Dimple Textures Research Articles

Enhancing tribological performance of AISI 52100: the role of laser surface texturing in dry and lubricated conditions

Abstract Laser surface texturing (LST) is a valuable technique in surface engineering that offers significant improvements in the tribological behavior of metals and alloys. This study investigates the synergistic effect of incorporating hexagonal boron nitride (h-BN) as a solid lubricant with laser surface texturing on the tribological performance of AISI 52100. Dimple textures with varying pitch distances (100, 150, and 200 μm) were created on the surfaces of the mentioned materials using LST. The friction coefficient and wear behavior of both non-textured surface (NTS) and textured surfaces (TS) were analyzed under dry sliding (DS) and lubricating sliding (LS) conditions. Wear tests were conducted using a universal tribometer under a load of 10 N, a sliding frequency of 10 Hz, and a sliding time of 1250 s. The results demonstrate that the presence of dimple textures significantly influences the tribological behavior of the materials. In DS, the wear coefficient exhibits a significant reduction compared to NTS, with decreases of 88.1% for TSP-100, 28.5% for TSP-150, and 76.1% for TSP-200. In LS, the TSP-L-100 (h-BN NPS) surface demonstrates the lowest average wear coefficient among all textured surfaces. Specifically, the TSP-L-100 surface shows a remarkable 97.61% reduction in average wear coefficient compared to NTS. This study demonstrates the potential of LST combined with h-BN as a solid lubricant in improving the tribological properties of metals, offering valuable insights for surface engineering applications in various industries.

Effect of lubricant inertia on textured journal bearing implementing mass conserving (JFO) boundary conditions

PurposeCavitation plays a significant role in the performance of textured journal bearings. Furthermore, because of the usage of low-viscosity lubricants and the high working speed of machines, it is pertinent to consider the lubricant inertia while analyzing the operating characteristics of bearings. This paper aims to investigate the influence of lubricant inertia in the case of a spherically textured journal bearing, considering both protrusion and dimple texturing and implementing the mass-conserving (JFO) boundary conditions.Design/methodology/approachA novel modified Reynolds equation has been developed to accommodate the effects of lubricant inertia and cavitation. The cavitation is treated by using mass-conserving (Jakobsson−Floberg−Olsson [JFO]) boundary conditions. The governing equation is solved by the Gauss−Seidel method with successive over-relaxation. To enhance computational efficiency and expedite the convergence process, the progressive mesh densification (PMD) method has been integrated into the solution process.FindingsThe current study indicates that the JFO boundary conditions result in higher load-carrying capacity and lesser friction variables for heavily loaded bearings, whereas the flow coefficient is reduced due to the application of JFO boundary conditions. The lubricant inertia effect enhances the flow coefficients for lightly loaded and protrusion-textured bearings.Originality/valueIt is crucial to understand the combined effects of lubricant inertia and cavitation for the effective design of textured journal bearings. The findings from this work will help in designing textured journal bearings more effectively and accurately, particularly when low-viscosity oil is used.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2024-0276/

Influences of Surface Texture on the Friction Characteristics of Powder Metallurgy Clutch Disks

Many studies have consistently demonstrated the positive effects of surface texture on the performance of friction couples. Circular dimple textures are made on the flat surfaces of the copper-based powder metallurgy friction disk samples from a multi-disk clutch with five different circular densities. Long-term pin-on-disk sliding experiments under different loads are conducted. Surface morphology analysis is also conducted to evaluate the wear characteristics of the sample disks. Results show that the working load does not significantly affect the coefficient of friction (COF) of the flat surface samples, but there exist significant differences of the COF at different radii with the same rotation speed. Compared with the flat surface samples, the textured samples have a 20–65% decrease of COF under light load conditions but have a more than 30% increase under heavy load conditions. Furthermore, the wear of the textured samples is substantially reduced by more than 19% and 40% respectively. Therefore, the circular dimple texture can significantly enhance the friction and wear performances of the copper-based powder metallurgy friction disks, especially under heavy load working conditions.

Experimental analysis of the effect of copper dimple tube with aluminum coating on the performance of parabolic solar water heater using helically twisted tape

In this research, a parabolic trough solar water heater (PTSWH) having helically twisted copper tubes and dimple texturing with an aluminum (AlC) coat was experimentally examined to identify the solar collector’s efficiency, friction factor, convective heat transfer, Nusselt numbers variations, and uncertainty during the test. For this purpose, helical copper dimple tubes with Al coating were used to pass water through it at mass flow rates of 0.5–2.5 kg/min, with 0.5 kg/min increments. Experimental tests were conducted using specific datasets to investigate the efficacy of PTSWH. These experiments aimed to evaluate the efficiency and performance of solar collectors in harnessing solar energy for various applications, such as space heating, water heating, and industrial processes. The results of these experiments are recorded and analyzed to assess the practical viability of solar thermal systems. The results showed that solar collector effectiveness was improved by about 31.2% at flow rates of 1.5 kg/min, while the friction factor was raised by approximately 0.23%. The convective heat transfer coefficient was enhanced by about 7%, and the Nusselt numbers were enhanced to nearly 298. The overall uncertainty of ±2.3% was also observed, indicating that the findings were within the permissible range. Moreover, the PTSWH system recorded an elevated pressure drop of 2.32 kPa. This approach of dimple texturing with Al coating may be best suited for the PTSWHs used in moderate and low solar intensity regions.

Nanosecond laser-induced dimple texturing of TB6 alloy surfaces: Tribological behavior under dry and starved-oil lubrication

This study investigates the improvement of tribological properties of TB6 (Ti-10V-2Fe-3Al) alloys through laser surface texturing. It examines the effects of laser scanning cycles (LSCs) and dimple spacing (DS) on the water contact angle and the coefficient of friction (CoF) under both dry friction and starved-oil lubrication conditions. Dimple-textured surfaces reduce wear and friction by decreasing the actual contact area between the friction pairs, preventing wear particle entrapment, and enhancing oil retention, thereby leading to stable oil films. The optimal LSCs and DSs significantly reduce the CoF by up to 66 % under dry friction conditions and by 61 % under starved-oil lubrication conditions, compared to original surfaces. Surfaces with increased LSCs and decreased DSs become superhydrophobic after octadecyltrichlorosilane modification.

Enhancing performance: insights into the augmentation potential of acrylonitrile butadiene styrene/boron nitride composites

Abstract This work aims to investigate the morphological, mechanical and thermal characteristics of boron nitride (BN)-reinforced acrylonitrile-butadiene styrene (ABS) composites. ABS and ABS/BN composites with a maximum BN loading up to 8 wt% were developed using two-roll mill followed by compression molding. Scanning electron microscopy (SEM) images presented interlinking of BN flakes in the dimple texture of ABS. A modest decrease in tensile properties was observed for the composites. The tensile strength and impact strength for the ABS/BN8 specimen were lowered by 4.7 and 81.7 %, respectively. On the other hand, hardness increased by 3.39 % for ABS/BN8 composite. The interaction effect of BN in the ABS matrix on the thermal properties was assessed using thermo-gravimetric analysis (TGA). An enhancement in the thermal-stability was observed for BN incorporated ABS. There is a modest shift in glass transition (T g) temperature to a higher value for the ABS/BN composites.

On dry machining of AZ31B magnesium alloy using textured cutting tool inserts

Magnesium alloys have many advantages as lightweight materials for engineering applications, especially in the fields of automotive and aerospace. They undergo extensive cutting or machining while making products out of them. Dry cutting, a sustainable machining method, causes more friction and adhesion at the tool-chip interface. One of the promising solutions to this problem is cutting tool surface texturing, which can reduce tool wear and friction in dry cutting and improve machining performance. This paper aims to investigate the impact of dimple textures (made on the flank face of cutting inserts) on tool wear and chip morphology in the dry machining of AZ31B magnesium alloy. The results show that the cutting speed was the most significant factor affecting tool flank wear, followed by feed rate and cutting depth. The tool wear mechanism was examined using scanning electron microscope (SEM) images and energy dispersive X-ray spectroscopy (EDS) analysis reports, which showed that at low cutting speed, the main wear mechanism was abrasion, while at high speed, it was adhesion. The chips are discontinuous at low cutting speeds, while continuous at high cutting speeds. The dimple textured flank face cutting tools facilitate the dry machining of AZ31B magnesium alloy and contribute to ecological benefits.

Image processing–based material removal rate analysis of morphable polishing tools with labyrinth and dimple textures

Image processing–based material removal rate analysis of morphable polishing tools with labyrinth and dimple textures

Sealing performance and optimization design of squamous textured mechanical seal

The work focuses on the optimization of surface texturing and their geometrical characteristics to improve the sealing performance of mechanical seal. The hydrodynamic model is developed to predict the sealing performance of four textures, including dimple, triangle, chevron and squamous textures. Result indicates that the squamous texture exhibits better sealing performance with high ratio of load-carrying capacity to leakage and ratio of oil film stiffness to leakage at various angular speeds and pressures. Furthermore, the functions of squamous texture characteristics with the load-carrying capacity and leakage ratio are revealed by the response surface methodology. And the squamous texture is optimized with high load-carrying capacity and low leakage ratio through the multi-objective optimization algorithm NSGA-II to achieve the Pareto-optimal set.

Research on the Tribological Properties of a New Generation of Multi-Layer Nanostructured PVD Coatings for Increasing the Technological Lifetime of Moulds

This paper presents the results of research focused on increasing the lifespan of HPDC moulds for casting aluminium alloys by applying duplex PVD coatings in combination with laser texturing the base material before the coatings’ deposition. This article describes the HPDC process and the degradation mechanisms of the moulds that arose during this process. The PVD nanostructured coatings utilised, the methods of their deposition, and the evaluation of their wear resistance are defined in this paper. The surface texturing process is described alongside the description of the analysis of the wear of the functional parts of the mould after decommissioning, which was carried out by visual inspection and optical and light microscopy. Three types of PVD duplex coatings were analysed during our study. The coatings were deposited using the LARC technology method (lateral rotating cathode). Subsequently, the procedure of laser texturing in the form of dimple textures using a laser was proposed. The quality of the coatings was evaluated under tribological conditions by means of the “Ball on disc” method. Based on the experimental results, recommendations for practice are established.

Advancements in parabolic trough water heaters with dimpled tube–CuO deionized nanofluid: experimental and numerical investigation

Abstract The goal of this study was to improve the performance of a parabolic trough solar water heater (PTSWH) by using a dimpled texture design on the water tube and copper oxide/deionized water (CuO/DI-H2O) as a cell-side nanofluid (NF). Experimental tests will be conducted to measure and validate the thermal performance improvements using the dimpled tube–CuO NF combination. The nanoparticle (NP) concentration in the NF and the water mass flow rate (MFR) through the dimpled tube were varied for experimental and numerical analysis. The PTSWH achieved the highest efficiency of 38.25% with a CuO volume concentration (VC) of 0.3% and a water MFR of 2.5 kg/min, 12% higher than the unembellished tube with base fluid. Furthermore, the PTSWH’s overall output performance index under the same conditions was 3.56. Furthermore, at an MFR of 3.0 kg/min and a VC of 0.5%, the pressure drop was 7.24% greater. For dimple tube (computational fluid dynamics analysis), at an MFR of 3.0 kg/min, the increase in temperature [$\Delta T=({T}_O-{T}_I$)] at CuO NP VC of 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% was found to be 54°C, 56°C, 58°C, 60°C, and 62°C, respectively. These findings show that using NF and dimpled tubes to improve the performance of PTSWH systems has a high potential for a more sustainable and efficient use of solar energy.

Investigation of machinability characteristics of Inconel 713C using new novel honeycomb and broken-parallel texture cutting inserts with graphene-based solid lubricants

The present investigation aims to investigate the machinability performances of graphene solid lubricant (S) deposited on dimple texture (T1-S), novel honeycomb texture (T2-S), and novel broken-parallel textures (T3-S) during dry turning of Inconel 713C has been carried out and compared with dry (D) textured tools (T1-D, T2-D, and T2-D). L24 orthogonal design was used to design the experiments by considering conditions (dry and solid lubricant), textured type, cutting speed, and feed rate. The experimental results reveal that the honeycomb without and with graphene (T2-D and T2-S) effectively reduced the generated cutting temperature by 14.5 % and 22.4 %, cutting force by 34.6 % and 39.4 %, surface roughness by 14.3 % and 22.4 % and tool flank wear by 11.9 % and 2.3 % compared dimple and broken parallel textured inserts. The honeycomb tool (T2-D and T2-S) exhibited shear angle increased by 7.45 % and 6.5 % and 29.3 %, and 33.33 % than dimple under dry and graphene textured cutting tool. The chip reduction coefficient was <1.5, resulting in an increased shear angle and decreased friction coefficient in graphene-deposited honeycomb texture conditions. The major mechanism credited to the improved performance of honeycomb with graphene tool was reduced chip curl diameter and chip width by 3.3 % and 5.7 % compared to other tools. SEM images showed that all textured inserts' primary tool wear mechanisms on the tool surface were built-up edges, micro-chipping, adhesions, and abrasions. EDS analysis and following elemental plotting showed the strong presence of workpiece constituents on the flank surface. But, the influence of adhesion and abrasion was more noticeable for all dry-textured tools. The findings of this study indicate that honeycomb textured tools are a superior alternative to dry machining of Inconel 713C. Additionally, broken-parallel textured tools were more effective than textured dimple tools.

Growth characteristics and wear properties of micro-arc oxidation coating on Ti-6Al-4V with different laser texture shapes

Poor wear properties severely limit the field of application and service life of titanium alloys. Three kinds of textures (dimple, groove and mesh) were prepared by laser texturing technique and compounded with micro-arc oxidation treatment to improve the tribological properties of titanium alloys in this study. The coatings' morphology, structure, and composition were characterized, and their antiwear properties were analyzed. The results show that the proportion of rutile phase in the coating increases with increasing textured area rate and that the textured edge coating has higher Si and P content, with increased thickness and densities. In terms of friction properties, the dimpled texture shows the best friction properties when textured alone, with a 28.6 % decrease in the average coefficient of friction compared to the substrate; in contrast, the meshed texture shows the best friction properties after the micro-arc oxidation treatment, with a 76.2 % decrease in the average coefficient of friction compared to the substrate. Studies have shown that laser texturing can reduce wear by retaining abrasive debris. However, laser texturing alone does not provide a significant increase in hardness at the edge location, which is more susceptible to damage during wear, leading to more severe wear. The “tip effect” encourages the growth of a micro-arc oxide layer, and the resulting hardness of the layer helps protect the texture structure from damage. The synergistic effect of the texture and the rough, hard structural features of the coating itself enhances the wear resistance of the composite coating.

Effects of different surface textures on tribological performances of the cylinder liner-piston ring: An experimental study

The tribological performance of internal combustion engines (ICEs) has an important impact on fuel efficiency and power consumption, and the wear of cylinder liner-piston ring (CLPR) system affects the operation reliability. The surface texture of CLPR can significantly improve the tribological performance of ICEs. Aiming at the friction and wear of CLPR, the different textures (dimple, equilateral triangle and square) are generated on the CLPR using laser processing, and the different tests are conducted on the UMT-TriboLab tester. The coefficient of friction, wear topography, surface roughness parameters and profiles are measured. The results show that, compared with the non-textured surface, the dimple texture surface of piston ring or cylinder liner has better tribological performance. If the textures coexist on the cylinder liner and piston ring, the tribological performances are better than single surface texture. Furthermore, the mixed textures can significantly improve the surface lubrication performance and the ability to store abrasive particles, and better surface quality can be obtained at the same operating conditions to enhance the tribological performance. This study can provide guidance for reducing the friction and wear of CLPR system of ICEs, and achieve energy saving and emission reduction of ICEs.

Enhanced Foam Package Design for Drop/Impact Using Accurate Predictive Simulation

The interconnections and chips of the internal components of electronic devices need to be protected to prevent damage during shipping, handling, and daily use. This paper studied an investigation into the abilities of foam as an outer packaging material to protect the detector device. This detector device is required to withstand a high-speed impact, 30 mph, and to avoid moisture damage. The finite element model of foam was validated by a compression experiment. The prediction simulation of foam samples was performed by using the validated foam model to obtain the correct stress-strain properties of foam samples. Different shapes, textures, and designs of foam outer packaging were investigated, which include tennis ball shape vs hockey puck shape, inner dimple texture vs outer pimple texture, and monotonic foam layer vs double foam layers. The different foam material combinations of packaging were also compared by using the predicted stress-strain properties of foam in ANSYS/LS-DYNA to study the effect on reducing the out-of-plane deformation of the printed circuit board (PCB).

Numerical investigation and optimization of the geometric profiles of dimple bottom structure in frictional interaction pairs

Dimple texture forming in the interaction pairs is a wear reduction technique like lubrication. Dimple-texturing is an efficient and sustainable way of altering the surface topography to improve the tribological characteristics of interacting surfaces. In this work, sliding interaction pairs with circular dimples, three different dimple bottom structures, namely flat, V-shaped and U-shaped, are selected for numerical investigation using the Reynolds equation to enhance the hydrodynamic characteristics. The numerical design and investigation on the dimple area density (ρ), aspect ratio (λ), and flow velocity (V) is done using unblocked central-composite design (UCD) under response surface methodology (RSM) along with multi-objective gray relation analysis method for individual dimple bottom structures to minimize the coefficient of friction and increase the load bearing capacity in the interaction pairs. The flat bottom structure exhibits excellent load-bearing capacity and minimum coefficient of friction when compared to V-shaped and U-shaped bottom structures. Compared to flat bottom structure, the V-shaped and U-shaped bottom structures has 40.37% and 7.81% lesser load-bearing capacity, respectively, and 54.08% and 7.81% higher coefficient of friction, respectively. In a flat bottom structure, the flow velocity is identified as an effective variable factor to improve the outcome characteristics, followed by dimple area density and aspect ratio. The optimal dimple area density and aspect ratio values are observed in the range of 30–40% and 0.025 – 0.030, respectively. In addition, the optimal value of flow velocity is observed to be 2.5 m/s.

Hydrodynamic performance study of a dimple textured surface at various area ratios and sliding speeds using CFD

A three dimensional computational fluid dynamic (CFD) analysis was conducted to understand the hydrodynamic performance of a dimple texture produced using recently invented low-cost dynamic-assisted tooling (DAT) in the machining process. Five different area ratios, αr of 0%, 1.63%, 3.26%, 6.53%, and 9.80%, and three different sliding speeds represented by Reynolds number, Re of 10, 45, and 80 were analyzed. From the study, there existed an optimum area ratio of 3.26%, which generated up to 290% higher load-carrying capacity compared to a fully textured surface. These findings revealed the benefits of dimple texture produced using DAT, as well as proposing the optimum area ratio needed to be considered in order to optimize the dimple performance for actual application on piston engine surfaces in the near future.

Synergistic influences of laser surface texturing and ZrO2-MoDTC hybrid nanofluids for enhanced tribological performance

This study uses nanofluids and laser surface texturing (LST) synergistically to enhance tribological performance. ZrO2-MoDTC hybrid nanoparticles of different concentrations were used as lubricant additives in base oil. Microtextured patterns of different shapes and sizes were designed and created on steel pin surface by laser ablation, and their tribological performances were assessed using a pin-on-disc tribometer. Appropriate circular dimple textured (DT) surfaces with 0.5 wt% ZrO2-MoDTC hybrid nanofluid produced outstanding friction reduction and anti-wear performance than cross-groove textured (GT) and untextured (UT) surfaces. The average friction coefficient of DT reduced by approximately 24–28% and 57–60% than GT and UT surfaces, respectively. Analysis of the worn surface showed that the synergetic influences of the nanofluid and LST produced excellent tribological performance.

Numerical and experimental study of micro-convex dimple developed by laser additive manufacturing for surface applications

Surface texturing using laser is one such technique exhaustively used for enhancing the surface properties of the components. In this work, a 2D FEM is built to simulate the thermo-fluidic phenomena of surface texturing in the preplaced IN718 powder. Transient heat transfer and fluid flow were used to predict the temperature and velocity fields. Experiments are conducted to develop micro-convex dimple texture on the surface, which usually enhances the surface hydrophobicity and tribological properties. The experimental and numerical results are in good agreement and reveal that with increase in the number of pulses, the height of the micro-convex dimples decreases.

The Proposition of Using Dimpled Surface Vibratory Conveyors in Confectionery Industries for Product Movement

The confectionery business in the overall food and beverage sector has been gaining popularity and growing at an exponential rate, with many new companies entering the market to embrace the untapped market and supply customers with higher quality products like gum, chocolate, chilling plates, candy, gummy candy, enrobers, etc. One of the significant challenges faced by all the companies in this sector is to manage the movement of the product, whether bulk or packaged, from one part of the production line to the other effectively and efficiently. Various companies traditionally rely on conveying systems procured from Original Equipment Manufacturers (OEM) or designing them in-house to fulfill this requirement. The capital investment in these conveying systems was kept to a minimum in the past as they were not considered critical to day-to-day operations. However, there has been a shift in the business strategy, and nowadays, companies do extensive research and allocate significant capital to deploy an effective and efficient conveying system to support their production. In this theoretical study, we explore different available conveying technologies used in confectionery companies and their challenges in dayto-day operations. We also review a new and upcoming technology of using a vibratory conveying system with a dimpled surface texture of the conveyor itself to support gentle handling of the product and how it is advantageous over the traditional conveying system. This study aims to aid confectionery companies in identifying and selecting the most effective and efficient conveying solution for their production lines to move products within the facility