Abrasive Particle Size Research Articles

Simulation and Optimization of the Nozzle Section Geometry for a Suspension Abrasive Water Jet

In order to improve the life cycle and cutting ability of a suspension abrasive water jet nozzle at the same time, hydrodynamics technology, an enumeration method and multiparameter orthogonal optimization are used to optimize the nozzle section geometry, taking the inlet diameter coefficient of the nozzle, the axial length coefficient of the contraction section and the contraction section curve as optimization variables, and selecting the peak velocity and the unit flow erosion rate as the indicators, it is concluded that the optimal contraction section curve is a Widosinski curve, the optimal inlet diameter coefficient of the nozzle is 0.333 and the optimal axial length coefficient of the contraction section is 2.857. Compared with the commercial product single cone nozzle, the performance of the optimal section nozzle improves by 5.64% and the life cycle increases by 43.2%. On this basis, the effects of operating parameters, including inlet pressure, abrasive particle flow rate and abrasive particle size, are further studied. It is determined that the optimal section nozzle has the best performance under the above operating parameters. It is demonstrated that by optimizing the nozzle section geometry, the cutting capacity and life cycle of the nozzle are improved, the performance of the nozzle can be significantly improved and the optimization of the performance of the nozzle is realized.

Size Effect of CeO2 Particle on Nanoscale Single-Asperity Sliding Friction

The size of abrasive particle has a great impact on the fundamental friction behavior and mechanical properties of the abrasive during ultra-precision polishing performance. Here, the size effect of the tribological behavior and mechanical properties of CeO2 single abrasive were studied. Experimental results show that the size effect plays a role on coefficient of friction (COF) of each regime in single-asperity sliding friction, especially in ploughing and cutting regimes. The residual depth of the scratch and COF both decrease with the increase of the CeO2 tip radius. These results relate to the mechanical properties of CeO2 nanoparticles. We found that the effective modulus increases with the decrease of abrasive size, which corresponds to the size effect of the single-asperity sliding friction experiment.

Study on magnetic preparation of dual disk based on silica gel magneto-elastic abrasive particles

Magneto-elastic abrasive grains have magnetism, low elastic modulus and excellent abrasive performance, and have the characteristics of bonded abrasive grains and loose abrasive grains. The dual-disk magnetic preparation greatly improves the preparation quality and efficiency. Firstly, the magneto-elastic abrasive particles are introduced into the edge preparation of the dual-disk magnetic tool, and the preparation method of 4035 silica gel magneto-elastic abrasive particles is proposed. According to the microscopic characteristics of the magneto-elastic abrasive particles, the finite element software ABAQUS is used to establish the magneto-elastic abrasive particles. The meso-level representative volume element (RVE) model is built to analyze the stress and strain law of magneto-elastic abrasive particles under tension and compression. Secondly, an experimental platform for magnetic preparation of magneto-elastic abrasive particles with dual disks was built to analyze the force of magneto-elastic abrasive particles. Finally, Through the magnetic preparation experiment of the magneto-elastic abrasive dual-disk magnetic force, the influence of the disk rotation speed, abrasive particle size and relative magnetic permeability on the cutting edge wear is studied. And compared to the magnetic abrasive particles double-disk magnetic and drag finishing method, the magneto-elastic abrasive particle double-disk magnetic preparation method can obtain the maximum edge wear amount and the maximum surface roughness decreasing amplitude. The research results are of great significance to promote the progress of our country's magnetic high-efficiency processing and magneto-finishing processing technology.

Insights of abrasive water jet polishing process characteristics and its advancements

Nowadays, Abrasive water jet (AWJ) machining is used in the manufacturing Industries as cutting, turning, milling and drilling processes. The application of this technology is further extended into polishing application. However, the cutting nature of the AWJ have produced the inappropriate surface conditions. Recently, the hybrid AWJ namely, Ultrasonic Assisted Abrasive Water Jet Polishing (UAAWJP) is mainly developed for polishing the complex shapes and the internal features of both metal and non-metals. Compared with other polishing technologies, UAAWJP has several advantages such as improvement in performance efficiency, higher kinetic energy, better surface quality, high precision, ease to control and absence of thermal distortions. The hybrid process is involved with variety of factors such as ultrasonic waves (frequency and vibration), abrasive particle type &size, jet pressure, traverse rate, abrasive mass flow rate, standoff distance, nozzle geometry, jet impact angle and processing time. However, the usage of conventional AWJ and UAAWJP techniques is scarce due to the lack of understanding of process mechanism and technical publications. It is mentioned that review article on AWJ polishing operations has not been published till date. Therefore, the present work is deals with the insights of previous studies on AWJ polishing and it advancements particularly in UAAWJP, and the results are presented with in view of process mechanism, features, benefits, effects and applications, and the results are also compared with other polishing techniques. The outcome of this study can also provide the better understanding and confident to the researchers and scientists on UAAWJP for further advancements and applications on it.

Theoretical and experimental investigation on surface generation and subsurface damage in fixed abrasive lapping of optical glass

Fixed abrasive lapping (FAL) is a promising technology increasingly used for finishing optical mirrors and molds in a number of materials due to its high finishing efficiency, environmental friendliness, and relatively better surface and subsurface quality. A theoretical model for fixed-abrasive lapping of optical glass was developed in this paper by using indentation fracture mechanics, contact mechanics, mathematical statistics, lapping kinematics, and convolution iterative principle to provide an enhanced scientific understanding of the surface microtopography generation and subsurface damage (SSD) control mechanisms. In the modeling, the influence of the shape, size, and spatial distribution of abrasive particles and the ductile and brittle removal mechanisms of the material were considered. A series of lapping experiments on fused silica glass was carried out to quantitatively analyze the feasibility and accuracy of the model and study the influence mechanism of process parameters on the surface and subsurface state. Results indicated that the models could well predict the surface micromorphology and the SSD depth, and the range of sharpness angle of abrasive particles and tool load affected the predicted SSD range. In addition, the material removal mechanism and lapping tool wear characteristics were revealed by the surface structure and element component analysis. Finally, the FAL process was optimized by the evaluation indices of material removal rate (MRR), surface roughness, and SSD.

Quality prediction of polygonal helical curved tube by abrasive flow precision machining

The polygonal helical curved tube is the main form of rifling barrel, which surface quality determines the shooting accuracy of the gun. Abrasive flow machining (AFM) technology can significantly improve its inner surface quality. In order to study the influence of AFM technical parameters on the inner surface quality of polygonal helical curved tube, orthogonal experimental design (OED) was used as the research method in this paper. Through the analysis of variance (ANOVA) of experimental data, the degree of influence of inlet pressure, abrasive concentration, abrasive particle size, and machining time on the inner surface quality of polygonal helical curved tube was determined, and the optimal combination of process parameters was obtained. Under the optimal process parameters, the surface roughness Ra value in the inlet area of the polygonal helical curved tube was reduced to 0.080μm. The surface quality was significantly improved. Based on the regression analysis of experimental data, the quality prediction model of polygonal helical curved tube roughness by AFM was established to realize the effective prediction of surface quality after machining. The fitting value calculated by the model with optimal process parameters is close to the experimental value, which proves the accuracy and validity of the prediction model.

Pre-Sintering Airborne Particle Abrasion Improves Surface and Biological Properties of Zirconia

kground: Surface topography of a zirconia dental implant has a major impact on osseointegration and clinical success. Modification of a fully sintered zirconia surface can be problematic due to its high strength and bio-inert surface.Methods: The present study therefore aimed to investigate the effect of airborne-particle abrasion of presintered zirconia on surface properties and biological performance of the resulting fully sintered zirconia.Results: The results showed that surface topographies of fully sintered zirconia were influenced by abrasive particle size and blasting time used in repeated pre-sintering airborne particle abrasion. Well-optimized pre-sintering airborne-particle abrasion of zirconia surface could render a highly roughened and hydrophilic surface with increased fibronectin-to-albumin adsorption ratio and mesenchymal stem cell adhesion.Practical implications: This technique may be suitable for modifying zirconia surface to facilitate osseointegration of zirconia-based dental implants.

Analysis of material removal of Inconel 718 cylinder using magnetic abrasive finishing process assisted with chemical etching

Application of Inconel 718 cylinders have been uprising with the up gradation of requirement of super alloys in this advance technological world. Although Inconel 718 possesses superior mechanical properties resulting into excellent performance in extreme environmental conditions but on the other hand make it difficult to machine and finish with available machining processes. This investigation has been used for the analysis of material removal of Inconel 718 cylinder using magnetic abrasive finishing process assisted with chemical etching. Finishing process has been conducted on 155 mm long and 5.7 mm thick Inconel 718 cylinder under specified investigating variable parameters such as duration of processing, work pole gap, abrasive weight percentage, and size of abrasive particles and concentration of etchant keeping certain factors as constant like rotational speed, etching temperature. Impact of processing variables represent through surface microstructure.

Study on the Electrorheological Ultra-Precision Polishing Process with an Annular Integrated Electrode.

Electrorheological (ER) polishing, as a new ultra-precision super-effect polishing method, provides little damage to the workpiece surface and is suitable for polishing all kinds of small and complex curved surface workpieces. In this paper, an ER polishing tool with an annular integrated electrode is developed. The orthogonal experiments are carried out on the six influencing factors of ER polishing which include the applied voltage, the abrasive particle size, the abrasive concentration, the polishing gap, the polishing time and the tool spindle speed. The influence order of these six factors on the ER polishing is obtained. On this basis, the effect of a single process parameter of ER polishing on surface roughness is studied experimentally.

Experimental investigation into internal roundness of Inconel-718 thick cylinder using chemical assisted magnetic abrasive finishing process

With the progression of technology, demands of super alloys have been increased dramatically. One such super alloy is Inconel-718. Although, it is having an extensive application in aerospace industries, steam power plants and oil and gas refineries due to possession of some stringent properties like hot hardness, resistance to wear, high strength. Possession of these rigorous characteristics makes it hard to finish this alloy with the conventional finishing processes almost impossible. So the present work focuses on the predominant role in Industries by giving an edge on surface finishing with more precision and accuracy. To establish the process experimental setup and magnetic tool have been created for chemical assisted magnetic abrasive finishing process to inspect the enhancement in internal roundness of Inconel-718 cylinder. The processing unit has been installed on the lathe machine. Experiments have been performed on Inconel-718 cylinders with 5.7 mm in thickness, 155 mm in length. The experiments have been planned by means of Response surface methodology. Results of the experiments have been analysed with the help of analysis of variance. It has been found that with the operating parameters having specified values like duration of processing-80 mins, Pole work gap-4 mm, and abrasive weight percentage-30%, size of abrasive particle- 40 µm and concentration of Etchant- 700 gm/litre internal roundness improvement percentage for Inconel 718 cylinder is achieved as 42.86%.

Modeling and analysis of the material removal rate for ultrasonic vibration–assisted polishing of optical glass BK7

The emergence of ultrasonic vibration–assisted polishing technology has effectively improved the machining accuracy and efficiency of hard and brittle materials in the modern optical industry; however, the material removal mechanism of ultrasonic vibration–assisted polishing (UVAP) still needs to be further revealed. This paper focuses on the material removal mechanism of ultrasonic vibration–assisted polishing of optical glass (BK7), the application of ultrasonic to axial vibration, and the atomization of the polishing slurry; the material removal model was established. Based on the analysis of the relationship between the nominal distance d of the polishing pad and the actual contact area distribution, the prediction of the material removal profile is realized. In addition, the effects of different parameters on the material removal rate (MRR) were analyzed, including polishing force, spindle speed, abrasive particle size, ultrasonic amplitude, feed rate, and flow rate of polishing slurry. Based on the motion equation of abrasive particles, the trajectory of abrasive particles in the polishing slurry was simulated, and the simulation results show that the introduction of the ultrasonic vibration field changes the motion state and trajectory of embedded and free abrasive particles. The new model cannot only qualitatively analyze the influence of different process parameters on MRR, but also predict the material removal depth and MRR, providing a possibility for deterministic material removal and a theoretical basis for subsequent polishing of complex curved surfaces of optical glass.

Characteristics of the Polishing Effects for the Stainless Tubes in Magnetic Finishing with Gel Abrasive

Magnetic abrasive finishing (MAF) is a fast, high efficiency and high-precision polishing method on the surface machining of the metals. Furthermore, MAF also can be utilized to polish the stainless tubes in industrial applications; however, stainless tubes are often a non-magnetic material that makes it difficult for the magnetic field line to penetrate into the stainless tubes, thus reducing the magnetic forces in the inner tubes polishing. That is why stainless tubes are not easy to finish using traditional MAF. Therefore, magnetic finishing with gel abrasive (MFGA) applies gels mixed with steel grit and abrasives that were developed to improve the polishing efficiency and surface uniformity of the steel elements. In this study, a guar gum or silicone gel mixed with steel grit and silicon carbides are used as the magnetic abrasive gel to polish the stainless inner tubes. A DC motor was used to control the rotation speed of the chuck and an AC induction motor connected with an eccentric cam to produce the reciprocating motion of the workpiece were utilized to finish the inner surface of stainless tubes in the polishing process. The parameters of abrasive concentration, abrasive particle sizes, rotation speeds of motor and electric currents were used to investigate the surface roughness and the removal of materials from the stainless tubes. The experimental results showed that since guar gum had better fluidity than the silicone gel did, guar gum created excellent polishing efficiency in MFGA. Furthermore, the surface roughness of the stainless tube decreased from 0.646 μm Ra to below 0.056 μm Ra after processing for 30 min with the parameters of current 3A, gel abrasive with guar gum, rotational speed 1300 rpm and vibration frequency 4 Hz.

Developmental and Experimental Study of Rotary Ultrasonic drilling process

Abstract: The proper selection of machining conditions and machining parameter is an important aspect, before going to machine a brittle material by rotary ultrasonic drilling process Because these conditions will determine such important characteristics as; Material removal rate (MRR) and Surface roughness (SR). The purpose of this work is to determine the optimal values of machining parameters of rotary ultrasonic drilling process. The work has been based on the effect of three design factors: Tool feed rate, vibration frequency and grain size of abrasive particle on such characteristic like material removal rate (MRR). This work has been done by means of the technique of design of experiment (DOE), which provides us to perform the above-mentioned analysis with small number of experiments. In this work, a L9 orthogonal array is used to design the experiment. The adequate selection of machining parameters is very important in manufacturing system, because these parameters determine the surface quality and dimensional accuracy of the manufactured part. The optimal setting of the parameters are determined through experiments planned, conducted and analyzed using the Taguchi method. Keywords: RUSM, Material removal rate, Drilling, Taguchi method

Erosion wear characteristics of cemented carbide for mud pulser rotor

Mud pulser is the most commonly used Measurement While Drilling(MWD) instrument for downhole data transmission to the surface. The rotor of the key component of the mud pulser is made of cemented carbide material. Under the action of high speed mud erosion containing solid phase, the rotor will produce erosion wear and reduce the quality of signal transmission. To explore the erosion wear mechanism of rotor carbide in mud containing solid phase particles, the influences of different erosion angles and different erosion abrasive sizes on the erosion wear properties of cemented carbides were studied by taking quartz sand as erosion abrasive. By means of surface profilometer, scanning electron microscope (SEM) and energy spectrum analysis (EDS), the erosion wear mechanism of cemented carbide was revealed. The experimental results show that the erosion wear rate increases gradually with the increase of erosion angle. When the erosion angle is 90°, the maximum average erosion rate of WC-5Co, WC-6Co and WC-10Co cemented carbides is 2.39%, 2.42% and 3.22%, respectively. With the increase of the abrasive particle size, the erosion wear rate of the material increases first and then decreases. When 100–200 um, the maximum average erosion rates of WC-5Co, WC-6Co and WC-10Co are 1.84%, 1.98% and 2.48%, showing a significant “particle size effect”. At low erosion angle, the wear mechanism is furrow and cutting mark, while at high erosion angle, the wear mechanism is pit. The erosion wear mechanism of small particle size abrasives is that a large area of surface layer falls off in the erosion area. The erosion wear mechanism of large particle size abrasive is the material loss in the erosion pit in the erosion area.

Particle Size Effects on Abrasion, Surface Polishing and Stain Removal Efficacy in a Tooth Model System

Four calcined alumina abrasive particles [ultrafine (0.05 μm), 3 μm, 9 μm and 20 μm] with defined sizes were investigated for their effects on toothbrush abrasion, surface polishing and stain removal in vitro. The existence of a critical particle size (CPS) was shown for the first time in a tooth model system and in the present study a CPS of ~2.3 μm for d10, 4.3 μm for d50 or 7.8 μm for d90 for the calcined alumina abrasives was apparent. The d10, d50 and d90 values indicate that 10%, 50% and 90% of the particles measured were less than or equal to the size stated. This dimension enabled maximum abrasive action on the tested specimens resulting in the largest wear depth, greatest surface polishing and best stain removal. The enamel wear depth decreased when brushed with abrasives above the critical particle size and became almost independent of further particle size increases, which is useful for minimising wear effects in the development of dentifrice. The findings provide new information on abrasive particle size for modification and control of toothpaste abrasivity and cleaning.

Theoretical and experimental investigation of material removal rate in shape adaptive grinding of HVOF sprayed WC-Co coating

Shape adaptive grinding (SAG) is conducted on the ground tungsten carbide-cobalt coating using diamond polishing pad. A material removal rate (MRR) model is proposed by considering the indentation of active abrasive particle, cross-sectional area and actual length of the finishing grooves. The effects of tool speed, tool compression, backing pad hardness and abrasive particle size of the polishing pads on the normal force, MRR and surface roughness are investigated. With an increase of the tool compression, the contact pressure increases and the surface peaks get sheared off at an enhanced rate that results in a higher MRR and lower surface roughness. On the other hand, SAG with harder tool (i.e., higher backing pad hardness) produces many deep finishing grooves owing to the aggressive mechanical interaction with the workpiece surface and that increases the surface roughness. Therefore, it is perceived that the harder SAG tool is not suitable as the final finishing step for precision finishing of cermet coating. The effect of tool speed on normal force is found to be insignificant as the contact area or pressure does not vary much with the tool speed. The polishing pad with lower particle size gets partially loaded at a higher tool compression and that impedes the reduction rate of surface roughness. By performing SAG with the polishing pads of reducing particle sizes in sequence, areal surface roughness (Sa) of 7 nm is attained. The residual stress of the finished coating is reduced to - 81 ± 7 MPa (compressive) which is around 29% of the ground surface. No abnormality is observed in the sub-surface of the finished coating.

Research into the Disintegration of Abrasive Materials in the Abrasive Water Jet Machining Process.

The size and distribution of abrasive particles have a significant influence on the effectiveness of the cutting process by the high-speed abrasive water jet (AWJ). This paper deals with the disintegration intensity of abrasive materials in AWJ cutting during the creation of the abrasive jet. An evaluation of the abrasive materials was performed after forming in the cutting head was carried out and grain distribution was evaluated using the geometric and logarithmic Folk and Ward method. The influence of the abrasive concentration of abrasive materials such as alluvial garnet, recycled garnet, corundum, and olivine on grain distribution was studied. A recovery analysis was also carried out and the recycling coefficient was determined for each abrasive material tested.

Brittle-ductile transition in compliant finishing of HVOF sprayed hard WC-Co coating

WC-Co coating with nanolevel surface finish is required in some special components in aviation, automobile and forming industries. In this study, compliant finishing of WC based coating is carried out using an in-house fabricated wheel based SAG tool. Theory of contact mechanics and the interactions of active abrasive particles with the workpiece surface are considered to develop a material removal rate (MRR) model. The brittle-to-ductile transition of WC-Co coating is investigated during compliant finishing with diamond abrasive pads having different particle size. It is observed that the material is purely removed through ductile mode when 6 μm polishing pad is used and the critical chip thickness for brittle to ductile transition lies in the range of 60–100 nm. Moreover, the lower wheel compression and higher wheel speed can slightly enhance the possibility of ductile machining. A low surface roughness of 21 nm is achieved using multistep compliant finishing operations with decreasing abrasive particle size in a sequence. The residual stress of the finished coating is found to be −78 ± 8 MPa which is almost 28% of the ground surface. The cross-section of the finished coating is analysed and no appreciable sub-surface damage is detected.

Tribological investigation of abrasion resistant steels with martensitic and retained austenitic microstructure in single- and multi–asperity contact

Steel making companies are developing new steels with complex microstructure to satisfy abrasion resistance issues. Three newly developed steels (fresh martensitic, tempered martensitic and a TRIP steel) were investigated under single and multi-asperity abrasion test conditions. Abrasive performance was linked to material properties. In the multi-asperity test, increasing the normal load and abrasive particle size resulted in increasing mass loss and in transition in micro-mechanisms from ploughing to micro-cutting. Martensitic materials showed better wear performance due to their higher hardness. As a result of the abrasive action a newly formed tribo-layer was observed in the contact zone of all steel specimen. In the single asperity testing a diamond spherical indenter was used with different normal loads. Wear micro-mechanisms were analysed during the scratching using optical microscopy and 3D-profilometry. The fresh and tempered martensitic steels showed a transition in micro-mechanism from micro-ploughing to micro-cutting at higher loads and smaller tip radius. For the multiphase steel with retained austenite, despite its TRansformation Induced Plasticity effect, micro-cutting was reached already at lower loads. The tempered martensitic material outperformed the fresh martensitic material despite the similar hardness and microstructure. For all materials single-asperity test data showed similar ranking in abrasion wear resistance as in the multi-asperity test.

Simultaneous improvement of microgeometry and surface quality of spur and straight bevel gears by abrasive flow finishing process

This article reports on influence of extrusion pressure, abrasive particle size and volumetric concentration on simultaneous reduction of surface roughness and microgeometry errors of spur and straight bevel gear by abrasive flow finishing (AFF) process. A vertical configured experimental apparatus was developed for two-way AFF and developed fixtures for finishing gears. Experimental investigations were conducted to identify optimum parametric combination, using response surface methodology, based on Box–Behnken design approach. Results revealed that higher values of abrasive particle size and volumetric concentration yield more percentage decrease in surface roughness and microgeometry error. Roughness profile, bearing area curve, microhardness, surface morphology, and wear resistance of the gear having best quality finishing were studied. Surface morphology analysis of the flank regions of the best finished spur and straight bevel gears found them to be smooth and free from cracks and burrs. Reciprocating wear test results revealed higher wear resistance of the AFF finished gears as compared to the unfinished gears. AFF also enhanced microhardness of the finished gears, which would enhance their operating performance and service life. This study shows that AFF is a flexible, economical, productive, easy to operate, and sustainable nontraditional process for precision finishing of gear that can simultaneously improve microgeometry, surface finish, microhardness, surface morphology, wear resistance, and residual stresses of the finished gears. Gear manufacturers and users will be benefited by the outcome of this study. JEL codes: C00, C20