Surface Texture Parameters Research Articles

Experimental investigation of the influence of surface topographic parameters on fluid leakage through static metallic seals

Purpose The purpose of this paper is to monitor leakage in the static sealing interface, using three-dimensional and two-dimensional surface topography parameters as indicators. Design/methodology/approach This study involved developing a test rig for examining fluid leakage in metallic seals. Leakage of water through the interface of the metallic valve and valve seats was measured. The analysis focused on the combined effect of roughness, waviness and form error of metallic seal surfaces on leakage, with a detailed emphasis on the significance of form errors through harmonic analysis. Findings The findings suggest that three-dimensional or areal surface texture parameters have more predictive control over leakage compared to two-dimensional or profile parameters, as they provide information about micro-leak channels in all directions. Moreover, it was observed that average amplitude parameters of surface topography, particularly the form error of metallic valves, are strongly correlated with leakage values compared with the roughness and waviness of the contact surface. In addition, the leakage in metallic seals is profoundly influenced by lower-order harmonics, with a corresponding increase as the average undulation number of the flatness profile rises. Originality/value This research contributes to the understanding of the relationship between surface topography and sealing performance, particularly in metallic seals. By emphasizing the importance of form errors and using advanced surface texture analysis techniques, the study offers insights that can aid in optimizing the design and performance of static seals in industrial applications. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0186/

Spindle vibration induced optical performance deterioration and its trans-scale characterization for diamond turned large-aperture optics

In ultra-precision diamond turning of large-aperture optics, the spindle vibration (SV) would cause a deterioration of optical performance. To discuss this issue, the spindle vibration was first excited by a series of designed mass center errors for diamond turning of large-aperture optics. Then, a trans-scale characterization was developed to reveal its dynamic behaviors by combining a white light interferometer and laser interferometer. Next, the amplitude variations were quantitatively evaluated by surface texture parameters and the scale bandwidth was revealed through power spectrum density (PSD). Finally, the point spread function (PSF), encircled energy ratio (EER), and modulation transfer function (MTF) were analyzed and compared. The results indicated that, with the increased SV, Sq and Sz increased and Ssk and Sku showed a transition from skew to normal height distribution. PSD showed that spindle vibration mainly affected the large-scale components rather than the small-scale components. The shape of PSF changed from a standard ring to a dispersed half ring. At the 1 µm radius of the Airy disk, the EER decreased from 82.0% (no SV) to 27.5% (high SV). At the scale of 200mm−1, the MTF decreased from 0.84 (no SV) to 0.44 (high SV). The work provides a fundamental understanding of the evolutionary mechanism of spindle vibration induced optical performance deterioration.

Characterization and correlation analysis of surface topography in ball-end milling

Abstract Surface texture is the most commonly used parameter for the quantitative characterization of surface topography. It is important for the study of the topography characteristics and functional properties of surfaces. In this paper, the surface topography characteristics, surface texture parameters, and change rule of the bearing area curve when the cutting vibration of the adjacent teeth of the ball-end milling cutter is asymmetric were analyzed, and the correlation between the inflection points and the surface texture parameters of the bearing area curve were studied according to the improved correlation analysis model. This study provides essential insights into the mechanism that drives the formation of the surface topography of ball-end milling and the intrinsic characteristic laws of the surface topography.

Influence of the Traverse Speed of the Stylus Tip on Changes in the Areal Texture Parameters of Machined Surfaces

Measurements of areal (3D) surface texture using optical methods are very popular because of the short measurement time compared to the stylus tip technique. However, they are very sensitive to measurement errors. In some cases, optical measurements are not recommended. The stylus measurement method is well known and can be the reference technique for surface texture measurement. The main disadvantage is the long measuring time. This time can be shortened using higher speeds of measurement. The effect of the speed of the measurement of stylus profilometer on changes in surface texture parameters was studied. Fifty surface topographies were measured using the stylus profilometer at speeds 0.5, 1, 2, 3, 4, and 5 mm/s in the same places. Surfaces after lapping, polishing, grinding, milling, laser texturing, and two-process random surfaces were measured and analyzed. Changes in parameters caused by the increase in the traverse speed depend on the characteristics and parameters of the surfaces. The random surfaces changed more than the deterministic ones. The increase in the traverse speed from 0.5 to 1 mm/s caused small changes in the parameters.

A Study of Tribological Performance Prediction Based on Surface Texture Parameters

Surface texture parameters are a quantitative way of characterising surface topographical features and are closely related to tribological properties. In this paper, the correlation between surface topographic features and friction coefficient is investigated on the basis of the proposed improved correlation analysis model for high-speed milling surface topography of hardened steel. It was found that the friction coefficient could not be accurately reflected by a single parameter, so a prediction model for the friction coefficient based on Sxp, Sq, Sp, Sz, Sku and Sdq was developed. In this paper, the parameter screening was completed based on the changing characteristics of the data, and a multi-parameter prediction model of the friction coefficient in the stable wear stage was established, which provides a new idea to investigate the influence of the characteristics of surface topography on tribological performance.

Fine evaluation of surface integrity of hardened 1.4418 stainless steel after finish dry turning

1.4418 hardened stainless steel (SS) is widely used in mechanical engineering because of its high functional properties. They can also be enhanced by procuring improvements in the state of the surface layer (SL) and, above all, in the factors of its strengthening, among others the average size of coherent scattering regions (ASCSR), dislocation density (DD), residual stresses (RS) of first and second orders, and relative micro-deformations of the crystal lattice (RMCL). This study investigates the effect of cutting speed (vc) ranging from 100 to 250 m/min and feed rate (f) ranging from 0.005 to 0.25 mm/rev on the indicators of SL condition after finish turning the steel tested. A reduction in ASCSR values below 8 nm was obtained for vc = 100–135 m/min, while an increase of ~ 20% was obtained for 180–250 m/min and with the f ranging from 0.2 to 0.25 mm/rev. An increase in RMCL of ~ 90% was registered for vc = 170–230 m/min and f = 0.2–0.25 mm/rev. A decrease in DD below 109 cm−2 was obtained for vc = 180–250 m/min and its ~ 25% increase for vc = 100–135 m/min. A high correlation between ASCSR and DD was shown. In the deformed material, the dislocation’s resistance to motion increases in proportion to the increase in its density. A high linear correlation coefficient in the range of 0.8–0.9 is found between ASCSR, DD, and first-order RS on the one hand, and Sa and Sz surface texture parameters, which are used in the industry to assess product quality, on the other. Additionally, the effect of plastic side flow (PSF) was observed and described. When machining with vc = 119 m/min and f = 0.22 mm/rev, the intense plastic deformation of the material causes outflow and shearing of the surface micro-hills. Favorable compressive stresses (below − 100 MPa) were registered in the range of vc = 225–250 m/min at f = 0.005–0.05 m/rev and 0.2–0.25 mm/rev, as well as vc = 115–180 m/min and f = 0.05–0.17 mm/rev. The study proved the existence of a relationship between the cutting parameters and indicators of the thin crystalline structure of SL. This means that by proper controlling of these parameters, it is possible to obtain such a state of the SL workpiece, which will ensure its long-term use.

Study of the Impact of Surface Topography on Wear Resistance

The surface texture parameter is a real reflection of the surface topography, which is closely related to the tribological properties of the surface, and the study of the correlation between the surface texture parameter and wear resistance is of great significance in revealing the tribological influence mechanism of the surface and realising the functional manufacturing of the surface. This paper takes the ball-end milling surface as the research object, establishes the three-dimensional simulation model of the surface topography, and analyses the surface topography and the surface texture parameter change rule. Based on the improved correlation analysis model, the correlation characteristics between the surface texture parameters, and between the surface texture parameters and the relative wear rate of per unit sliding distance KV, were investigated, and the prediction model of KV was established based on the surface texture parameters Sku, Sa, Sxp, Sp, and Ssk, and the correctness of the model was verified by experiments. The study in this paper provides a new idea to further reveal the relationship between surface topographical features and wear resistance and to guide the functional manufacturing of surfaces.

Spatial frequency decomposition with bandpass filters for multiscale analyses and functional correlations

To address the essential problem in surface metrology of establishing functional correlations spatial, frequencies in topographic measurements are progressively decomposed into a large number of narrow bands. Bandpass filters and commercially available software are used. These bands can be analyzed with conventional surface texture parameters, like average roughness, Sa, or other parameters, for detailed, multiscale topographic characterizations. Earlier kinds of multiscale characterization, like relative area, required specialized software performing multiple triangular tiling exercises. Multiscale regression analyses can test strengths of functional correlations over a range of scales. Here, friction coefficients are regressed against standard surface texture parameters over the range of scales available in a measurement. Correlation strengths trend with the scales of the bandpass filters. Using bandpass frequency, i.e., wavelength or scale, decompositions, the R2 at 25 μm, exceeds 0.9 for Sa compared with an R2 of only 0.2 using the broader band of conventional roughness filtering. These improved, scale-specific functional correlations can facilitate scientific understandings and specifications of topographies in product and process design and in designs of quality assurance systems.

Influence of annealing temperature on 3D surface stereometric analysis in C-Ni films

PurposeThe purpose of this paper is to study the correlation between the thicknesses of the C–Ni films that have been prepared by RF-magnetron sputtering on quartz substrates and their three-dimensional (3D) micro morphology. In this work by AFM images, this paper studied stereo metric analysis of these films.Design/methodology/approachThe C–Ni films have been prepared by RF-magnetron sputtering on quartz substrates using a mosaic target consisting of pure graphite and strips of pure nickel approximately 2 cm2 attached to the graphite race track. The field emission scanning electronic microscopy (FESEM) images were used for the morphological characterization.FindingsThe histogram peaks are zero for all samples and the histograms are almost symmetric around zero. Temperature did not have much effect on the degree of isolation, so all four diagrams have similar results. The qualitative observations through statistical parameters of the 3D surface texture revealed that the smoothest surface has been obtained for C-Ni films annealed at 500 °C (Sa, Sq, Sz and Sv have the lower values), while the most irregular topography has been found for C-Ni films annealed at 300 °C (the fractal dimension D = 2.01 ± 0.131).Originality/valueAs shown in FESEM images, the size of the particles was increased for films deposited from 300 ºC to 800ºC; however, at 1000ºC, it decreased significantly. The histogram peaks are zero for all samples and the histograms were almost symmetric around zero. Also, the largest and lowest root mean heights (Sq) belong to films at 300 °C and 500 °C. Furthermore, the more irregular surface was found at 300 °C, and the more regular surface was found at 500 °C. As the temperature was increased to 800 °C, the values of the IAPSD function increased systematically, and then the values of the IAPSD function was decreased in the fourth sample. The surface skewness of samples annealed at 1000 °C was positive which confirms the lack of dominance of cavities on their surface with the highest amount of C-Ni films at 800 °C.

Multi-parameterised surface texture characterisation for ultra-precision machined surfaces

Abstract In surface metrology, the multi-parameterised characterisation of surface texture measurement is beneficial not only for surface quality evaluation but also for manufacturing process inspection. To bridge this gap for ultra-precision machined surfaces, a white light interferometer was firstly employed for measuring surface texture generated by orthogonal ultra-precision machining experiments. Next, surface texture was filtered by the zero-order Gaussian regression filter to the limited scale bandwidth. Then, twenty-one surface texture parameters were calculated based on seventy-five S-L surfaces according to the ISO 25178-2. Finally, the outlier effect of surface measurement was investigated by the 95%-99% rule and the Spearman correlation coefficient matrix was proposed to determine their statistical correlation. The results revealed that most of the height parameters (Sp, Sv, Sz, Ssk, and Sku), several function and related parameters (Vmp, Vvv, Spk, and Svk), and the spatial parameter (Str) and hybrid parameter (Sdr) presented a strong sensitivity to the outlier effect. The height parameters (Sa, Sq, Sp, Sv, and Sz), the function and related parameters (Vmp, Vmc, Vvv, Vvc, Spk, Svk, and Sk), and the spatial parameters (Sdq and Sdr) showed a strong correlation to each other, while the miscellaneous parameter Std had a weak correlation to the other parameters. This study provides a systematic multi-parameterised surface texture characterisation for ultra-precision machined surfaces to promote the advancement of nanotechnology and nanometrology.

Thermo-mechanically joined hybrids from carbon fiber-reinforced PA12 with die-cast alloy AlSi10Mg: how surface and interlayer design affect shear strength and fracture behavior

ABSTRACT Infrared radiation was used as a tool to heat laser-structured AlSi10Mg for subsequent fusion bonding with thermoplastic carbon fiber-reinforced PA12. When the two adherends are brought into contact, the bond is formed by melting of the surface-near polymer matrix and pressing it into the laser structure of the aluminum alloy. When investigating different fiber volume contents, the amount of fusible material was identified as a key parameter for the achievable bonding strength. Therefore, the best results were achieved with low fiber volume content (25 vol.-%) or under the use of an additional PA12 interlayer. Moreover, the influence of different surface texture parameters was investigated and the aspect ratio between structure depth and width was found to correlate best with the measured shear strengths. Aspect ratios from 0.18 to 1.15 increased the bond strength up to the interlaminar shear strength of the thermoplastic composite. Especially, aspect ratios of 0.61 or greater proved to be very effective, with resulting mean strength values of almost 30 MPa. While even lower ratios allowed higher loads on the joints compared with untreated surfaces, greater aspect ratios show lower bond strengths, as the laser structures were no longer completely filled with fused PA12.

Integration of soft tooling by additive manufacturing in polymer profile extrusion process chain

Integrating additive manufacturing (AM) into polymer extrusion offers process chain flexibility and design freedom. It reduces the need for time-consuming iterations and trial-and-error in the die design process. Consequently, polymer AM of extrusion (i.e., soft tooling) allows for a shorter product development cycle and cost-effectiveness for small-scale production and highly customized products. In this study, carbon fibre (CF)-polyether-ether-ketone (PEEK) dies were manufactured using the fused filament fabrication (FFF) AM process, employing a streamlined die design achieved through freeform transition planes. Calibration slides were produced using masked stereolithography (MSLA), FFF, and conventional manufacturing techniques (i.e., machining) to preserve the final product’s cross-section during the cooling process. The dimensional and surface characteristics of these calibration slides were evaluated to assess the dimensional accuracy and surface topography of various materials and manufacturing processes. The dimensional evaluation reveals that MSLA-printed parts exhibit deviation from the nominal dimension closer to the conventionally manufactured part. The integrated soft tooling in the polymer extrusion line was tested with polypropylene (PP) and acrylonitrile butadiene styrene (ABS) as extruded materials. The surface topography of the CF-PEEK die displays distinctive ripple features resulting from the FFF process, identified by relatively flat peaks and deep valleys. The overall surface texture parameter values of CF-PEEK were higher due to the presence of deep valleys. Considering that the areas around the peaks interacted more with polymer molecules during the extrusion, the surface texture parameters of the extrudates were closer to the value observed in 90 µm region areas around the peaks. Notably, extrudates of AM calibration slides have lower surface texture parameters than extrudates of conventionally manufactured calibration slides, even though surface defects in the form of dimple sink marks were observed in extruded material of PP from extrudates using AM calibration slides.

Sensitivities of surface texture parameters to measurement errors – A review

The surface texture is functionally important. It can be characterised using a set of parameters. The errors in determining the parameters should be small. In this paper, areal surface texture parameters are presented. The errors in the determination of areal parameters are studied, with focusing on the field parameters. Inaccuracies typical for stylus and optical methods are considered. Errors caused by the digitisation process, errors created during data processing, and parameter variations on typical surfaces are studied. The relations between measurement errors and surface texture parameters are analysed and discussed. On the basis of this review, parameters of considerable changes due to measurement errors and stable parameters are selected. Spatial parameters are robust, while the skewness and kurtosis are susceptible to measurement errors. Feature parameters with high sensitivity to measurement errors should not be used during routine measurements.

A Generalised Method for Friction Optimisation of Surface Textured Seals by Machine Learning

Friction behaviour is an important characteristic of dynamic seals. Surface texturing is an effective method to control the friction level without the need to change materials or lubricants. However, it is difficult to put the manual prediction of optimal friction reducing textures as a function of operating conditions into practice. Therefore, in this paper, we use machine learning techniques for the prediction of optimal texture parameters for friction optimisation. The application of pneumatic piston seals serves as an illustrative example to demonstrate the machine learning method and results. The analyses of this work are based on experimentally determined data of surface texture parameters, defined by the dimple diameter, distance, and depth. Furthermore friction data between the seal and the pneumatic cylinder are measured in different friction regimes from boundary over mixed up to hydrodynamic lubrication. A particular innovation of this work is the definition of a generalised method that guides the entire machine learning process from raw data acquisition to model prediction, without committing to only a few learning algorithms. A large number of 26 regression learning algorithms are used to build machine learning models through supervised learning to evaluate the suitability of different models in the specific application context. In order to select the best model, mathematical metrics and tribological relationships, like Stribeck curves, are applied and compared with each other. The resulting model is utilised in the subsequent friction optimisation step, in which optimal surface texture parameter combinations with the lowest friction coefficients are predicted over a defined interval of relative velocities. Finally, the friction behaviour is evaluated in the context of the model and optimal value combinations of the surface texture parameters are identified for different lubrication conditions.

Effect of Laser Parameters on Colour Marking of Ti6Al4V Titanium Alloy

Colour laser marking is a contemporary method for adding colours onto metal surfaces, suitable for creating logos, barcodes, metal crafts, and jewelry. This study focused on colour laser marking on the biomedical alloy Ti6Al4V (TC4), examining how different colours manifest on its surface. Power settings ranged from 9 W to 18 W, while frequencies spanned 500 kHz to 2000 kHz. The research investigated how altering laser frequency and defocus distance influenced colour variation. Surface features were assessed using 3D optical microscopy, revealing texture and roughness traits. Results illustrated a spectrum of colours, shifting from the alloy’s original silver hue to shades like blue, gold, orange, shiny silver, violet, and several greys. Each colour displayed distinct surface texture and roughness parameters. The highest mean roughness of 2.504 μm occurred with grey, while silver had the lowest at 0.504 μm. Nevertheless, trends differed when measuring parameters like maximum peak-to-valley height and valley depth, emphasizing surface topography’s role in colour effects. This research advances the understanding of colour laser marking’s intricacies on TC4 alloy, providing insights into optimizing laser settings for specific colour outcomes and underlining the nuanced relationship between colour, texture, and surface characteristics.

Influence of surface texture of electric discharge machined Ti6Al4V on the surface wettability

This study examines the effects of crucial ISO 25178 parameters, including height, functional, spatial, functional (stratified), hybrid, and functional (volume), on surface wettability and the influence of key electric discharge texturing process parameters, including current and pulse ON time, on surface roughness (Sa) and water droplet contact angle. To examine the level of significance of each parameter and to determine the level of correlation, a three-level full factorial experimental design, and ANOVA analysis are used. The findings showed that over pulse ON time, the important factor influencing surface roughness (Sa) and contact angle is current. The surface roughness (Sa) is observed to vary between 4.2 and 12.7, whereas the water droplet contact angle varies between 90.7° and 120.4°. In order to find out the correlation between the surface texture parameters based on the ISO 251718, Pearson Correlation analysis were adopted and it is observed that Sa, Sq, Str, Smrk1, Sdr, Vm, and Vmp are having a substantial correlation with the contact angle. Among the ISO25178 parameters examined, Smrk1, however, has demonstrated a highest impact on the contact angle with a highest pearson correlation coefficient of −0.757.

Effect of textured parameters on tribological properties of hydrodynamic journal bearing

PurposeThis study aims to improve the tribological properties of hydrodynamic journal bearing via surface texture, as well as the wear and antifriction mechanisms of textured bearing were represented. It provides a design direction for solving the tribological problem of rotor-bearing system.Design/methodology/approachIn this paper, the variation of surface texture parameters (e.g. texture diameter, d; area density, sp; and depth, hp) were analyzed based on finite difference method. The optimal surface texture parameters were obtained by designing orthogonal experiments, and the relationship between friction and wear properties and microstructure was studied via combining electron probe microanalyzer, scanning electron microscope, X-ray diffractometer and friction and wear testing machine.FindingsDimensionless film pressure P increased as the d increased, whereas P first increased and then decreased as the sp and hp increased, and the maximum P was got as sp = 15% and hp = 25 µm, respectively. The friction coefficient of textured surface with suitable parameters was effectively reduced and the textured surface with the best antifriction effect was 5#. Orthogonal experimental design analysis showed that the influence order of factors on friction coefficient was as follows: sp > sp × d > d > d × hp > hp > sp × hp and the friction coefficient first decreased and then increased as the sp, d and hp increased. In addition, the friction and wear mechanism of textured bearing were three body friction and abrasive wear as the matrix structure and hard phase were a single β phase and Mn5Si3, respectively. While the antifriction mechanism of textured surface was able to store abrasive particles and secondary hydrodynamic lubrication was formed.Originality/valueThe sample with reasonable texture parameter design can effectively reduce friction and wear of hydrodynamic journal bearing without reducing the service life, which can provide a reference for improving the lubrication performance and mechanical efficiency of rotor-bearing system.

Calculation of Wear of Metallic Surfaces Using Material’s Fatigue Model and 3D Texture Parameters

Today, when it comes to manufacturing parts and components for various mechanisms, the tendency is to use both approaches – the latest technologies and new material combinations- to achieve a longer product's lifetime. That is why the issue of machine parts' working capacity criteria, one of the most important of which is wear and its prediction, remains vitally important. Having studied the prediction theories of the wear process that have been developed over time, one can state that each has shortcomings that might strongly impair the results, thus making unnecessary theoretical calculations. Also, predicting wear based on lengthy, time-consuming, costly experiments is still prevalent. The article discusses a new wear calculation model, which is based on the application of theories from several branches of science. This model considers the surface texture (3D) parameters' values in modelling the surface's micro-topography with the random field theory while the friction surfaces' destruction – with the fatigue theory. The new wear calculation model is synthesised based on a developed friction surface contact model, providing a more complete surface description, which is essential for wear calculation and gives more accurate results. The proposed new wear calculation formula includes parameters that can be easily determined using modern measurement methods, thus speeding up the product design process and significantly contributing to sustainable development. Experimental studies on the steel-bronze sliding friction pair validated the analytical wear calculations' results.

An investigation of the effects of ironing parameters on the surface and compression properties of material extrusion components utilizing a hybrid-modeling experimental approach

Thermoplastic filament Material Extrusion (ME) is one of the most expansive 3D printing processes. Owed to the ME process’s simplicity, low cost of materials, popularity, and flexibility, considerable attention has been devoted to manufacturing specific parts in industries manipulating the polylactic acid (PLA) polymer, such as automotive and biomedical. This work aims to experimentally investigate the material flow and temperature for different layer heights on the surface texture parameters and compression strength of a tailored PLA hexagonal prismatic part. An experimental approach based on L9 Taguchi’s array and residual analysis (ANOVA) was employed to clarify the parameters’ effects and trends regarding the response variables. The analysis of means showed that the material flow and layer height are critical variables in defining ME parts’ roughness and compression. Based on ANOVA and mean absolute percentage errors (MAPE) results, additive models (ADMO) were used to predict all combinatorial response values. Then, the experimental and the ADMO values feed as trained data for developing a feed-forward back-propagation neural network (FFBP-NN). Three independent experiments confirmed the validity of the proposed methodology resulting in reasonable accuracy of all the performance metrics, making the proposed hybrid-modeling approach adequate for process multi-parameter multi-objective optimization 3D printing cases.

Influence of Extrudate-Based Textural Properties on Pellet Molding Quality.

As the precursor of pellets, the extrudate has a direct impact on the molding quality of the pellets. Therefore, the correlation between the surface roughness of the extrudates and the molding quality of pellets with pure microcrystalline cellulose (MCC) formulations and those containing traditional Chinese medicine (TCM) formulations was explored. MCC was used as a pelleting agent, mixer torque rheometry (MTR) was used to guide the optimal dosage of the wetting agent, and TCM extracts (drug loadings of 20% to 40%) were selected as model drugs to prepare the extrudates and pellets under the same extrusion spheronization process conditions. The surface roughness and texture parameters of extrudates were analyzed via a microscope and texture analyzer, respectively, and the quality of pellets was evaluated. The extrudate roughness of the pure MCC prescription decreased and then increased with increasing water addition, while the extrudate roughness of the prescription containing TCM extracts tended to increase and then decrease. The addition of water affected the extrudate properties, with TCM extract molecules filling gaps in the MCC structure, leading to rough surfaces. The extrudate roughness of the TCM prescriptions was significantly greater than that of the pure MCC prescriptions at optimal water addition levels, resulting in ideal pellets.