Abrasive Air Jet Research Articles

Influence of bioactive glass addition on the machinability, mechanical and biological response of Mg-PSZ-based biocomposites

The incorporation of bioactive glass (BG) into zirconia-based composite materials shows a feasible option to enhance the biological properties, reduce the sintering temperature, and resist the transformation of the tetragonal phase of zirconia. In this present work, the bioceramic composites, having the general formula [(100-x) (8 Mg-PSZ) – x (13–93 BG)] where x = 0 to 25 wt%, have been prepared and evaluated the effect of BG amounts on the machinability, mechanical and biological behavior of the composite material. The machining experiment is performed on an abrasive air jet machine (AAJM), and machinability is evaluated in the form of material removal rate (MRR), surface roughness (SR), and mechanics of material erosion (MME) at room temperature. The machinability results show that MRR decreases with enhancing the BG contents, and the SR follows the opposite trend of MRR. The MME indicates that the material is removed from the surface mainly due to the erosion crater and brittle fracture. Further, mechanical properties are evaluated, and it is found that the inclusion of BG frits and sintering temperature is substantially associated with the relative densities and the mechanical characteristics. Adding BG reinforcements increases the mechanical characteristics at lower sintering temperatures (1250 °C) while reducing the mechanical characteristics except hardness at higher sintering temperatures (1350 °C). Elastic modulus decreases with the addition of BG content up to 15 wt%; after that, it slightly increases up to 25 wt%. The in-vitro bioactivity and bio-degradation are tested in simulated body fluid (SBF), and both are increased by enhancing the BG contents up to 25 wt%. The in-vitro cell culture is performed on the MG-63 cell line. The biocompatibility increases with BG concentration (up to 25 wt%). Based on experimental results, it may be concluded that 8 Mg-PSZ/13-93BG bioceramic composites may be a potential choice for biomedical applications.

A novel approach of jet polishing for interior surface of small-grooved components using three developed setups

It is a challenge to polish the interior surface of an additively manufactured component with complex structures and groove sizes less than 1 mm. Traditional polishing methods are disabled to polish the component, meanwhile keeping the structure intact. To overcome this challenge, small-grooved components made of aluminum alloy with sizes less than 1 mm were fabricated by a custom-made printer. A novel approach to multi-phase jet (MPJ) polishing is proposed, utilizing a self-developed polisher that incorporates solid, liquid, and gas phases. In contrast, abrasive air jet (AAJ) polishing is recommended, employing a customized polisher that combines solid and gas phases. After jet polishing, surface roughness (Sa) on the interior surface of grooves decreases from pristine 8.596 μm to 0.701 μm and 0.336 μm via AAJ polishing and MPJ polishing, respectively, and Sa reduces 92% and 96%, correspondingly. Furthermore, a formula defining the relationship between linear energy density and unit defect volume has been developed. The optimized parameters in additive manufacturing are that linear energy density varies from 0.135 J mm−1 to 0.22 J mm−1. The unit area defect volume achieved via the optimized parameters decreases to 1/12 of that achieved via non-optimized ones. Computational fluid dynamics simulation results reveal that material is removed by shear stress, and the alumina abrasives experience multiple collisions with the defects on the heat pipe groove, resulting in uniform material removal. This is in good agreement with the experimental results. The novel proposed setups, approach, and findings provide new insights into manufacturing complex-structured components, polishing the small-grooved structure, and keeping it unbroken.

Вдосконалення процесу обробки абразивно-повітряним струменем робочих поверхонь лопаток моноколіс закритого типу на основі даних чисельного моделювання за допомогою програмного комплексу ANSYS CFX

The correct choice of technological modes can guarantee the results of inkjet processing. However, the need to consider a significant amount of input data, namely the parameters of the equipment, the abrasive jet, the physical and mechanical properties of the material, and the shape of the processed product surfaces, as well as the lack of clear recommendations and technological data, significantly complicates the process. The subject of this study is the process of processing the surface of closed-type blades with an abrasive-air jet made in one piece with a disk of the "monowheel" type, using the SLM technology of Inconel 718 alloy. The goal of this task is to model the jet processing of closed-type monowheel blades using the ANSYS CFX finite element analysis software system. This article presents the results of numerical modeling of the surface treatment of closed turbine blades and the identification of technological factors that affect the roughness and quality of the surface of the compressed air environment on samples of closed turbine blades made of Inconel 718 alloy. The task: to develop a research plan and study the processing process and accompanying phenomena occurring during processing using the finite element method using the ANSYS CFX software complex, considering the physical and mechanical properties of the abrasive often, the environment, and the processed material. The following results were obtained: during mathematical modeling using the finite element method, data were obtained for sixteen calculation variants of blade surface treatment, from which the most optimal one was chosen, which provides the largest contact area of abrasive particles and their uniform interaction with the processing surface. In addition, during the research, the impact of "unevenness of erosion" and the graininess of abrasive materials on the quality of the treated surface was studied. Further analysis of the data of the research results made it possible to find ways to solve these tasks, which was confirmed by the control and verification results. Conclusions. The scientific novelty of the obtained results is as follows: for the first time, the processing of closed turbine blades made in one piece with a "monowheel" type disk and obtained by the additive method with an abrasive air jet was investigated. The obtained research data were used as a basis for developing a real route technological process for processing closed-type turbine blades manufactured using the additive method.

Exploration of machining parameters by using Taguchi technique on MAAJDM

In this investigation non conventional machine is used to drill a ceramic composite work piece with given input parameters abrasive particles (SiC) are combined with gas in a mixing chamber the size of the abrasive particles is 30 µm and these particles are impinged targeted surface on the work piece with high velocity. An experiment was carried out in accordance with Taguchi's design of experiments in order to determine the signal-to-noise ratio and prediction values of 27 experiments. Four input parameters were used to carry out the experiment on an abrasive air jet drilling machine. We ran one experiment for each orthogonal array combination, and using ANOVA we discovered that the process parameters have a significant influence on kerf. According to the ANOVA, the input parameter standoff distance has the greatest impact on the kerf, followed by air pressure, abrasive flow rate, and finally specimen type. In this work, the investigation brings as per L27 orthogonal array (OA) by varying Pressure, Standoff distance, Abrasive Flow Rate, and percentage of reinforcement into matrix material respectively.

Numerical and experimental investigations on the effect of particle properties on the erosion behavior of aluminum alloy during abrasive air jet machining process

Numerical and experimental investigations on the effect of particle properties on the erosion behavior of aluminum alloy during abrasive air jet machining process

An Investigation into the Multi-Pass Radial-Mode Micro Abrasive Air Jet Turning of Fused-Silica Rods

With the increased requirement of miniaturization structures on hard and brittle substrates, micro abrasive air jet turning technology has become a promising machining technology for manufacturing miniaturization structures. This paper presents an investigation on multi-pass radial-mode micro abrasive air jet turning of fused silica. The effect of machining parameters on the depth of cut and materials removal rate was analyzed. The waviness and striation formation mechanisms were studied. It was found that increasing the number of passes significantly increases the depth of cut and materials removal rate. When the surface speed is reduced, the depth of cut and materials removal rate significantly increases. The waviness may be attributed to the intersection and overlap of the adjoint jet footprint. The crossed striations have been found, which may lead to the elimination of the striation. A predictive model of the material removal rate was developed using the dimensional analysis method. The model was assessed and shown to be able to give adequate predictions.

Study of a new method for the instant preparation of ice particles in ice abrasive air jet

The ice abrasive air jet is a clean surface treatment technology, which currently has limitations such as high energy consumption, uncontrollable particle size and hardness. Realizing the instant preparation and utilization of ice particles are crucial for solving the energy consumption problem. This paper based on the icing principle of heterogeneous nucleation, proposed a new method of ice making, the heat transfer mechanism of low temperature droplets was studied, and the method was proved to be feasible. Using the FLUENT solidification and melting model combined with the VOF model to calculate the freezing process of droplets, the effects of droplet particle size, initial temperature, and wall temperature on the freezing time were analyzed, and the calculation equation of the freezing time was determined, which was corrected by the icing test results. The results showed that the outside of the droplet freezes first, the liquid–solid boundary is parabolic, and the parabolic concavity increases with time and droplet size. In the freezing process, the larger the droplet size, the longer the droplet phase transition time; the higher the droplet initial temperature, the longer it took to reach the phase transition; the higher the wall temperature, the longer the ice formation time.

Effect of process parameters on Mg/Gr (MMC) and GFRP by using abrasive air jet machine

Conventional methods are difficult to use for machining hard materials. The non-conventional techniques like Abrasive Air Jet Machine (AAJM) are suitable for machining hard materials. The main objective is to evaluate and optimize the machining parameters of Magnesium alloy (AZ91D) / Graphene (MMC) and Glass fiber reinforced polymer (GFRP) using Abrasive air jet machine. In this study, we examined the influence of multiple process parameters on the predominant machining criteria for metal removal rate (MRR), including air pressure, stand-off distance and time. Sic particles were used as an abrasive particle during machining process. In addition to analyzing and optimizing the machining parameters of an abrasive jet machine, Taguchi's L9 is used to determine the Material Removal Rate (MRR) and the kerf taper angle (θ) during the machining process. Based on the experimental results, the machining parameters like pressure and stand of distance influenced the material removal rate.

Development of Coating Removing from GFRP Surface by Abrasive Air Jet Using Amino Thermoset Plastic Abrasive

Development of Coating Removing from GFRP Surface by Abrasive Air Jet Using Amino Thermoset Plastic Abrasive

Improvement of process repeatability and resolution in abrasive air jet machining via viscous slurry entrainment

The unsteady powder mass flowrate of the available feeding systems and the bad control of the areas being eroded have been often noticed in the abrasive air jet machining process. In addition to the delivery of dry powder, the powder can be evenly mixed with liquid to form a slurry, and then sent to the mixing chamber of an air jet machine; i.e., multiphase jet machining (MJM) was proposed in this paper. The method whereby using the viscous water to suspend the abrasives was found to enhance the stability of powder mass flowrate, thereby decreasing the fluctuation in the machining depth. Whereafter, five types of liquid-based slurries were prepared and their effects on the jet erosion zone were investigated. It was found that the control of the erosion zone was improved to varying degrees when the abrasives were transported into the air jet by viscous liquid as the carrier fluid due to the two roles: reducing the occurrence of third and/or second particle impacts; inducing a viscous boundary layer that could reduce the negative effect of the divergence of jet beam and particle rebounding. In particular, the use of an oil-based slurry could completely eliminate the unwanted frosted zone around the machined features. CFD simulations were used to understand the mechanisms causing these effects. Overall, it is shown that the abrasive air jets can be designed to have a good resolution, so it is feasible to mill or polish surface without the need for a mask to define the edges.

Characteristics of cryogenic abrasive air-jet direct-write machining: A comparison with abrasive air-jet direct-write machining at oblique angles

• The velocity model of abrasive particles in the radial direction is modified. • Abrasive air-jet (AAJ) direct-writing of PDMS at 15° is presented. • Cryogenic abrasive air-jet (CAAJ) direct-writing of PDMS is presented. • CFD models of AAJ and CAAJ direct-writing are established. • "U"-shaped micro-channels are obtained by CAAJ and compared against AAJ at 15°. Cryogenic abrasive air-jet (CAAJ) machining technology is performed simultaneously with the occurrence of the glass transition for PDMS material. However, the mask material is also cooled with cryogenic PDMS cooling. Then, they both show significant brittle characteristics. Therefore, this leads to very poor selectivity between the mask and the PDMS. To solve this problem, CAAJ direct-write machining under unmasking conditions are proposed based on the modified velocity model of abrasive particles in the radial direction. This technique was used to direct-write machined the PDMS materials under small SOD. Then, the effect of cryogenic conditions on machining characteristics of PDMS micro-channels was studied by comparing the abrasive air-jet direct-write machining at oblique angles and CAAJ direct-write machining technologies through a series of experimental studies and CFD simulations. The results show that the material removal mode is transformed to a semi-brittle one, which greatly improves erosion removal efficiency, aspect ratio and bottom surface roughness of the micro-channel. On the other hand, the change in the viscosity of the jet medium has a crucial influence on the geometry of the micro-channel. The rebound direction of abrasive particles changes, and the sidewall of micro-channels is secondarily eroded due to an increase in jet medium viscosity in CAAJ. This, in turn, leads to a micro-channel with "U"-shaped profile. In addition, during CAAJ direct-write machining, sliding, scratching, and rolling of abrasive particles caused by bubble bursting can effectively reduce the bottom surface roughness of the micro-channel.

Effect of nozzle pressure ratios on the flow and distribution of abrasive particles in abrasive air jet machining

Effect of nozzle pressure ratio (NPR) on the flow and distribution of abrasive particles was investigated to improve supersonic abrasive air jet machining (AAJM) effect. The supersonic air-particle flow was simulated via CFD-DEM modeling, which was verified by AAJM experiments. It was concluded that NPR determined the acceleration and distribution of particle flow by controlling the structure and turbulent kinetic energy of the air jet free-flow field. When NPR = 1.12, the particle flow field had a longer stable region and a higher particle velocity, and the radial distribution resembled an n-shape. Further, in AAJM experiments, when the material was fixed in the stable region of particle flow field, the impact stresses were relatively high and uniformly distributed. Thus, when NPR = 1.12, the target material is fixed in the stable region of the abrasive particle flow, and the target material can obtain a better machining effect in the AAJM.

Optimization of process parameters on machining of graphene reinforced with magnesium based composite using abrasive jet machine

The abrasive air machine has been used widely to machine the hard materials and making the complex shapes. The main objective of this work is to evaluate and optimize the machining parameters of the Abrasive air jet machine. The machining parameters are air pressure, abrasive flow rate, and stand off distance. The Silicon carbide particles were used as an abrasive particle. The Taguchi’s L27 used to analyze and optimize the machining parameters of the abrasive jet machine, and used to determine Material Removal Rate (MRR) and kerf taper angle (θ) during the machining process. The experimental results revealed that the material removal rate was influenced by the machining parameters. The machining surfaces were evaluated by the scanning electron microscope.

Modeling and simulation of micro-hole fabrication on brittle material using abrasive air jet machining

The investigation of overlapping impacts and resultant erosion is of great significance for improving the AAJ micromachining performance of brittle and difficult-to-machine materials. In this work, a computational model coupling the Monte Carlo (MC) method and discrete element method (DEM) is developed to study the erosion process of micro-hole fabrication on glass using abrasive air jet (AAJ) at a 90° impact angle. We employ the MC method combined with probability distribution functions to model the impinging particle flow. Brittle erosive behaviors of the overlapping impacts between the impacting particles and the target specimen are simulated by the DEM model. The modeling framework is firstly validated by experimental results using patterns and sizes of micro-holes on the specimen. We then conduct mechanism investigations on the particle and crack behaviors in the erosion process and the overlapping condition effect in the multiple impacts. The relationship between the jet characteristics with the machining efficiency and surface quality of micro-holes is further discussed. The results indicate that the presented DEM model can capture the particle interference effects, which play an essential role in controlling the material removal and microstructure geometry in AAJ machining. The model and findings can help understand the microscopic erosion mechanism and optimize the processing performances of microstructures on brittle materials in AAJ.

Characteristics of multiphase jet machining: A comparison with the absence of water

Abstract Multiphase jet machining (MJM) is a recently developed surface texturing method that introduces water into a dry abrasive air jet. However, there are still some unknown issues with MJM, especially regarding the effects of adding water. Hence, we conducted a series of comparative studies when water was added (wet conditions) or not (dry conditions). Dimples and masked channels were machined on Si wafer and cemented carbide (YG6) surfaces to quantify the machining profile, erosion rate and roughness. Numerical simulations and high-speed cameras were used to help understand the particle erosion mechanisms. It was found that the inhaled water was completely atomized to form droplets and wrapped the abrasive particles; thus, the abrasives tended to follow their original trajectories without being deflected by the divergent airflow. This convergent effect could reduce the jet diameter and thus improve the machining resolution. The machining footprint was found to be reduced by 47.2 % at a jet distance of 13 mm compared to without water. Experimental and numerical results confirmed that under wet conditions, most of the particles would flow close to the machined surface, thus introducing a sliding grinding effect. The net result was a decrease in erosion ability but an improvement in surface roughness. Particularly, for the machining of sintered materials, the roughness could be improved more than 2.5 times.

Erosion Wear Characteristics of Rock Eroded Using Abrasive Air Jet at 90° Impingement Angle

An abrasive air jet, which is sufficiently powerful to break rock, has significant potential in the field of assisted rock breaking, such as assistive tunnel excavation using a tunnel boring machine. To make its application more efficient and beneficial, a clear and definite erosion mechanism of an abrasive air jet is necessary. However, the present erosion mechanisms of an abrasive air jet have mostly neglected the secondary erosion of rebounding particles. The effect of rebounding particles on rock erosion was analyzed by numerical simulation and scanning electron microscopic images. We obtained a variety of stresses and the distribution when a perpendicular abrasive air jet erodes rock through smoothed particle hydrodynamics (SPH). In addition, the particle trajectory and a variety of velocities were also obtained, which provide the data necessary to analyze the formation and characteristics of the erosion pits. It can be concluded that the rebounding abrasive particles play an indispensable role in the stress formation and distribution of rock, and are also the primary cause of a particular erosion pit feature, that is, a semi sphere-like bottom, under an annular platform. The incident abrasive at the center of an air jet deepens the erosion pit with a large impact force and its energy propagates into the rock with a stress wave. Meanwhile, the rebounding abrasive enlarges the diameter of both the erosion pits and the semi sphere-like bottom. Because the diameter of an erosion pit is larger than that of a semi sphere-like bottom, an annular platform is formed. The incident abrasive at the jet boundary involves the formation of an annular platform. The incident and rebounding abrasives have different roles in the erosion wear of rock. The main wear characteristics of the rock are cutting and deformation wear. The incident abrasive with a high velocity induces the deformation and cutting wear at the semi sphere-like bottom. Only a cutting wear can be induced at an annular platform by an incident abrasive with a lower velocity. The rebounding abrasive induces the cutting wear of the rock only. However, the features of an erosion rock surface vary depending on the eroding angle of the rebounding abrasive.

Surface Formation Mechanics and its Microstructural Characteristics of AAJP of Aluminum Alloy by Using Amino Thermosetting Plastic Abrasive

In this study, a two-dimensional model according to the microcutting mechanism of abrasive particle was developed to demonstrate the mechanics of surface formation of the abrasive air jet polishing (AAJP) of aluminum alloy using amino thermosetting plastic (ATP) abrasive. It is shown that due to the characteristics of medium hardness and angular shape of ATP particle, the impacted surface can be generated by particle sliding, ploughing, microcutting, and indentation with the impinging angle increasing from 0o to 90o. Moreover, the effects of particle impacting on the surface microstructural characteristics, especially residual stress, have been analyzed. It has been found that, compared with particle ploughing and sliding processes, particle microcutting and indentation processes have an obvious effect on the surface residual stress; furthermore, particle microcutting process that can cause the impacted surface with high material deformation and ductility is more beneficial for improving the compressive residual stress than particle indentation process. The results of the study are expected to be applied to improve the fatigue performance of integral and large aircraft structures made of aluminum alloy or other metal materials.

Semi-resolved CFD-DEM modeling of gas-particle two-phase flow in the micro-abrasive air jet machining

Abrasive air jet (AAJ) machining is attractive for micromachining hard and brittle materials, while it is usually a big challenge to numerically investigate the particle velocity and concentration distribution in the particle erosion process in the AAJ. In this work, a recently developed semi-resolved CFD-DEM approach which bridges the simulation gap between the resolved and unresolved CFD-DEM, is further improved to reconstruct the background information with a double cosine kernel function. The semi-resolved CFD-DEM is then employed to numerically investigate the gas-particle two-phase flow in the AAJ and numerical results show that this semi-resolved CFD-DEM is more accurate in modeling particulate flow in the fine AAJ nozzle than the conventional unresolved CFD-DEM. We further conduct mechanism investigations on the AAJ micromachining process including particle flow characteristics inside the cylindrical nozzle, velocity, and concentration distribution over the nozzle exit, which are essential jet characteristic features. We identified the particle flow patterns, analyzed the particle distribution, and its correlation with air pressure, abrasive mass flow rate, and turbulence effects. The present simulation results and analyses can be great helpful in understanding the erosion mechanism and optimizing the setting parameters to improve the cutting performance of AAJ.

MACHINING OF HARDSTONE QUARTZ WITH MODIFIED AJM PROCESS USING HOT SiC ABRASIVES: ANALYSIS, MODELING, OPTIMIZATION, AND COST ANALYSIS

Machining of hard and brittle materials such as engineering ceramics, glass, and silicon is a formidable task. Unlike cutting processes employing plasma and lasers, better machining capabilities of abrasive jet machining are characterized by thermally damaged free surface which is highly competitive as well as important for survival of materials in service. In this paper, an attempt has been made to combine hot abrasives and compressed air to form a hot abrasive air jet. This study aims to analyze the cutting performance in hot-abrasive jet machining (HAJM) of hardstone quartz concerning surface roughness, taper angle (TA), and material removal rate (MRR). Combined approach of Box–Behnken design — analysis of variance, response surface methodology, and statistical technique (here desirability function approach), followed by computational approach (here genetic algorithm), is, respectively, employed for experimental investigation, predictive modeling, and multi-response optimization. Thereafter, the effectiveness of proposed two multi-objective optimization techniques is evaluated by confirmation test and subsequently, the best optimal solution (i.e. at air pressure of 7[Formula: see text]kgf/cm2, abrasive temperature of [Formula: see text]C, stand-off distance of 4 mm) is used for economic analysis. Result shows that the most significant parameter is abrasive temperature for surface roughness, whereas it is pressure in case of both TA and MRR. Applications of hot abrasives in AJM process have shown attention in enhancing the cutting performance for material removal. Due to lower percentage contribution of error (6.68% to Rz, 9.89% to TA, and 6.42% in case of MRR), a higher correlation coefficient ([Formula: see text]) was obtained with the quadratic regression model, which showed values of 0.92, 0.9, and 0.93 for surface roughness, TA, and MRR, respectively.

Sensitivity analysis of abrasive air-jet machining parameters on machinability of carbon and glass fiber reinforced hybrid composites

Carbon and glass fiber reinforced epoxy polymer hybrid composites facilitate to tailor the mechanical properties of the composites. However, the machining of hybrid fiber reinforced polymer composite is a challenge by conventional processes due to the different types of fiber reinforcements and anisotropic nature of composites. Researchers and scientists have evaluated the machinability of plain or single fiber reinforced polymer composites through abrasive water jet machining and abrasive air jet machining. Therefore, the present investigation emphasizes on the development of symmetrical hybrid composites, evaluation of mechanical properties and machining of the hybrid composites through abrasive air jet machining (AAJM). There are three types of hybrid composites such as C2G3]S, [CG3C]S and [CG2CG]S along with plain glass ([G]10) and carbon ([C]10) fiber reinforced polymer composites fabricated by hand lay-up technique. It is observed that the [CG2CG]S type hybrid composite has the optimum tensile and flexural strength as compared to other composites. Hence, [CG2CG]S type hybrid composites along with plain glass and carbon fiber reinforced polymer composites was considered for the machinability study. The sensitivity of AAJM process parameters on material removal rate (MRR), depth of cut (DOC) and surface roughness (Ra) are investigated and optimized through response surface methodology (RSM). The optimum machining process output predicted by the RSM model for [CG2CG]S type hybrid composite is MRR = 3.26 × 10−3 g/sec, DOC = 1.48 mm and surface roughness (Ra) = 1.48 μm. The predicted model results compared with the experimental values and found a good agreement between them. The surface morphology of the drilled composite sample is investigated under scanning electron microscope. It is observed that the surface damage of the drilled surface of the composites is minimal. Thus, the abrasive air jet machining process can be employed for drilling of polymer matrix composites to overcome the conventional machining issues.