Polishing Method Research Articles

Effect of polishing methods on Candida albicans adhesion and contributing factors in heat-cured acrylic dentures: an in-vitro comparative study

IntroductionHeat-polymerized acrylic resin is widely used in prosthodontics due to its various advantages. However, its susceptibility to microbial colonization, influenced by surface properties such as roughness, water sorption, and free surface energy, poses challenges in maintaining oral health. Microbial adhesion, particularly of Candida albicans, plays a significant role in the overall microbial load on the denture surface, predisposing several oral and health related complications. While polishing techniques improve surface smoothness, their effects on water sorption and free surface energy, which are critical to microbial adhesion, remain understudied. This study explores the impact of Mechanical Polishing (MP) and Chemical Polishing (CP) methods on these surface properties and their potential to reduce Candida albicans adhesion.Materials and MethodsTwenty-four square samples of heat-cured acrylic were fabricated and divided into two groups of 12 for MP and CP respectively. Surface roughness (Ra) was measured using a profilometer. Scanning Electron Microscopy (SEM) analysis was conducted on polished and unpolished specimens. Water sorption was assessed through weekly weighing, and free surface energy was determined using a goniometer. Candida albicans identification was done using Dichloran Rose-Bengal Chloramphenicol (DRBC) agar and confirmation was achieved through microscopy and growth on selective media. Adherence and viable assays were performed on both polished and non-polished specimens. Statistical analysis was performed using SPSS (Version 24.0). Mann-Whitney U test compared surface roughness, water sorption, free surface energy, and initial adherence between MP and CP groups. Linear regression analysis examined the influence of these factors on Candida albicans adherence.ResultsSurface roughness did not significantly differ between the two polishing methods. However, CP resulted in significantly reduced water sorption, lower free surface energy, and decreased Candida albicans adhesion compared to MP. A significant negative association was observed between CP and Candida adherence.ConclusionBoth polishing methods achieved the desired level of surface smoothness. However, CP demonstrated superior performance in reducing water sorption, free surface energy, and Candida albicans adhesion. This suggests its practical benefits in clinical settings, particularly intaglio surfaces where MP is impractical.

Abrasive Flow Material Removal Mechanism Under Multifield Coupling and the Polishing Method for Complex Titanium Alloy Surfaces

This study addresses the challenge of uneven surface quality on the concave and convex regions during the precision machining of titanium alloy thin-walled complex curved components. An electrostatic field-controlled liquid metal-abrasive flow polishing method is proposed, which is examined through both numerical simulations and experimental investigations. Initially, a material removal model for the liquid metal-abrasive flow under electrostatic field control is developed, with computational fluid dynamics (CFD) and discrete phase models employed for the numerical simulations. Subsequently, the motion characteristics of liquid metal droplets under varying amplitudes of alternating electric fields are experimentally observed within the processing channel. This serves to validate the effectiveness of the proposed method in enhancing surface quality uniformity across the concave and convex regions of titanium alloy thin-walled complex curved components. Our results demonstrate that by controlling the distribution of the electric field in regions with varying flow strengths, the roughness differences between the concave and convex surfaces of the workpiece are reduced to varying degrees. Specifically, in the experimental group subjected to a 24 V alternating electric field, the roughness difference is minimized to 58 nm, representing a 44% reduction compared to conventional abrasive flow polishing. These findings indicate that the proposed electrostatic field-controlled liquid metal-abrasive flow polishing method significantly enhances the uniformity of surface polishing on concave and convex areas of titanium alloy thin-walled complex curved components.

Study on Cu CMP method using the superconductive assisted machining

Abstract We have developed a polishing method for Cu CMP using superconductive assisted machining (SUAM) with levitated magnets in the air. SUAM enables a non-contact pressure system by using the pinning effect of superconductivity to polish Cu electroplated films for backend processing. This method offers key advantages: reduced dust generation, polishing at room temperature, and precise pressure control between the polishing pad and wafer based on contact area and holding force from the pinning effect. Results show that, same as conventional Cu-CMP, the polishing rate with SUAM is proportional to pressure and rotational speed, particularly in high-pressure regions, demonstrating its effectiveness.

Experimental study of polishing systems on surface roughness and color stability of novel bulk-fill composite resins

ObjectiveThis in vitro study aimed to investigate the effect of five polishing systems on the surface roughness (SR) and color change (CC) of novel bulk-fill composite resins.MethodsFifty composite resin samples were prepared for each of the five groups: Stark Bulk Fill, SDR Plus, SonicFill 3, Charisma Bulk Flow One, and Filtek Z250. Each group of composite resins was further subdivided into five subgroups based on the polishing method applied: OptraGloss (OG), OptraGloss combined with Diapolisher paste (OGD), OptiDisc (OD), OptiDisc combined with Diapolisher paste (ODD), and Occlubrush (OCC) (n = 10). Surface roughness was measured using a profilometer following the polishing procedures, while surface morphology was assessed through atomic force microscopy and scanning electron microscopy. Subsequently, the samples were divided into two further subgroups for aging in distilled water and coffee (n = 5). The initial color parameters and those measured after 7 days were recorded to evaluate color change. Statistical analysis was performed using two-way ANOVA, followed by Tukey’s post-hoc tests (α = 0.05).ResultsSR significantly varied based on the composite resin and polishing system (p < 0.001). OCC polishing yielded the smoothest surface for STARK and SDR composites, while Charisma exhibited the lowest roughness in the ODD group (p < 0.05). OGD group consistently produced lower SR across multiple composites compared to the OG group (p < 0.001). Significant color changes (ΔE00) were found, with SonicFill and Filtek showing the greatest color stability when polished with OGD and OCC. For all polishing systems, except ODD, the SDR composite showed the greatest CC in coffee storage (p < 0.003).ConclusionThis study demonstrated that both the polishing technique and composite resin type significantly influenced SR. SR was notably affected by the interaction between the polishing method and resin type, with the OCC system consistently producing the lowest SR values. Additionally, Charisma exhibited surface properties similar to Filtek. Variations in color change were also observed based on both the polishing method and resin type, highlighting the critical role these factors play in determining the color stability of restorative materials.

Research on Deterministic Ring Removal Method for Full-Aperture Double-Sided Polishing of Large Aperture Optical Components

Research on Deterministic Ring Removal Method for Full-Aperture Double-Sided Polishing of Large Aperture Optical Components

Reverse growth surface planarization mechanism and high-efficiency polishing of KDP

ABSTRACT This paper proposes a reverse growth surface planarization mechanism for achieving high-efficiency precision processing of the potassium dihydrogen phosphate (KDP) crystal. The KDP crystal reverse growth has ordered and controllable characteristics similar to growth, which differs from the disordered and random dissolution in the natural state. Experiments are conducted using a high-precision annular polisher to investigate the surface characteristics, material removal, and surface planarization of different crystallographic planes in reverse growth. The repeat utilization of polishing liquids is studied to reduce processing costs. The difference in material removal and surface roughness of different crystallographic planes obtained from the same reverse growth polishing process is within 8%. The suitable undersaturation range for reverse growth surface planarization is 0.01–0.18, with a maximum material removal rate of 90 μm/min, 50 times that of the microemulsion polishing methods. Finally, a mirror-like KDP crystal surface is obtained with a surface roughness Ra of 0.00975 μm.

A Comparative Analysis of Car Surface Polishing Methods for Pollution Prevention

A Comparative Analysis of Car Surface Polishing Methods for Pollution Prevention

Review of Patents on Small Grinding Wheel Polishing Technology

Abstract: Grinding disc polishing is an important polishing method that can be used to manufacture various high-precision and high-quality optical components. The smoothing effect of grinding discs is a simple and effective method widely used to suppress MSF errors. Grinding disc technology has good polishing effects on flat, spherical, aspherical, and free form surfaces. The polishing mechanism is to generate chips through the small plastic cutting of abrasive particles, but it only uses a very small amount of abrasive particles to exert force and uses the flow friction between the abrasive particles and the grinding disc and the workpiece to flatten the surface roughness of the workpiece. It can be seen from the relevant literature that the floating tool holder maintains a constant pressure to solve the problem of uneven pressure distribution between optical components. The adjustable tool holder can adjust the amount of spring deformation to adapt to local surface changes of optical parts, ensuring consistent material removal. The force-adaptive tool holder can be adjusted in real time during the machining process to reduce errors generated during machining. The jointed tool holder improves the fit between the grinding wheel and optical components, ensuring a tight fit between the grinding wheel and optical components. This patent paper aims to introduce grinding wheel polishing technology as an essential method for manufacturing high-precision, high-quality optical components. It explores the optimization of abrasive tool design and the improvement of processing efficiency and proposes suggestions and prospects for future research, applications, and development. Through querying literature and patent databases, patent documents related to grinding disc polishing technology were collected and analyzed. The design characteristics of the device structure, technological innovations, as well as the effectiveness and improvements in practical applications were focused. Grinding disc polishing technology effectively removes surface defects and enhances the optical performance of optical components, particularly in suppressing MSF errors. This technology is suitable for flat, spherical, non-spherical, and freeform surfaces, with broad potential applications. Despite the numerous advantages of grinding disc polishing technology, such as simplicity, effectiveness, and wide applicability, critical issues still need to be addressed, including surface morphology control, improving polishing efficiency, and enhancing consistency. Future research should focus on optimizing tool design and developing new polishing materials and processes to improve the manufacturing quality and efficiency of optical components.

Control of surface edge roughness for an aluminum alloy mirror based on sub-aperture polishing

With current polishing methods, it is hard to guarantee roughness uniformity between the edge and inner regions of the surface. Hence, this paper develops a sub-aperture polishing method based on chemical mechanical action to remove turning periodic marks and improve surface roughness uniformity. A compliant polishing pad with a rigid tool holder is proposed to ensure that the pressure in the contact area remains constant when the polishing tool moves out the edge of the workpiece. The optimal process parameters were investigated in the full aperture polishing experiment. Numerical simulation was implemented to analyze the relationship between the overhang ratio and removal uniformity and optimize the polishing trajectory parameters. The polishing experiments with aluminum alloy mirrors reveal that the impurities inside the aluminum alloy restrict the further improvement of surface roughness. The average surface roughness is improved from 8.82 nm to 1.71 nm, and the peak and valley roughness value is reduced from 2.51 nm to 0.71 nm, which indicates the proposed sub-aperture polishing method can improve the surface roughness uniformity.

Green Chemical Shear-Thickening Polishing of Monocrystalline Silicon.

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.

Solid dielectric electrochemical polishing of 3D-printed parts: Performance and mechanisms

Surface post-processing of metal additive manufacturing components is challenging due to their typically complex geometries (e.g., curved surfaces) coupled with high initial surface roughness. Herein, we propose an efficient solid dielectric electrochemical polishing (SDECP) method employing ion exchange resin particles with a porous structure that absorbs and stores electrolytes as a conductive medium. This method enhances the surface quality of additively manufactured components with Bézier curved surfaces to a mirror finish, achieving improvements in Sa, Sq, and Sz of 91.5%, 91.7%, and 86.9%, respectively. Planetary motion strategies are implemented to optimize mass transfer on the anode surface in the discontinuous solid dielectric. Results indicate that bidirectional planetary motion (BPR) in SDECP effectively improves the uniformity of surface roughness and material removal across different regions of the part. Furthermore, we quantitatively describe the relationship between material removal rate (MRR) and average current in SDECP. The intermittent material removal mechanism of SDECP is elucidated utilizing discrete element method (DEM) simulations. Our work offers innovative insights into the material removal mechanisms of SDECP, presenting an efficient approach for overall surface post-processing of metal additive manufacturing components.

Ultra-precision process of soluble optical crystal considering non-aqueous shear-thickening polishing method

Ultra-precision process of soluble optical crystal considering non-aqueous shear-thickening polishing method

Experimental study of chemical mechanical polishing of polycrystalline diamond based on photo-Fenton reaction

Polycrystalline diamond (PCD) is widely used in cutting tools, optical devices, and heat dissipation tools due to its exceptional hardness, wear resistance, and thermal conductivity. However, these excellent properties also make polishing the PCD surface a challenge. Traditional polishing methods struggle to achieve both high material removal efficiency and high-quality surface finishes simultaneously. This paper proposes a chemical mechanical polishing (CMP) method for PCD based on the photo-Fenton reaction. The method utilizes the reaction between H₂O₂ and Fe₃O₄ under ultraviolet (UV) light to generate highly oxidative hydroxyl radicals (·OH), effectively oxidizing the PCD surface to reduce the difficulty of processing. The concentration of ·OH and Fe2⁺/Fe³⁺ in different reaction solutions was measured using spectrophotometry. Results indicate that the concentration of ·OH is highest in the photo-Fenton solution, and UV light promotes the conversion of Fe³⁺ to Fe2⁺, sustaining the ongoing photo-Fenton reaction. Through single-factor polishing experiments, the effects of various processing parameters on the CMP performance of PCD were investigated. The results show that the material removal rate of PCD increases with increasing concentrations of H₂O₂, abrasive particle size, polishing pressure, and polishing disc speed. In contrast, the removal rate first increases and then decreases with increasing UV light intensity and Fe₃O₄ concentration. Additionally, the surface roughness (Ra) of PCD decreases initially and then increases with increasing UV light intensity, abrasive particle size, polishing pressure, and polishing disc speed, while it decreases with increasing Fe₃O₄ and H₂O₂ concentrations. Under the conditions of 100 mW/cm2 UV light intensity, 2 wt% Fe₃O₄, 10 wt% H₂O₂, 5 wt% abrasive concentration, 0.5 μm abrasive particle size, 0.89 MPa polishing pressure, and a polishing disc speed of 60 r/min, the material removal rate of PCD reaches 698.7 nm/h, and the surface roughness Ra is 3.78 nm. The photo-Fenton reaction-based CMP method proposed in this paper provides a new approach to polishing hard-to-process materials.

Functional microstructured surface polishing: mechanism and applications

Functional microstructured surfaces are becoming increasingly important in the fields of optics, microfluidics, and surface engineering. These parts' functional surface roughnesses and microstructure molding accuracies directly affect their final service performance characteristics. To improve the machining qualities of functional microstructured surfaces, subsequent polishing treatment is necessary. This paper discusses the different polishing methods and effects of functional microstructured surface parts. Moreover, the challenges and bottlenecks in polishing functional microstructured surfaces are analyzed and discussed by considering the microstructure feature sizes, shapes, and substrate surface shapes. Then, the advantages, disadvantages, applications, and limitations of functional microstructured surface polishing methods are elucidated. Finally, the development trends of form-preserving polishing methods for functional microstructured surfaces are noted.

Chemical magnetic field-assisted batch polishing method of 316L stainless steel

316L stainless steel has been extensively employed in the manufacturing of medical equipment and biomedical implants because of its good ductility, corrosion resistance and biocompatibility, etc. However, there has always been a non-neglected problem of low polishing precision and efficiency in the whole machining chain for such parts, hence, it is difficult to meet the batch demand of the market for 316L stainless steel with high-precision surface. Based on the principle of magnetic field-assisted batch polishing (MABP) proposed by our research team previously, a novel chemical magnetic field-assisted batch polishing (CMABP) method here is developed by adding chemical reagents (i.e., the mixture of oxalic acid and hydrogen peroxide) in the preparation process of regular magnetic brush, desiring and expecting to further realize the polishing of 316L stainless steel with higher precision and efficiency simultaneously. The preliminary experimental results demonstrated that the value of surface roughness Sa after CMABP became smaller and the material removal rate increased comparing to that after MABP, which did verify the potential advantage of the established CMABP approach. In detail, CMABP experiments with pH value and H2O2 concentration as variables were carried out quantitatively. The results suggested that, within the set range of pH value (from 2 to 7) and H2O2 concentration (from 0.3 wt.% to 2.0 wt.%), when pH was chosen as 4 and H2O2 concentration was adjusted as 2.0 wt.%, the value of Sa after CMABP was the minimum, which could be 38% lower than that of MABP approximately. Nonetheless, material removal rate reached to the maximum, which could be around 168% more than that after MABP, when pH and H2O2 concentration were determined as 3.0 and 2.0 wt.%, respectively. Additionally, the discrepancy between the chemical and the regular magnetic brushes were detected and analyzed comparatively both at macro and micro scales. Also, the products on the surface of 316L stainless steel, such as the weak-binding layer and the passive layer, were discovered and taken to interpret the experimental phenomena of the surface roughness and material removal rate varying with the content of chemical reagents in CMABP, thereby revealing the material removal mechanisms correspondingly and interestingly. This work is capable of providing valuable reference undoubtedly for batch precision polishing of 316L stainless steel and other significant functional materials.

Study on Oxygen Plasma-Based Copper Etching Process

A plasma-based, room-temperature copper etch process using the chlorine- or bromine-containing feed gas was reported. This simple process could potentially replace the chemical mechanical polishing method in preparing copper interconnects. However, the chlorine- and bromine-containing gases are corrosive and must be handled with expensive equipment following stringent safety procedures. In this paper, the oxygen plasma-based copper etch process is presented. The copper film was converted into a porous and polycrystalline copper oxide film which was subsequently dissolved in a dilute hydrochloric acid solution. The copper film was expanded when converted into an oxide film. The oxidation precursors, i.e., oxygen radicals and ions, were generated in the plasma phase and then transported through the oxide layer to the underneath copper film where the oxidation reaction proceeded. The oxide growth rate is affected by plasma parameters, such as pressure and power, and the kinetics of the oxidation reaction. This new oxygen plasma-based process is a simple solution for preparing copper interconnects for nano and microelectronic products.

The science of printing and polishing 3D printed dentures.

To analyze the effectiveness of various techniques available for printing, finishing and polishing of 3D printed prosthesis. The articles were selected from electronic databases including PubMed and Scopus. Recently, lot of advancements have been observed in the field of 3D printing in dentistry. Numerous studies were found explaining the factors affecting the surface roughness such as printing speed, direction, layer thickness, post curing, etc., and the significance in achieving a smooth surface finish of a 3D printed prosthesis. The methods employed to achieve this range, similar to conventional and chairside polishing, are to use advanced coating materials such as light cured glazes to nanoparticles. 3D printing is being used in day-to-day practice and the prosthesis must be aesthetic looking to satisfy the patients' expectations. There is a lack of data supporting any one polishing method for the prosthesis. There is a need for further research on the existing techniques and newer advancements yielding aesthetic prostheses with an optimal surface finish.

Characterization of identical lithium-ion battery electrodes before and after charge/discharge cycles via in-plane large-area polishing

As an effective method to fabricate a large-area cross-sectional sample for lithium-ion battery electrodes, we perform in-plane polishing of LiNi0.8Co0.15Al0.05O2(NCA) cathode samples and obtain a large cross-sectional area with a diameter of 1.5 mm. The polished cross-sections of NCA cathode particles are sufficiently flat to perform the atomic force microscopy (AFM) measurements on each cathode particle. Following AFM-based Kelvin probe force microscopy and scanning spreading resistance microscopy measurements, an identical in-plane polished NCA sample is assembled into a coin cell for the charge and discharge processes. After 90 charge/discharge cycles, the in-plane-polished sample is successfully disassembled from the coin cell without causing critical damage. In addition, a microcrack structure, which is a typical degradation feature of the cycles of NCA particles, is observed for the identical in-plane polished NCA sample. This indicates that the in-plane polishing method is effective for investigating identical NCA electrode samples before and after the charge/discharge process. Furthermore, the in-plane polishing method can be successfully applied to the large-area polishing of a Si-based anode which is a mixture of Si carbon complexes and graphite particles. This study presents a novel methodology for analyzing the degradation of lithium-ion battery electrode materials.

Effect of Different Polishing Methods on Composite Surface Roughness

Effect of Different Polishing Methods on Composite Surface Roughness

Recent Patents for Optical Component Polishing Technology

Background: Fluid jet polishing, Airbag polishing, Magnetorheological polishing, and Ion beam polishing are all emerging polishing technologies commonly used for processing optical components, which can be used to manufacture various high-precision and high-quality optical components. Their processing mechanisms are to remove materials by high-speed jet impacting the surface of the workpiece; using a spherical flexible airbag as a polishing tool to obtain a super-smooth surface by adding polishing fluid containing fine abrasives; controlling the magnetic field to form a flexible polishing belt of Magnetorheological fluid, which undergoes relative motion to achieve material removal; using a neutral ion beam to bombard the surface of the workpiece to remove workpiece surface atoms and obtain a super-smooth surface through energy and momentum transfer between ions and workpiece atoms. The characteristics and removal mechanisms of various polishing methods are briefly described, and the advantages and key issues that need to be addressed for each polishing technology are pointed out, and suggestions and prospects for future research, application, and development are also given. Objective: In order to meet the growing demand for high-precision optical components and mass-manufactured optical components, this paper aims to study the various polishing technologies that are continuously improved and suggestions are made for future research and development directions. Method: This paper reviews the current patents related to various polishing technologies, such as Fluid jet polishing, Airbag polishing, Magnetorheological polishing and Ion beam polishing and other representative polishing technologies. Results: Various types of polishing technologies have been studied, and the main problem at the current stage is the lack of accuracy. The problem of the polishing device, such as fluid jet polishing, only considers the change of fluid velocity and pressure to construct the removal function model for analysis and summary, and suggestions for the latest research progress of various polishing technologies are given. Conclusion: The improvement and optimization of polishing technology are beneficial to improving the polishing accuracy and quality of optical components and have great help for the future development of related patents.