Search Results (7)

Shear-thickening polishing (STP) technology achieves efficient processing by modulating the non-Newtonian properties of the slurry, while temperature has an important effect on its rheological behavior. To reveal the effect of temperature on material removal rate (MRR) during the shear-thickening polishing process, this study measured the rheological profiles of the shear-thickening polishing slurry (STPS) at different temperatures and observed the rheological behavior using a high-speed video camera, as well as monitored the changes in the polishing force exerted on the workpieces, MRR, and the surface roughness. Experimental data show that the peak viscosity of the slurry in the shear-thickening state decreases from 0.81 Pa·s to 0.49 Pa·s as the temperature increases from 30 °C to 50 °C. High-speed video observations show that the wavy solid layer in the thickening area diminishes with increasing temperature, the distribution area shrinking, and nearly vanishing at 50 °C. When the temperature rises from 30 °C to 40 °C, the average polishing force at 30 min decreases from 25.3 N to 22.6 N by 10.6%. MRR decreases from 33.5 nm/min to 7.9 nm/min by 75.5%. The decrease in MRR is much greater than the polishing force. This study provides an experimental basis for the effect of temperature on STP. Full article

Shear-thickening fluid (STF) is widely applied in various practical engineering fields due to its rheological properties of increased viscosity under load. We investigated the integration of STF with fiber brushes to prepare a novel composite material for polishing applications. The impact of composite material properties is studied in surface finish, specifically roughness and morphology, across flat and uneven surfaces. The effects of the critical variables, including polishing speed, feed depth, and STF concentration, are analyzed through experimentation and simulation. After the STF polishing, the surface roughness of the aluminum alloy sample decreases from 3.125 μm to 0.528 μm, which increases the processing efficiency by 40% compared to Newton polishing slurry. The unique shear-thickening performance of the composite material ensures excellent surface quality and high efficiency in the precision machining of workpieces. Full article

Abrasive machining processes have long been integral to various manufacturing industries, enabling precise material removal and surface finishing. In recent years, the integration of non-Newtonian fluids has emerged as a promising strategy to enhance the performance and efficiency of these processes. This review paper provides a comprehensive overview of the current state of research on abrasive machining processes, including abrasive lapping, abrasive polishing, and chemical mechanical polishing, and then analyzes in detail the abrasive machining processes enhanced with non-Newtonian fluids. It explores the fundamental principles underlying the rheological behavior of non-Newtonian fluids and their application in abrasive machining, with a focus on shear-thickening fluids. The paper will begin by introducing the abrasive machining processes, including abrasive lapping, abrasive polishing, and chemical mechanical polishing. Then, the current research status of non-Newtonian fluids will be comprehensively analyzed, and we will explore the enhancement of abrasive machining processes with non-Newtonian fluids. Finally, the paper will conclude with a discussion of the future directions and challenges in the field of abrasive machining enhanced with non-Newtonian fluids. Overall, this review aims to provide valuable insights into the potential benefits, limitations, and opportunities associated with the use of non-Newtonian fluids in abrasive machining, paving the way for further research and innovation in this promising area of manufacturing technology. Full article

In this study, shear rheological polishing was used to polish the Si surface of six-inch 4H-SiC wafers to improve polishing efficiency. The surface roughness of the Si surface was the main evaluation index, and the material removal rate was the secondary evaluation index. An experiment was designed using the Taguchi method to analyze the effects of four critical parameters (abrasive particle size, abrasive particle concentration, polishing speed, and polishing pressure) on the Si surface polishing of SiC wafers. By evaluating the experimental results for the signal-to-noise ratio, the weight of each factor was calculated using the analysis of variance method. The optimal combination of the process parameters was obtained. Below are the weightings for the influence of each process on the polishing result. A higher value for the percentage means that the process has a greater influence on the polishing result. The wear particle size (85.98%) had the most significant influence on the surface roughness, followed by the polishing pressure (9.45%) and abrasive concentration (3.25%). The polishing speed had the least significant effect on the surface roughness (1.32%). Polishing was conducted under optimized process conditions of a 1.5 μm abrasive particle size, 3% abrasive particle concentration, 80 r/min polishing speed, and 20 kg polishing pressure. After polishing for 60 min, the surface roughness, R_a, decreased from 114.8 to 0.9 nm, with a change rate of 99.2%. After further polishing for 60 min, an ultrasmooth surface with an R_a of 0.5 nm and MRR of 20.83 nm/min was obtained. Machining the Si surface of 4H-SiC wafers under optimal polishing conditions can effectively remove scratches on the Si surface of 4H-SiC wafers and improve the surface quality. Full article

This research effort is geared towards revealing the latent potential of discarded shoe polish that might be repurposed as an asphalt fluxing agent for the construction of durable and sustainable road surfaces. To drive this creative invention, the effect of various proportions of waste shoe polish (e.g., 5, 10 and 15 wt. % WSP) on the performance of base AP-5 bitumen was inspected in great detail. A meticulous investigation of the chemical, physical, and rheological properties of the resultant combinations was carried out using a variety of state-of-the-art laboratory techniques, specifically: thin-layer chromatography-flame ionization detection (TLC-FID), Fourier transform-infrared spectroscopy (FT-IR), needle penetration, ring-and-ball softening point, Brookfield viscometer, ductility, flash/fire points, dynamic shear rheometer (DSR), multiple stress-creep recovery (MSCR), and bending beam rheometer (BBR) tests. The Iatroscan data disclosed that the continuous feeding of binder with WSP had a minor impact on SARA fractional distribution, regardless of aging. According to the FT-IR scan, the stepwise addition of WSP to the binder did not result in any significant chemical alterations in the blends. The combined outcomes of the DSR/BBR/empirical test methods forecasted that the partly bio-sourced additive would greatly improve the mixing–compaction temperatures, workability, and coating–adhesion properties of bituminous mixtures while imparting them with outstanding anti-aging/cracking attributes. In short, the utilization of waste shoe polish as a fluxing agent for hot asphalt mix production and application is not only safe, feasible, and affordable, but it has the potential to abate the pollution caused by the shoe-care market while simultaneously enhancing the overall performance of the pavement and extending its service lifespan. Full article

Drag finishing is a widely used superfinishing technique in the industry to polish parts under the action of abrasive media combined with an active surrounding liquid. However, the understanding of this process is not complete. It is known that pyramidal abrasive media are more prone to rapidly improving the surface roughness compared to spherical ones. Thus, this paper aims to model how the shape of abrasive media (spherical vs. pyramidal) influences the material removal mechanisms at the interface. An Arbitrary Lagrangian–Eulerian model of drag finishing is proposed with the purpose of estimating the mechanical loadings (normal stress, shear stress) induced by both abrasive media at the interface. The rheological behavior of both abrasive slurries (media and liquid) has been characterized by means of a Casagrande direct shear test. In parallel, experimental drag finishing tests were carried out with both media to quantify the drag forces. The correlation between the numerical and experimental drag forces highlights that the abrasive media with a pyramidal shape exhibits a higher shear resistance, and this is responsible for inducing higher mechanical loadings on the surfaces and, through this, for a faster decrease of the surface roughness. Full article

The areas of Central and Eastern Europe and, thus, Poland are not exposed to the effects of seismic actions. Any possible tremors can be caused by coal or copper mining. Wind, rheological effects, the impact of other objects, or a nonuniform substrate are the predominant types of loading included in the calculations for stiffening walls. The majority of buildings in Poland, as in most other European countries, are low, medium-high brick buildings. Some traditional materials, like solid brick (>10% of construction materials market) are still used, but autoclaved aerated concrete (AAC) and cement-sand calcium-silicate (Ca-Si) elements with thin joints are prevailing (>70% of the market) on the Polish market. Adding reinforcement only to bed joints in a wall is a satisfactory solution (in addition to confining) for seismic actions occurring in Poland that improves ULS (ultimate limit state) and SLS (serviceability limit state). This paper presents results from our own tests on testing horizontal shear walls without reinforcement and with different types of reinforcement. This discussion includes 51 walls made of solid brick (CB) reinforced with steel bars and steel trusses and results from tests on 15 walls made of calcium-silicate (Ca-Si) and AAC masonry units reinforced with steel trusses and plastic meshes. Taking into account our own tests and those conducted by other authors, empirical relationships were determined on the basis of more than 90 walls. They are applicable to the design and construction phases to determine the likely effect of reinforcements on cracking stress that damage shear deformation and wall stiffness. Full article