Surface Roughness Measurements Research Articles

Comparative analysis of surface roughness level for bearing coating using VMD of vibration signal

Degradation in surface finish of the material is an important concern in engineering applications. However, most of the conventional techniques available to monitor the surface roughness requires dismantling of the machine element. Though in rotary components like bearing, it is practically not feasible. Therefore, in this work, an on-board technique is proposed to compare the level of surface roughness based on vibration signature. To demonstrate, five different industrial standard coatings (Nickel, Copper, Zinc phosphate (ZnP), Silver, and Black oxide) were carried out on raw five ball bearings (NBC6205). Two sets of coated bearing were prepared, where first set was utilised for experimentation and second for the purpose of measuring surface roughness of bearing surface. These coated bearings were tested at five different RPMs ranging from 300 RPM to 1500 RPM and their vibration signals were recorded. The recorded vibration signals must be having characteristics originated from ball rolling on different level of surface roughness and hence distributed in nature. Further, to target distributed characteristics present in the signal, commonly used statistical parameters for vibration signature analysis (RMS, Crest factor, Variance, Skewness, Kurtosis, Shannon entropy and Log energy) were calculated. Then, correlation of the parameters was checked in relation to the different levels of surface roughness but no relation was found. The signals were then decomposed into six intrinsic mode functions (IMFs) using Variational Mode Decomposition (VMD) method. Again, same statistical parameters were calculated for these decomposed levels, it has been noted that Shannon entropy have shown correlation to surface roughness in at least one decomposed level between 900 to 1500 RPM with minimum value of chain index as 176.65. Moreover, in this RPM range, responsive frequency bands found to be shifted towards higher side i.e. from 567 to 4590 Hz.

Exploiting Turmeric’s Coloring Capability to Develop a Functional Pigment for Wood Paints: Sustainable Coloring Process of Polyamide 11 Powders and Their Strengthening Performance

Currently, the wood coatings industry is focusing on creating unique, vibrant finishes using new functional pigments. Simultaneously, there is a growing adoption of eco-friendly bio-based materials, reflecting trends in other sectors and supporting the circular economy. Thus, the aim of this study is to unveil a straightforward, cost-effective, and notably sustainable process for exploiting the coloring potential of turmeric powder and coloring polyamide 11-based fillers, employed as multifunctional pigments for wood coatings. Through the incorporation of this additive into a wood paint, the study demonstrates its dual effect of enhancing the aesthetics of the final composite layer while leveraging the beneficial protective properties inherent to polyamide 11. The impact of these additives on sample aesthetics is assessed through optical observations, as well as measurements of color, gloss, and surface roughness. The strengthening contribution of the functional pigment is evaluated using the Taber abrasion resistance test, static friction coefficient measurements, and Buchholz surface hardness test. Finally, the aesthetic consistency of the bio-based filler and the coloring efficiency of the sustainable process are tested by subjecting the samples to aggressive conditions, including the UV-B chamber exposure test, cold liquids resistance tests, and water uptake test. Ultimately, the study illustrates how this functional bio-based pigment not only provides sufficient protection but also meets current eco-requirements, thereby contributing to the sustainability of the wood coatings industry.

The 1st Step of Surface Roughness Measurement and Filtering

The 1st Step of Surface Roughness Measurement and Filtering

Influence of heating temperature and time on mechanical-degradation, microstructures and corrosion performances of Teflon/granite coated aluminum alloys used for non-stick cookware

This study explores the functional characteristics (erosion, corrosion, mechanical damage, and microstructural features) of non-stick cookware made from aluminum alloys. Typically coated with polytetrafluoroethylene (PTFE-Teflon) or ceramic for non-stick properties, we conducted a systematic investigation using corrosion, abrasion, and mechanical tests on six types of cookware from different manufacturers (Manuf-1-6). The cookware was heated at various temperatures [Room temperature (RT), 100, 175, 250, & 350 °C] and times (45 & 120 min). Tests included Taber wear, Adhesive Pull-off, hot & RT corrosion, and surface roughness measurements. Characterization involved optical microscopy, scanning electron microscope (SEM) with electron backscattered diffraction (EBSD), and x-ray diffraction (XRD). Ceramic-coated cookware from Manuf-4 demonstrated superior mechanical strength, wear, and corrosion resistance due to refined microstructures. Manuf-1's PTFE-coated cookware also performed well. Optimal results were observed when heating below 250 °C for up to 45 min. Prolonged heating and temperatures beyond 250 °C adversely affected internal structures of all cookware. Thus, it is advisable to use Al-based non-stick cookware below 250 °C for a maximum of 45 min.

Development of Microstructure on Titanium Implant Surface Using CO2 Laser Processing

Background: Dental biomaterials made of titanium are commonly used. It depends on the implant surface texture to improve fixation and prevent the unwanted adhesion of bone cells. This study aimed to investigate whether continuous laser beam carbon dioxide (CNC - CO2) lasers produce specific textures on titanium surfaces with micrometer-sized indentations that influence cell behavior. Materials and method: (CNC - CO2) red laser device; with a fundamental wavelength of λ=10600 nm and power pulses of 34 W were applied, and textures on the surface of titanium discs were achieved. Results: Excellent degrees of uniformity and repeatability were achieved for the desired portions of the surface by creating different surface textures. The surface topography and chemical composition of the specimens were investigated by scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, and surface roughness measurements. Also, a laser power of 34 watts raised the surface roughness, Ra (1.71 nm), and Rz (1.99 nm). Conclusion: Titanium surface textures with unique qualities can be formed in response to an increased heat input. When excessive laser power was used, the measured roughness increased because of instantaneous re-melting. The use of a right continuous-wave (CNC - CO2) laser on titanium used in dental implants can form specific surface textures.

Response of PLA material to 3D printing speeds: A comprehensive examination on mechanical properties and production quality

This study investigates the impact of printing speed on the mechanical properties of parts produced through the fused deposition modeling (FDM) method using a three-dimensional (3D) printer. Tensile test specimens, fabricated with Polylactic Acid (PLA) material on an Ender 3 S1 3D printer, were subjected to varying printing speeds from 15 mm/s to 105 mm/s in 15 mm/s increments, maintaining a 100% infill rate. Detailed measurements of sample masses, hardness values, and surface roughness were conducted to assess the potential effects of printing speed on PLA’s mechanical properties. Porosity values were also calculated to evaluate internal structure homogeneity and void ratios. The results indicate that an increase in printing speed leads to a substantial reduction in production time. For instance, at a speed of 15 mm/s, the printing time was 119 minutes, decreasing to 15 minutes at 105 mm/s. As speed increased, there was a tendency for a decrease in sample masses, with a notable 12% reduction from 8.21 grams at 15 mm/s to 7.21 grams at 105 mm/s. While lower speeds (15 and 30 mm/s) exhibited higher Shore D hardness values, an overall decrease in hardness was observed with increasing speed. Surface roughness showed a proportional increase with printing speed; for example, at 0° angle, the roughness value increased from 0.8 at 15 mm/s to 1.9 at 105 mm/s. Moreover, tensile strength values decreased with higher printing speeds. For samples printed at 15 mm/s, the tensile strength was 60 MPa, decreasing to 44 MPa at 105 mm/s, representing a 27% reduction. These numerical findings underscore the significant influence of 3D printing speed on both production efficiency and the mechanical properties of the printed material.

The Effect of Natural Plant and Animal Fibres on PLA Composites Degradation Process

One of the methods to reduce long-term excessive plastic waste is the development and use of composite materials based on biodegradable polymers and natural fibres. Composites with natural fibres can exhibit very good mechanical properties, and the presence of natural fibres can significantly accelerate the degradation of the material. This study aimed to manufacture and analyse the biodegradation process of composites based on biodegradable polylactide (PLA) filled with flax and sheep wool fibres. The effect of flax and wool fibres and their content on the degradation rate compared to that of pure PLA was investigated. The degradation progress and properties of the composites were studied using an optical microscope, SEM, measurement of surface roughness, and contact angle. Additionally, flexural strength tests, a dynamic mechanical analysis (DMA), and a thermogravimetric analysis (TGA) were conducted. The effect of natural fibres on the phase transition and degree of crystallinity was analysed using differential scanning calorimetry (DSC). The results showed that PLA degrades only under UV light, but not in the composter simulating the natural environment. However, the incorporation of both types of fibres accelerated degradation of PLA/fibres composites in soil. Flax fibre composites exhibited better mechanical properties than pure PLA. For composites with wool fibres, although they showed a significant acceleration of the degradation process in the soil, their large content in the composite caused a reduction of mechanical properties. This research showed the positive effect of the addition of natural fibres on the biodegradation of PLA.

A comparative study on photodegradation of twenty-three wood species after UV irradiation

The study investigates the effect of UV irradiation on different native and exotic wood species which is an open subject of research. Thirteen native wood species and ten exotic wood species, totally twenty-three wood species, all important for wood industry in Turkey, were subjected to UVA-340nm irradiation with a constant irradiance of 0.89 W/m2/nm and a temperature of 60 °C for 2, 4, 8, 16, 24, 48, 72, 96, 120, 144, 168, 252 and 336 h to determine the critical degradation time for the wood species. A short exposure time (from 2h to 48h) was especially studied since the previous studies reported that important and rapid changes occurred within the initial exposure periods. The effect of UV irradiation on wood surfaces was investigated by color, surface roughness, and FTIR-ATR measurements. The results proved that UV radiation caused a rapid color change for extractive-rich wood species at the initial period of exposure (16h–48h) which decreases upon prolonged exposure. The overall color change and surface roughness were higher for native wood species in a long exposure period than for exotic ones. Elm, oak, plane, walnut, acacia and linden as native wood species, iroko, tiama, acajou, okoume, garapa, sapelli, dibetou and teak as exotic wood species were found to be more resistant to color changes in prolonged irradiation periods, probably due to content of their components especially extractives and lignin. Similar to greater color change found within the beginning of the irradiation period (16h–48h), the first 8h–24h seemed to cause a greater increase in roughness for exotic species and 16h–24h for native wood species probably due to the changes in surface chemistry. Acacia, elm, cherry, beech, tiama, teak and okoume had the highest RI whilst S. pine, ash, poplar, plane, sapelli, limba and iroko had the lowest RI among the wood species. FTIR–ATR analysis demonstrated that UV light ended up with photodegradation of lignin and photooxidation of hemicelluloses which leads carbonyl-containing chromophores, even after short-time exposures (8h–24h).

Surfalize: A Python Library for Surface Topography and Roughness Analysis Designed for Periodic Surface Structures.

Surface roughness measurement is an integral part of the characterization of microtextured surfaces. Multiple established software packages offer the calculation of roughness parameters according to ISO 25178. However, these packages lack a specific set of features, which we hope to address in this work. Firstly, they often lack or have limited capabilities for automated and batch analysis, making it hard to integrate into other applications. Secondly, they are often proprietary and therefore restrict access to some potential users. Lastly, they lack some capabilities when it comes to the analysis of periodic microtextured surfaces. Namely, common parameters such as the peak-to-valley depth, spatial period and homogeneity cannot be calculated automatically. This work aims to address these challenges by introducing a novel Python library, Surfalize, which intends to fill in the gaps regarding this functionality. The functionality is described and the algorithms are validated against established software packages or manual measurements.

Examining enamel-surface demineralization upon exposure to acidic solutions and the remineralization potential of milk and artificial saliva.

The enamel surface may undergo demineralization due to exposure to acidic substances and the remineralization of the etched enamel is crucial to regain or maintain integrity. This study aimed to investigate the erosive effect of 10 acidic solutions on tooth enamel and the remineralization capacity of milk and artificial saliva by measuring surface roughness (Ra), enamel depth, and microhardness. A total of 80 bovine incisor enamel specimens were immersed in 10 different acidic solutions, including four different acidic drinks, three different citric acid solutions, and three different citric acid buffer solutions, for 1h. After demineralization, the specimens were immersed in milk and artificial saliva for 3h. Surface roughness, enamel abraded depth, and microhardness were measured before demineralization, in-between time intervals and after remineralization. Data were analyzed using Friedman and Kruskal-Wallis tests (p < 0.05). The results indicate a significant difference in surface roughness between the measurements taken at different time intervals, particularly between the baseline and after 1h demineralization. Also, the specimens immersed in CAB1 exhibited greatest increase in Ra among other acidic solutions (Δ: 0.18 ± 0.07). Moreover, only the microhardness increased after remineralization (p < 0.05). Enamel demineralization using various acidic solutions revealed increased Ra and enamel abraded depth, and decreased microhardness. The use of remineralization agents, milk and artificial saliva, demonstrated an increase in microhardness. This study provides insights into the effects of different acidic solutions and potential remineralization agents on tooth enamel.

A new surface roughness measurement method based on QR-SVM

A new surface roughness measurement method based on QR-SVM

Influence of Yarn and Fabric Properties on Mechanical Behavior of Polymer Materials and Its Retention over Time.

The mechanical properties of textile materials play a crucial role in determining their comfort, functionality, performance, safety, and aesthetics. Understanding and optimizing these properties is essential to meet consumer demands. Key aspects of mechanical properties, such as surface roughness, abrasion resistance, and compression, have a significant impact on the touch and durability of the material, as demonstrated by various research studies. This study focuses on analyzing the mechanical properties of materials produced of different polymer yarns and their changes under combined aging factors. The findings emphasize the significance of textile abrasion resistance and surface roughness measurement, particularly for aged materials. Although the use of recycled polyester yarn is sustainable and offers advantages such as higher tensile strength, the results have shown that the use of conventional polyester yarn is more advantageous overall as it has higher abrasion resistance, a smoother surface texture, and better elasticity retention after aging. The insights presented are vital for designing high-performance sportswear, which is crucial in today's competitive environment.

COMPARISON OF CUTTING TOOL GEOMETRIES BASED ON CUTTING FORCES AND ROUGHNESS OF HARD TURNED SURFACES

Surface quality and energy consumption are two widely studied topics of hard machining. Due to the increasing need of companies for new, more efficient materials, tools and procedures, their manufacturers or suppliers have to deliver innovative solutions from time to time. In this study the latest development of a hard turning insert manufacturer is used in comprehensive machining experiments to show how the new tool (a wiper insert) behaves compared to its standard counterpart. Based on surface roughness and machining force measurement and analysis, this efficiency is proved by quantitative results: the wiper geometry ensures significantly better surface quality, while the energy consumption of the used machine tool is considerably lower.

Evaluation of the turning parameters of AISI 5115 steel in dry and MQL cutting environments with the use of a coated carbide cutting insert: An Experimental Study

This study investigates the effects of cutting parameters on turning AISI 5115 steel in both dry and MQL environments using a coated carbide insert. The cutting parameters are determined using a full factorial design. A comprehensive full factorial experimental design was executed in order to investigate the effect of cutting parameters, including cutting speed, feed rate, and depth of cut, on surface roughness, cutting force and cutting temperature. Following the completion of the turning trials, surface roughness measurements were meticulously recorded. Also cutting force and cutting temperature were measured. The results of the study indicated that the most significant influence on surface roughness is exerted by the feed rate. Moreover, the impact of the depth of cut became more significant as the cutting speed decreased. While the surface roughness increased by 23% in the dry environment due to the increased feed rate at low cutting speed, the increase in the MQL environment was 32%. The cutting temperature is influenced by a number of factors, including the cutting parameters and the material properties. The maximum temperature for turning in the MQL environment was 381°C compared with an average cutting temperature of 430°C in dry machining conditions. The application of high-speed cutting in a dry cutting environment was found to result in a 10% increase in cutting temperature. The influence of cutting speed on the outcome was less pronounced in the MQL environment. At high cutting speeds and low parameter values in the MQL environment, the cutting force decreased by 75% in contrast to the low cutting speeds and high cutting parameters in the dry environment. The optimal cutting conditions for minimising cutting force were identified in the MQL environment, characterised by high cutting speeds and low feed rates.

Selected Errors in Spatial Measurements of Surface Asperities.

This work presents issues related to selected errors accompanying spatial measurements of surface roughness using contact profilometry. The influence of internal heat sources, such as engines or control electronics, on the thermal expansion of the drive responsible for the measurement probe's movement in the X-axis direction was investigated. In terms of starting measurements on a thermally unstable device, the synchronization error of individual profile paths was 16.1 µm. Based on thermographic studies, the time required for full thermal stabilization of this drive was determined to be 6-12 h from when the device was turned on. It was demonstrated that thermal stabilization of the profilometer significantly reduced positioning errors of the measurement probe on the X-axis. Thermal stabilization time should be determined individually for a specific device variant. This research also determined how changes in the center of gravity caused by the measurement probe's movement affected the overall rigidity of the profilometer structure and the leveling of the tested surface. Laser interferometry was used for this purpose. The determined vulnerability of the profilometer structure was 0.8 µm for a measurement section of 25 mm. Understanding the described relationships will reduce errors associated with conducting measurements and preparing equipment for tests. Additionally, it will enable the correct evaluation of surface geometry.

Fracture mechanisms of selective laser sintered parts manufactured in build direction

Selective laser sintering (SLS) is an additive manufacturing process that, in addition to rapid prototyping, is becoming increasingly popular to produce end-use parts. Predictable mechanical properties of the produced parts through this process is a desired primary goal. It has long been known that the mechanical properties especially the elongation at break of SLS components decrease in the build direction. In various test series with tensile specimen fabricated in build direction by SLS, it was found that, on the one hand, these have a very large scatter of the elongation at break, and, on the other hand, it was noticed that these frequently break outside the test range in the upskin radius. The upskin area describes regions that point in a positive build direction relative to the building plate. The fracture occurs at a point where, due to the specimen cross-section, a lower fracture stress occurs than in the test area of the specimen. This fracture leads to a much lower elongation at break than in the case of specimens that fracture in the test area. This study investigates which mechanism triggers this behavior. It turns out that different roughnesses can be determined in the upskin and downskin radius and different defects can be seen in the fracture surfaces, especially in the edge areas. It cannot be predicted based on surface roughness measurements or surface profiling exactly where, or in which layer the fracture occurs. However, the defects lead to a local stress spike, at which the failure of the specimen begins.

Investigating the Impact of Shot Materials on Surface Roughness in Ti6Al4V Alloy-Based Bone Implants treated by Shot Peening Process

This study explores the impact of different shot materials on the surface roughness of Ti6Al4V alloy-based bone implants treated with shot peening. Shot peening is a prevalent surface treatment method in the biomedical field used to enhance implant osseointegration. The choice of shot material can significantly influence surface morphology and, consequently, biological responses. This research examines the effects of various shot materials, including mild steel, stainless steel, glass beads, and alumina, on the surface roughness of Ti6Al4V alloy-based bone implants subjected to shot peening. Surface roughness measurements reveal distinct outcomes: glass beads result in the lowest roughness at 1.45 µm, while stainless steel leads to a higher roughness of 6.27 µm. These findings highlight the critical role of shot material selection in modulating surface characteristics essential for implant integration and performance. Understanding these variations provides valuable insights for optimizing implant design and enhancing biomedical applications. Key Words: shot peening, shot materials, surface roughness, Ti6Al4V alloy

Elucidating the Role of InGaAs and InAlAs Buffers on Carrier Dynamics of Tensile-Strained Ge Double Heterostructures.

Extensive research efforts of strained germanium (Ge) are currently underway due to its unique properties, namely, (i) possibility of band gap and strain engineering to achieve a direct band gap, thus exhibiting superior radiative properties, and (ii) higher electron and hole mobilities than Si for upcoming technology nodes. Realizing lasing structures is vital to leveraging the benefits of tensile-strained Ge (ε-Ge). Here, we use a combination of different analytical tools to elucidate the effect of the underlying InGaAs/InAlAs and InGaAs overlaying heterostructures on the material quality and strain state of ε-Ge grown by molecular beam epitaxy. Using X-ray analysis, we show the constancy of tensile strain in sub-50 nm ε-Ge in a quantum-well (QW) heterostructure. Further, effective carrier lifetime using photoconductive decay as a function of buffer type exhibited a high (low) defect-limited carrier lifetime of ∼68 ns (∼13 ns) in 0.61% (0.66%) ε-Ge grown on an InGaAs (InAlAs) buffer. These results correspond well with the measured surface roughness of 1.289 nm (6.303 nm), consistent with the surface effect of the ε-Ge/III-V heterointerface. Furthermore, a reasonably high effective lifetime of ∼78 ns is demonstrated in a QW of ∼30 nm 1.6% ε-Ge, a moderate reduction from ∼99 ns in uncapped ε-Ge, alluding to the surface effect of the overlying heterointerface. Thus, the above results highlight the prime quality of ε-Ge that can be achieved via III-V heteroepitaxy and paves a path for integrated Ge photonics.

Direct estimation of fractal dimension for an irregular surface using the roughness parameter approach

The fracture process of any material is a natural response towards external loading. These fracture surfaces exhibit a fractal pattern that can be analyzed quantitatively by measuring its fractal dimension (FD). Subsequently, this FD value can be correlated with different properties of the material. Various versions of the cubic covering method (CCM) can accurately describe the fractal patterns present on irregular surfaces with minimum approximation. However, these methods are not direct methods for determining the FD, as they rely on the covering process of cubes rather than considering the irregular surface area. Considering this, a new approach known as the Roughness Parameter Method (RPM) was studied. This method involves the surface area of an irregular surface to measure surface roughness parameters for the direct estimation of the FD. Comparative analysis between direct and indirect methods to measure FD was carried out using Takagi surfaces and real-world irregular surfaces.

Fractal analysis on the surface topography of Monocrystalline silicon wafers sawn by diamond wire

The direct impact of diamond wire slicing on the cost of subsequent silicon wafer processing underscores the significance of reducing slicing costs for both the integrated circuit and photovoltaic industries. Effectively and reasonably evaluating monocrystalline silicon wafer quality is thus a crucial challenge. In this paper, fractal theory was used to analyze the monocrystalline silicon wafer sawn surfaces combining with surface roughness measurement. The findings reveal the presence of scratches, pits, and prominent saw marks on the sawn surface. Notably, the surface roughness is significantly higher along the feed direction compared to that along the wire direction. Moreover, an increase in the ratio of feed speed to wire speed leads to a rougher surface. The fractal dimension of the sawn surface is inversely proportional to its roughness, indicating that a higher fractal dimension corresponds to a finer surface texture. Moreover, the two dimensional fractal dimension can effectively capture the anisotropic characteristics of monocrystalline silicon wafers. The two dimensional fractal dimension of the wafer surface obtained by removing materials in ductile mode has a strong symmetry. However, the two dimensional fractal dimension of the surface obtained in brittle mode fluctuates obviously and is weakly symmetric. By combining traditional surface roughness analysis with fractal methods, we can gain insights into the material removal mechanisms involved in slicing monocrystalline silicon wafers using diamond wire, which is of great significance for optimizing diamond wire slicing.