Search

Abrasive machining processes have long been integral to various manufacturing industries, enabling precise material removal and surface finishing. In recent years, the integration of non-Newtonian fluids has emerged as a promising strategy to enhance the performance and efficiency of these processes. This review paper provides a comprehensive overview of the current state of research on abrasive machining processes, including abrasive lapping, abrasive polishing, and chemical mechanical polishing, and then analyzes in detail the abrasive machining processes enhanced with non-Newtonian fluids. It explores the fundamental principles underlying the rheological behavior of non-Newtonian fluids and their application in abrasive machining, with a focus on shear-thickening fluids. The paper will begin by introducing the abrasive machining processes, including abrasive lapping, abrasive polishing, and chemical mechanical polishing. Then, the current research status of non-Newtonian fluids will be comprehensively analyzed, and we will explore the enhancement of abrasive machining processes with non-Newtonian fluids. Finally, the paper will conclude with a discussion of the future directions and challenges in the field of abrasive machining enhanced with non-Newtonian fluids. Overall, this review aims to provide valuable insights into the potential benefits, limitations, and opportunities associated with the use of non-Newtonian fluids in abrasive machining, paving the way for further research and innovation in this promising area of manufacturing technology. [ABSTRACT FROM AUTHOR]

As an important indicator of the surface quality of workpieces, surface roughness has a great impact on production costs and the quality performance of the finished components. Effective surface roughness prediction can not only increase productivity but also reduce costs. However, the current methods for surface roughness prediction have some limitations. On the one hand, the prediction accuracy of classical experimental and statistical-based surface roughness prediction methods is low. On the other hand, the results of deep learning-based surface roughness prediction methods are uninterpretable due to their black-box learning mechanism. Therefore, this paper presents an ensemble learning with a differential evolution algorithm, applies it to the prediction of surface roughness of abrasive water jet polishing (AWJP), and conducts an interpretability analysis to identify key factors contributing to the prediction accuracy of surface roughness. First, we proposed automatically constructing features by an Evolution Forest algorithm to train the base regression models. The differential evolution algorithm with a simplified encoding mechanism was then used to search for the best weighted-ensemble to integrate the base regression models for obtaining highly accurate prediction results. Extensive experiments have been conducted on AWJP to validate the effectiveness of our proposed methods. The results show that the prediction accuracy of our proposed method is higher than the existing machine learning algorithms. In addition, this is the first of its time for the contributions of machining parameters (i.e., features) on surface roughness prediction by using interpretable analysis methods. The analysis results can provide a reference basis for subsequent experiments and studies. [ABSTRACT FROM AUTHOR]

Double-sided planetary grinding (DSPG) with a fixed abrasive is widely used in sapphire substrate processing. Compared with conventional free abrasive grinding, it has the advantages of high precision, high efficiency, and environmental protection. In this study, we propose a material removal rate (MRR) model specific to the fixed-abrasive DSPG process for sapphire substrates, grounded in the trajectory length of abrasive particles. In this paper, the material removal rate model is obtained after focusing on the theoretical analysis of the effective number of abrasive grains, the indentation depth of a single abrasive grain, the length of the abrasive grain trajectory, and the groove repetition rate. To validate this model, experiments were conducted on sapphire substrates using a DSPG machine. Theoretical predictions of the material removal rate were then juxtaposed with experimental outcomes across varying grinding pressures and rotational speeds. The trends between theoretical and experimental values showed remarkable consistency, with deviations ranging between 0.2% and 39.2%, thereby substantiating the model's validity. Moreover, leveraging the insights from this model, we optimized the disparity in the material removal rate between two surfaces of the substrate, thereby enhancing the uniformity of the machining process across both surfaces. [ABSTRACT FROM AUTHOR]

Super-reduced phases (SRPs), such as silicon carbide (SiC) and metal silicides, have increasingly been reported in various geological environments. However, their origin remains controversial. SRP inclusions (e.g., metal silicides and metallic silicon (Si0)) within SiC are commonly believed to indicate a natural origin. Here, we identified an unusual SRP assemblage (SiC, (Fe,Ni)Si2, and Si0) in situ in an H5-type Jingshan ordinary chondrite. Simultaneously, our analysis showed that the SiC abrasives contain (Fe,Ni)Si2 and Si0 inclusions. Other inclusions in the artificial SiC were similar to those in natural SiC (moissanite) reported in reference data, including diverse metal silicides (e.g., FeSi, FeSi2, Fe3Si7, and Fe5Si3), as well as a light rare earth element-enriched SiO phase and Fe-Mn-Cr alloys. These inclusions were produced by the in situ reduction of silica and the interaction between Si-containing coke and hot metals during the synthesis of the SiC abrasives. The results demonstrate that the SRP assemblage in the Jingshan chondrite originates from abrasive contamination and that the SRP inclusions (with a low content of Ca, Al, Ti, and Zr) cannot be used as a conclusive indicator for natural SiC. Additionally, the morphologies, biaxiality, and polytypes (determined by Raman spectroscopy) of SiC abrasives bear resemblance to those reported for natural SiC, and caution must be exercised when identifying the origin of SRP in samples processed by conventional methods using SiC abrasives. At the end of this paper, we propose more direct and reliable methods for distinguishing between natural and synthetic SiC. [ABSTRACT FROM AUTHOR]

In order to evaluate the abrasive belt grinding performance, this paper proposes to conduct nickel-based superalloy robot abrasive belt grinding experiment based on different types of abrasive belts with multiple grit sizes. First, the single grinding performance evaluation is performed through five performance parameters: material removal rate, surface roughness, tangential force, specific grinding energy, and specific wear height. Then, based on the evaluation results of single grinding performance, a weighted evaluation function is established to comprehensively evaluate the grinding performance. It is found that the structured abrasive belt has relatively better grinding performance. The main factors affecting the abrasive belt grinding performance are identified through the evaluation results, with the effect of grit size being more significant. In addition, this paper analyzes the characteristics of material deformation based on the grinding subsurface microstructure, and discusses the effects of abrasive belts on material deformation. [ABSTRACT FROM AUTHOR]

This paper introduces an Acoustic Emission (AE)-based monitoring method designed for supervising the Abrasive Waterjet Cutting (AWJC) process, with a specific focus on the precision cutting of Carbon Fiber-Reinforced Polymer (CFRP). In industries dealing with complex CFRP components, like the aerospace, automotive, or medical sectors, preventing cutting system malfunctions is very important. This proposed monitoring method addresses issues such as reductions or interruptions in the abrasive flow rate, the clogging of the cutting head with abrasive particles, the wear of cutting system components, and drops in the water pressure. Mathematical regression models were developed to predict the root mean square of the AE signal. The signal characteristics are determined, considering key cutting parameters like the water pressure, abrasive mass flow rate, feed rate, and material thickness. Monitoring is conducted at both the cutting head and on the CFRP workpiece. The efficacy of the proposed monitoring method was validated through experimental tests, confirming its utility in maintaining precision and operational integrity in AWJC processes applied to CFRP materials. Integrating the proposed monitoring technique within the framework of digitalization and Industry 4.0/5.0 establishes the basis for advanced technologies such as Sensor Integration, Data Analytics and AI, Digital Twin Technology, Cloud and Edge Computing, MES and ERP Integration, and Human-Machine Interface. This integration enhances operational efficiency, quality control, and predictive maintenance in the AWJC process. [ABSTRACT FROM AUTHOR]

The generation of abrasive particles is an unavoidable consequence of sliding electrical contact wear in conductive slip rings (SRs). The adhesion of abrasive particles to the insulators may lead to a decrease in flashover voltage, posing a risk to satellite power transmission. In this paper, the effect of abrasive particles on flashover is first studied. Surface abrasive particles can distort the surface electric field of the dielectric, absorb scattered electrons, and then re-emit them, thereby accelerating the development and formation of secondary electron avalanches. Flashover test results indicate that surface abrasive particles lead to a significant reduction in flashover voltage. To mitigate the impact of particle adhesion on flashover, a method of constructing particle traps on the surface of insulators is proposed. The location and structural parameters of the particle trap are further optimized and determined. The flashover test results using planar dielectric samples and SR insulator samples both demonstrate that the optimized particle trap can significantly improve the flashover voltage. The dielectric maintains high electrical strength even when particles are trapped in particle traps. The physical details of the impact of particles on flashover and the effect of particle traps are analyzed utilizing an electron movement simulation, corroborating the experiment from a microscopic aspect. [ABSTRACT FROM AUTHOR]

A supercritical suspended abrasive water jet with dual inputs of pressure and heat is proposed to improve the cutting performance of the conventional suspended abrasive water jet in deep-sea environments. The paper studies the flow and kinetic characteristics of the supercritical suspended abrasive water jet. The CFD simulation method is proposed to investigate these characteristics by integrating a programmed database of supercritical water material properties with Ansys Fluent. The simulation and comparison show that abrasive particle density, abrasive particle size, inlet pressure, and water temperature affect the acceleration process of the abrasive particles. At the nozzle outlet, the velocity of the abrasive particles reaches over 95% of the supercritical water velocity. With the proposed supercritical abrasive water jet, the jet velocity is increased by 192.2% to 402.40 m/s compared to the conventional suspended abrasive water jet, reducing the amount of water used by 67.7% at a specified temperature of 773.15 K. Correspondingly, the medium kinetic energy is increased by 177.7% and the medium kinetic energy ratio is 2.78. The particle kinetic energy is increased by 723.2% and the particle kinetic energy ratio is 8.23. [ABSTRACT FROM AUTHOR]

Abrasive belt condition (BC) monitoring is significant for achieving profile finishing precision and quality in grinding of difficult-to-machine materials like Inconel 718. While indirect signal-based BC monitoring methods are ineffective when varying grinding parameters, existing image-based direct monitoring methods currently suffer from a lack of: (i) a unified and quantitative definition of the belt condition; (ii) in situ tool-surface image capture and relevant feature extraction; and (iii) continuous monitoring of the entire belt conditions. This paper proposes a partitioned BC monitoring method that is adaptable to ever-changing grinding conditions. Based on the belt surface analysis, a unified BC coefficient is quantitatively defined by using two critical BC-dependent features, the average area and number of worn flats of abrasive grains per unit area. The belt surface image is in-situ captured from moving belts and is preprocessed to eliminate image defects in a unified form, then the entire belt is partitioned, and finally the image features are extracted by Gabor filter and K-means clustering. The proposed robust method which has a maximum relative repeatability error of 9.33%, and less computation was validated by the experimental results. This study provides an adaptable and efficient way for continuously monitoring the conditions of the entire belt and the grinding area. [ABSTRACT FROM AUTHOR]

The demand for high-precision and high-efficient machining of high-performance materials and components has increased in various industries such as optical, automotive, communication, life sciences, and medical sciences. Certain difficult-to-machine materials can be reliably machined using deterministic precision cutting processes. However, hard and brittle materials such as ceramics, carbides, hardened steel molds, glassy materials, or semiconductor materials, require precision abrasive technologies with super abrasives like diamond, cBN, or new tool materials for machining. However, machining high-precision components and their molds/dies using abrasive processes is considerably more difficult due to their complex and non-deterministic nature and textured surfaces. Furthermore, high-energy processes such as laser technology can assist abrasive technologies in ensuring higher precision and efficiency. Precision grinding and polishing processes are primarily used to generate high-quality and functional components, typically made of difficult-to-machine materials. Thus, the surface quality achievable by precision grinding and polishing processes becomes more important for reducing machining time and costs. This special issue features 10 papers on the most recent advances in precision abrasive technologies. These papers cover the following topics: - Ultrasonic grinding of micro holes using cemented WC tools - Drilling holes in CFRP aircraft using cBN electroplated ball end mill - In situ evaluation of drill wear using tool images - Grinding belt based on modified information entropy - Radial directional vibration-assisted grinding of Al2O3 ceramics - Chatter vibration suppression using fixed superabrasive polishing stone - Free abrasive finishing of internal channels with different cross-sectional geometries - High-quality machining of cemented carbide using PCD ball end mills - Fixed-abrasive machining with magnetic brush for Ti-6Al-4V ELI alloy - High-efficient polishing of polymer surfaces using catalyst-referred etching This issue will provide an understanding of the recent developments in abrasive technologies, leading to further research. We deeply appreciate the careful work of all the authors, and we thank the reviewers for their incisive efforts. [ABSTRACT FROM AUTHOR]

Kinematic principle in lapping process is an essential theoretical foundation to achieve high lapping accuracy. The motion path of abrasive grains determines the machined area on workpiece, thereby affecting the surface accuracy. To improve lapping uniformity, this paper established a kinematic model of swing fixed-abrasive lapping (SFAL) and investigated the effect of kinematic parameters (rotational speed ratio, swing ratio, swing angle) on lapping uniformity. Non-uniformity coefficient (NUC) was adopted to evaluate the lapping uniformity, and the impact mechanism of kinematic parameters on the trajectory of abrasive grains were revealed by Taguchi experiments and numerical simulation. Furthermore, response surface experiments were employed to optimize the parameter combination, and a prediction model for NUC was developed. This work provides theoretical guidance for the selection of kinematic parameters in SFAL process, and has reference significance for improving the lapping accuracy. [ABSTRACT FROM AUTHOR]

The preparation of cubic boron nitride (CBN) grinding tools using laser cladding has the advantages of strong bonding, short time consumption and customizable abrasive arrangement. In this paper, a two-step laser cladding method was used to prepare CBN abrasive blocks with the aim of reducing laser damage to CBN grits during the laser cladding process. The cross-sectional morphology of CBN abrasive blocks under different laser power conditions was characterized, and the relationship among laser power, preparation method, and forming quality of Cu–Sn–Ti/CBN cladding layer was investigated. Then, the microstructure at the Cu–Sn–Ti/CBN interface under different laser power conditions was characterized, and the main phase compositions at the Cu–Sn–Ti/CBN interface were analyzed. Finally, the grinding tests were carried out on CBN abrasive blocks. The results show that as the laser power increases from 250 W to 400 W, the fracture ratio of CBN grits increases dramatically from 4.3 % to 17.3 %. TiN, TiB 2 , and TiB compounds are all detected at the Cu–Sn–Ti/CBN interface under different laser power conditions. The mass loss of the TC4 wheel caused by the CBN abrasive block initially increases and then decreases as the laser power increases from 250 W to 400 W. The CBN abrasive block has the optimum material removal performance at the laser power of 300 W using two-step laser cladding. The results provide a theoretical basis for the preparation of high-performance CBN grinding tools using laser cladding. [ABSTRACT FROM AUTHOR]

Cutting and abrasive processes affect the surface layer state of the components treated. This determines their performance in service. An adjustment of the surface layer properties would allow for enhanced performance. This paper introduces the influences of named processes on the surface layer state and their systematics. Models and sensor concepts for surface conditioning are described and combined to soft sensors which are the basis for active control within the processes. A validation study and actual applications of the conditioning concept are shown, allowing for further technological and scientific understanding of surface conditioning and its contribution to material and energy efficiency. [ABSTRACT FROM AUTHOR]

The hydraulic oil of marine equipment contains a large number of abrasive contaminants that reflect the operating condition of the equipment. In order to realize the detection of particulate contaminants, this research first proposes a shape-based classification method for oil abrasive particles, designs an oil abrasive particle collection system, and constructs a new dataset. After that, the research introduces deep learning target detection technology in computer vision, and uses GhostNet to lighten the network structure, the CBAM (Convolutional Block Attention Module) attention mechanism to improve the generalization ability of the model, and the ASPP module to enhance the model sensory wildness, respectively. A lightweight target detection model, WDD, is created for the identification of abrasive particles. In this study, the WDD model is tested against other network models, and the mAP value of WDD reaches 91.2%, which is 4.8% higher than that of YOLOv5s; in addition, the detection speed of the WDD model reaches 55 FPS. Finally, this study uses real ship lubricating oils for validation, and the WDD model still maintains a high level of accuracy. Therefore, the WDD model effectively balances the accuracy and detection speed of marine oil abrasive particle detection, which is superior to other oil abrasive particle detection techniques. [ABSTRACT FROM AUTHOR]

In this paper, the abrasion resistance of a carbon fiber composite based on epoxy nanocomposite matrix filled with layered-silicate clay nanoparticles was evaluated. In the first step of the work, the clay-epoxy nanocomposite was first studied to assess the dispersion and the performance, and then to select the best content for the fiber composite production. The nanocomposite mixture was prepared by finely dispersing clay nanoparticles into the epoxy monomer through mechanical stirring, then the hardener was added. After this step, the fiber reinforced composite was produced by vacuum infusion, and then the properties were evaluated. The abrasion resistance has been assessed using different approaches. A test was specifically designed to simulate the impact of abrasive powders which could potentially be found in the atmosphere and crash into aircraft or air vehicles (such as for instance volcanic ashes). The results showed that the presence of nanoclay reduces the weight loss of the sample with the impacted surface, which can be clearly correlated to a damage reduction. Highlights • Sandblasting tool made to mimic impact of abrasive powder on composite surface • Presence of nanoclay does not significantly affect the vacuum infusion process • Layered-silicate nanoparticles lead to improve composites abrasion resistance. [ABSTRACT FROM AUTHOR]

The relative motion between the workpiece and the fixed abrasive pad (FAP) determines the abrasive trajectories and the distribution of abrasives' sliding distance (ASD), and further affects the surface accuracy of the lapping process. To improve the surface accuracy of the swinging fixed abrasive plane lapping (SFAPL), the influence of the workpiece's swinging modes on the lapping uniformity was studied in this paper. The kinematics model of SFAPL was established by the coordinate transformation method based on the kinematical principle of the crank-rocker mechanism. The numerical simulation method was adopted to investigate the abrasive trajectories and the ASD on the workpiece surface in different swinging modes. Furthermore, the regional meshing and statistical methods were applied to visualize the simulation results, and the non-uniformity coefficient (NUC) and root mean square (rms) were employed to quantitatively evaluate the lapping uniformity. Finally, the verification experiments were carried out. Results indicated that the additional swinging could avoid the periodic distribution of material removal on the workpiece surface. The swinging mode significantly affected the lapping efficiency and lapping uniformity. Compared with the traditional lapping method, the lapping uniformity was optimal when the workpiece swung out of the FAP from the bottom and inner sides, and the lapping uniformity could be improved by 44.3 %; The lapping efficiency was the highest when the workpiece swung out of the FAP from the bottom side, and the material removal rate could be increased by 45.23 %. The appropriate swinging mode should be selected based on different processing requirements in SFAPL. [Display omitted] • Swinging fixed abrasive plane lapping (SFAPL) was introduced to improve the lapping accuracy of BK7 glass. • The lapping uniformity of SFAPL was investigated through kinematics and trajectory analysis. • Simulation results were visualized based on regional meshing and statistical methods. • The influence of swinging modes on the lapping performance was revealed. • The optimal swinging mode to ameliorate the lapping uniformity was determined. [ABSTRACT FROM AUTHOR]

In order to reveal the material removal behavior of robot abrasive belt grinding (RABG) of nickel-based superalloy, the experimental research method of single grit grinding is proposed. In the research, ceramic alumina grits are used to scratch superalloy K438 based on the experimental setup of RABG. Four material removal parameters, namely real cutting depth, number of cutting edges involved in grinding, effective cutting area of cutting edges and pile-up ratio, are used to quantitatively describe the material removal behavior. The experimental results show that the grits have good cutting performance. And the cutting edges involved in grinding change dynamically, which has a significant influence on material removal. In addition, this paper analyzes the differences between RABG and wheel grinding (WG), studies the effect of cutting depth on material removal, and determines the factors that affect the material removal ability by evaluating the material removal ability of different grits. [ABSTRACT FROM AUTHOR]

The issue of wear failure in High-Pressure Abrasive Water Jet (HP-AWJ) nozzles is an unavoidable challenge, and studying methods to enhance and predict the effective lifetime of nozzles is worth deep exploration. This paper employs a CFD-DEM coupling numerical approach to investigate wear phenomena inside the HP-AWJ nozzle, aiming to capture the realistic particle wear and erosion failure issues at the focusing tube region, which is a high-wear area of the HP-AWJ nozzle. Furthermore, the study considers realistic particles and nozzle wall constitutive models, incorporating material properties into the physical model, and employs computer-aided design methods to reflect wear failure conditions at different time intervals in the inner wall of the focusing tube at the nozzle. The results demonstrate that the number of realistic particles and initial inlet velocity has no impact on the particle exit kinetic energy. However, the particle-wall restitution coefficient affects the average particle kinetic energy at the outlet in the AWJ nozzle. The equivalent model of the realistic particles reflects the influence of the particle roundness on particle kinetic energy, acceleration, and stress concentration variations in the nozzle. These variations further affect the particle erosion rate on the nozzle wall and the actual wear failure problems on the wall surface. Finally, by combining the proposed erosion and wear model, a representative erosion profile at the AWJ focusing tube location comparable to experimental results is obtained, and the wear depth of the focusing tube changing with time is also studied. The results and methodologies presented in this paper provide valuable guidance for controlling the effective service lifetime of the AWJ nozzle, improving machining efficiency, and extending the lifespan of the AWJ nozzle. [Display omitted] • A numerical CFD-DEM coupling approach to study wear in the HP-AWJ nozzle. • Three particle equivalent models based on nozzle wall contact for abrasive shapes. • The results and methods guide AWJ nozzle lifetime control. • The Finnie wear model with a stress model analyzes realistic wear locations. • Investigate nozzle wear depth in high-stress areas using Archard's wear law. [ABSTRACT FROM AUTHOR]

The challenge of machining ceramic matrix composites (CMCs) arises from their hard and brittle, anisotropic, and heterogeneous nature, making them prone to damage such as edge chipping, fiber fracture, and interfacial debonding during grinding. To gain a thorough understanding of CMCs' grinding performance, this paper discusses in detail the removal behavior under the action of abrasive grain, focusing on the micro-interaction of abrasive grain and material. Following this analysis, various strategies for modeling grinding forces are elaborated. Then, we outline the quality evaluation of CMCs and offer solutions to mitigate grinding damage by comprehensively assessing the factors affecting material removal in CMCs. Ultimately, the prospects and potential advancements in the application of grinding processes for CMCs are highlighted. [Display omitted] [ABSTRACT FROM AUTHOR]

Ultrasonic vibration polishing (UVP) is an important method for the precision processing of optical glass, which is good for improving surface quality and processing efficiency. So far, the material removal mechanism in UVP is not well understood and the various process parameters involved are not considered. To achieve ultra-precision polishing under optical glass, this paper carries out the axial UVP method. The material removal profile (MRP) is critical to affect the surface accuracy. A new MRP is developed for UVP based on the Urick attenuation model and the proposed material removal coefficient distribution function, considering the dynamic pressure changes under ultrasonic vibration, the attenuation effect of the acoustic pressure propagation process and the inhomogeneous distribution of the abrasive particles in the contact area during the ultrasonic electro-spindle rotation. Through a series of polishing experiments and simulations, the results show that the maximum errors of the actual material removal depth (MRD) and the actual material removal rate (MRR) from the model simulation results are 8.54% and 9.92%, respectively. The accuracy of the model is further demonstrated by the Pearson correlation coefficient. When the amplitude of UVP is 9 µm, Sa and Ra are 60 nm and 68 nm, which are reduced by 37.50% and 22.73%, respectively, compared with conventional polishing. This research can contribute to the deterministic processing of UVP, and provide a theoretical basis for the application of optical glass. [ABSTRACT FROM AUTHOR]

In this paper, protruded NiCoCrAlYTa-Al 2 O 3 abrasive coatings were prepared by vacuum infiltration sintering, and the effect of the filler metal content on the microstructure before and after oxidation is investigated. The results show that, the Al 2 O 3 grits are bonded to the coating matrix by a layer of Y-Al-O compound, and various types of G-phase are presented depending on the locations. Adjacent to the G-phase, larger γ' phase and γ/γ' eutectics are presented due to the expel of Al during the formation of G-phase. With the increase of the filler metal content, G-phase precipitation and the Si penetration depth into the single crystal superalloy substrate increase. After 1000 °C/100 h oxidation, the Y-Al-O intermediate layer between Al 2 O 3 grits and the coating matrix is little changed, with an additional thermally grown oxide (TGO) layer between the Y-Al-O layer and the coating matrix presented. The selective oxidation of Al and Cr facilitates the formation of G-phase layer underneath the oxide film, and the rapid diffusion of Ti and the selective oxidation of Al yields the formation of γ' depletion region adjacent to the G-phase and on coating surface without Al 2 O 3 grits. • NiCoCrAlYTa-Al 2 O 3 abrasive coatings for blade tips are prepared by vacuum infiltration sintering. • The effect of filler metal content on the microstructure before and after oxidation is investigated. • The formation mechanism of G-phase is discussed in detail. • The evolution mechanism of G-phase and γ′ depletion region during oxidation is investigated. [ABSTRACT FROM AUTHOR]

• A grinding depth analytical model of the abrasive belt was established. • Grinding depth and surface quality of SX superalloy were analyzed by topography. • Subsurface damage and recrystallization mechanism of belt grinding were revealed. • Belt grinding realized the large cutting depth and low damage processing of SX superalloy. Single crystal superalloy has been widely utilized as a crucial manufacturing material for aeroengine turbine blades due to its excellent properties. However, machining this alloy is easy to cause subsurface damage, resulting in the engineering failure of blades. To explore a large cutting depth and low damage processing method, this paper established a grinding depth analytical model for the abrasive belt. The model provides insights into the material removal behavior mechanism during belt grinding and predicts the impact of process parameters on the grinding depth. Subsequently, the grinding experiments of this alloy with different abrasive belts were conducted. The experimental results showed that grinding depth increased as normal force amplified and exhibited a nonlinear growth pattern with the reduction of feed velocity. This preliminary verified the prediction model of grinding depth. The material removal properties of the pyramid, diamond, and hollow-sphere belts were analyzed, and the ratio of material removal capacity for the three was found to be 12:8:5. Based on the analysis of the topography and roughness of the grinding surface, the study examined the influence mechanism of grinding force, feed velocity and abrasive grain morphology on grinding depth and surface quality. The subsurface damage behavior mechanism and recrystallization depth change law of belt grinding were revealed. The grinding depth of the pyramid and diamond belts could exceed 160 μm and the recrystallization depth was less than 5 μm. To achieve efficient and low-damage machining, it is recommended to reduce the feed velocity rather than increase the grinding normal force. It is important to note that the feed velocity should not exceed 10 mm/s. This study is to furnish a theoretical groundwork and offer engineering technical recommendations for achieving large grinding depth and low damage machining of single crystal superalloy. [ABSTRACT FROM AUTHOR]

The existence of striations, and scratches in Abrasive waterjet (AWJ) cutting surface necessitates an exploration of these features for enhancing the cutting accuracy of AWJ machining. This article investigates surface roughness and micro-scratch morphology characteristics on brass cutting surfaces. According to the variation law of surface roughness values, the cutting section can be divided into three regions: the initial region, smooth region, and rough region. Numerous micron-scale scratches were observed in the cutting section. The scratch length, width, and depth values all show an increasing trend as the cutting depth increases, with the scratch length experiencing the greatest growth and variability. The influence of position and traverse speed on scratch size was studied using variance analysis. Furthermore, the length and width of the scratches on the cutting surface are significantly influenced by their position, accounting for 89.19% and 81.13%, respectively. Traverse speed had a minor effect on scratch length and width, accounting for 0.01% and 2.64% respectively. The depth of the scratches is influenced by their position on the cutting surface at a rate of 41.12%, while traverse speed had an impact of 38.10%. Finally, a mathematical method based on standard scores was proposed to assess the quality of the cutting section based on micro-scratch dimension. [ABSTRACT FROM AUTHOR]

Unsubmerged cavitating abrasive waterjet (UCAWJ) has been shown to artificially create a submerged environment that produces shear cavitation, which effectively enhances rock-breaking performance. The shear cavitation generation and collapse intensity depend on the pressure difference between the intermediate high-speed abrasive waterjet and the coaxial low-speed waterjet. However, the effect of the pressure of the coaxial low-speed waterjet is pending. For this purpose, the effect of low-speed waterjet pressure on rock-breaking performance at different standoff distances was experimentally investigated, and the effects of erosion time and ruby nozzle diameter on erosion performance were discussed. Finally, the micromorphology of the sandstone was observed at different locations. The results show that increased erosion time and ruby nozzle diameter can significantly improve the rock-breaking performance. At different standoff distances, the mass loss increases first and then decreases with the increase of low-speed waterjet pressure, the maximum mass loss is 10.4 g at a low-speed waterjet pressure of 0.09 MPa. The surface morphology of cavitation erosion was measured using a 3D profiler, the increase in both erosion depth and surface roughness indicated a significant increase in the intensity of the shear cavitation collapse. At a low-speed waterjet pressure of 0.18 MPa, the cavitation erosion surface depth can reach 600 mm with a roughness of 127 mm. [ABSTRACT FROM AUTHOR]

To enhance the erosion efficiency in traditional abrasive water jet processing, an abrasive water jet processing method based on self-excited fluid oscillation is proposed. Traditional abrasive water jet methods suffer from reduced jet kinetic energy due to the presence of a stagnation layer, which hinders efficient material removal. By integrating a self-oscillation chamber into the conventional abrasive water jet nozzle, the continuous jet is transformed into a pulsed jet, thereby increasing the jet velocity and enhancing the kinetic energy of the process. This modification aims to improve material removal efficiency. Using Ansys Fluent, we simulated the material removal efficiency on workpiece surfaces with varying lengths of self-oscillation chambers. The simulation results reveal that the optimal length of the self-oscillation chamber for maximum erosion is 4 mm. SiC materials were used to evaluate the impact of self-oscillation chamber length (L), jet pressure (P), abrasive flow rate (M), and abrasive grain size (D) on erosion. Experimental results show that the self-oscillation chamber increases erosion depth by 33 μm. The maximum erosion depths recorded were 167 μm when L = 4 mm, 223 μm when P = 16 MPa, 193 μm when M = 80 g/min, and 268 μm when D = 2000 μm. Overall, the self-excited oscillation effect enhances the erosion efficiency of the waterjet by 14%. This study further elucidates the factors influencing erosion behaviors in oscillating abrasive water jet processing. [ABSTRACT FROM AUTHOR]

To extend the working life of products made of titanium alloy, it is necessary to improve the polishing method to diminish the remaining defects on the workpiece surface. The Halbach array-assisted magnetic abrasive particle polishing method for titanium alloy was employed in this work. The distribution of magnetic field strength was simulated and verified at first to learn the characteristics of the Halbach array used in this work. Then, the polishing performance of the polishing tool was studied by conducting the polishing test, which aimed to display the relationship between shear force and surface roughness with polishing time, and the surface morphology during polishing was also analyzed. Following the establishment of the response surface model, a study on the optimal polishing parameters was conducted to obtain the suitable parameters for maximum shear force and minimum surface roughness. The results show that the maximum shear force 6.11 N and minimum surface roughness Sa 88 nm can be attained, respectively, under the conditions of (1) polishing tool speed of 724.254 r·min−1, working gap of 0.5 mm, and abrasive particle size of 200 μm; and (2) polishing tool speed of 897.87 r·min−1, working gap of 0.52 mm, and abrasive particle size of 160 μm. [ABSTRACT FROM AUTHOR]

Numerical simulations were conducted based on the smoothed particle hydrodynamics–finite element method coupling method to investigate the damage evolutions and failure mechanism of reinforced concrete impacted by abrasive water jet. The response processes of damage and fragmentation of reinforced concrete were analyzed. The influences of key jet parameters on fracture characteristics of reinforced concrete were obtained. In addition, evolution laws of stress and damage and the failure mechanism of reinforced concrete impacted by abrasive water jet were revealed. The results indicate that the morphologies of broken pits undergo changes in the following sequence: V-shape, U-shape, and hourglass-shape. The broken pit range almost linearly increases with the impact time. Increasing abrasive concentration is more conducive to peeling concrete above steel, but an appropriate concentration is more suitable for cutting steel. Increasing jet diameter can expand the broken pit width, especially its bottom width, and increase damage to concrete below steel. The concrete stresses beneath steel display a raindrop-like distribution pattern. The concrete protective layer mainly suffers from the multiple stepwise damage accumulation failure caused by compressive shear and tensile stresses, and the interface concrete between steel and protective layer undergoes brittle failure due to weak bonding strength and massive stress concentration. The concrete beneath steel mainly undergoes brittle failure due to strong extrusion effect of steel. In addition, the concrete within steel reinforcement framework is influenced by various forces, such as tensile stress and shear stress, leading to occurrence of damage accumulation without failure. The research results would lay the theoretical foundation for abrasive water jet efficiently crushing reinforced concrete. [ABSTRACT FROM AUTHOR]

• Established a micro dynamic model of magnetorheological polishing fluid. • Simulated the formation of magnetic chains and the precipitation of abrasive particles under a magnetic field. • Building a test bench to verify the precipitation pattern of abrasive particles. This study aims to address the issue of poor workpiece surface machining quality due to inadequate abrasive particle precipitation during the processing of magnetorheological polishing fluid. The paper employs magnetic dipole theory and molecular dynamics theory to establish a microdynamics model for magnetorheological polishing fluid and conducts kinematic and dynamic analyses of magnetic and abrasive particles. The chaining process of magnetic particles in magnetorheological polishing fluid was simulated under an external magnetic field, and the precipitation process of abrasive particles under the action of magnetic particles was simulated and analyzed. Furthermore, we established a microscopic observation experimental platform for magnetorheological polishing fluid and verified the precipitation law of abrasive particles under the action of dynamic magnetic field. The study findings indicate that the magnetic particles will form a chain structure, when the rotating magnetic field has an effect on the magnetorheological polishing fluid, and the abrasive particles will precipitate from the magnetorheological polishing fluid and adhere to the upper end of the magnetic chain. Moreover, the precipitation rate of abrasive particles is also affected by the magnetic field strength, the volume fraction of magnetic particles, and the rotating magnetic field speed, with the abrasive particles' precipitation rate specifically increasing with higher magnetic field strength. At a magnetic field strength of 100 kA/m, the abrasive precipitation rate reaches 80 % in approximately 90 s, which increases to 80 % in only 60 s at a magnetic field strength of 200 kA/m. Additionally, with the increase of magnetic particle volume fraction, the precipitation rate of abrasive particles decreases. Within the first 40 s of the test, the magnetic particle volume fraction increases from 10 % to 30 %, and the precipitation rate of abrasive particles decreases by about 11 %. Similarly, the abrasive precipitation rate is affected differently by the rotating magnetic field speed. As the rotating magnetic field speed increases, the abrasive precipitation rate shows a trend of first increasing and then decreasing. When the rotating magnetic field speed increases from 20 r/min to 40 r/min, the abrasive precipitation rate of the first 40 s increases by about 25 %. When the speed continues to increase to 60 r/min, the precipitation rate of abrasive particles gradually decreases. [ABSTRACT FROM AUTHOR]

This paper uses the weight function to modify the particle volume fraction algorithm. The VOF model is modified by adding the particle phase volume fraction and momentum source to the control equation, the semi-resolved VOF-DEM model is established, and PTV experiment is used to verify the model. Based on this model, the flow and distribution characteristics of the abrasive are obtained: 1) The water-abrasive flow near the outlet of the convergent section of the nozzle has a significantly dense two-phase flow characteristic, and the collision between particles dominates particle flow. 2) The particles at the nozzle outlet are distributed in the radial direction of "n", and with the increase of the stand-off distance of the jet, the particle phase volume transitions from "n" to "m" distribution. The research on the flow characteristics of particles can provide a basis for the nozzle design of pre-mixed abrasive water jets. [Display omitted] • A two-way coupled CFD-DEM model of an abrasive water jet was proposed and validated. • The semi-resolved VOF-DEM model reduces the dependence of calculation on grids. • Acceleration and distribution of abrasive are obtained based on the modified model. • Collision between particles dominates particle flow at the convergent section exit. [ABSTRACT FROM AUTHOR]

Magnetic abrasive finishing (MAF) is an efficient finishing process method using magnetic abrasive particles (MAPs) as finishing tools. In this study, two iron-based alumina magnetic abrasives with different particle size ranges were synthesized by the plasma molten metal powder and powder jetting method. Characterization of the magnetic abrasives in terms of microscopic morphology, phase composition, magnetic permeability, particle size distribution, and abrasive ability shows that the magnetic abrasives are spherical in shape, that the hard abrasives are combined in the surface layer of the iron matrix and remain sharp, and that the hard abrasives combined in the surface layer of the magnetic abrasives with smaller particle sizes are sparser than those of the magnetic abrasives with larger particle sizes. The magnetic abrasives are composed of α-Fe and Al2O3; the magnetic permeability of the magnetic abrasives having smaller particle sizes is slightly higher than that of the magnetic abrasives having larger particle sizes; the two magnetic abrasives are distributed in a range of different particle sizes; the magnetic abrasives have different magnetic permeabilities, which are higher than those of the larger ones; both magnetic abrasives are distributed in the range of smaller particle sizes; and AZ31B alloy can obtain smaller surface roughness of the workpiece after the grinding process of the magnetic abrasives with a small particle size. [ABSTRACT FROM AUTHOR]

The automated removal of layers by scarfing to repair carbon fibre reinforced plastics (CFRP) has been investigated with vacuum suction blasting (VSB) showing promising results. However, its removal mechanism and particle behaviour were not yet fully understood. The removal leads to cavities on the surface and the central area is less removed after longer static blasting times. Further theoretical considerations and experiments of measured forces and velocities of the VSB particles can explain these effects to optimize the large-scale removal. Former studies on abrasive blasting used simplified approaches with incompressible Bernoulli equations taking the same velocities of particles and carrier medium. For VSB, the air is much faster than the particles and more complex equations are derived in this study. Additionally, it is taken into account, that the impinging forces act against the vacuum forces. To specify the power and removal mechanism of VSB for large scale removal, forces and velocities of the blasting particles are studied. Calculations by compressible Bernoulli equations, measurements of blasting particle velocities and impact forces give a good approximation. The air velocities and forces are calculated and compared with the measurements. Forces are measured by a piezo-electric sensor. Particle velocities are measured with a Particle Image Velocimetry (PIV) system tracking the abrasive particle movement through a transparent outer nozzle. The influence of different blasting parameters on the forces and velocities are identified. Results correspond to the material removal from former experiments and indicate the favourable process parameter set. Despite the impinging forces are in general low, they lead together with the particle velocity to the large-scale removal rate. The measured particle directions explain the removal behaviour of this VSB process. The measured velocities match to those well-known from grinding with bonded grinding tools. Article highlights: Force and velocity measurements of vacuum suction blasting process PIV measurements of blasting particles Forces calculated and measured by piezo-electric sensor. [ABSTRACT FROM AUTHOR]

CeO2 is widely used in the field of chemical–mechanical polishing for integrated circuits. Morphology, particle size, crystallinity, and Ce3+ concentration are crucial factors that affect polishing performance. In this study, we successfully synthesized two novel triangular CeO2 abrasives with similar particle sizes (600 nm) but different morphologies and Ce3+ concentrations using a microwave-assisted hydrothermal method with high-concentration raw materials, and no surfactants or template agents were added. It is generally believed that CeO2 with a higher Ce3+ concentration leads to better polishing performance. However, the results of polishing indicate that CeO2 synthesized at 200 °C, despite its lower Ce3+ concentration, demonstrates outstanding polishing performance, achieving a polishing rate of 324 nm/min, and the Sa of Si wafers decreased by 3.6% after polishing. This suggests that, under similar particle size conditions, the morphology of CeO2 plays a dominant role in the mechanical effects during the polishing process. Additionally, compared to commercial polishing slurries, the synthesized samples demonstrated better polishing performance. This indicates that, in CMP, the pursuit of smaller spherical abrasives may not be necessary. Instead, the appropriate shape and particle size can better balance the material removal rate and surface roughness. [ABSTRACT FROM AUTHOR]

The study aimed to compare various toothpastes and mouthwashes on permanent tooth dentin after erosive and abrasive challenges. 130 sound premolars dentin were randomly submitted to an initial erosive challenge and a cycle of erosive and abrasive challenges for five days. The five experimental groups (n = 26) were: (1) Control group (artificial saliva), (2) Elmex erosion protection toothpaste and mouthwash, (3) Vitis anticaries biorepair toothpaste and mouthwash, (4) Oral B Pro-expert toothpaste and Oral B Fluorinse mouthwash, and (5) MI Paste ONE toothpaste and Caphosol mouthwash. Microhardness, surface roughness values, and the topographical characteristics of the dentin surface were assessed. The highest percentage of recovered dentin microhardness (%RDMH) value was observed in groups 2 and 4, followed by groups 5 and 3, respectively. The %RDMH values in groups 2 and 4 did not demonstrate a significant difference (p = 0.855). The highest percentage of improvement in surface roughness was recorded in groups 2 and 4, with no significant differences (p = 0.989). The atomic force microscopy (AFM) findings were consistent with the surface roughness data. The best recovery of dentin microhardness and roughness were measured with the Elmex and Oral B toothpaste and mouthwash, followed by MI Paste ONE toothpaste and Caphosol mouthwash and Vitis anticaries biorepair toothpaste and mouthwash. [ABSTRACT FROM AUTHOR]

Currently, the sol-gel technique is employed in the synthesis of high-performance vitrified bonds; however, its application in the fabrication of stacked abrasives has been minimally explored. Furthermore, the methods utilized in the production of abrasive particles for stacked abrasives are technically challenging and incur high costs, which hinders their actual industrial application. Consequently, this study utilizes the sol-gel approach to synthesize a Na2O-B2O3-SiO2 ternary system vitrified bond powder and employs a molding and crushing method, which offers a lower technological barrier and reduced preparation costs, for the production of abrasive particles subsequently fabricating corundum stacked abrasives. Upon setting the binder composition to a molar ratio of n(SiO2):n(B2O3):n(Na2O) = 65:23:12, it was observed that the crystallization within the glass matrix was minimized and the optimal sintering temperature for the synthesized laminate abrasive to be sustained at 820 °C. At the aforementioned temperature, the binder melt is capable of flowing uniformly amongst the abrasive granules, thereby ensuring a robust encapsulation of the particles. The average single particle compressive strength of the prepared corundum stacked abrasive with a grain size of forty mesh can reach the highest of all composition points at 28.56 N and the average single particle compressive strength of the prepared diamond stacked abrasive is 28.14 N. [ABSTRACT FROM AUTHOR]

This contribution presents a novel wear dependent virtual flow rate sensor for single stage single lobe progressing cavity pumps. We study the wear-induced material loss of the pump components and the impact of this material loss on the volumetric efficiency. The results are combined with an established backflow model to implement a backflow calculation procedure that is adaptive to wear. We use a laboratory test setup with a highly abrasive fluid and operate a pump from new to worn condition to validate our approach. The obtained measurement data show that the presented virtual sensor is capable of calculating the flow rate of a pump being subject to wear during its regular operation. [ABSTRACT FROM AUTHOR]

Designing novel lubricants with easily customized structures, devisable compositions, and simple and economic synthesis over traditional lubricants is critical to fulfilling complex applications, prolonging machine lifetime, and saving energy. Deep eutectic solvents (DESs), which show tunable composition, adjustable structure, easy fabrication, and environmental friendliness, are promising candidates for variable and complicated lubricants applications. To promote the use of DESs as lubricants, a series of PEG200-based DESs with active heteroatoms were fabricated to tailor the tribological performance via tribo-chemistry. Thereinto, PEG200/boric acid (BA) DES shows optimal lubrication performance by forming tribo-chemical reaction film composited of B2O3, iron oxides, and FeOOH, and PEG200/thiourea (TU) DES displays abrasive wear-reducing property by producing FeS tribo-chemical film. Given the excellent abrasive wear-resistance of PEG200/TU DES and friction reduction of PEG200/BA DES, ternary PEG200/BA/TU DESs, composited of PEG200/TU DES and PEG200/BA DES, are first exploited. The ternary DESs possess superior wettability and thermal stability, which render them potential lubricants. Tribological tests of the ternary DESs demonstrate that synergistic lubrication is achieved by forming a transfer film consisting of FexBy, BN, B2O3, and FeS. Wherein FexBy, BN, and B2O3 increase load bearing of the film, and FeS mitigates severe abrasive wear. The proposed design philosophy of novel DESs as lubricants opens up a unique realm that is unattainable by traditional DESs lubrication mechanisms and provides a platform to design next-generation DESs lubrication systems. [ABSTRACT FROM AUTHOR]

This study aims to predict machinability and high performance optimum surface roughness (Ra) by developing multiple regression models and artificial neural network (ANN) model for abrasive water jet cutting (AWJC) of Aluminum 7068 alloy. Important basic processing parameters such as pump pressure (3500-4000 Bar), nozzle distance (2-5 mm), abrasive flow rate (200-350 g/min), abrasive grain size (100-110 mesh), and nozzle traverse speed (240-300 mm/min) were selected in the study. To examine the effects of these parameters on Ra, 32 experiments were conducted using the L32 orthogonal array, and data was collected. Additionally, the most important factors and interactions affecting Ra were determined using multiple regression analysis and analysis of variance (ANOVA). The Artificial Neural Network (ANN) model was designed to have multiple hidden layers using MATLAB. The model was trained and evaluated using experimental data, and its performance was measured using mean squared error (MSE) and mean absolute error (MAE). The model was optimized using hyper parameter tuning and cross-validation techniques. As a result, it was determined that the best R2 value of 95.65% from the multiple regression models created to estimate the surface roughness could be obtained from the linear regression model. While selecting the optimum process parameters for AWJC, it was determined that nozzle rotation speed, abrasive grain size and flow rate had the greatest effect by 35.5%, 25.4% and 21.9%, respectively. The optimized ANN model showed high accuracy in predicting Ra for different input parameter combinations. This study provides a reliable and efficient tool for predicting Ra in AWJC, which can contribute to improving process planning and control. [ABSTRACT FROM AUTHOR]

Diamond surfaces must be of high quality for potential use in semiconductors, optical windows, and heat conductivity applications. However, due to the material's exceptional hardness and chemical stability, it can be difficult to obtain a smooth surface on diamond. This study examines the parameters that can potentially influence the surface quality of chemically vapor-deposited (CVD) diamonds during the chemical and mechanical polishing (CMP) process. Analysis and experimental findings show that the surface quality of polished CVD diamonds is significantly influenced by the crystal structure and the growth quality of the diamond. In particular, when the surface roughness is below Ra 20 nm, the pores and grain boundaries on CVD diamond obstruct surface roughness reduction during mechanical polishing. To obtain a smooth polished surface, careful consideration of the size of diamond abrasives and polishing methods is also a prerequisite. Chemical mechanical polishing is a novel method to achieve a surface quality with roughness below Ra 3 nm, as in this method, the anisotropy of the CVD diamond allows the uneven steps to be efficiently erased. However, the chemical actions of polishing slurry should be controlled to prevent the formation of chemical etching pits. [ABSTRACT FROM AUTHOR]

In order to solve the problem of the corrosion and wear of N80 metal pipelines exposed to corrosive media and abrasive sand during the development of petroleum resources, the proposed solution involves utilizing HC-PECVD technology to deposit a series of multilayer Si-DLC films with varying thicknesses on the inner surfaces of the N80 steel pipes. This investigation systematically explored the microstructure, mechanical properties, tribological features, and corrosion resistance of the multilayer Si-DLC films. Remarkably, after coating the multilayer (Si-DLC)40 film on the inner wall of the N80 tube, the friction coefficient decreased from 0.7~0.75 to 0.2~3, and the wear rate decreased by two orders of magnitude. In addition, the corrosion current decreased by 50%, and the impedance doubled in a 3.5 wt% NaCl solution saturated with CO2. Thus, the multilayer (Si-DLC)40 film on the inner wall of the N80 tube exhibited superior tribological properties and exceptional corrosion resistance. These findings are anticipated to furnish valuable data and technical insights for mitigating corrosion in N80 steel pipes during petroleum exploitation. [ABSTRACT FROM AUTHOR]

Inner surface components with a high level of precision are extensively utilized in contemporary industry. Polishing of inner surfaces and precise control of profile contours are extremely difficult due to space constraints and the surface shape. To realize ultraprecision polishing of inner surfaces, this paper proposes an abrasive rotating jet polishing (ARJP) method, in which a new type of polishing process with an infinitely adjustable incidence angle is adopted to realize ultraprecision polishing of the inner surfaces of workpiece made of aluminium alloy 6061. The precision of inner surface profiles strongly depends on the accuracy of the material removal profile prediction. A computational fluid dynamics approach is used to simulate and analyse the material removal profile of the workpiece inner surface during the ARJP process for a novel polishing process and tools. A series of inner surface polishing experiments demonstrate that the average error between the actual material removal depth and model simulation results is less than 5.9% and that the roughness of the inner surface is reduced from 0.200 µm to 0.046 µm, a 77% improvement in inner surface roughness. [Display omitted] • A new polishing method and system for polishing inner surface are proposed. • The material removal profile of inner surface is predicted and analyzed by CFD model. • The average error is less than 5.9% and that the roughness is reduced from 0.200 µm to 0.046 µm. [ABSTRACT FROM AUTHOR]