Surface Topography Parameters Research Articles

Prediction of contact resistance between copper blocks under cyclic load based on deep learning algorithm

This paper establishes a data-driven Neural Network (NN) framework. The contact resistance of T2 copper blocks with different roughnesses is predicted by deep learning at room temperature and cyclic loading. The contact resistance problem can be regarded as a regression problem of mapping the high-dimensional array space of multiple variables to the contact resistance. This paper measures the contact resistance of copper blocks with different surface roughnesses under loading and unloading states and obtains the original dataset required by the algorithm. The data characteristics include three surface topography parameters, number of cyclic loads, loading and unloading conditions, and load magnitude, with the data labeled contact resistance. This paper compares the results of the NN model and Holm model results to verify the NN model’s effectiveness. The comparison results show that the prediction results of the NN are consistent with the predictions of the Holm model. After training and debugging, the root mean square error of the multiple hidden layers neural network test set is 6.81%, showing a good prediction effect. In conclusion, the deep learning algorithm provides a new way for fast and accurate prediction of the relationship between T2 copper blocks and contact resistance under cyclic loading times and unloading states.

Ultrathin film formation under combined effect of surface roughness and surface force for elastohydrodynamic lubrication of point contact problems

PurposeThe purpose of this study is to investigate the combined effect of surface force, solvation and Van der Waals forces and surface topography parameters of amplitude and wavelength on the formation of ultrathin films for elastohydrodynamic lubrication of point contact problems.Design/methodology/approachThe Newton–Raphson technique is used to simultaneously solve the Reynolds’ film thickness including surface roughness and elastic deformation, surface force of solvation and Van der Waals forces and load balance equations. Different values of surface amplitude and wavelength were simulated in addition to the load variation.FindingsThe simulation results revealed that roughness effects are important as the film thickness decreases. The oscillation in the pressure and film thickness is due to the combined action of the solvation force and surface topography parameters. The limiting values of the surface topography parameters of the amplitude and wavelength varied and depended on the load. For different values of wavelength and load, amplitude values up to 0.25 nm have no effect on ultrathin film formation.Originality/valueThe combined effect of the surface force and surface roughness on the formation of ultrathin films was evaluated for elastohydrodynamic lubrication of point contact problems under different operating conditions of load and surface topography parameters of amplitude and wavelength. The limited surface topography parameters of the amplitude and wavelength are shown and analyzed.

The influence of the surface roughness, creep and relaxation on the performance of elastomeric liners for sustainable glass bottle closures

Glass bottles having a metal closure are preferred for oxygen sensitive beverages e.g. beer. Using thinner closure which comprise polyvinyl chloride-free component is more sustainable. However, protecting the sealing performance as a result of metal closure thickness reduction is challenging. Here we show the relation between the leakage in beer bottles and surface roughness of three different thermoplastic elastomer seals. Compression relaxation and creep-recovery behavior of seals have been analyzed by using a dynamic mechanical analyzer. The results showed that metal downsizing was possible with Liner A (low density polyethylene (LDPE)/styrene-ethylene-butylene-styrene) and B (LDPE/ styrene-butadiene-styrene), but not with Liner C (high-density polyethylene/butyl rubber). Optimizing smaller surface topography parameters such as the surface roughness depth Rz, kurtosis Sku, average void volume Vvv, arithmetic mean peak curvature Spc, the density of surface peaks Spd and higher peak material volume Vmp, peak material portion Smr resulted in a better sealing performance. Liner C was found to show an increased leakage risk, since there was a high level of stress relaxation leading to a reduced sealing force. The sealing liner material with low relaxation, low elastic modulus and high creep recovery compliance was found to ensure better sealing when thinner metal closures are used.

Analysis of High-Speed Milling Surface Topography and Prediction of Wear Resistance.

Surface topography parameters are an important factor affecting the wear resistance of parts, and topography parameters are affected by process parameters in order to explore the influence law of process parameters on surface topography parameters and to find the quantitative relationship between milling surface topography parameters and wear resistance. Firstly, this paper took the surface after high-speed milling as the research object, established the residual height model of the milled surface based on static machining parameters, and analyzed the relationship between the residual height of the surface and the machining parameters. Secondly, a high-speed milling experiment was designed to explore the influence law of processing parameters on surface topography and analyzed the influence law of processing parameters on specific topography parameters; Finally, a friction and wear experiment was designed. Based on the BP neural network, the wear resistance of the milled surface in terms of wear amount and friction coefficient was predicted. Through experimental verification, the maximum error of the prediction model was 16.39%, and the minimum was 6.18%.

The Use of a High-Pressure Water-Ice Jet for Removing Worn Paint Coating in Renovation Process.

The paper presents the results of investigations into the possibility of using ahigh-pressure water-ice jet as a new method for removing a worn-out paint coating from the surface of metal parts (including those found in means of transportation) and for preparing the base surface for the application of renovation paint coating. Experimental investigations were carried out in four stages, on flat specimens, sized S × H = 75 × 115 mm, cut from sheet metal made of various materials such as steel X5CrNi18-10, PA2 aluminium alloy and PMMA polymethyl methacrylate (plastic). In the first stage, the surfaces of the samples were subjected to observation of surface morphology under a scanning electron microscope, and surface topography (ST) measurements were made on a profilographometer. Two ST parameters were analysed in detail: the maximum height of surface roughness Sz and the arithmetic mean surface roughness Sa. Next, paint coatings were applied to the specimens as a base. In the third stage, the paint coating applied was removed by means of a high-pressure water-ice jet (HPWIJ) by changing the values of the technological parameters, i.e., water jet pressure pw, dry ice mass flow rate , distance between the sprinkler head outlet and the surface being treated (the so-called working jet length) l2 and spray angle κ for the following constants: the number of TS = 4 holes, water hole diameter φ = 1.2 mm and sprinkler head length Lk = 200 mm. Afterwards, the surface morphology was observed again and the surface topography of the specimen was investigated by measuring selected 3D parameters of the ST structure, Sz and Sa. The results of investigations into the influence of selected HPWIJ treatment parameters on the surface QF removal efficiency obtained are also presented. Univariate regression functions were developed for the mean stripping efficiency based on the following: dry ice mass flow rate , working jet length l2 and spray angle κ. Based on these functions, the values of optimal parameters were determined that allow the maximum efficiency of the process to be obtained. A 95% confidence region for the regression function was also developed. The results demonstrated that HPWIJ treatment does not interfere with the geometric structure of the base material, and they confirmed the possibility of using this treatment as an efficient method of removing a worn paint layer from bases made of various metal and plastic materials, and preparing it for applying a new layer during renovation.

Vol4 num2-17 Influence of surface topography parameters on the structural adhesive of aluminum 7075 polishing by robot and TEPEX®

In the process of continuous improvement of manufacturing processes in the field of the automotive sector comes this study developed within the framework of the Ecovoss project. Its objective is based on substitution of aluminum welding operations with the option of adhesive operations with other types of materials such as polyamides or, in this case, a TEPEX® composite material (dynalite 202-c200 / 50% TYP 13). In this work we try to test the best texturing in the union of 7075 aluminum specimens manufactured by robotized polishing with ABB 6640 robot, with specimens in TEPEX® material cutted in order to have a surface for application of the adhesive product. It uses a structural adhesive film AF-163-2 from 3M, which must be applied with determined pressure and temperature. The tests carried out are based on the topographic measurement of the surfaces to be adhesively bonded with the Alicona interferometer and in the tests for cutting the adhesive bond. The expected results must provide the state conditions of the surfaces to optimize the adhesiveness of the materials studied.

Modelling of 3D topographic parameters of machined surfaces using Artificial Neural Network regression approach

Surface Topography is very important to understand many manufacturing and industrial processes. Traditionally 2D surface characterization has been carried out in research laboratories and industries to understand the surface topography of material. However later, sophisticated instruments were developed to measure 3D surface topography parameters. Compared to 2D surface topography of material, 3D surface topography holds more detailed information. It provides insight into the 3D nature of material surface rather than its 2D cross section. Measurement of 2D parameters require less effort and investment than 3D surface parameters. A need thus exists to explore ways to identify 3D surface topography parameters from the 2D parameters which can be obtained more easily. The main objective of this paper is to estimate 3D surface topography parameters of a machined material from 2D parameters using Machine Learning techniques. The current paper focuses on the collection of data of 2D and 3D surface topography parameters for various machining processes. For the inspection of surface parameters, sophisticated 3D surface profilometer was used. The Artificial Neural Network Regression based Machine Learning model is thus proposed, implemented and rigorously tested for various machined surfaces for different operating parameters.

Superhydrophobic surface processing for selective laser melting of metal parts

Surface modification has been extensively applied to metal alloys to achieve extraordinary surface wettability for a wide range of applications. However, only limited research has been done on the surface wettability modification of 3D-printed metal parts. In this study, AlSi10Mg and Ti6Al4V parts fabricated using selective laser melting (SLM) were functionalized with silane reagent. With the assist of laser texturing or not, the surface showed different wetting behaviors, as the surfaces only treated by chemical solutions showed higher water adhesion (rose petal effect), while the surfaces gone through laser texturing exhibited lower water adhesion (lotus effect). The formation mechanism of the different wetting regimes was investigated. The results showed that the surface topography played an important role in determination of the wetting behavior. By applying surface topography parameters including Sa, Spc, and Sdr, the distinction in terms of surface topography between the surfaces with petal effect and lotus effect was quantitatively described.

Relating the surface topography of as-built Inconel 718 surfaces to laser powder bed fusion process parameters using multivariate regression analysis

The surface topography of 3D printed parts differs from that of wrought or machined parts of the same material. This work specifically focuses on Inconel 718 specimens manufactured with laser powder bed fusion (L-PBF). Predicting the surface topography of the as-built surfaces based on the L-PBF process parameters is important to manufacture parts with a specific surface topography without costly post-processing. We measure the surface topography of Inconel 718 as-built surfaces manufactured with different bulk and contour laser power, scan speed, layer thickness, and build orientation, and perform multivariate regression analysis with traditional R- and S-parameters, statistical and deterministic parameters, and even combinations of surface topography parameters, to determine which parameters most closely relate to the L-PBF process parameters. The deterministic surface topography parameters derived from a 9-point peak-identification scheme resulted in the best-fit regression equations with the highest adjusted-R2 and, thus, showed the closest relationship to the L-PBF process parameters. In contrast to the R-, S-, and statistical parameters, the deterministic approach considers the actual peaks of the surface topography rather than relying on a discrete number of traces of the surface. This conclusion is different from existing knowledge on the surface topography of as-built L-PBF surfaces, which only considers traditional R- and S-parameters.

Grinding performance oriented experimental evaluation on TiC-Steel cermet with vitrified bond cBN wheel

TiC-Steel cermet is widely used in aerospace and mining machinery owing to its excellent performance. However, the high wear resistance and the heterogeneity make its machining a challenging task. To investigate the grinding performance of TiC-Steel cermet, vitrified bond cBN wheel was customized to conduct dry grinding experiments. Grinding force was measured using a Kistler dynamometer; surface topography and 3D surface roughness parameters were measured by laser microscopy and scanning electron microscopy. Results indicate that plastic removal of steel phase, brittle fracture of ceramic phase, ceramic phase wear, ceramic phase debonding and microcracks are main removal modes of TiC-Steel cermet. 3D surface roughness parameters S a , S q , and S z consistently increase with increasing grinding depths from 25 μm to 125 μm and decrease with increasing spindle rotation speed. Effect of feed rate on the 3D surface roughness parameters is less than that of the grinding depth. The trend of the grinding force and surface topography is similar to that of 3D surface roughness parameters. Hence, the optimal processing parameters ( v w = 1–2 m/min, a p = 25 μm, n s = 5130 rpm) were used to obtain the best surface quality and the lowest grinding force (the minimum F N and F T of 9.2 N and 3.5 N, respectively). This study is devoted to broaden the research on the machinability of carbide-based cermets and promote utilization rate of cermets in industry.

Physical features of control of the surface relief of precision products

The quality precision measurements of the product manufacturing or their surface treatment are considered. The importance of high-precision measurements at high speed, which does not require delivering the product to a special control laboratory, is shown. A precision laser measuring system is developed and manufactured, its kinematic diagram is presented and the calibration process is described. The verification of the measuring process results is given on the example of the parts obtained by polishing and grinding the surface. The dependence of the measurement error calculation is given, it is shown that the error of the measuring system is within acceptable limits. The presented measuring system has the capabilities of processing measurement results and constructing 3D images. Thus, the possibility of obtaining the surface topography parameters in accordance with ISO 25178-1, 25178-2 is shown. The methods of the surface treatment and filtering are used to improve the result accuracy of measuring the manufactured part quality, among which the elimination of the average slope, median filtering, and Wiener filter are described. It is shown that the highest accuracy of measurement results in the nanometre range with minimizing distortion losses is possible using the Wiener filter.

Surface Roughness after Milling of the Al/CFRP Stacks with a Diamond Tool.

This study presents the results of research on the surface quality of hybrid sandwich structures after milling with a diamond blade tool. It identifies the effects of feed and machining strategy on the roughness and topography of the surface. It provides an analysis of Ra and Rz surface roughness parameters as well as Sp, Sz, and Sv surface topography parameters. The processed object was a two-layer sandwich structure consisting of aluminium alloy 2024 and CFRP (carbon fibre-reinforced polymer) composite. The minimum values of the Ra and Rz surface roughness parameters were obtained on the aluminium alloy surface, whereas the maximum values were obtained on the CFRP surface. The same was true for the 3D surface roughness parameters—the lowest values of Sp, Sz, and Sv parameters were obtained on the surface of the metal layer, while the highest values were obtained on the surface of the composite layer (the maximum value of the Sp parameter was an exception). A surface topography analysis has revealed a targeted and periodic pattern of micro-irregularities for the vast majority of the samples considered. The statistical analysis shows that the surface roughness of the aluminium alloy was only affected by the feed rate. For the CFRP, the feed rate and the interaction of milling strategy and feed rate (S fz) had a statistically significant effect. The obtained results provide a basis for designing such sandwich element processing technology, for which differences in roughness and topography parameters for the component materials are lowest.

Correlation between Fractal Dimension and Areal Surface Parameters for Fracture Analysis after Bending-Torsion Fatigue

This paper investigates the fracture surface topography of two steel and aluminum alloys subject to bending-torsion fatigue loadings, as well as their susceptibility to fatigue performance and failure mechanisms. Using fracture surface topography data analysis, elements with different geometries were elaborated. A correlation between the fractal dimension, other selected parameters of surface topography such as areal Sx, and fatigue loading conditions was found. Distinctions in particular regions of cracks were also recognized through proving the correctness and universality of the total fracture surface method. The influence of fatigue loading parameters on the surface topography of fatigue fractures was demonstrated. For the analyzed cases, results show that the fractal dimension and standard surface topography parameters represent a correlation between them and loading conditions. As a single parameter, the appropriate loading ratio cannot be outright calculated with fractal dimension, but can be estimated with some approximation, taking into account additional assumptions.

Surface topography prediction in peripheral milling of thin-walled parts considering cutting vibration and material removal effect

The thin-walled parts have the characteristics of low stiffness and time-varying dynamics in the milling process, and the vibration in the milling system plays a major role in surface topography generation. In this paper, a novel surface topography prediction model is developed considering cutting vibration and material removal effect for the peripheral milling of thin-walled parts with curved surfaces. Compared with the traditional surface topography generation model, the relative tool-workpiece vibration, material removal effect and workpiece surface geometry are considered simultaneously. The time-varying dynamic modal parameters of the thin-walled part are estimated through the structural dynamic modification method. Then the influences of cutting vibration and material removal effect are investigated. The milling experimental results indicate that the proposed model can predict the surface topography and roughness parameters accurately under the machining condition of large axial cutting depth, which can also perform well at a slight chatter state. The material removal effect and system vibration jointly contribute a great deal to surface topography generation.

Suppression of the High-Frequency Errors in Surface Topography Measurements Based on Comparison of Various Spline Filtering Methods.

The metrology of so-called “engineering surfaces” is burdened with a substantial risk of both measurement and data analysis errors. One of the most encouraging issues is the definition of frequency-defined measurement errors. This paper proposes a new method for the suppression and reduction of high-frequency measurement errors from the surface topography data. This technique is based on comparisons of alternative types of noise detection procedures with the examination of profile (2D) or surface (3D) details for both measured and modelled surface topography data. In this paper, the results of applying various spline filters used for suppressions of measurement noise were compared with regard to several kinds of surface textures. For the purpose of the article, the influence of proposed approaches on the values of surface topography parameters (from ISO 25178 for areal and ISO 4287 for profile standards) was also performed. The effect of the distribution of some features of surface texture on the results of suppressions of high-frequency measurement noise was also closely studied. Therefore, the surface topography analysis with Power Spectral Density, Autocorrelation Function, and novel approaches based on the spline modifications or studies of the shape of an Autocorrelation Function was presented.

Human osteoblast and fibroblast response to oral implant biomaterials functionalized with non-thermal oxygen plasma

Plasma-treatment of oral implant biomaterials prior to clinical insertion is envisaged as a potential surface modification method for enhanced implant healing. To investigate a putative effect of plasma-functionalized implant biomaterials on oral tissue cells, this investigation examined the response of alveolar bone osteoblasts and gingival fibroblasts to clinically established zirconia- and titanium-based implant surfaces for bone and soft tissue integration. The biomaterials were either functionalized with oxygen-plasma in a plasma-cleaner or left untreated as controls, and were characterized in terms of topography and wettability. For the biological evaluation, the cell adhesion, morphogenesis, metabolic activity and proliferation were examined, since these parameters are closely interconnected during cell-biomaterial interaction. The results revealed that plasma-functionalization increased implant surface wettability. The magnitude of this effect thereby depended on surface topography parameters and initial wettability of the biomaterials. Concerning the cell response, plasma-functionalization of smooth surfaces affected initial fibroblast morphogenesis, whereas osteoblast morphology on rough surfaces was mainly influenced by topography. The plasma- and topography-induced differential cell morphologies were however not strong enough to trigger a change in proliferation behaviour. Hence, the results indicate that oxygen plasma-functionalization represents a possible cytocompatible implant surface modification method which can be applied for tailoring implant surface wettability.

Nanoscale physico-mechanical properties of an aging resistant ZTA composite

ObjectiveTo characterize the effects of aging on the nanomechanical properties and 3D surface topographical parameters of an experimental Zirconia Toughened Alumina (ZTA) composite compared to its respective individual counterpart materials. MethodsDisk-shaped specimens comprised of three material groups were processed: 1) ZTA 70/30 (70% alumina reinforced with 30% second-generation 3Y-TZP); 2) Zpex (Second-generation 3Y-TZP), and; 3) Al2O3 (High purity Alumina) (n = 10/material, 12 × 1 mm). After synthesis, ceramic powders were pressed, the green-body samples were sintered and polished. Nanoindentation testing was performed to record elastic modulus (E) and hardness (H). Interferometry was utilized to assess 3D surface roughness parameters (Sa, Sq), while X-ray diffraction (XRD) and scanning electron microscope (SEM) assessed the crystalline content and microstructure. All tests were performed before and after simulated aging (134°C, 2.2 bar, 20 h). Statistical analyses were performed using linear mixed-model and least square difference pos-hoc tests (α = 5%). ResultsXRD spectra indicated increase of monoclinic peaks for Zpex (~18%) relative to ZTA 70/30 (~2.5%) after aging. Additionally, aging did not affect the surface roughness parameters of ZTA 70/30 and Al2O3, although a significant increase in Sa was recorded for Zpex following aging (~90 nm) (p < 0.001). Al2O3 yielded the highest H and E values (H:21 GPa, E: 254 GPa), followed by ZTA 70/30 (H: 13 GPa, E: 214 GPa) and Zpex (H:11 GPa, E: 167 GPa), all significantly different (p < 0.03). ConclusionZTA 70/30 and Al2O3 presented high hydrothermal stability with respect to all evaluated variables, where artificial aging significantly increased the monoclinic content and surface roughness of Zpex.

The Effect of Surface Topography Feature Size Density and Distribution on the Results of a Data Processing and Parameters Calculation with a Comparison of Regular Methods.

In this paper, the influence of occurrence of surface texture features on the values of surface topography parameters calculated after the application of various data processing techniques was presented. Different types of surface topographies were considered, as follows: cylinder liners, some with additionally burnished dimples, turned, ground, milled, laser-textured, composite, ceramic, or isotropic in general. The effects of feature size on the areal form removal, noise suppressions, or end-effect reducing in surface texture measurements were studied. The variations of the ISO 25178 standard surface topography parameters were taken into consideration in detail. It was assumed that some of the feature sizes, distributions, and densities have a substantial impact on the values of surface topography parameters calculated after applications of regular (commonly used) algorithms and procedures, defined as basic operations, provided for raw surface texture data obtained directly from the measurement process. In the end, some of the practical applications for receiving the relevant values of surface topography parameters were proposed.

Prediction of the Geometric Accuracy Attenuation of the Slide Guide of Machine Tools With Analysis of Worn Surface

Abstract A guide pair is a core part of the feed system in a machine tool. Its geometric accuracy is attenuated due to wear, thus directly affecting its guiding accuracy and the processing accuracy and quality of a machine tool. In this article, based on the statistical principle, the influences of the surface wear of guideway on its straightness attenuation were explored and an analytical prediction model for the geometric accuracy attenuation of slide guide was established. The reciprocating wear test of slide guide samples was performed with a test bench to explore the attenuation of guideway surface straightness under various machining conditions: isometric feeding, random length distribution feeding (normal distribution, negatively skewed distribution and positively skewed distribution), and feeding-retracting (with unequal reciprocating speeds). The comparison between experimental results and predicted results showed that the prediction model could well predict the precision attenuation of the guideway under stable working conditions. The experimental results also proved that machining workpieces with the same size or machining workpieces with a larger size as possible was beneficial to extend the precision maintaining life of slide guide. The prediction model suggested the quantitative relationship between the precision attenuation of slide guide and the main factors including material properties, surface topography parameters, working conditions, operation parameters, and surface friction properties. With this model, the real-time straightness on the guideway surface can be calculated and the geometric precision maintaining life of slide guide can also be predicted.

A novel method for optimizing the topography parameters of mechanical mating surfaces focus on performance and cost requirements

The surface machining precision of parts is closely related to the contact performance between the mating surfaces of the assembly, and it will create a waste of resources to ensure the system performance by excessively improving the machining accuracy of parts. In order to ensure the high performance of the system on the basis of low cost and low manufacturing precision, this study proposes a method to achieve the goal by adjusting the surface topography parameters in the design phase. First, the surface topography information of the measured parts was characterized by different parameters to realize the parametric expression of the surface topography; second, the mechanical properties of the mating surface with different surface topographies were obtained by numerical analysis and experimental methods; third, the functional relationship models between different surface topography parameters and the contact performance of the mating surface were obtained by using the fitting algorithm; finally, taking the contact stiffness of the mating surface as the objective and the surface machining accuracy as the constraint condition, the surface topography parameters are optimized. The results show that the average variance σ of the surface topography of the two different specimens after optimization increases by 0.98% and 2.71%, respectively, compared with that before optimization, which indicates the relative reduction in the difficulty and cost of surface processing. This study can provide an effective way to improve the optimization design of surface topography parameters and the performance of the whole machine.