Quality Of Polished Surface Research Articles

Environmentally Friendly Chemical–Magnetorheological Finishing Method for Ti–6Al–4V Biological Material Based on Fe3O4@SiO2, Oxaloacetate Acid and H2O2

Titanium alloy is extensively utilised in various advanced equipment across multiple industries, especially in biological implantable devices. The surface machining of such devices is required to provide a finished surface with high precision and gloss. This study presents an established ecofriendly slurry for a hybrid polishing process utilising a highly efficient chemical and magnetorheological fluid (C-MRF) to obtain ultraprecise surface quality. This slurry incorporated Fe3O4@SiO2 abrasive particles, oxaloacetate acid (C4H6O5), deionised water and hydrogen peroxide (H2O2) as an oxidiser. Ti–6Al–4V workpieces polished with C-MRF based on Fe3O4@SiO2 abrasives and polishing performance were used to investigate the influence of the oxidising agent H2O2 and oxaloacetate acid (monitored with a pH indicator) on the surface finish of Ti–6Al–4V biomaterial. In contrast to the traditional mechanical and chemical polishing methods for titanium alloys that often include strong bases and acids along with chemicals that endanger the environment and humans, the proposed polishing process based on the newly developed ecofriendly magnetic composite leveraged the advantages of magnetorheological fluid with chemical reactions to create an ultra smooth surface. Experiments were performed to investigate the influence of different polishing durations and factors on the quality of polished surfaces, thereby optimising technological parameters, reducing time and improving surface quality. Various technological parameters were evaluated through single-factor and orthogonal experiments to assess their distinct effects on surface quality and material removal capability. This work proposed an environmentally friendly C-MRF method for finishing Ti–6Al–4V biomaterial with high efficiency and industrial applicability.

Machining performance and material removal mechanism of sapphire with novel polishing slurry

Enhancing the interfacial reactivity of polishing slurry is crucial for improving the polishing efficiency and surface quality of sapphire wafers. In this study, a novel green polishing slurry was developed, comprising aminomethyl propanol, xylitol, highly active silica, and deionized water. The processing quality and removal mechanism of this novel green polishing slurry on semi-solid flexible polishing were investigated to achieve ultra-precision, high-efficiency, and environmentally friendly polishing of sapphire wafers. Experimental results demonstrated that the novel green polishing slurry reduced surface roughness by 12.5% and increased the material removal rate by 71.3% compared with traditional polishing slurry. Various analytical techniques, including wear debris analysis, molecular simulation, infrared detection, electrochemical testing, and physical phase detection, were utilized to explore the material removal mechanism. The findings indicated that aminomethyl propanol promotes chemical reactions between the green polishing slurry and sapphire wafers, leading to the conversion of the intermediate product Al(OH)3 to Al(OH)4-. In addition, the complexation reaction between xylitol and Al(OH)4- ions during polishing was found to accelerate the removal of surface materials from sapphire wafers, resulting in improved polishing efficiency and surface quality.

FLAW DEFECTION ANALYSE OF THE SURFACE OF ACRYLIC BASE PLASTICS

This study examines the possibility of assessing the quality of removable orthopedic devices by measuring the smoothness of their surfaces and detecting microscopic defects. The methodology involves comparing standard samples of the base material with samples that have been intentionally defective, using defectoscopy techniques for analysis. Initially, twenty samples of basic acrylic plastic were selected: half of them were perfectly machined to dental standards and the other half were intentionally scratched with sandpaper. These samples were then examined by macrophotography and analyzed using Image J software for quantitative image measurement. This analysis provided numerical data on the polished surface's quality, focusing on metrics such as the total number of defects, and the average size and perimeter of these defects. Statistical evaluation through the JUSP program compared the two sets of samples, highlighting significant differences between them. From the most prominent data points provided by Image J, conclusions were made regarding the surface quality of the acrylic plastic and how it is affected by specific mechanical imperfections. This method of using optical flaw detection offers a new way to clinically evaluate the quality of detachable orthopedic devices (like base plastic) in terms of their susceptibility to bacterial buildup, which could lead to inflammation in the prosthetic bed's mucosal lining. The use of flaw detection analysis allows for a general assessment of the quality of the material surface polishing, detection of surface defects in its structure that may occur during the production stage or during operation, thereby preventing areas of biofilm accumulation. Light-optical flaw detection in the experiment proved its effectiveness and makes us pay attention to the prospects of its improvement and wider implementation in clinical practice.

Effect of Oxidant Concentration on the Oxide Layer Thickness of 304 Stainless Steel.

Ultra-thin 304 stainless steel can be used to flexibly display substrates after they have been subjected to chemical mechanical polishing (CMP). The thickness of the chemical oxide layer directly affects the polishing efficiency and surface quality of 304 stainless steel. In the study presented in the following paper, the thickness variation of the chemical oxide layer of 304 stainless steel was analyzed following electrochemical corrosion under different oxidant concentration conditions. Furthermore, the impact of the oxidant concentration on the grooves, chips, and scratch depth-displacement-load curves was investigated during a nano-scratching experiment. Through this process, we were able to reveal the chemical reaction mechanism between 304 stainless steel materials and oxidizers. The corrosion rate was found to be faster at 8% oxidant content. The maximum values of the scratch depth and elastic-plastic critical load were determined to be 2153 nm and 58.47 mN, respectively.

Electrochemical polishing properties of AlMgScZr alloy produced by laser powder bed fusion in NaNO3 and NaCl solutions

Electrochemical polishing (ECP) is a potential process to improve the surface quality of AlMgScZr alloy components produced by laser powder bed fusion (LPBF). Replacing traditional acid electrolytes with environment-friendly electrolytes is of great significance to the environment and safety. This work aims to study the ECP properties of LPBF AlMgScZr alloy in environment-friendly electrolytes (NaNO3 and NaCl solutions). In ECP, the electrochemical dissolution behavior of anode materials determines the polished surface quality. To this end, the effect of electrolyte type, uneven microstructure and applied current density on the anodic dissolution behavior of LPBF AlMgScZr alloy was examined experimentally. The results provide information about the suitability of the electrolytes selected for the ECP of LPBF AlMgScZr alloy, the dissolved surface quality in NaNO3 solution is significantly better because of the existence of a dense passive film. In addition, a microstructure analysis reveals that the bimodal distribution of grain size is the main factor leading to an uneven dissolved surface. Finally, the inner surface of LPBF AlMgScZr alloy channel was successfully polished in NaNO3 solution, the semi-welding particles were completely removed, and the surface roughness Sa was reduced from 20.73 μm to 2.48 μm.

Theoretical and experimental investigation on magnetorheological shear thickening polishing force using multi-pole coupling magnetic field

The magnetorheological shear thickening polishing method, with its dual-stimulus response of shear thickening and magnetization enhancement, has emerged as a promising magnetic field-assisted polishing technology. However, in existing theories and experimental studies on polishing forces, the phenomenon of magnetization enhancement was mainly considered. The shear thickening effect has not yet to be incorporated into. Furthermore, there have been few systematic investigations on the polishing mechanism considering variations of force characteristics. The study aims to fill in these research gaps by developing theoretical models for both normal and tangential forces, and revealing the microscopic polishing mechanism during the magnetorheological shear thickening polishing process. Both normal and tangential polishing force models were established through taking the rheological properties of polishing media under magnetic field and plastic indentation theory into account. Polishing force measurement experiments under a multi-pole coupling magnetic field were conducted to reveal the variations of the polishing forces with different polishing parameters and to validate the established models. Furthermore, the microstructural evolutions of the polishing media components and the surface morphologies after polishing were combined with in-depth analysis to elucidate the polishing mechanism. The polished surface quality was significantly improved without visible scratches. The surface roughness of 48 nm was achieved from the initial value of 245 nm under the normal force of 3.36 N and the tangential force of 2.42 N. The study provides deep insights into the polishing forces characteristics and the polishing mechanism, which contributes to a theoretical guidance for optimizing polishing parameters and improving polishing quality.

Synergistic effect of abrasive friction and glycine on improving chemical mechanical polishing performance of single-crystal GaN substrate

With the rapid development of the third-generation semiconductor materials, the chemical mechanical polishing rate and surface quality of single-crystal gallium nitride (GaN) substrates have been a research hot-spot. In this work, the synergistic effect of abrasive friction and glycine (Gly) on improving the chemical mechanical polishing (CMP) performance of single-crystal GaN substrate is proposed and studied systematically. The results indicated that the polishing solutions with Gly have a 2.3-fold improvement in material removal rate (MRR) as well as scratch-free surface than that without Gly. The maximum MRR of the single-crystal GaN substrate is 129.4 nm/h with surface roughness (Ra) of 0.64 nm attained by using the polishing solutions containing only 3 wt% potassium persulfate (K2S2O8). In contrast, when Gly is added as a reaction reagent, which can be activated by abrasive friction, the maximum MRR is increased to 304.2 nm/h with Ra of 0.42 nm. Meanwhile, the epitaxial evaluation indicates that two-dimensional (2D) MoS2 grown on processed single-crystal GaN substrate has superior crystalline quality and optical properties. Finally, the polishing mechanism of the single-crystal GaN substrate using the mixed solutions of K2S2O8 and Gly is discussed. The proposed CMP method has potential applications in the semiconductor and microelectronics industries.

Research on polishing aluminum alloy optical elements with a new solid flexible bonnet tool

As a common optical element material, aluminum alloy has been widely used because of its high reflectivity, easy lightweight design and other advantages. However, due to the soft texture and large plasticity of aluminum alloy, the surface is prone to mechanical damage during processing. In order to improve the surface quality and processing efficiency, this paper designs a new type of solid flexible bonnet tool to polish aluminum alloy optical elements. Then the finite element analysis method is used to compare the performance of several bonnet tools. Finally, the aluminum alloy polishing experiment is carried out, and the material removal mechanism and the factors affecting the polishing surface quality are analysed. The results show that the new solid flexible bonnet tool has good deformation stability, good fit with the workpiece, and can achieve high efficiency and precision polishing of aluminum alloy optical elements. According to the pressure distribution in the contact area, the abrasive particles in the sliding state are divided into three removal modes: micro-cutting, micro-plowing and micro-rubbing. At the same time, the hard particles in aluminum alloy have an important influence on the surface morphology after polishing. Due to the strong plasticity and viscosity of aluminum alloy, the abrasive dust is easy to adhere to the surface of the workpiece, reducing the surface roughness.

Micro-arc plasma discharge polishing for multi-material parts

Multiple material parts (MMP) have good physical and mechanical properties, which are commonly used in some critical applications such as engine blades. Current polishing techniques for MMP suffer from low efficiency and poor surface quality. To effectively polish MMP with complex shapes, this paper proposes an environmentally friendly micro-arc plasma polishing method that combines electrochemical and electrical discharge machining. The material removal mechanism of micro-arc plasma discharge polishing of MMP is analyzed. The experiments show that the proposed method is feasible by polishing 304 stainless steels, and the influence factors of the polishing efficiency and surface quality are discussed. The parameters’ optimization is conducted that provides the technical theory basis and control strategy for MMPs’ engineering application.

AL-ProMP: Force-relevant skills learning and generalization method for robotic polishing

Skill learning in robot polishing is gaining attention and becoming a hot issue. Current studies on skill learning in robot polishing are mainly about trajectory skills, and force-relevant skills learning models are less studied. A skill learning method with good generalization and robustness is one of the elements worth investigating. In this study, a force-relevant skills learning method called arc-length probabilistic movement primitives (AL-ProMP) is proposed to improve the efficiency of robot polishing force planning. AL-ProMP learns the mapping between the contact force and polishing trajectory, and the temporal scaling factor and force scaling factor in AL-ProMP enable better robustness of force planning in speed scaling tasks and polishing tasks in different scenarios. Speed scaling is an important property for adaptation of the polishing policy. For the generalization of polishing skills to different polishing tools in robotics disc polishing tasks of unknown geometric model workpieces, a novel force scaling factor for different polishing discs is proposed according to the contact force model. In addition, polishing contact position learning provides the basis for polishing trajectory generalization. Finally, it is experimentally verified that the proposed method is effective in learning and generalizing the demonstrated skills and improving the polishing surface quality of the workpiece with unknown geometric model.

Improving the Polishing Speed and Surface Quality of 4H-SiC Wafers with an MnO<sub>2</sub>- Based Slurry

We carried out chemical mechanical polishing (CMP) on commercially available 6 inch SiC wafers (epi-ready products) with slurries containing different abrasive types and evaluated the latent scratch density from the mapping measurement of the wafers using mirror projection electron microscope (MPJ). Comparing to the wafer before polishing, the latent scratch density decreased on the wafer polished with MnO2+KMnO4, while that increased by polishing with Al2O3+KMnO4. The two-step polishing using first Al2O3+KMnO4 and then SiO2+H2O2 can reduce the latent scratch density to the same level as that with MnO2+KMnO4, but long polishing time is required because of the low polishing rate in the process with SiO2+H2O2. We investigated the reason why MnO2 slurry can suppress the occurrence of latent scratches by a polishing test on a wafer with an SiO2 film on its (0001)Si surface. The results suggest the oxidation of the SiC surface is rate-determining step for polishing with MnO2+KMnO4. It was also found that wafers without an SiO2 film could not be polished with only MnO2 abrasives. Thus the mechanical contribution to polishing by MnO2 abrasives in KMnO4-based slurry is smaller than the chemical contribution, which can suppress the occurrence of latent scratches. KMnO4-based slurry containing MnO2 abrasives performs the CMP process with low latent scratch density in a time shorter than that containing Al2O3 or SiO2 abrasives.

Comparative Analysis of Finite Element Simulation and Experiment on the Polished Surface Quality of Hard Anodized Film of Aluminum Alloy

According to the abrasive morphology and distribution of sandpaper surface, the finite element model of hard anodic oxide film polishing was established by using ABAQUS finite element software, and the hard anodic oxide film and aluminum alloy matrix were defined respectively. The effects of hard anodic oxide film polishing process, polishing surface quality and polishing parameters on the polishing force were simulated. The polishing surface quality and polishing force simulated by finite element model were verified by experiments. The results show that in the polishing process, the residual stress of polishing surface is mainly distributed in the range of 0.0034mm, and the chips produced by polishing are mainly broken and long strips with microscopic morphology, and polishing mainly depends on the front part of abrasive particles in the feeding direction of sandpaper. Under the action of abrasive particles of sandpaper, the results of finite element simulation and test show that there are certain grooves on the surface of oxide film. The finite element simulation of the normal polishing force of hard anodic oxide film is consistent with the polishing test results. During the process of polishing hard anodic oxide film, the normal polishing force increases as the polishing speed increases; the normal polishing force increases as the polishing removal amount increases; the polishing removal amount parameter has a greater degree of influence on the polishing force.

Research on the Chemical Mechanical Polishing Process of Aluminum Alloy Wafers with Acidic Slurry

Aluminum alloy has low density, good thermal conductivity, and low resistivity, which has been widely used in the fields of the defense industry, aerospace, and machinery manufacturing. As technology advances, there is a growing demand for high-precision parts and green processing. In this paper, a green chemical mechanical polishing (CMP) slurry for aluminum alloy is developed to optimize the rotational speed and pressure and improve the quality of polished aluminum alloy surface. The influence of CMP slurry composition on the quality of aluminum alloy surface and its mechanism are analyzed. Orthogonal experiments and single-factor experiments are used to investigate the effects of CMP slurry composition and process parameters on the surface quality of polished aluminum alloy. A green chemical mechanical polishing slurry consisting of deionized water, 6 wt.% SiO2, 2 wt.% H2O2, and citric acid to adjust pH=3 was proposed, with the pressure of 24 kPa and rotational speed of 90 r/min. After the CMP of aluminum alloy, surface roughness was reduced from 45.587 nm to 0.876 nm in the scan range of 70 μm × 50 μm. The mechanism was analyzed by X-ray photoelectron spectroscopy (XPS).

Parameter Optimization of RB-SiC Polishing by Femtosecond Laser

Reaction-boned silicon carbide (RB-SiC) is considered a new material for large lightweight ground-based space telescopes due to its high specific stiffness, low thermal deformation, and excellent optical quality. The excellent mechanical properties of RB-SiC result in the low efficiency of traditional polishing and mechanical polishing. In this paper, a polishing method for RB-SiC based on a femtosecond laser is proposed to improve surface quality. A theoretical heat conduction model was established in the process of femtosecond laser irradiation of SiC. We analyzed the ablation type and calculated the single-pulse ablation threshold of SiC, which verified the feasibility of femtosecond laser polishing. Further, the effects of polishing parameters on the polished surface quality were analyzed by a series of experiments, and the optimal parameters were selected. It was observed to improve polishing efficiency and can replace the intermediate steps of traditional mechanical polishing.

Effects of Scanning Speed on the Polished Surface Quality of Mold Steel by Dual-Beam Coupling Nanosecond Laser

In this paper, a novel dual-beam coupled nanosecond laser was used to polish S136D mold steel. The effects of scanning speed, total fluence, spot overlap ratio, and SPSN on surface quality were analyzed. The polished surface roughness Ra without ultrasonic cleaning is too large due to slag, splash, and dust produced by laser polishing. When scanning speed is 1250 mm/min, surface roughness Ra with ultrasonic cleaning is reduced from the original surface 1.92 μm to 0.72 μm, and the surface roughness Ra is reduced by 62.50%. When the Ftot is 35.38 J/cm2, the minimum value of surface roughness Ra is 0.72 μm. If the total fluence is higher or lower, it is not conducive to reducing the surface roughness, the total fluence is higher, and there is a polished surface with SOM phenomenon. The polished surface with spot overlap ratio of 98.55% has a smooth morphology, and a minimum value of surface roughness Ra of 0.41 μm. When the specimen is inclined at a certain angle, the high-magnification camera captures color on the polished surface. It is found that the microscopic texture of molten material flow trace and polishing scanning track is obvious. Polished surface is mainly distributed with Fe, Cr, C, and O elements. The surface material processing speed per unit time is low, and the polishing surface quality is improved less. The maximum surface roughness Ra is 1.98 μm. The minimum Ra of polished surface with smoother morphology is 0.41 μm, and surface profile height is basically the same. The research results show that the new dual-beam coupled nanosecond laser polishing technology can improve surface quality of materials. This research work provides process guidance for laser polishing effect analysis and mechanism innovation.

Experimental research on the polished surface quality of hard anodized film of aluminum alloy

An experimental study was conducted for the surface polishing of the oxide film after hard anodizing of 2D70 aluminum alloy. The surface roughness and surface morphology of aluminum alloy before, after anodizing and after polishing were analyzed, and the effects of polishing force, polishing speed, feeding amount and sandpaper grit on the polished surface roughness were investigated experimentally. The results showed that the surface roughness of 2D70 aluminum alloy decreased by 1 grade on average after hard anodizing. The hard anodized film surface has more linear protrusions, large pits and a large number of small pores. After polishing, the linear protrusions and small pores disappear, and a small number of new linear grooves appear, while the condition of large pits does not change much. The depth of small pores on the oxide film surface is within 11μm in most cases. As the polishing force, feeding amount and sandpaper grit increase, the decreasing trend of roughness value also gradually increases, and the decreasing trend of the thickness of hard anodic oxide film gradually increases. As the polishing speed increases, there is no clear trend in the decreasing trend of rough

Surface Generation Mechanism and Experimental Investigation of Ultrasonic Vibration Assisted Belt Flapwheel Flexible Polishing Process

To further improve the polished quality of blades surface, a new polishing process-ultrasonic vibration assisted belt flapwheel flexible polishing (UBFP) is proposed in this paper. The trajectory state of abrasives and the continuous polishing process were analyzed, and the interlace phenomenon was described. The influences of main parameters on the quality of machined surface were discussed through experiments, and the prediction models of surface roughness(Ra and Rz) were established. The results showed that lower surface roughness and less polishing marks could be achieved by UBFP, and the models were reliable that can be used in further processing and research. This study can be considered as a theoretical and experimental reference to advancing the polishing surface quality of the blisk blade.

Enhancing the Polishing Efficiency of CeO2 Abrasives on the SiO2 Substrates by Improving the Ce3+ Concentration on Their Surface

The polishing activity of CeO2 abrasives is enhanced by improving the Ce3+ concentration on their surface. In this study, a series of Ce1–xLaxO2 abrasives with different La3+ doping were prepared. The abrasives were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The effects of La3+ doping on the morphology, size, and Ce3+ concentration of the abrasives were studied. The morphology of the particles changes from sphere to octahedron with the La3+ doping. The lattice expansion of the CeO2 crystal after La3+ doping also significantly improves the Ce3+ concentration on the abrasive surface. However, the Ce3+ concentration on the surface gradually became saturated when the x was 0.2 or more. The polishing performance proved that the material removal rate (MRR) is closely related to the Ce3+ concentration generated by La3+ doping. The MRR of pure CeO2 abrasives with a Ce3+ concentration of 20.53% on a SiO2 substrate is 59.31 nm/min, while the Ce0.7La0.3O2 abrasives with the Ce3+ concentration increased to 34.41% achieved 101.12 nm/min. The polished surface quality was characterized by atomic force microscopy, which shows improved roughness of all samples. Furthermore, the differences in the removal rate of Ce3+ and Ce4+ in CeO2-based abrasives on the SiO2 substrate were also discussed.

Electrochemical Polishing of Ti6Al4V Alloy Assisted by High-Speed Flow of Micro-Abrasive Particles in NaNO3 Electrolyte.

Electrochemical polishing (ECP) is an efficient and low-cost technology for polishing difficult-to-machine materials with complex structures. However, when an environmentally friendly neutral salt solution is used as the polishing electrolyte, a dense passivation film forms on the surface of passive metals, such as titanium alloy, with a serious detrimental effect on the polishing efficiency and surface quality. In this paper, we introduce an ECP method assisted by a high-speed flow of micro-abrasive particles (ECFAP). The contribution of the flowing micro-abrasive particles in the ECP process enables the electrochemical dissolution and abrasive polishing to occur simultaneously on the workpiece surface. The high-speed abrasive particles remove the passivation film formed under ECP, thereby improving the polishing efficiency and quality. We carried out the comparative tests of conventional ECP and the proposed ECFAP on a Ti6Al4V alloy in 10% NaNO3 electrolyte; the results show that, while the matrix material forms a soft high-impedance passivation film under ECP, this film is removed by the high-speed flowing abrasive particles under ECFAP. The proposed ECFAP method improves both the polishing efficiency and the surface quality. Finally, ECFAP-treated specimens with an optimum voltage of 3 V for 10 min exhibited an average surface roughness of 0.0953 µm.

Comparative Analysis of the Applicability of Feed-Forward and Recurrent Neural Networks for Prediction of Surface Quality of Laser Polished Surfaces

Comparative Analysis of the Applicability of Feed-Forward and Recurrent Neural Networks for Prediction of Surface Quality of Laser Polished Surfaces