested, and the results indicated that the new criterion was also applicable to predict the peak shear strength of natural rock joints.

3D optical surface profiler for quantifying leaf surface roughness

Biological efficiency of pesticide droplets is affected by leaf surface fine structures; however, few reliable methods exist to physically measure and quantify surface roughness. A 3D optical surface profiler was evaluated for its effectiveness as a novel and reliable method to measure and quantify leaf surface roughness in terms of areal roughness parameters. Evaluations included its accuracy for measuring 3D roughness parameters relating mean roughness length, Sa, skewness, Ssk, and kurtosis, Sku. Their values were compared with the wettability of seven leaf types ranging from easy-to-wet to very difficult-to-wet. Measurement accuracy was validated by a qualitative visual analysis comparing 3D surface renderings of measured leaf surfaces generated by the profiler and micrographs taken with a scanning electron microscope (SEM). The accuracy was also validated by measuring and comparing the micrometer and sub-micrometer scaled roughness on leaf types with hierarchical (multi-scale) structuring and smooth surfaces. Both the renderings and the SEM showed visual agreement in surface variations from waxes and trichomes. The measured roughness lengths for the multi-scale and smooth surfaces were on the same order of magnitude for micrometer scale roughness, approximately 1×100 μm, but different orders of magnitude for sub-micrometer scale roughness, approximately 1×10−1 μm and 1×10−3 μm, respectively. Comparisons for Ssk and Sku to wettability were inconclusive, however, comparisons between Sa and wettability showed a positive linear fit, suggesting that Sa could be a viable metric for relating leaf surface roughness to wettability. The results from the micrometer and sub-micrometer scale surface roughness quantification could be used to improve pesticide spray deposition quality, leading to reductions in pesticide use and negative environmental impact.

Analysis of the Effect of Trochoidal Milling on the Surface Roughness of Aluminium Alloys after Milling

The paper presents the results of the surface morphology of aluminium alloys after milling. The 3D surface roughness parameters Ra, Rz, RSm were examined. Functional relationships between the cutting forces, the torque and the roughness parameters were established. The investigation was carried out with respect to functional characteristics of the surface of aluminium alloys. Two different aluminium alloys: 2024 and 6082, were investigated. Two different milling strategies were employed: milling with a trochoidal tool path and milling with a conventional tool path. Different radial depths of cut were applied in the tests. The percentage of the radial depth of cut was increased every 5 %, from 5 % to 40 %. The results were compared with the conventional machining.

Roughness analysis of general-shape particles, from 2D closed outlines to 3D closed surfaces

Surface roughness plays an important role in macro and micro-scale granular behaviors; however, there is currently lack of a unified approach to quantify the roughness of closed outlines and surfaces, which can consider the overall morphological characteristics of particles. This paper proposes approaches that are suitable for roughness evaluation of 2D general-shape closed outlines and 3D general-shape closed surfaces. For 2D closed outlines, the roughness is evaluated by comparing the real outline with the benchmark outline reconstructed based on the Fourier analyses. For 3D closed surfaces, the roughness is calculated by comparing the real surface against the benchmark surface reconstructed by the spherical harmonic analyses. The local deviation as well as the overall roughness of 2D closed outlines, and 3D closed surfaces, can be evaluated via the approach. After analyzing the roughness of two types of particles with different morphological characteristics by the proposed approaches, it is found that the 2D arithmetic average roughness and the 2D root mean square roughness are well correlated, and so are their 3D counterparts. Nevertheless, values of the 2D and 3D indices are not well correlated for each type of particles, and the particles with different texture can be more clearly distinguished from each other based on the 3D roughness parameters than on the 2D counterparts.

Surface integrity analysis for high-pressure jet assisted machined Ti-6Al-4V considering cooling pressures and injection positions

High-pressure jet assisted machining has been proposed in order to solve the problems of high cutting heat and difficult heat dissipation. This research investigated the multiple surface integrity indicators during high-pressure jet assisted machining Ti-6Al-4 V considering cooling pressures and injection positions, involving surface topographies (surface defect and 3D roughness parameters), microstructural behaviors (plastic layers and phase compositions), mechanical performances (microhardness and residual stresses). Compared with dry cutting conditions, surface roughness Sa and Sdr decreased under high-pressure jet assisted machining. The plastic layer depth correspondingly decreased with the cooling pressures increasing. The phase transformation occurred under different cooling pressures and injection positions, which part of α-phase transformed to β-phase. With the cooling pressures increasing, the peak intensity of β-phase of Ti-6Al-4 V was gradually enhanced, the work hardening degrees were reduced, and the residual compressive stresses of machined surfaces increased.

Research of the influence of the 2D and 3D surface roughness parameters of bearing raceways on the vibration level

The level of generated vibrations is one of the most important exploitation parameters of rolling bearings. The vibration analysis allows for the evaluation of the technical condition of new and operating bearing assemblies. There are numerous factors affecting the level of generated vibrations. The condition of topography of active surfaces of rolling bearings is one of them. The state of the surface texture may be described with the use of 2D and 3D roughness parameters. Since there are no unanimous guidelines, the paper’s authors decided to analyse whether, when evaluating topography of the active surface of rolling bearings it is beneficial to measure 3D roughness parameters, or whether the evaluation of 2D roughness parameters fully suffices. Fifth pieces of type 6304 ball bearings were examined. The measurement of selected 2D and 3D roughness parameters of the bearings races was performed using a contact method on a Form Talysurf PGI 1230 device made by Taylor Hobson. The measurement of vibrations generated by the bearings was performed with an Anderometer, a device developed by the employees of the Kielce University of Technology. Statistical analysis based on the correlation calculation was used to evaluate the impact of 2D and 3D roughness parameters of active surfaces of rolling bearings on the level of generated vibrations.

EVALUATION OF SURFACE ROUGHNESS PRODUCED BY NANOCUTTING COPPER STRUCTURE USING A LEAST SQUARE MEAN METHOD

This work performed molecular dynamic simulations to study the 2D profile and 3D surface topography in the nanometric cutting process. The least square mean method was used to model the evaluation criteria for the surface roughness at the nanometric scale. The result showed that the cutting speed was the most important factor influencing the spacing between the peaks, the sharpness of the peaks, and the randomness of the profile. The plastic deformation degree of the machined surface at the nanometric scale was significantly influenced by the cutting speed and depth of cut. The 2D and 3D surface roughness parameters exhibited a similar variation tendency, and the parameters Ra and Rq tended to increase gradually with an increase in the cutting speed and a decrease in the depth of cut. Finally, it is concluded that at the nanometric scale, the 3D surface roughness parameters could more accurately reflect the real surface characteristics than the 2D parameters.