Abrasive Machining Process Research Articles

An investigation into the challenges of the point grinding machining process

Point grinding is an abrasive machining process that utilises miniature single layer superabrasive tools to remove material. The use of such small diameter tools offers advantages in the manufacturing of small or difficult to access complex 3D geometries, however, in their current state, these tools suffer from several critical challenges preventing their successful implementation. An investigation into the use of a typical commercially available point grinding tool for machining of hardened steel components has been carried out, with the aim of identifying the critical process challenges. The requirement for high rotational speeds, high tool deflection, variation in grit protrusion heights and bond layer thickness, accelerated tool wear, increased sensitivity to runout, zero cutting speed at tooltip and high tool loading have been identified as the main issues affecting the point grinding process. It is crucial that these challenges are correctly understood to facilitate future tool development.

Unconventional Machining of ceramic matrix Composites – A review

With an increase in demand for materials that are lightweight, thermally stable, and can sustain higher temperatures, ceramic matrix composites or CMC’s turned out to be potential candidates however, the major challenge with these materials was the manufacturing aspect and so, there was a demand for machining methods which could easily machine these materials without having much tool wear, provide higher material removal rate (MRR), and produce low surface roughness. Conventional machining (CM) processes like milling, grinding, drilling, and so on were turning out to be disadvantageous as the hardness of these materials is high and it results in excessive tool wear, high surface roughness, and low MRR. Recent researches in unconventional machining processes such as laser machining, plasma machining, electric discharge machining, and abrasive water jet machining, etc. are showing positive results when compared with CM. The current work presents a review of the unconventional machining process of these difficult to machine materials. The unconventional machining processes considered here are the laser-assisted machining process, rotatory ultrasonic machining process, and abrasive water jet machining process. Furthermore, it also discusses how these machining processes are better than conventional machining processes and it compares their MRR, surface roughness (SR), change in the properties, and also discusses the effect of these machining processes on the same parameters.

Augmenting the design of a nozzle used in abrasive jet machining process with computational fluid dynamics

The nozzle is an important part that affects the performance of the abrasive jet machining. It is a micromachining process, where the target material is being eroded by the effect of a high-speed continuous flow of abrasive particles, which are move out from a nozzle. A nozzle is required to carry out the particles to remove the material with the help of a large velocity of the microjet. The common nozzle shape presently used in this process is a rectangle and circular shape, which gives a low flow rate and further demands to reduce the material removal rate (MRR). In this work, three different geometrical types of nozzles: (i) convergent nozzle (25 mm) length, (ii) convergent nozzle (50 mm) length, (iii) modified convergent nozzle has been designed. The simulations of the flow have been analyzed using computational fluid dynamics. The velocity and pressure of the particles inside the nozzle were compared. The results show the improvements in the modified convergent nozzle are about 42.84 m/s of velocity and the pressure inside the nozzle tip is about 994424.5 Pa. Due to the swirl flow in a modified convergent nozzle, the high material removal rate is achieved.

Analysis and Modeling of the Micro-Cutting Process of Ti-6Al-4V Titanium Alloy with Single Abrasive Grain

Modeling of material displacements in the microcutting zone is complex due to the number and interdependence of factors affecting the results of the process. An important problem in the modeling process is the selection of the constitutive model and its parameters, which will correctly describe the properties of the material under the conditions of triaxial compression, which is characteristic for the areas of the contact zone of the blade and the processed material in abrasive machining processes. The aim of the work was to develop computer models (with the use of the finite element method) of the microcutting process with a single abrasive grain, which were verified with the results of experimental tests. The paper presents the methodology of modeling the processes of microcutting with abrasive grains, whose geometrical models were created based on optical scanning methods. Observations of the microcutting process were carried out with the use of a high-speed camera and an optical profilometer. This enabled a detailed observation of the chip formation process, as well as the analysis of the surface topography of microcutting traces. The results presented in the paper indicate the convergence of the results of the numerical and experimental simulations with regard to the geometric parameters describing the scratches formed in the microcutting process and the compliance of the chip-forming process. Thus, the correctness of the selection of the constitutive model (Johnson Cook equation) and its parameters was demonstrated, as well as the correctness of the applied methodology for creating a geometric model that allowed for a reflection of the geometrical parameters of the abrasive grains that coincided with the real objects, thanks to which it was possible to reflect in detail the phenomena occurring in the vicinity of the abrasive grain tip.

IoT based smart machinability system and performances of MRR on Haynes alloy

The research work and applications of advanced materials have been increased in industries. At the same time, researchers are tried to convert the machining system into automatic process. In this paper is discussed about the internet of Things (IoT) based monitoring system of unconventional machining processes of Haynes 230 alloy. The water level, water pressure, abrasive quantity and its flow rate have been monitored through IoT in Abrasive Water Jet Machining (AWJM) processes. The different sensors, micro controller, wireless sensor network and modules have been used to improve the machinability of Haynes alloy. The machining performances have been evaluated with and without IoT system. Hence, the total process is called as smart machinability system which is applied on AWJM process.

Ultra-precision grinding of Gd3Ga5O12 crystals with graphene oxide coolant: Material deformation mechanism and performance evaluation

• GO lubrication assisted grinding was innovatively applied in crack-free machining of GGG crystals. • Plastic deformation of GGG induced by GO assisted grinding was dominated by polycrystallization nanocrystals and amorphous transformation. • Interlayer slip and filling actions of GO significantly affect the deformation and removal processes of GGG crystals. • Compared with conventional grinding, surface roughness and friction coefficient of GO assisted grinding were effectively reduced. Laser crystals of rare-earth oxide are primary host materials for making solid-state lasers of large power. However, brittle fractures and cracks are easily formed on the crystal’s surface and subsurface during abrasive machining process owing to their high hardness and brittleness, which will seriously reduce output power of the lasers. In this work, a grinding coolant was synthesized through dispersing GO nanosheets in water, and the grinding experiment of GGG laser crystals assisted by GO coolant lubrication was systematically performed. The plastic deformation mechanism of GGG crystals induced by GO assisted grinding was revealed at close-to-atomic scale by Raman spectrum and cross-section TEM detection technologies. The results indicated that the plastic deformation of GGG crystals during GO assisted grinding was affected by the interlayer slip and filling actions of GO, and was dominated by polycrystallization nanocrystals and amorphous transformation caused by the crystal plane slipping. The use of the GO coolant enabled to lower friction at the abrasive-substrate interface significantly owing to their self-lubricating effect, thus resulting in improved ground surface quality, in comparison with conventional grinding. This work will provide a new theoretical basis and technical support for high-efficiency and low-damage ultra-precision grinding of laser crystals.

Assessment of the classification ability of parameters characterizing surface topography formed in manufacturing and operation processes

The new parameters for the parametric assessment of differentiating the features of surfaces formed in different machining processes was presented in the paper. Classification capacity indicators were analyzed and their interdependencies were presented proposing multi-criteria indicators. Eighty three parameters characterizing geometrical features were determined for 22 surfaces formed in various abrasive and erosive machining processes, as well as for surfaces with different wear conditions. The set of surfaces analyzed was a pattern with a high degree of diversity in the geometric structure of the surfaces studied, but with a similar range of ordinates. In the case of the analyzed surfaces, the functional parameters S5p, S10z, height parameters Sp and Sv as well as new parameters regarding surface elevation features indicate a high ability to distinguish characteristic surface features.Advantages of applying various criteria and aggregating the results of the obtained classification ability assessments for individual parameters have been demonstrated. The test results can be the basis for choosing the parameters forming a complementary set used to assess the suitability of the surface for specific applications. The new parameters of surface topography assessment, useful in assessing contact areas of cooperating surfaces was also presented.

Study on the improvement of the surface integrity and efficiency of electrical-discharge-machined TC4 titanium alloy via abrasive flow machining

To simultaneously optimize the surface quality and machining efficiency of the electrical discharge machining (EDM) processes used to produce titanium alloy quadrilateral group small hole parts, a combined “EDM + AFM” machining technology is proposed in this paper as an efficient and high-quality machining approach. In the proposed method, TC4 titanium alloy is first machined using the EDM process with graphite electrodes and the abrasive flow machining (AFM) process is then used to finish the machined surface. The effects of various electrical parameters on EDM-derived surface quality and improvements in EDM-derived quality under the application of AFM were assessed and, using the final surface roughness as a constraint condition, the effects of various combinations of EDM and “EDM + AFM” on efficiency were studied. The results revealed that the thickness and surface roughness of the superficial recast layer of the TC4 titanium alloy increase with both current and pulse width; in particular, increasing these parameters can increase the surface roughness by two to three grades. Following AFM, the alloy has a more uniform hardness distribution and the surface stress state changes from tensile to compressive stress, indicating that the combined “EDM + AFM” machining scheme can significantly enhance the surface quality of EDM-produced titanium alloy quadrilateral small group holes. The combined scheme achieves a balancing point beyond which increasing the roughness or the number of machining holes enhances either the machining efficiency or the machining surface quality. In the case of typical titanium alloy quadrilateral group small hole parts, the combined machining process can improve the finishing efficiency and total machining efficiency by 71.2% and 25.36%, respectively.

Experimental Study of the Impact of a Vibrating Wire on Free Abrasive Machining as Correlated to the Modeling of Vibration Subject to an Oscillating Boundary Condition

Abstract In this paper, we study experimentally the impact of a vibrating wire on the free abrasive machining (FAM) process in removing material from the surface of brittle materials, such as silicon. An experimental setup was designed to study the FAM process on silicon substrate surface by using a slurry-fed wire with a periodic excitation. An analytical solution of a wire moving axially, subject to an oscillating boundary condition with damping from abrasive slurry, was derived based on the partial differential equation of motion. Experiments were conducted on the apparatus using a wire with an oscillating boundary. It was found that the amplitudes of vibration were larger at the side of the oscillatory boundary, which caused more FAM interaction near the edge of the oscillatory boundary with larger material removal that was measured and validated. Furthermore, experiments were conducted to elucidate the effectiveness of brittle material removal using FAM with abrasive grits: (i) under dry condition, (ii) with water, and (iii) with abrasive slurry. Experimental results showed that the vibration of wire resulted in plastic deformation on the surface of silicon wafer. The abrasive grits in slurry driven by a vibrating wire generated material removal through observable grooves and fractures on the surface of silicon due to FAM in just a few minutes. The grooves from FAM process is an outcome of brittle machining through fracture formation and concatenation, generated by the indentation of abrasive grits on the silicon surface.

Wear analysis of abrasive waterjet nozzle using suprathreshold stochastic resonance technique

The performance of an abrasive water jet machining (AWJM) process is mainly dependent on the jet diameter, which is prone to change with time due to the nozzle wear. The present study is aimed to monitor the nozzle wear during operation using vibrational spectrum. Experiments are conducted with four focusing nozzles of different diameters under same parameters considering water and water-abrasive mixture as the jet. The obtained vibration spectrum through an accelerometer and data acquisition system are analyzed by Suprathreshold Stochastic Resonance (SSR) technique using MATLAB. The results obtained shows that SSR technique is easy to implement and gives a better performance in monitoring and analyzing the wear severity.

Investigation on Slicing Behavior of Single Crystal Silicon Wafer in AWJM and Influence of Micro Dimple Textured Surface for Solar Applications

The current investigation focuses on the slicing characteristics of silicon, a hard and brittle solid that is very difficult to cut, with abrasive water jet machining (AWJM) process by varying different operational parameters like abrasive flow rate (QA), traverse rate (TR), water pressure (P) and stand-off distance (SOD). The trials were carried out based on Taguchi L9 orthogonal array with multi-response characteristics optimization using the Technique of Order Preference Similarity to the Ideal Solution (TOPSIS) approach. The main effect plot is drawn for the relative closeness coefficient (Cn*) and TOPSIS. The most favorable combinations of the experiment are obtained from the response diagram, traverse rate at level 3, abrasive flow rate at level 3, water pressure at level 3 and standoff distance at level 1 for minimizing the surface roughness, and maximizing the Material Removal Rate (MRR) and flatness. A Field Emission Scanning Electron Microscope (FESEM) and Atomic force microscopy (AFM) study were carried out to observe the quality of the obtained sliced surfaces. The optical characteristics like reflectance and absorption of the laser textured and sliced surfaces are measured using a UV-VIS spectrophotometer, which reveals the significant enhancement in the optical properties, in the case of the laser textured surface.

Genetic Based Experimental Investigation on Finishing Characteristics of AlSiCp-MMC by Abrasive Flow Machining

Implementing non-conventional finishing methods in the aircraft industry by the abrasive flow machining (AFM) process depends on the production quality at optimal conditions. The optimal set of the process variables in metal-matrix-composite (MMC) for a varying reinforcement percentage removes the obstructions and errors in the AFM process. In order to achieve this objective, the resultant output functions of the overall process using every clustering level of variables in a model are configured by using genetic programming (GP). These functions forecast the data to vary the percent of silicon carbide particles (particles without experimentation obtaining the output functions for material removing rates and surface roughness changes of Al-MMCs machined with the AFM process by using GP. The obtained genetic optimal global models are simulated and, the results show a higher degree of accuracy up to 99.97% as compared to the other modeling techniques.
 

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.

Fluid-structure interaction modeling of the abrasive waterjet drilling of carbon fiber reinforced polymers

Abstract The major challenges facing engineers while fabricating high precision components from carbon fiber reinforced polymers (CFRP) especially when using an abrasive waterjet (AWJ) include the predominant interlaminar delamination and tapered kerfs. Therefore, in the present work, a comprehensive 3-D transient fluid-structure interaction (FSI) model is developed and numerically simulated to investigate mechanisms leading to delamination and hole-geometric defects while drilling autoclave cured aerospace grade multidirectional CFRP laminates. The FSI model comprised a two-way interaction between the computational fluid dynamics (CFD) flow model and structural finite element (FE) model. The CFD model explored the dynamic jet characteristics while impinging the anisotropic CFRP surface. The resulting forces from the CFD domain acted as loads in the transient FE model to predict the initiation of cracks and delamination. Subsequently, extensive experiments were conducted to validate the proposed numerical model. The results illustrated that during abrasive waterjet drilling of CFRP, delamination was initiated by the hydraulic impact as the abrasive waterjet penetrated the workpiece. Additionally, the study revealed that an increase in abrasive waterjet pressure and abrasive particle size resulted in a higher inter-ply debonding and crack propagation. Correspondingly, an increase in the standoff distance (SoD) resulted in reduced crack propagation and delamination. Further, the liquid-solid interface exhibited asymmetric cracks. The present findings not only provide requisite guidelines to achieving high-precision drilling of multidirectional CFRP but also provide technical guidelines to improving the performance characteristics of the abrasive waterjet machining (AWJM) process.

Modeling and analysis of developed Thermal additive Centrifugal Abrasive Flow Machining process

In the present scenario due to manufacturing revolution there is a huge demand of mechanical components having high surface finish and a long life cycle. Demand of high surface finish, leads to development of new techniques for nano finishing of intricate shapes, such as Abrasive flow machining (AFM) and hybrid forms of it. During the abrasive flow finishing process, abrasive particles impart a huge impact force on the work piece surface to increase surface finish. This research paper discuss about a newly developed thermal additive centrifugal abrasive flow machining process (TACAFM) and also develops a mathematical model for the material removal of developed process at a given thermal energy pulse. Novelty of TACAFM process reduced the force applied by the abrasive particles and also decreased the loss of energy. In this hybrid process abrasive particles can easily remove the molten/ semi molten material from the work surface under thermal spark mechanism. The experimental results showed material removal in case of TACAFM process is almost double in comparison of conventional AFM process. The oxide layers and molten material on work surface was also observed from SEM images, which clearly indicated the domination of thermal effect over AFM. Also the parameters were optimized for the residual stress in case of TACAFM process and optimum residual stress was found as −152.21 MPa, which shows compressive stress developed on the surface due to the thermal effect. The experimental result showed current is the most significant parameter in TACAFM process and its contribution was found as 91.8%.

Pengembangan Proses Gerinda Silinder Permukaan Luar

The abrasive machining process is called the grinding process using a wheel grinding. The process of abrasive machining is usually in the final stages of making a product or finishing product so that it becomes essential in making products because it determines the final quality of a product. The purpose of this research is to develop the external cylindrical grinding process in column products for one of the components for drilling machines by modifying the grinding process in the lathe machine. The study was conducted using a wheel head of tools sharpening machine that is mounted on a lathe machine. The stages of this research began with the lathe process. Then without removing the product from the lathe, the external surface cylindrical grinding process is carried out so that there is no need to be set up the workpiece because the central inertia axis of the workpiece has one axis with its geometric axis. The measurement results of the external surface cylindrical grinding process are carried out using a bird-cage strategy by dividing the measurement into six segments. From each segment, the data is collected at eight measuring points. Based on the measurement results, in sample no.3 in segments B and D there is an increase in measurement results, that is Ø 100 + 0.018, but still below the maximum limit of Ø 100 + 0.020.

Performance Evaluation of Recently Developed New Process HAJM during Machining Hardstone Quartz Using Hot Silicon Carbide Abrasives: an Experimental Investigation and Sustainability Assessment

The better machining capabilities of abrasive jet machining characterized by the absence of thermal distortion make it highly competitive with other cutting processes employing plasma and lasers. In this article, an attempt has been made to combine hot abrasives and compressed air to form a hot abrasive air jet. Hot abrasive jet machining (HAJM) can be applied to various operations such as drilling, surface etching, grooving and micro finishing on the glass and ceramics. This research work involved in cutting performance evaluation of hot abrasive jet machining (HAJM) process and machinability investigation of hardstone quartz concerning surface roughness, taper angle, and material removal rate. Three levels each for air pressure, stand-off distance, and abrasive temperature were selected as control parameters. Experimental results in accordance of Box-Behnken’s design of experiments are analyzed by employing analysis of variance (ANOVA) and statistical technique (here, desirability function analysis of RSM) followed by computational approach (here, genetic algorithm) for experimental investigation, predictive modeling, and multi-response optimization, respectively. Additionally, the effectiveness of proposed two multi-objective optimization techniques are evaluated by confirmation test. Thereafter, the mechanism of material removal has been discussed using a non-contact three-dimensional surface measurement system and scanning electron microscopy images. Finally, a novel approach has been proposed for cost saving economic analysis and sustainability assessment in order to rationalize the operational feasibility and usefulness of hot abrasives in AJM process with an intention to raise the awareness in the manufacturing industry. Analysis of experimental findings revealed that, application of hot abrasives in AJM process have shown an attention in enhancing the cutting performance for material removal. The statistical evaluation and optimization results in this study can contribute to the evaluation of HAJM machinability of hardstone quartz.

Optimization of awj process using fuzzy taguchi method for improving surface characteristics of silicon wafer

This study investigates the slicing capabilities and surface characteristics of Silicon wafer by optimizing the operation parameters of the Abrasive water jet machining process. Slicing carried out on single crystal pure silicon ingot in AWJM by using an abrasive particle of size 80 mesh. To optimize the AWJ operation parameters L9 Taguchi orthogonal array is used and compare the superficial feature like surface roughness, topography, and slicing rate using different input parameters like SOD, water jet pressure, and flow rate of abrasives. To know the significant slicing parameter, which impact in the surface finish of silicon wafer by ANOVA analysis and the empirical model of the slicing process is find by using a regression model, Further Fuzzy logic analysis used to predict the abrasive water jet machining process parameters with Mamdani fuzzy rules and Triangular membership function. SEM analysis is portrayed by the surface morphology of different mesh size machined on pure Si wafer.

The multi-scale analysis of ceramic surface topography created in abrasive machining process

The paper looks at the issues related to the shaping technology of the parts made of ceramic materials and at the influence that machined surface topography has on surface functional properties. The mono- and polycrystalline ceramic parts were shaped in the four treatments of finishing process. The studies of surface topography were performed using three measurement instruments: interference microscope, scanning electron microscope, and atomic force microscope. It was noticed that multi-scale analysis of surface topography allows for obtaining a complementary and detailed overview of changes that ceramic parts undergo during abrasive machining process. The characteristics of the machined surface created in finishing operations were prepared based on the quantitative and qualitative descriptions. Parametric analysis of surface texture allowed for assessing the quality and changes of the machined surface in the technological process. During the non-parametric analysis, surface views after each abrasive machining treatment showed different kinds of surface defects (cracks, crumbles, dents or scratches) which could play an important role in the operation process, i.e. generating various wear mechanisms.

An investigation on machining characteristics in abrasive water jet machining of hybrid laminated composites with SiC nano particles

Abrasive Water Jet Machining process is widely employed in the machining of composite materials. In this work, a novel combination of hybrid laminated composite materials is developed, with Carbon and S-Glass fibers as primary reinforcement and filler material as SiC nano particles. An experimental investigation were conducted to assess the influence of abrasive water jet machining process parameters on kerf taper (Kt) and average surface roughness (Ra) of laminated hybrid composites. The effects of process parameters on experimentally obtained quality characteristics (Ra and Kt) values were empirically correlated by generating response surface graphs and also optimized within the tested range based on desirability approach. The optimal combination process parameters are traverse speed of 145 mm/min, abrasive mass flow rate of 115 g/min, water pressure of 200 MPa and stand-off distance of 1 mm. The optimum parameter levels were also confirmed by verification test. It is clear that, for obtaining a better quality characteristics abrasive mass flow rate and water pressure are significant parameters. The machined surfaces were examined with a Scanning Electron Microscope (SEM) to observe the quality of machined composite surface with the optimal settings obtained through response surface method.