Abrasive Polishing Research Articles

Characteristic of fixed abrasive polishing for fused silica in anhydrous environment

In order to overcome the randomness of free abrasive polishing (CMP), abrasive waste and the resulting hydration layer, this paper presents a fixed abrasive polishing technique in the anhydrous environment. We have achieved a stable polishing wheel sintering process. The pellet we made have applied to fused silica polishing.It is found that the surface profile accuracy and roughness convergence speed are significantly improved comparing with the free abrasive polishing, and the pellet did not break and wears evenly. The influences of changing parameters including pressure, rotation speed on the material removal rate and surface roughness is examined. Removal rate does not increase with applied pressure and rotation speed, which is inconsistent with Preston's formula. The heat generated in machine process is paramount parameters determining removal efficiency. In order to get the most suitable processing temperature, We employed in-situ infrared camera and finite element analysis to test the temperature, which clarify the material removal does not increase with applied pressure and rotation speed in dry fixed abrasive polishing. Further, for testing the properties and stability of the pellet, the chips and polishing wheel were chemical analyzed using EDS and XRD, the results show a probable mechanism.

Formation mechanism and quality control technology for abrasive flow precision polishing vortex: large eddy simulation

Abrasive flow polishing technology (AFPT) is a novel method of precision machining for improving the surface precision of the workpiece, where the micro-cutting process can be achieved for the finishing process of the inner surface of the workpiece through its contact with an abrasive. In order to investigate the vortex formation mechanism of the baffle servo valve nozzle of abrasive flow precision polishing (AFPP), the large eddy simulation (LES) method has been employed to analyze the flow path of abrasive flow and the effect of the vortex on the nozzle wall surface. To clarify the precise polishing action of abrasive flow, the impact of cutting behavior of abrasive particles is carried out with the vortex of the nozzle wall surface. The quality control method of abrasive flow precision polishing (AFPP) baffles servo valve nozzle is revealed from the formation mechanism of different cross-section vortices. It is concluded that the grinding speed of the abrasive flow has an important influence on the polishing quality of the abrasive flow. The higher the grinding speed, the better the precision of the abrasive flow. Finally, our results led us to conclude that the abrasive flow precision polishing technology (AFPPT) can effectively improve the surface quality of the nozzle orifice. Moreover, it can improve the abrasive flow grinding speed which can effectively improve the surface accuracy of the workpiece for the ideal surface quality.

A novel polishing method for single-crystal silicon using the cavitation rotary abrasive flow

Traditional low-pressure abrasive flow polishing can produce highly smooth surfaces, but the efficiency of this method is too low for polishing of hard-brittle materials parts. This paper proposes a novel cavitation rotary abrasive flow polishing (CRAFP) method. The energy generated from the cavitation bubble collapse is used to increase the kinetic energy of the abrasive particles in the low-pressure abrasive flow and the motion randomness of the abrasive particles near the wall; thereby, the efficiency and quality of low-pressure abrasive flow polishing are improved. The CRAFP mechanism was first introduced, and then the characteristics of the CRAFP process were investigated using computational fluid dynamics (CFD)-based abrasive flow simulation. Subsequently, a single-crystal silicon wafer polishing test was carried outperformed to verify the validity of the CRAFP method. The polishing results were compared with those of the traditional low-pressure abrasive flow polishing method. After 8 h of polishing using the CRAFP method and the traditional low-pressure abrasive flow polishing method, the surface roughness of the workpiece decreased to7.87 nm and 10.53 nm, respectively. Furthermore, by starting at similar initial roughness values, the polishing time required to reduce the roughness to 12 nm was 3.5 h and 6 h, respectively. The experimental results demonstrated that CRAFP can satisfy the surface requirements of single-crystal silicon (Ra < 12 nm) and exhibit high polishing efficiency and good quality.

Numerical study of three-body diamond abrasive polishing single crystal Si under graphene lubrication by molecular dynamics simulation

In this study, molecular dynamics (MD) simulation was used to investigate a new mechanical polishing method for three-body polishing of single crystal Si under the lubrication of graphene. The polishing depth and polishing speed were adjusted under the same processing parameters to compare the results. The development of polishing force, atomic displacement, coordination number, temperature, potential energy, friction coefficient, and polishing surface morphology was studied during nano-polishing. The analysis shows that the polishing depth in silicon polishing plays a crucial role in the change of coordination number of silicon. The deeper the polishing depth, the higher the polishing force, the more obvious the subsurface damage layer, the higher the potential energy. High defect atomic number and high normal stress. Moreover, the material removal rate is proportional to the polishing depth; a larger polishing speed significantly increases temperatures and potential energy. However, a smaller polishing rate does not result in fewer defective atoms and Bct5-SI/SI-II type atoms, as well as lower material removal efficiency. Finally, graphene-lubricated three-body polished single crystal silicon can improve the surface quality and reduce material removal efficiency.

Polystyrene-supported dendritic mesoporous silica hybrid core/shell particles: controlled synthesis and their pore size-dependent polishing behavior

This work described a straightforward synthetic route to fabricating polymer/silica hybrid particles with controllable architectures and their advantages as abrasives. The poly(vinylpyrrolidone)-modified and divinyl benzene cross-linked polystyrene (PS) cores were synthesized via a developed soap-free emulsion polymerization, and the outer dendritic-like mesoporous silica (D-mSiO2) shells were coated onto the cores using an oil–water biphase approach combined with a selective removal of hexadecyltrimethylammonium bromide templates. The resulting core/shell PS/D-mSiO2 samples were characterized by SEM, TEM, XRD, FTIR, and nitrogen adsorption/desorption, offering comprehensive information on the composition, structure, morphology, pore size, shell thickness, and surface area. The pore size of D-mSiO2 can be controlled within the range of 3–9 nm by varying the upper oil phases, which serve as swelling agents to enlarge the mesochannels. The PS/D-mSiO2 particles can be used as novel polishing abrasives and present superior surface quality (0.16 ± 0.02 and 0.26 ± 0.03 nm of root-mean-square roughness) compared to the commercial solid SiO2 ones (0.54 ± 0.05 nm). Moreover, the PS/D-mSiO2 hybrids with an enlarged pore size result in an inferior structural stability, which is important for final surface finish and removal rate. The presented results provide not only a strategy for preparing PS/D-mSiO2 core/shell particles with tunable pore sizes, but also a regulation that can be applied to prepare other core/shell hybrids with dendritic-like mesosilica shells.

Evaluation on ultrasonic abrasive water jet surface processing of aluminum nitride

In the present study, the processing performance of ultrasonic assisted abrasive waterjet polishing was experimentally investigated by using response surface method. The experiment was designed with the application of Box-Behnken method. The second order multiple regression equations were established to acquire the response surfaces. The ANOVA results showed that impact angle, the second order term of pump pressure and the interactive term of impact angle and ultrasonic power are the most significant factors in affecting the surface roughness. The interactive effects on surface roughness of the processing parameters were investigated with the response surfaces. It has been found that better finish can be acquired at higher ultrasonic power as a consequence of the enhancement of the ductile removal ability in the abrasive erosion process. Finally, the processing optimization was conducted with the use of response surfaces. The results of the validation experiment positively verified the optimization and prediction capacity of the response surface model.

Precision Polishing of Single Crystal Diamond (111) Substrates Using a Sol-Gel (SG) Polishing Pad

In recent years, the application prospect of single crystal diamond (SCD) in the field of electronics is remarkable, and material processing technologies are the basis for the application of semiconductor materials. In this paper, a novel polishing method for SCD substrates was developed utilizing a sol-gel (SG) polishing pad, which is a semi-fixed abrasive polishing tool fabricated by SG technique. The surface morphology of SCD substrates was observed with a 3-D optical profiler and scanning electron microscopy (SEM). The results showed that the surface roughness was 1.32 nm Ra and the material removal rate of SCD (111) was about 120 nm/h. The polished diamond surfaces and wear debris were investigated using Raman spectroscopy and transmission electron microscopy (TEM), respectively. The results showed the removal mechanism of SCD using an SG polishing pad was mainly dominated by the mechanical removal and phase transformation, including the mechanical cleavage, amorphization, and graphitization.

Post-Processing Effects on Surface Properties of Direct Metal Laser Sintered AlSi10Mg Parts

Direct metal laser sintering is a powder bed fusion type additive manufacturing (AM) method. It provides opportunity to create near net shape parts layer-by-layer. Because of poor surface quality post processing operations are required. This paper investigates the effect of surface finishing operations such as abrasive blasting, shot peening and polishing on surface texture properties and green tribological behavior of direct metal laser sintered AlSi10Mg parts. 2D and 3D surface roughness characterization, density and hardness measurements were implemented. Ball-on-disc wear tests were applied under 10 N load with palm oil and soybean oil as green lubricants. Petrol based, commercial machine oil was used for control. The results revealed that post processing operations affected surface texture and tribological properties of the samples. Abrasive blasting increased surface hardness to the 187 HV, while it was measured as 178 HV and 124 HV for shot peening and polishing processes respectively. Average surface roughness Ra, was measured as 18.71 µm for shot blasted surface. This value recorded as 5.39 µm for shot peened and 1.39 µm for polished surfaces. Minimum wear rate was calculated as 3.88 × 10−4 mm3/Nm for shot peened surface with palm oil while maximum was calculated as 7.92 × 10−4 mm3/Nm for polished surface with MO lubrication. Palm oil and soybean oil represented superior lubricating properties than petrol based commercial machine oil for all surfaces. It can be concluded that surface post processing has important effect on texture properties of metal AM parts. Moreover, vegetable oils are promising lubricants for increasing tribological properties of AM surfaces.

Application of taguchi method to investigation of optimal abrasive jet polishing parameters

The surface finish of N-BK7 optical glass is improved by abrasive jet polishing (AJP) process. Taguchi’s method is employed to investigate optimal AJP parameters. The important parameters that influence the N-BK7 surface finish are determined by Analysis of variance (ANOVA). The optimal parameters are found based on Taguchi’s experimental results and signal noise ratio (S/N). These optimal parameters are: polishing time of 45 min, pump pressure of 5 kgf/cm2, standoff distance of 12 mm, abrasive grain type of Al2O3, abrasive grain concentration of 20 %, and impact angle of 40°. The surface finish (Ra) of the N-BK7 is improved significantly from 0.350 µm to 0.018 µm.

Study on the surface quality of marble tiles polished with Sol-Gel derived pads

Sol–gel (SG) pads are used to polish different types of marble tiles and obtain high-gloss, low roughness, and scratch-free surfaces. The main features of such tools are semiconsolidated abrasives and flexible substrates. Through experiments with three types of polishing methods and two different types of tools used to polish marble tiles, the polishing mechanism of SG pads was confirmed. An abrasive yield phenomenon was observed for the semiconsolidated abrasive polishing tool with a flexible matrix, which resulted in a mirrored marble surface with high gloss, and the polishing steps were simplified. For SG polishing pads, a larger abrasive can be used to obtain high-gloss marble surfaces compared to the fine abrasives used in traditional resin polishing tools. Therefore, the agglomeration problem associated with fine particle size abrasives is avoided. In addition, after SG pad polishing, the surface of the marble tiles exhibited hydrophobic properties, and the oleophobic properties were simultaneously improved.

Droplet Spreading and Wettability of Abrasive Processed Aluminum Alloy Surfaces

One of the main cause of a droplet metastable state is found to be surface roughness. This state is characterized by a large contact angle hysteresis and condition when the static contact angle is larger than the advancing dynamic contact angle. Besides the texture, other factors can influence the deviation from the equilibrium state, in particular, the fluid flow rate (the growth rate of a droplet) affecting the contact line speed. An experimental study was done to determine the effect of roughness and fluid flow rate on wetting of aluminum-magnesium alloy surfaces with random roughness processed by abrasive polishing. Three-dimensional roughness parameters were used to evaluate their texture. The correlations between these parameters, static, advancing and receding dynamic contact angles, hysteresis, and contact line speed were obtained. The molecular-kinetic theory of wetting was used to interpret the dynamic contact angle data.

Development of abrasive jet polishing by using amino thermosetting plastic abrasive for aluminum alloy

A novel hybrid method, using a medium-hardness amino thermoset plastic (ATP) particles in abrasive jet polishing (AJP), was developed. Based on the theoretical and experimental analysis of the influence of critical operative variables on the trend of the polished surface, wonderful discoveries were obtained. ATP abrasive can not only be used in AJP to polish aluminum alloy and achieve uniform surface finish, but also possess a great advantage over the conventional abrasive jet polishing (AJP) technologies using superhard abrasives (e.g., Al 2O3, SiC), that is, abrasive embedding combined with ploughing-groove defeats can be resolved. This significant observation is especially expected to be useful for improving surface quality and fatigue properties of large and complex aircraft structural components made of aluminum alloys or other aerospace materials including titanium alloys and magnesium alloys.

Ti6Al4V Surface Modification by Hydroxyapatite Powder Mixed Electrical Discharge Machining for Medical Applications

Titanium surface modification by the Hydroxyapatite (HA) mixed Electrical Discharge Machining (EDM) is an alternative and promising technique to enhance the biocompatibility and to promote the biological performance in bone, which is dependent on surface properties, such as surface roughness, chemistry, and wettability. HA powder is used for the first time with electrical discharge machining to improve osteoblastic cell activity on the developed surfaces for Ti6Al4V. Different HA concentrations in deionized water were tested as an experimental variable during EDM. Abrasive polishing and electrical discharge machined control surfaces without powder addition also analyzed to compare the results. The surface characteristics of analyzed samples were evaluated by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffractometry (XRD), white light interferometry, and contact angle measurements. The wettability tests suggest that the hydroxyapatite powder mixed EDM’ed surfaces shows highly hydrophilic characteristics compared the other surfaces, abrasive polished and EDM’ed without powder addition in the dielectric. The results from the MTT assay revealed that those surfaces modified using HA powder addition in distilled water dielectric liquid promoted the most significant cell attachment/growth. The results indicate that HA powder mixed EDM offers a promising method for the surface modification of biomaterials such as titanium alloys

Surface Correction Control Based on Plasticized Multilayer P(VDF‐TrFE‐CFE) Actuator—Live Mirror

AbstractThe interdisciplinary approach presented here creates next‐generation large mirrors using electroactive polymer (EAP) actuators without classical glass abrasive polishing (“live mirrors”). The outstanding electromechanical coupling properties of terpolymer are taken advantage of, particularly when doped with plasticizer, e.g., diisononyl phthalate (DINP). This doped terpolymer creates a large strain response as well as excellent mechanical energy density under relatively low electric fields. Classical EAPs (e.g., polyurethane, silicone) require extremely high input voltages to reach sufficient mechanical strain. Using the high‐permittivity doped terpolymer and the concept of stacking multilayers, high displacements and large forces are generated. The actuation performance of multilayered terpolymer filled with DINP has been proven to shape mirror glass with a preliminary prototype of an 8‐layer actuator stack. The experimental results demonstrate surface deformations under load conditions of several microns. This is large enough to usefully control large optical telescope mirrors. This technology may enable much larger high‐quality optical mirror systems for ground‐ and space‐based astronomy and communications telescopes.

Design and Finite Element Analysis of Ultrasonic Composite Abrasive Vibration Polishing Equipment

In order to develop a workpiece surface polishing equipment with high performance and high precision, the overall structural design and parameter selection of ultrasonic composite abrasive vibration polishing equipment were mainly completed. Secondly, static analysis of the crankshaft connecting rod piston mechanism is performed by ANSYS Workbench software. We can know that the crankshaft connecting rod piston mechanism has the most concentrated stress at the contact between the small end of the connecting rod and the connecting rod shaft. And the stress value is 121.04MPa but less than the allowable stress value of the connecting rod. Therefore, the strength of the crankshaft connecting rod piston mechanism meets the design requirements, and the modal analysis of the crankshaft is carried out, and the crankshaft right crank displacement deformation amount is the most. It provides a theoretical basis for the optimization design of the crankshaft later and provides a reference for the research of ultrasonic composite abrasive vibration polishing equipment.

Research on High Precision and Deterministic Figuring for Shaft Parts Based on Abrasive Belt Polishing.

A deterministic figuring method for cylindrical surface based on abrasive belt polishing is proposed in this study in order to improve the geometric accuracy of metal shaft parts. The principal motion of material removal is performed through the axial oscillation of the abrasive belt, and the different material removal at different positions can be obtained through servo control of the machine tool spindle by removing high error spots on the cylindrical surface and finally deterministically corrects the roundness error. An abrasive belt-based deterministic figuring device was built, and the figuring experiments were performed on the surface of steel workpieces 100 mm in diameter and 130 mm in effective length. The roundness errors of the entire workpiece after twice figuring iterations decreased nearly from the initial 3 μm to 1 μm, which preliminary verified the feasibility of this method. This deterministic figuring method is expected to break the machining accuracy limit and improve the rotation precision of the precision shaft parts such as the aerostatic spindle.

Analytical model of dynamic and overlapped footprints in abrasive air jet polishing of optical glass

Abstract Thanks to the superior machined surface integrity, high machining feasibility, and limited tool wear, the Abrasive Air Jet Polishing (AAJP) has been considered as a widely used finishing process, especially for high-valued small and complex optics products. Therefore, many experimental, theoretical and processing technology studies have focused on this topic. However, experimental studies cannot provide an in-depth understanding of the process principle while most of the theoretical models/methods have been established based on many unrealistic assumptions. To fill this gap, this paper suggests an analytical model of the polished surface topography (or footprint) considering (i) the horizontally asymmetric cross-section profiles of a single-abrasive impact footprint, (ii) the abrasive-workpiece elastic deformation and further springback when the abrasive bounces back, and (iii) the overlapping footprints generated by multiple abrasives having a normal-distributed size. The systematic validation trials proved the model accuracy and feasibility. Based on the validated model, the effects of the polishing parameters including the jet pressure, jet angle, and abrasive size on both machined surface roughness and removed material volume are studied. The proposed model is anticipated for not only exploring and laying the theoretical foundation of the AAJP process in more depth, but also to provide guidance for industrial manufacturing in terms of polishing parameter optimization and polished surface prediction.

A study of ultraprecision mechanical polishing of single-crystal silicon with laser nano-structured diamond abrasive by molecular dynamics simulation

In the present study, a newly proposed mechanical polishing method of single-crystal silicon with nano-structured diamond abrasives fabricated by laser was investigated, using molecular dynamics (MD) simulations. The results were compared to conventional mechanical polishing under the same machining parameters. Polishing forces, atomic displacement, development of hydrostatic and von Mises stresses in the subsurface zone, temperature distribution, and polished surface morphologies during nano-polishing were investigated. An analysis model was also built to explore the subsurface damage mechanism in terms of examining the hydrostatic and shear stress distributions during nano-polishing. The analyses demonstrated that structured abrasives in silicon polishing lead to lower polishing forces, thinner subsurface damage layer, lower hydrostatic stresses, lower defect atom numbers, and less compressive normal stresses. Nevertheless, structured nanoscale abrasive polishing leads to lower material removal rates. Additionally, more Si-II forms from Si-I, when polishing with #-shaped groove abrasive is performed.

Numerical simulation of the variable diameter pipe based on abrasive flow machining

Based on the numerical analysis model of abrasive flow polishing, the effects of fluid turbulent kinetic energy, turbulent intensity and turbulent viscosity on the quality of polishing on polishing quality are studied and analyzed by taking variable diameter pipe as an example. The results of numerical simulation show that the polishing quality becomes better with the decrease of aperture. Therefore, the optimal processing parameters can be simulated according to the specific size of the workpiece, which can provide technical support for the production.

Molecular dynamics simulation of SiC removal mechanism in a fixed abrasive polishing process

Abstract Precision polishing of mono-crystalline SiC wafers on a fixed abrasive pad is investigated by double-nano-abrasives cutting at micro/nano scale in this report. Prior to this report, a single abrasive approach in molecular dynamics simulation had been employed to illustrate the material removal mechanism in SiC polishing process, which is quite different from the real situation of the fixed abrasive polishing process. Cutting depth and spacing of abrasive particles in a fixed abrasive pads were tested to gain insights on phase transformation, subsurface damage, surface quality, material removal and friction characteristics of polished SiC wafers by molecular dynamics simulation. By following the coordination number and radial distribution function, we clearly see that the number of phase transformation atoms caused by cutting and abrasion increases with the cutting depth of nano-abrasives on the surface of SiC workpiece. Simulation results also suggest that t he phase transformation of the SiC crystal phase increases with the lateral spacing of abrasive particles in pads, while does not change much with the increase of the longitudinal spacing. It is also found that the deeper the abrasive cutting depth, the deeper subsurface damage, resulting more materials’ removal from SiC workpiece. The lateral and longitudinal abrasive spacings lead to little change the depth of subsurface damage on the wafer in MD simulation for a fixed double abrasive polishing. The surface roughness is better with the larger lateral abrasive spacing, but no clear correlation with the longitudinal abrasive spacing.