Abrasive Slurry Concentration Research Articles

Surface topography characterization of USMM during machining of zirconia ceramic using silicon carbide abrasives: An experimental and simulation approach

Zirconia is a highly biodegradable ceramic material with excellent fracture resistance, in biomedical engineering, particularly dental implants. This research work has been focused on optimizing the quality of micro-hole generation in zirconia ceramic through ultrasonic micromachining (USMM). Three key process parameters such as abrasive slurry concentration, tool feed rate, and power rating are considered in this research work. The material removal rate, overcut, and taper angle are considered as responses. Response surface methodology has been employed for modeling during the USMM process, and a mathematical model has been developed to understand material removal mechanisms. Finite element analysis has been utilized to provide insights into the impacting process for industry requirements. A 3D model has been created to perform dynamic analysis under practical conditions. Multi-objective optimization has been applied to achieve optimum material removal rate (MRR), overcut, and taper angle. From multi-objective optimization, a slurry concentration of 49.59% g/l, tool feed rate of 1.16 mm/min, and power rating of 386.87 W has been found and in this parameter settings maximum MRR of 0.5333 mm3/min, minimum taper angle of 0.3428 degrees, and minimum overcut of 36.64 µm has been obtained during machining of ZrO2 ceramics.

Generation of array of square microcavity on quartz by ultrasonic micromachining process utilizing developed micro tool

Quartz possesses distinct characteristics such as exceptional hardness, high brittleness, non-conductivity, remarkable corrosion resistance, efficient transmission within specific wavelengths, strong electrical insulation properties, and the ability to withstand high temperatures and thermal shocks. These extraordinary attributes have led to its component in a wide range of applications, including the fabrication of microelectronic chips, biochips, biological channels, microfluidics, optical lenses, beam-splitting lenses, etc. Ultrasonic micromachining (USMM) is a highly promising technique within the realm of micromachining to create micro features on quartz surfaces. In the present research, array of square micro tools has been designed and developed by the wire-electrical discharge machining (EDM) process. By utilizing the developed array of square micro tools, microcavity arrays have been generated by the USMM process. The influences of process parameters on material removal rate (MRR), width deviation (WD), angular deviation, and taper of square microcavities have been investigated in the present research work. The higher MRR is obtained as 1.427 mm3/min at higher abrasive slurry concentration and lower WD of micro cavities is obtained as 37 µm and lower taper angle is 1.109° at 5% abrasive slurry concentration. The lower value of angular deviation is obtained as 0.836° at a lower power rating during the generation of an array of square microcavity on quartz by the USMM process. By employing array of micro tools, the accuracy of micro features can be improved, and also productivity can be increased.

Study on the Wear Modes of PVD Films Using Different Concentrations of Al2O3 Abrasive Particles and Textured Rotating Balls

Abrasive wear is a wear mechanism that results in a loss of material from the interaction of a surface with hard particles. This type of wear is frequently found in the surface of machining tools. Microscale abrasion equipment is often used to characterize the resistance to abrasive wear of a surface. The different parameters able to control micro-abrasion wear tests, such as ball rotation, sliding distance between ball and surface sample, abrasive slurry concentration, normal load acting on the sample, and abrasive flow rate over the sample, have been widely studied. The combination of different variables, including sliding distance, concentration of abrasive particles, their hardness, and size of abrasive particles, promotes the transition between two-body, three-body, or mixed abrasive wear modes. However, the influence of the ball surface on the dragging of abrasive particles, which is reflected in the wear modes, is still poorly studied. One of the variables possible to control and less studied is the influence of the ball surface texture on the dragging of abrasive particles in micro-abrasion wear tests. This work intends to correlate the effect of different testing times (500, 1000, and 1500 cycles) and different concentrations of 3 μm Al2O3 abrasive slurry (25, 35, and 45 g/100 mL) on the micro abrasion resistance of a TiN thin coating film, using balls of AISI 52100 steel whose texture and roughness were prepared by 60 s chemical etching. The rotation speed of each test was 80 rpm, applying a normal load of 2 N. Subsequently, the craters were carefully analyzed using SEM to evaluate the transition of the wear mode as a function of the applied load, the abrasive particle concentration, and the sliding distance. The textured ball tracks were observed via SEM to assess the particle dynamics. The results showed that, contrarily to what is reported in the literature regarding wear modes where rolling is promoted with increasing abrasive concentration, in this work grooving took place instead. This is a result of the rough balls use in the experiments which, due to the embedment of abrasive particles in the ball grooves, promotes the abrasion mechanism. The higher the abrasive concentration, the higher the grooving mechanism, since more particles are available to scratch the surface.

Effect of slurry particles on PVA brush contamination during post-CMP cleaning

PVA (polyvinyl acetal) brush scrubbing is a widely used post-CMP cleaning process due to its low cost and high cleaning efficiency. However, during these processes, the PVA brush gets contaminated with abrasive particles that result in wafer cross-contamination and reduced cleaning efficiency. This study investigated the effects of abrasive types such as silica and ceria, the slurry pH, and the scrubbing process parameters on brush contamination. Ceria slurries showed significantly more contamination of brushes compared to silica slurries. The brush contamination increased with a decrease in pH from 7 to 4 due to increased electrostatic attractive forces between the ceria particles and the brush surfaces, although very low brush contamination was observed by the ceria slurries at pH 10 due to a strong electrostatic repulsion. Conversely, very low brush contamination was observed for the silica slurries at all pH values due to the reduced interaction between the particles and the brush surface (electrostatic repulsion). Furthermore, there was no significant effect of gap distance and brush rotation speed on brush contamination. The abrasive concentration and the contamination process time showed a linear relationship as the contamination was significantly increased by increasing the abrasive concentration in slurry and process time. These results indicate that brush contamination is more sensitive to the abrasive nature and concentration, the slurry pH, and the process time than to other parameters.

Process parameter optimization of Al/SiC metal matrix composites during ultrasonic machining process

Metal matrix is highly acceptable composites providing good strength for industrial use. In many field of industries, especially aerospace industry metal matrix composites of type Al/SiC is used because of its superior properties. In this research work, experimentalanalysis has been done for producing through hole on metal matrix composites with suitable quality ultrasonic machining (USM) process. Three unconstrained process parameters are chosen, like abrasive slurry concentration, power rating sand tool feed rate. Material removal rate (MRR) is considered as response parameter. The effects of each parameter have been analyzed here. Analysis of variance (ANOVA) has also been applied to identify the most significant factor. Response surface methodology (RSM) has been utilized to developed empirical model for determine the performance of ultrasonic process. Optimization technique has been used to find out the maximum process MRR. Confirmation verification test has been done to improve optimal parametric condition for getting maximum MRR. This research paper gives viability application of USM process for producing of through hole on metal matrix composites and various applications in industry.

Micro-abrasive Wear Behavior of Nitrided and Multilayer Coated High Vanadium Powder Metallurgy Alloy

The micro-abrasive behavior of plasma nitrided Vanadis 10, a high vanadium powder metallurgy alloy, combined with TiCN/AlTiN/CrAlTiN/CrN multilayer film was evaluated and compared with different treatment conditions. Microstructural evolution with treatments was evaluated. The tribological behavior was accessed using the fixed ball micro-abrasion test and SiC as abrasive. The counter-body was an AISI 52100 steel sphere (O 25.4 mm), the SiC abrasive slurry concentration was 0.50 g/cm3, the rotary speed was set at 75 rpm, and the applied load was 0.49 N. The wear crater was characterized by scanning electron microscopy (SEM). Results indicated that the film is effective in reducing the wear coefficient in more than 80 pct for all conditions compared with Vanadis 10. Nitriding treatments impaired the samples’ wear resistance because of the presence of cracks in this layer. Sliding/grooving abrasion was observed for the conditions with higher wear coefficients. The change in the micro-abrasion wear mechanism from grooving abrasion to rolling abrasion is attributed to the protection of the surface by the hard multilayer coating, producing a reduction in the wear coefficient.

Micro-abrasive wear mechanisms of P/M AISI M2 steel with different surface treatments

Boriding, heat treatment (quenching and tempering) and PVD (Physical Vapor Deposition) film deposition were applied to P/M (Powder Metallurgy) AISI M2 steel. Four sample conditions were produced: Quenched and tempered AISI M2 (QT), Borided AISI M2 (B), Quenched and tempered AISI M2+Film (QTF) and Borided AISI M2+Film (BF). The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and the Vickers microhardness test. The load applied in the micro-abrasion tests (fixed-ball) was 0.49N and abrasive slurry concentration was 0.1g/cm3. Silicon dioxide (SiO2) abrasive powders (approximately 80% of particles between 1 and 5μm) were used in the abrasion experiments. Wear coefficient and mechanisms of all conditions were compared. The XRD analysis revealed the presence of a biphasic layer of borides (FeB and Fe2B phases) on the borided samples. The film thickness was 2.1±0.4μm and the hardness of the multilayered AlTiN/CrN film was about 3912HV0.025. The borided layer thickness was 46.5±5.1μm and the hardness average of 2162HV0.025. The wear mechanism for the QT and QTF samples was two-body abrasion (grooving abrasion). There was a reduction on the signs of grooving abrasion for the B and BF samples due to the increase in plastic deformation resistance.

Grey Relational Analysis of Chemical Assisted USM of Polycarbonate Bullet Proof (UL-752) & Acrylic Heat Resistant (BS-476) Glass

This paper is developed an innovative process of chemical assisted ultrasonic machining of polycarbonate bullet proof UL-752 and acrylic heat resistant BG-476 glass and conduct an investigation for optimize the machining parameters associated with multiple performance characteristics using Grey relational analysis. Machining of polycarbonate bullet proof UL-752 and acrylic heat resistant BS-476 glass are difficult process via conventional machining, however, it can be easily machined by Ultrasonic machining. Carefully selected parameters gives the optimum results. In this experimental work input parameters abrasive slurry concentration, type of abrasive, power rate, grit size of abrasive particles, hydro-fluoride acid concentration and tool material are selected. The effect of input parameters viz material removal rate, tool wear rate and surface roughness are investigate. Grey relational analysis and analysis of variance are performed to optimize the input parameters and better output results. In PBPG UL-752, increment in material removal rate by 75.58%, tool wear rate by 45.34% and surface roughness by 34.18%. In other hand, in AHRG BS-476, increment in material removal rate by 61.24%, tool wear rate by 31.46% and surface roughness by 23.85%. The surface topography is investigate through SEM images. It also observed that HF acid have the significant role in surface roughness. It also reduce the micro cracks on machined zone. Harder tool and harder abrasive slutty gives the higher material removal rate, but it also enhance the tool wear rate.

Micro hole fabrication on Quartz using Ultrasonic Micromachining Process

Ultrasonic micromachining (USMM) has immense potential for micro-machining on quartz which is used in different field of applications such as optics, metrology and micro electro mechanical system (MEMS) etc. In this paper the influences of process parameters such as power rating, abrasive slurry concentration and tool feed rate on material removal rate (MRR), overcut and taper angle of the micro hole on quartz by USMM have been investigated. Stainless steel of grade 304 has been selected as the micro-tool material for ultrasonic micro drilling on quartz. The higher value of MRR of 0.4235 mm/min has been obtained at power rating of 400 W, abrasive slurry concentration of 40% and tool feed rate of 1.2 mm/min. The lower value of overcut of 55 µm and taper angle of 0.600 of micro hole have been obtained at abrasive slurry concentration of 20%, power rating of 300 W and tool feed rate of 1 mm/min.

Experimental Investigation of Material Removal and Surface Roughness during Optical Glass Polishing

It has been a challenge to finish optical glass surfaces due to their hard and brittle nature. Moreover, tight tolerances of surface figure and finish make polishing a more critical operation. This work reports the results of an experimental study performed for full aperture polishing of BK7 optical glass. Flat samples of borosilicate (BK7) glass are polished using an optical pitch polisher and cerium oxide (CeO2) slurry. Taguchi's L9 orthogonal array is used for the design of experiments. Abrasive concentration, pressure and overarm speed are considered as variable process parameters. Polishing is performed for duration of 120 minutes for each combination of parameters. Material removal is measured using the precision weighing balance. Surface roughness was measured using a Form Talysurf PGI 120 profiler. Abrasive slurry concentration is observed to be one of the most significant parameters in the optical polishing process. It affects both the material removal rate (MRR) and the surface roughness. Pressure applied at the workpiece–polisher interface affects the MRR, but the variation of pressure is not found to affect the surface roughness significantly. Relative motion at the workpiece–polisher interface is also observed to be significant in defining the final polishing outputs.

Experimental studies of ultrasonic machining on hydroxyapatite bio-ceramics

Hydroxyapatite bio-ceramics are used for producing implants for bio-medical applications. The generation of hemispherical shaped cavity on hydroxyapatite bio-ceramic is highly demanded for making hip joint. Ultrasonic machining is suitable for the machining of all kind of hard and fragile materials, which are electrically non-conducting. This paper is aimed to design and develop a tool and holding arrangement in ultrasonic machining (USM) for generating hemispherical shaped cavity on hydroxyapatite bio-ceramic which is highly demanded for hip joint replacement. This paper also includes the study of the influences of process parameters such as abrasive grain diameter, abrasive slurry concentration, tool feed rate and power rating on material removal rate, diametrical deviation, and circularity error during ultrasonic machining. From the basic parametric studies, it is observed that the abrasive grain diameter, power rating, and tool feed rate are the most important parameters, which have greater influence on the material removal rate (MRR), diametrical deviation, and circularity error of hemispherical cavity on hydraxyapatite bio-ceramics. It is also concluded that the hemispherical shaped cavity on hydroxyapatite bio-ceramics with dimensional accuracy can be generated by USM with the aid of developed tool geometry and proper control of process parameters during ultrasonic machining.

Analysis of the micro-abrasive wear behavior of an iron aluminide alloy under ambient and high-temperature conditions

This study examines the micro-abrasive wear behavior of an iron aluminide alloy to determine correlations between the abrasive wear modes, volume of wear (V), and coefficient of friction (µ). Experiments were conducted with a specimen of Fe–30Al–6Cr (at.%) iron aluminide alloy, a sphere of AISI 52100 bearing steel and abrasive slurries prepared with black silicon carbide (SiC) particles and glycerin. Different levels of sliding distance (S), normal force (N), abrasive slurry concentration (C), and temperature of test (Te) were used for the micro-abrasive wear tests by rotative ball; during the experiments, the abrasive slurry was continuously agitated and fed between the sphere and the specimen, and, in parallel, the normal (N) and the tangential (T) forces were simultaneously monitored. Subsequently, the volume of the craters and the coefficient of friction acting in the tribological system “sphere–abrasive particles–specimen” were calculated. The results showed that i) the abrasive wear mode reported for all wear craters was rolling abrasion, independent of the temperature; ii) the temperature has an important effect on the behavior of the volume of wear and the coefficient of friction; and iii) with an increase in the temperature, a decrease in the volume of wear and the coefficient of friction was observed.

Influence of the normal force, abrasive slurry concentration and abrasive wear modes on the coefficient of friction in ball-cratering wear tests

The purpose of this work is to study the influence of the normal force (N), abrasive slurry concentration (C) and abrasive wear modes on the coefficient of friction in ball-cratering wear tests. Experiments were conducted with balls of AISI 52100 steel, an AISI H10 tool-steel specimen and abrasive slurries prepared with black silicon carbide (SiC) particles+distilled water. The tangential (T) and normal loads were monitored throughout the tests and the results have shown that: (i) the coefficient of friction behavior was independent of the normal force and (ii) both the concentrations of abrasive slurries and the subsequent action of the abrasive wear modes, generally, did not affect the behavior or magnitude of the coefficient of friction.

Optimisation of ultrasonic machining of zirconia bio-ceramics using genetic algorithm

Ultrasonic machining is one of the most extensively used non-traditional machining processes for the machining of non-conductive, brittle materials such as carbides, glasses and bio-ceramics. The present paper includes the investigation into surface roughness of machined of hexagonal holes and material removal rate during ultrasonic machining of zirconia bio-ceramics. The response surface methodology was employed for developing empirical models. Abrasive grit size, abrasive slurry concentration, power rating and tool feed rate have been considered as controlling parameters of ultrasonic machining process. Multi-objective optimisation has been carried out for minimising surface roughness of hole surface and maximising material removal rate during hexagonal profile generation by USM. However, for searching out the best optimal solution, genetic algorithm (GA) is used. Unlike traditional optimisation techniques, GA is strong and performs well in multi objective optimisation problems. Using genetic algorithm, maximum MRR of 0.2365 g/min and minimum surface roughness of 0.58 μm were obtained at the optimal parametric combination such as abrasive grit size of 57 μm, abrasive slurry concentration of 42 g/l, power rating of 492 W and tool feed rate of 0.88 mm/min.

Sensitivity of wear rates in the micro-scale abrasion test to test conditions and material hardness

Micro-scale abrasion (ball cratering) tests were performed with different combinations of ball and bulk specimen materials, under different test conditions, such as load and abrasive slurry concentration. Wear modes were classified into two types: with rolling particle motion and with grooving particle motion. Wear rates observed with rolling particle motion were relatively insensitive to test conditions, whereas with grooving motion they varied much more. It is suggested that rolling abrasion is therefore a more appropriate mode if reproducible test results are desired. The motion of the abrasive particles can be reliably predicted from the knowledge of hardnesses and elastic properties of the ball and the specimen, and from the normal load and the abrasive slurry concentration. General trends in wear resistance measured in the micro-scale abrasion test with rolling particle motion are similar to those reported in tests with fixed abrasives with sliding particle motion, although the variation in wear resistance with hardness is significantly smaller.

CMP 결과에 영향을 미치는 마찰 특성에 관한 연구

Chemical mechanical polishing (CMP) process was studied in terms of tribology in this paper. CMP performed by the down force and the relative motion of pad and wafer with slurry is typically tribological system composed of friction, wear and lubrication. The piezoelectric quartz sensor for friction force measurement was installed and the friction force was detected during CMP process. Various friction signals were attained and analyzed with the kind of pad, abrasive and abrasive concentration. As a result of experiment, the lubrication regime is classified with ηv/p(η, v and p; the viscosity, relative velocity and pressure). The characteristics of friction and material removal mechanism is also different as a function of the kind of abrasive and the abrasive concentration in slurry. Especially, the material removal per unit distance is directly proportional to the friction force and the non~uniformity has relation to the coefficient of friction.