Search Results (13)

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

Zinc sulfide (ZnS) is extensively utilized in various applications due to its exceptional optical transmittance across numerous spectral bands. To achieve ultra-high surface quality ZnS optical components, shear thickening polishing (STP) is employed to reduce roughness. A comparison between traditional fixed abrasive polishing (FAP) and STP for ZnS glass showed that FAP results in poor surface quality due to its low removal efficiency and uneven abrasive exposure, while STP provides better surface quality due to its flexible removal process, proving its feasibility and advancement. The Taguchi method was used to study the impact of three key polishing parameters on surface roughness (Ra) and the material removal rate (MRR), finding that polishing angle most influenced roughness and speed most influenced MRR. With optimal parameters, ZnS glass surface roughness was reduced from 110 ± 15 nm to 8.85 ± 0.5 nm, with an MRR of 32.5 nm/min. Scanning electron microscope (SEM) images further confirmed STP’s effectiveness in removing microdefects and smoothing the ZnS glass surface, offering a new method for the efficient, high-quality polishing of chalcogenide glasses without surface damage. Full article

The polishing of rotary workpieces, which were characterized by large curvature edges, presents considerable challenges due to the difficulty of applying uniform polishing forces. Numerous solutions have been proposed to address this issue. However, none have successfully achieved an optimal balance between efficiency and surface quality. To this end, a “gentle” but effective method known as shear thickening polishing (STP) has been developed, which can improve the surface roughness to less than Ra 30 nm within a matter of minutes and without any surface abnormality. Influences of the STP were systematically investigated by single factor experimental designs, including abrasive type, abrasive concentration, installation angle, and polishing speed. And an illustrative case study involving the polishing of a rotary workpiece with a large curvature edge was presented, wherein the surface roughness can be reduced to Ra 25 nm within a mere 15 min and without the occurrence of burns or scratches typically associated with conventional polishing techniques. In contrast, traditional cashmere ball polishing requires approximately 30 min to achieve a similar surface quality, which often results in residual burns and scratches. The findings confirm that shear thickening polishing is an effective and efficient approach for enhancing the surface quality of rotary workpieces with significant curvature. Full article

This study aimed to enhance the efficiency and surface quality of shear-thickening polishing (STP) for optical glass through optimizing the polishing parameters. Sixteen orthogonal experiments were conducted to assess the effects of polishing speed ($V$), angle ($\theta$), and slurry concentration ($C$) on the material removal rate (MRR) and surface roughness (Ra). Grey relational analysis simplified the multi-objective optimization problem, and a regression model was formulated to determine the optimal combination of polishing parameters. The results indicate that slurry concentration has the most significant impact on the optimization objective, followed by polishing angle, whereas polishing speed has the least effect. Under the optimal combination of polishing parameters—polishing speed of 70 rpm, polishing angle of 70°, and slurry concentration of 12%—the surface roughness (Ra) of optical glass was significantly reduced to 8.23 nm during a 20 min polishing process, while the material removal rate (MRR) reached 813.63 nm/min. Shear-thickening polishing under the optimized process parameters can effectively remove scratches from the workpiece surface and significantly enhance surface quality. 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

A green chemical shear-thickening polishing (GC-STP) method was studied to improve the surface precision and processing efficiency of monocrystalline silicon. A novel green shear-thickening polishing slurry composed of silica nanoparticles, alumina abrasive, sorbitol, plant ash, polyethylene glycol, and deionized water was formulated. The monocrystalline silicon was roughly ground using a diamond polishing slurry and then the GC-STP process. The material removal rate (MRR) during GC-STP was 4.568 μmh⁻¹. The material removal mechanism during the processing of monocrystalline silicon via GC-STP was studied using elemental energy spectroscopy and FTIR spectroscopy. After 4 h of the GC-STP process, the surface roughness (Ra) of the monocrystalline silicon wafer was reduced to 0.278 nm, and an excellent monocrystalline silicon surface quality was obtained. This study shows that GC-STP is a green, efficient, and low-damage polishing method for monocrystalline silicon. 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

Carbide tools are extensively used in the automotive, aerospace, and marine industries. However, an unsuitable tool-edge treatment can affect the cutting performance of carbide tools. In the tool-cutting process, the cutting edge radius is one of the major factors that affect the cutting force, temperature, and quality. In this study, a cutting simulation model of carbide inserts was used to analyze the effect of the cutting edge radius on the cutting performance. The cutting edge radii of the inserts were prepared using shear-thickening polishing methods, followed by cutting experiments. The accuracy of the cutting simulation model was verified through cutting experiments. The simulation results showed that under low-speed cutting conditions, the cutting force and temperature tended to increase with an increase in the cutting edge radius, and the cutting temperature was less affected by the cutting edge radius. The results of the cutting force and cutting temperature obtained from the experiment and simulation were consistent; therefore, the cutting simulation model was verified to be reliable. The results indicate that modeling cutting simulation is a promising research method for predicting the cutting performance of tools. Full article

To improve medical device hole inner wall quality and overcome issues of traditional abrasive flow methods—limited fluidity in small holes causing deformation due to high inner wall pressure, and slow processing with low viscosity abrasives—a new method called shear thickening abrasive flow polishing is suggested. It uses shear thickening fluid as the medium. By leveraging the Preston equation and fluid dynamics theory, this study establishes both an abrasive flow dynamics model and a material removal model for the shear thickening abrasive flow machining of small titanium alloy hole workpieces in medical instruments. Utilizing the COMSOL software, the flow field state of shear thickening fluid within small holes is examined under varying flow behavior indexes and flow velocities. The findings demonstrate that shear thickening fluid yields superior polishing effects compared to Newtonian fluid. Elevating the flow behavior indexes facilitates a higher material removal rate on the inner wall surface; however, excessively large flow behavior indexes diminish the uniformity of material removal, thereby hindering the attainment of a high-quality polished surface. Furthermore, excessively large flow behavior indexes can reduce fluidity and consequently lower the efficiency of the polishing process. Conversely, while maintaining a constant flow behavior index, increasing the flow velocity contributes to an enhanced material removal rate and improved polishing efficiency. Nevertheless, as the flow velocity rises, the uniformity of inner wall surface roughness diminishes, posing challenges in achieving a high-quality polished surface. Full article

Micro-electro-mechanical systems (MEMS) hemispherical resonant gyroscopes are used in a wide range of applications in defense technology, electronics, aerospace, etc. The surface roughness of the silicon micro-hemisphere concave molds (CMs) inside the MEMS hemispherical resonant gyroscope is the main factor affecting the performance of the gyroscope. Therefore, a new method for reducing the surface roughness of the micro-CM needs to be developed. Micro-ultrasonic machining (MUM) has proven to be an excellent method for machining micro-CMs; shear thickening fluids (STFs) have also been used in the ultra-precision polishing field due to their perfect processing performance. Ultimately, an STF-MUM polishing method that combines STF with MUM is proposed to improve the surface roughness of the micro-CM. In order to achieve the excellent processing performance of the new technology, a Categorical Boosting (CatBoost)-genetic algorithm (GA) optimization model was developed to optimize the processing parameters. The results of optimizing the processing parameters via the CatBoost-GA model were verified by five groups of independent repeated experiments. The maximum absolute error of CatBoost-GA is 7.21%, the average absolute error is 4.69%, and the minimum surface roughness is reduced by 28.72% compared to the minimum value of the experimental results without optimization. Full article

To improve the cutting performance of the core drill, the flexible fiber assisted shear-thickening polishing (FF-STP) for cutting edge preparation was proposed to eliminate the microscopic defect and obtain proper radius of the cutting edge of the core drill. The flexible fiber was introduced into the shear-thickening polishing process to break the thickened agglomerates and improve the efficiency of cutting edge preparation. The influence of the polishing speed, abrasive concentration and the flexible fiber contact length with the core drill on the cutting edge radius r and surface morphology of the core drill edge was analyzed, and the drilling experiments were carried out after preparation, the cutting heat and drilled holes’ roughness were employed as evaluation indexes to evaluate the performance of the core drill. The results show that the cutting edge radius increases with the increase of polishing speed, abrasive concentration and contact length. However, too high a polishing speed and contact length reduce the abrasive particles involved in the polishing process, and then lead to a decline in preparation efficiency. Under the selected processing conditions, the cutting edge radius increases from the initial 5 μm to 14 μm and 27 μm with 4 min of treatment and 6 min of treatment preparation, respectively. The sharp cutting edge becomes rounded, the burrs and chipping on the cutting edge are eliminated, and the average roughness (R_a) of the flank face decreases from 110.4 ± 10 nm to 8.0 ± 3 nm. Nine holes were drilled consecutively by core drills after cutting edge preparation, and the cutting temperature and drilled holes’ roughness were recorded. The maximum cutting temperature (122.4 °C) in the process with the prepared core drill (radius r = 14 μm) is about 20 °C lower than that with untreated one, and the roughness of the drilled hole (R_a 510.5 nm) about 189.9 nm lower. The results indicates that FF-STP is a promising method for high consistency preparation of the core drill cutting edge. Full article

Reasonable cutting edge preparation can eliminate microscopic defects and improve the performance of a cutting tool. The flexible fiber-assisted shear thickening polishing method was used for the preparation of cemented carbide insert cutting edge. The influences of the polishing angle and polishing speed on the cutting edge preparation process were investigated, and the cutting edge radius and K-factor were employed as evaluation indexes to evaluate the edge shape. A prediction model of the cutting edge radius was also established using the mathematical regression method. The results show that the polishing angle has a more significant effect on the cutting edge radius. The cutting edge preparation efficiency is the highest under the polishing angle of 10°, and the cutting edge radius increased from the 15 ± 2 μm to 110 ± 5 μm in 5 min. The cutting edge shape can be controlled by adjusting the polishing angle, and the K-factor varies from 0.14 ± 0.03 to 0.56 ± 0.05 under the polishing angle (from −20° to 20°). The polishing speed has a less effect on the cutting edge radius and shape, but increasing the polishing speed within a certain range can improve the efficiency of cutting edge preparation. The flank face roughness decreased from the initial Ra 163.1 ± 10 nm to Ra 5.2 ± 2 nm at the polishing angle of −20°, which is the best polishing angle for the flank face surface roughness. The ANOVA method was employed to evaluate the effective weight of the polishing angle and polishing speed on preparation efficiency. The polishing angle (86.79%) has the more significant influence than polishing speed (13.21%) on the cutting edge preparation efficiency. The mathematical regression method was used to establish the model of the prediction of the cutting edge radius with polishing angle and speed, and the models were proved rationally. The results indicate that the FF-STP is an effective method for the high consistency preparation of cemented carbide insert cutting edge. Full article

Quartz glass is a typical optical material. In this research, colloidal silica (SiO₂) and colloidal cerium oxide (CeO₂) are used as abrasive grains to polish quartz glass in the shear thickening polishing (STP) process. The STP method employs the shear-thickening mechanism of non-Newtonian power-law fluid to achieve high-efficiency and high-quality polishing. The different performance in material removal and surface roughness between SiO₂ and CeO₂ slurries was analyzed. The influence of the main factors including polishing speed, abrasive concentration, and pH value on the MRR, workpiece surface roughness, and the surface topography was discussed. Two different slurries can both achieve fine quartz surface in shear thickening polishing with the polishing speed 100 rpm, and pH value 8. The quartz glass surface roughness R_a decreases from 120 ± 10 to 2.3 nm in 14 minutes’ polishing with 8 wt% 80 nm SiO₂ slurry, and the MRR reaches 121.6 nm/min. The quartz glass surface roughness R_a decreases from 120 ± 10 to 2.1 nm in 12 minutes polishing by 6 wt% 100 nm CeO₂ slurry and the MRR reaches 126.2 nm/min. Full article