Effect Of Abrasive Size Research Articles

Optimization of abrasive slurry assisted rotating ultrasonic machining for enhanced micro-channel fabrication on ceramic silicon wafer (111)

This study examined the impact of abrasive slurry assisted Rotating Ultrasonic Machining (RUM) using Boron Carbide (B4C) powder of three mesh sizes: 400 Mesh, 600 Mesh, and 800 Mesh. The effects of abrasive size, feed rate, and tool rotation on Material Removal Rate (MRR) and Surface Roughness (SR) were investigated. The highest MRR of 3.454 mm³/min was achieved with 400 mesh, 30 mm/min feed rate, and 1250 rpm due to larger abrasive size, medium feed rate, and medium tool rotation velocity, while the lowest MRR of 0.284 mm³/min was noted with 600 mesh, 30 mm/min feed rate, and 1500 rpm, attributed to intermediate abrasive size and high tool rotation. The lowest SR of 1.16 μm was observed at 800 mesh, 15 mm/min feed rate, and 1500 rpm, resulting from smaller abrasive size and higher tool rotation facilitating polishing action and vibrational dampening. The highest SR of 3.71 μm occurred at 400 mesh, 45 mm/min feed rate, and 1500 rpm, due to larger abrasive size, higher feed rate, and tool rotation, increasing surface corrosion. ANOVA and regression analyses highlighted mesh size as the most significant parameter for both MRR and SR, with strong model-experimental value correlations. The findings demonstrate the suitability of abrasive slurry assisted RUM for fabricating micro-channels in X-Ray, optoelectronic, and semiconductor applications.

Surface generation modelling and form maintenance strategy in maskless fluid jet polishing of structured array surface

Structured array surfaces are extensively utilized in the fields of functional optical components and molds. However, high surface form accuracy of these surfaces is usually needed to implement superior performance, leading to great challenges in manufacturing. In this study, fluid jet polishing (FJP) was utilized to polish the cylindrical array surface. The effect of abrasive size and jet pressure on the form maintainability was elucidated by combining computational fluid dynamics (CFD) simulation. The abrasive trajectory and abrasive impact information were analyzed to reveal the material removal process. Tool influence functions (TIF) at different positions were simulated to model the surface generation process and provide a theoretical basis for the optimization of polishing parameters. A surface form maintenance strategy was proposed to achieve high form accuracy together with excellent surface quality by controlling the feed rate of the nozzle. A series of experiments were conducted to validate the effectiveness of the form maintenance strategy. The results revealed that the form error agreed well with the requirement after polishing with the designed feed rate. This study paves a new way for the polishing of structured array surfaces with a good surface form control.

Study on rheological properties and polishing performance of viscoelastic material for dilatancy pad

Shear dilatancy polishing (SDP) is an emerging flat polishing method for hard and brittle materials, which can achieve high-efficiency and high-precision polishing of workpieces under high-pressure and high-speed conditions. In our research, a novel viscoelastic material (VM) with non-Newtonian fluid properties was prepared. The dilatancy pad was subsequently obtained based on VM, abrasives, and a polyurethane pad. The effects of abrasive size and abrasive concentration on the rheological properties of VM were analyzed. The mechanism of abrasives in VM was investigated, and the principle of SDP was revealed. VM-30 wt%Diamond (0.5 μm) with excellent shear hardening performance was selected in the polishing experiment to study the effects of polishing time, polishing speed, and polishing pressure on polishing performance, and the optimal polishing parameters of SDP for tungsten were determined. Compared with traditional abrasive free polishing (AFP), SDP can realize a higher material removal rate (MRR increased by 33.4%) and better surface quality (Sa reduced by 32.2%) due to the shear dilatancy effect under high-pressure and high-speed conditions. After 90 min of SDP, the surface roughness (Sa) of tungsten workpiece was reduced from 307.9 nm to 12.1 nm. Results show that SDP is a promising and feasible polishing method for hard and brittle materials.

The good, the bad and the ugly polishing: Effect of abrasive size on standardless EDS analysis of Portland cement clinker’s calcium silicates

Standardless Energy dispersive spectroscopy (EDS) on polished samples of Portland cement clinker is routinely performed both for unhydrated phases as well as in cement pastes. Typically, the calcium to silica ratio is investigated. EDS analyses are highly dependent on the polishing quality of the sample. It is thus worth studying the Ca/Si ratios of cement phases in a clinker since they can be used as a reference. Indeed, alite (Ca3SiO5 or C3S in cement chemistry notation) and belite (Ca2SiO4 or C2S) should have an atomic Ca/Si ratio of 3 and 2, respectively. EDS carried out under the scanning electron microscope (SEM) is routinely used on polished samples to assess the composition of such phases. In the present study, Ca/Si ratios are investigated on a commercial clinker polished at various steps (6, 3, 1 and 0.25 µm diamond pastes, 0.05 µm alumina). All along the polishing process, ratios are coherent with theoretical ones and with the reference ones obtained by electron probe microanalysis (EMPA) in the present study.

Comparative analysis of ultrasonic drilling process using static and rotary tools

Ultrasonic drilling (USD) is widely used for drilling of glass. A comparative study of USD for 2.0 mm diameter hole in 3.0 mm thick soda lime glass has been performed using static (USD-ST) and rotary tool (USD-RT) of mild steel. To make the process more cost effective and productive, statistical models of material removal rate (MRR), hole circularity at entry and exit (HCentry, HCexit) and hole taper (Ht) have been developed using Box–Behnken approach of response surface methodology. The effect of abrasive size, frequency, ultrasonic power and tool rotational speed have been investigated and it was observed that abrasive size is the most significant factor to control MRR during USD-ST. In USD-RT, MRR, HCentry, HCexit and Ht are significantly affected by frequency. The combination of low frequency and small grain size produces high MRR in USD-RT. Increase of frequency from 22 to 24 kHz increases HCentry by 4.3% in USD-ST, whereas for rotating tool the increase of frequency from 22 to 25 kHz decreases the value by 2%. HCentry increases with the rise of frequency at constant ultrasonic power, USD-ST provides 7.14% more circular hole at entry compared to USD-RT for a combination of frequency and grit size. In multi-objective optimization of USD-ST, a desirability value of 0.8589 was obtained at ultrasonic power of 90%, frequency 23.47 kHz and abrasive grit no 60, whereas for USD-RT the desirability value of 0.8499 were correspondingly obtained at 78.48%, 25.5 kHz, 770.20 rpm and 60.

Development of Barrel Finishing Machine to Improve Surface Finish of the Wire Arc Additive Manufactured Parts

The wire + arc additive manufactured (WAAM) parts form wavy surfaces due to layer over layer deposition of the metal wire. These parts are often difficult to finish/clean for the intricate shapes and complex geometries. The barrel finishing technique which utilises abrasive media has been widely recognised as a mass finishing process. The commonly used designs for the barrel finishing process keeps the barrel either in the horizontal or vertical position. The proposed design has inclined barrel, taking advantage of both centrifugal and avalanche actions of forces produced by the vertical and horizontal barrel, respectively. The system utilises a barrel of diameter 400 mm and height 500 mm, supported by the two wheels on the periphery. A universal joint was used to transmit the motion from the power shaft to the barrel, which was also taking care of misalignment generated due to the eccentric loading. The effect of abrasive size and rotational speed was studied to determine the optimum finishing time for minimum surface roughness. The surface roughness (Ra) for representative corroded samples of various geometries was found to be decreasing and further increasing with processing time. The optimised finishing time was found to be in the range of 4–6 hours. The process was successfully implemented to finish WAAM parts having different geometries.

Molecular dynamics simulation of abrasive characteristics and interfaces in chemical mechanical polishing

Molecular dynamics simulation is employed to analyze the effect of sliding, rolling and oscillating movements on nanotribology properties of a diamond abrasive on a silicon substrate. The abrasive oscillating mechanism is achieved by simulating megasonic vibration-assisted on the planarization process. In this paper, the effects of abrasive size, sliding velocity, depths of polishing, rolling velocity, rolling direction, oscillating amplitude and oscillating frequency on material removal are considered. The results showed that the rolling mechanism reaches the highest number of atoms removed while the suitable oscillating mechanism gains the lowest height of asperity. The oscillating movement has remarkable results in wiping out the asperity atoms, although at a high amplitude and a low frequency causing some atoms from the flat substrate stuck to the abrasive and left some surface defects. Moreover, a multi-asperities model is set up to simulate the global-scale ability of sliding, oscillating and rolling mechanisms on polishing. This model indicates the saturated behavior of the rolling mechanism, while the lowest value of the surface roughness attained by the sliding mechanism. Combining three types of removing mechanisms could create a smooth surface with a high effective removal rate on both local and global-scales.

Simulation and experimental study on the effect of abrasive size, rotational speed, and machining gap during ultra-precision polishing of monocrystalline silicon

Monocrystalline silicon wafers are the key materials for micro-electro-mechanical-systems. These wafers require high surface quality with damage-free subsurface. Because of the high-speed deformation during the ultra-precision polishing of these wafers, Smoothed Particle Hydrodynamics (SPH) which is a meshless method with good self-adaptability can be useful in the simulation of the polishing process. In this work, SPH analysis model of Magnetic Abrasive finishing (MAF) is established according to the principle of the polishing process. Moreover, experiments are done to reveal the effects of polishing variables on the reduction in surface roughness (ΔRa) and material removal (MR). Also, verification of simulation results is done with experiments. Our findings showed that MR and ΔRa value increase with increasing abrasive size, rotational speed and, decreasing machining gap. According to our experimental findings, maximum ΔRa and MR are 0.65 and 39.09 mg, respectively. Finally, it is possible to optimize polishing parameters and provide the theoretical guidance for production.

Manuscript numerical simulation on ultra-precision polishing of monocrystalline silicon by SPH method

Ultra-precision polishing is an important processing method for monocrystalline silicon, in order to improve the machining efficiency and obtain good machining quality, it is necessary to investigate the material removal process and process parameters of ultra-precision polishing. Smoothed particle hydrodynamics (SPH) is a meshless method with good self-adaptability, it can be used in the simulation of ultra-precision polishing which has high speed deformation characteristics. The calculation model and SPH analysis model of ultraprecision polishing are established according to the principle of ultra-precision polishing, SPH method is used to simulate and analyze ultra-precision polishing of the monocrystalline silicon. The material removal process of ultra-precision polishing is investigated, the effects of abrasive size and indentation depth on the equivalent plastic strain (PEEQ), Mises stress and the force of abrasive is investigated. The result is that, at the different time of ultra-precision polishing, the maximum PEEQ is different, but the difference is not obvious; the X direction force of the abrasive increases with the indentation depth; the size of abrasive has a great influence on the soft coefficient of stress state in ultra-precision polishing. According to the simulation results, it is possible to optimize the technological parameters of ultra-precision polishing, and provide the theoretical guidance for practical production.

Effect of abrasive size on friction and wear characteristics of nitrile butadiene rubber (NBR) in two-body abrasion

Elastomeric seals are prone to failure caused by abrasion during sliding against rough surfaces. This study is devoted to investigate the two-body abrasion wear characteristics of NBR and effect of abrasive size on abrasive wear. The reciprocating abrasive wear tests were performed on a NBR pin against a SiC sandpaper, the abrasive sizes of SiC ranging from very large (200μm) to small (2.5μm). The morphologies of the NBR worn surface were examined using scanning electron microscopy and surface profilometry. In addition, the friction coefficients and wear rates were analyzed and compared. The results showed that abrasive size had a significant effect on the wear mechanical and tribological properties of the NBR. Overall, the wear mechanism of NBR transformed from abrasive wear to adhesive wear as the abrasive size decreasing. It is shown that for small abrasives, the friction coefficients decrease with the increasing abrasive size. However, for large abrasives, the reverse trend is observed. This difference is partially explained by the changes of wear mechanisms. The knowledge gained herein provides a better understanding of the rubber degradation and wear mechanism associated with abrasive sizes, and is useful to reduce sealant wear and lengthen their service life.

Effect of abrasive size on wear of metallic materials and its relationship with microchips morphology and wear micromechanisms: Part 1

In this paper, the effect of abrasive particle size on the wear of white cast iron with M3C carbide and with austenitic and martensitic matrices was investigated. Abrasive wear tests using a pin on alumina paper were carried out using abrasive sizes between 16 μm and 192 μm. The wear surface of the specimens was examined by SEM for identifying the wear micromechanism and the type of microchips (wear debris) formed on the abrasive paper. The results show that the mass loss for the white cast iron with both austenitic and martensitic matrices increases linearly with the increase of particle size until the critical particle size is reached. After the critical particle size is reached, the rate of mass loss of the iron with austenitic matrix increases at a lower linear rate, and for the iron with martensitic matrix the curve of mass loss is non-linear and flattens when the critical particle size is reached. The abrasive paper in contact with the iron of both austenitic and martensitic matrices presents continuous microchips and the main wear mechanism was microcutting before reaching critical particle size, and after that, it presents deformed discontinuous microchips and the main wear mechanism was microploughing. The results show that the critical abrasive size on wear is related to the wear micromechanisms and the microchips morphology.

Effect of abrasive size on wear of metallic materials and its relationship with microchips morphology and wear micromechanisms: Part 2

Abstract In this paper, the effect of abrasive particle size on the wear of three different metallic materials (AISI 1045 steel, aluminum alloy and gray cast iron) was investigated. Abrasive wear tests using a pin on alumina paper were carried out using abrasive sizes between 16 μm and 192 μm. The wear surface of the specimens was examined by SEM for identifying the wear micromechanism and the type of microchips (wear debris) formed on the abrasive paper. The results show that the mass loss for the AISI 1045 steel and for the aluminum alloy increases linearly with the increase of particle size until the critical particle size is reached. After the critical particle size is reached, the rate of mass loss of the aluminum alloy increases at a lower linear rate, and for the AISI 1045 steel the curve of mass loss is non-linear and flattens when the critical particle size is reached. The abrasive paper in contact with the AISI 1045 steel presents continuous microchips before reaching the critical particle size (about 116 μm) and after it, it presents deformed discontinuous microchips and abrasive fracture. The abrasive paper in contact with aluminum presents clogging and continuous microchips before the critical particle size (about 36 μm) and after it, it presents discontinuous microchips. The wear surfaces of the AISI 1045 steel and the aluminum alloy present microcutting as the main wear mechanism before reaching critical particle size, and after that, it presents microploughing as the main wear mechanism. The gray cast iron did not show a transition in the curve of abrasive size against mass loss. The morphology of the microchips was similar for the different sizes of abrasive (discontinuous). However, at smaller abrasive sizes, some thin continuous microchips and clogging were formed. The main abrasive wear micromechanism was microcutting for the different abrasives sizes tested. The results show that the effect of critical abrasive size on wear in metallic materials can be related with the wear micromechanisms and the microchips morphology.

Modeling and Predicting Roughness of the Abrasive Jet Finishing with Grinding Wheel as Restraint

Based on the modeling and experiments concerning the surface roughness in abrasive jet finishing with grinding wheel as restraint, the effect of abrasive size, abrasive fluid concentration, machining cycles, wheel velocity and carrier fluid on machined surface quality was investigated. Surface grinder M7120 was employed in a jet machining experiment conducted with W18Cr4V and 40Cr materials, profilometer TALYSURF was used to measure the micro geometrical parameters after machining, and SEM was used to observe surface micro-morphology. Experimental results show that with W7 Al2O3 powder at the mass fraction of 10% and antirust lubricating liquid being adopted in jet machining for 20 to 30 cycles, not only high surface shape precision can be kept or obtained, but also defect-free machined surface with the roughness of Ra0.15～1.6µm can be obtained with high efficiency. Experimental observation and experimental results proved that the experimental results agree well with a mechanism-based machining model.

Theoretical Modeling and Experimental Verification of Surface Roughness in Abrasive Jet Finishing

Based on the modeling and experiments concerning the surface roughness in abrasive jet finishing with grinding wheel as restraint, the effect of abrasive size, abrasive fluid concentration, machining cycle, wheel velocity and carrier fluid on machined surface quality was investigated. Surface grinder M7120 was employed in a jet machining experiment conducted with W18Cr4V and 40Cr materials, profilometer TALYSURF was used to measure the micro geometrical parameters after machining, and SEM was used to observe surface micro-morphology. Experimental results show that with W7 Al2O3 powder at the mass fraction of 10% and antirust lubricating liquid being adopted in jet machining for 20 to 30 cycles, not only high surface shape precision can be kept or obtained, but also defect-free machined surface with the roughness of Ra0.15～1.6µm can be obtained with high efficiency. Experimental observation and experimental results proved that the experimental results agree well with a mechanism-based machining model.

Chemical-Mechanical Polishing of Wafers with Copper Film by Nano-Scale Abrasives

In this paper, experiments are designed and conducted to investigate the effects of abrasive size for Chemical-Mechanical Polishing (CMP) of copper film under different additives in HNO3-based polishing slurries. Alumina modified colloidal silica 100S (φ26nm), 200S (φ40nm) and Al2O3 (φ90nm), are used as polishing abrasives in this study. Experiments showed the following results. (1) With citric acid as an additive to slurry, the removal rate (RR) of the CMP process increases with abrasive size. Surface quality, however, becomes worse at the same time. (2) With benzotriazole (BTA) as an additive, RR of the slurry with Al2O3 powder is slightly higher but it does not increase with the abrasive size in general. Surface quality tends to be worse at the same time though it is not as strong as that in the slurry with citric acid as the additive. (3) The size effect of abrasive on RR with citric acid as additive is stronger than that with BTA.

Modeling the effects of abrasive size, surface oxidizer concentration and binding energy on chemical mechanical polishing at molecular scale

No conclusive results have been proposed for the influence of the abrasive particle size on the material removal during the chemical mechanical polishing (CMP). In this paper, a mathematical model as a function of abrasive size and surface oxidizer concentration is presented for CMP. The model is proposed on the basis of the molecular-scale removal theory, probability statistics and micro contact mechanics. The influence in relation to the binding energy of the reacted molecules to the substrate is incorporated into the analysis so as to clarify the disputes on the variable experimental trends on particle size. The predicted results show that the removal rate increases sub-linearly with the abrasive particle size and oxidizer concentration. The model predictions are presented in graphical form and show good agreement with the published experimental data. Furthermore, variations of material removal rate with pressure, pad/wafer relative velocity, and wafer surface hardness, as well as pad characteristics are addressed. Results and analysis may lead further understanding of the microscopic material removal mechanism from molecular-scale perspective.

Fluidized Bed Assisted Abrasive Jet Machining (FB-AJM): Precision Internal Finishing of Inconel 718 Components

Abstract The relatively new technique of fluidized bed assisted abrasive jet machining (FB-AJM) is applied to finishing the inner surfaces of tubular Inconel 718 components. The effects of abrasive size, jet pressure, and machining cycle were evaluated, and the behavior of abrasive cutting edges acting against the surface during the process to remove material is accounted for. The finished surface was found to be highly dependent on jet pressure because it affects the abrasive contact against the surface as well as the finishing force acting on the abrasive, on the abrasive grain size, which controls the depth of cut, and on machining cycle, which controls the interaction time between the abrasives and the surface being finished. By altering these conditions, this process achieves surface roughness (Ra) as fine as 0.1μm and imparts minimal additional residual stress on the surface. This study also reveals the mechanisms that determine the smoothing of the inner surface of Inconel 718 tubes and improve the form accuracy, i.e., the internal roundness of the Inconel 718 tube.

Effects of Abrasive Size and Concentration with An-ionic Surfactant on the Non-Prestonian Behavior of Ceria Slurry in STI-CMP

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Molecular Dynamics Analyze on Effects of Abrasive Size and Cut Depth on the Monocrystal Silicon Grinding

Molecular dynamics (MD) simulation is carried out to analyze the effects of abrasive ngrain size and cut depth on monocrystal silicon grinding process. Tersoff potential is used to describe the interactions of diamond and silicon atoms. Based on classical Newtonian mechanics law, the motion equations of atoms are established and the trajectory of each atom in phase space is obtained with the aid of Velocity Verlet algorithm. Debye model is introduced to convert between kinetic energy and temperature of an atom. The grinding processes of by single grain with different size and different cut depth are investigated in atomic space. Through comparing shearing force and potential energy in the single grain grinding process, the effects of cut depth and grain size on the grinding process are discussed. From the results of MD simulation, it is revealed that when the cut depth increases, both the shearing force in silicon crystal and potential energy between the silicon atoms rise, deformation and dislocations in the silicon lattices increase. As a result, all theses lead to^more severe surface and subsurface damage. With the decreasing of grain size in the same cut-depth nanometric grinding processes, the shearing force in silicon crystal and potential energy between the silicon atoms become larger, deformation and dislocations in the silicon lattices increase.

Computational investigation of microstructural effects on abrasive wear of composite materials

Abrasive wear of composite materials is a complicated surface damage process, affected by a number of factors, such as microstructure, mechanical properties of the target material and the abrasive, loading condition, environmental influence, etc. Microstructure is one of the major factors; however, its effect on the wear mechanism is difficult to investigate experimentally due to the possible synergism with other influences. Computer simulation is an effective approach for such studies, since controllable “computational experiments” can be performed to investigate the separate contribution of the individual factors on wear. In this work, a dynamic model, based on the Newton's law of motion, was applied to simulate abrasive wear of hard particle reinforced metallic matrix composite materials. In the simulation, a material system is mapped onto a discretized lattice. Each lattice site represents a unit mass which may move under an external wearing force and through the interaction with adjacent sites. The site–site interaction is a function of the mechanical properties of the reinforcement and the matrix. When the strain of a site–site bond exceeds a critical value for fracture, the bond is broken. A lattice site or a cluster of lattice sites is worn away if all bonds connecting the site or the cluster to its neighbours are broken. Microstructure largely influences the wear behaviour of a composite material. When abraded by abrasive particles, the reinforcement volume fraction, size and its distribution play important roles in resisting abrasive wear. In the present study, the above-mentioned factors, especially the effect of the size distribution of reinforcing particles in a composite on wear, were computationally investigated. Furthermore, the effects of abrasive size and the ratio of the abrasive size to that of the reinforcement particles were also studied. Mechanisms responsible for the microstructural effects on abrasive wear of composite materials are discussed.