Abrasive Process Research Articles

Evolution of Electroplated Cubic Boron Nitride Tool Surface Texture Parameters During Point Grinding

Abstract Point grinding is an abrasive machining process that utilizes small diameter superabrasive single-layer grinding tools for accurate machining of complex 3D geometries. Due to the small nature of these tools, high wear-rates and uneven wear around the tool circumference present a challenge for their successful application for the finish machining of metallic components. It is, therefore, essential to monitor the surface condition of the point grinding tools, to ensure their safe and reliable operation. In this investigation, the 3D topography evolution of single-layer B126 cubic boron nitride (cBN) point grinding tools was characterized using focus-variation imaging. Given the wealth of information obtained using this method, a decision-matrix methodology was used to identify the most important parameters for monitoring the wear condition of the point grinding tools. Grinding trials were also performed with fixed cutting parameters and varied cutting durations up to 520 mm3 of material removed to assess the evolution of the point grinding tool surfaces over time as a result of wear during grinding of hardened D2 tool steel. The best criteria for the characterization of the surface texture of electroplated cBN point grinding tool surfaces were identified to be the average surface height (Sa), skewness (Ssk), root mean square gradient (Sdq), reduced peak height (Spk), peak material volume (Vmp), and developed interfacial area ratio (Sdr). These parameters performed best for direct measurement of point grinding tool surfaces, paving the way for the application of the imaging technique under manufacturing conditions as an on-machine monitoring method for performance assessment.

Grain erosion wear properties and grinding performance of porous aggregated cubic boron nitride abrasive wheels

Cubic boron nitride (cBN) superabrasive grinding wheels exhibit unique advantages in the grinding of difficult-to-cut materials with high strength and toughness, such as titanium alloys and superalloys. However, grinding with multilayered metallic cBN superabrasive wheels faces problems in terms of grain wear resistance, the chip storage capability of the working layers and the stability and controllability of the dressing process. Therefore, in this work, novel metallic cBN superabrasive wheels with aggregated cBN (AcBN) grains and open pore structures were fabricated to improve machining efficiency and surface quality. Prior to the grinding trials, the air-borne abrasive blasting process was conducted and the abrasive blasting parameters were optimized in view of wear properties of cBN grains and metallic matrix materials. Subsequently, the comparative experiments were performed and then the variations in grinding force and force ratio, grinding temperature, tool wear morphology and ground surface quality of the multilayered AcBN grinding wheels were investigated during machining Ti–6Al–4V alloys. In consideration of the variations of grain erosion wear volume and material removal rate per unit of pure metallic matrix materials as the abrasive blasting parameters changes, the optimal abrasive blasting parameters were identified as the SiC abrasive mesh size of 60# and the abrasive blasting distance and time of 60 mm and 15 s, respectively. The as-developed AcBN grains exhibited better fracture toughness and impact resistance than monocrystalline cBN (McBN) grains because of the existence of metal-bonded materials amongst multiple cBN particles that decreased crack propagation inside whole grains. The metallic porous AcBN wheels had lower grinding forces and temperature and better ground surface quality than vitrified McBN wheels due to the constant layer-by-layer exposure of cBN particles in the working layer of AcBN wheels.

Effect of crystal orientation on micro-stress distribution in a damage-tolerant titanium alloy TC21

Micro-stress distribution interior of TC21 alloy under abrasive processing was systematically investigated by combining EBSD data and crystal plasticity finite element model (CPFEM). The ductility enhanced of ground specimens after aging treatment, which can be attributed to the randomness of crystal orientation increased result in the decrease of micro-stress in polycrystal. For prismatic slip {101¯0}〈12¯10〉, the α-colonies with SF value of 0.16 suggest that further slip activation becomes difficult, leading to a higher local stress concentrated on grain boundaries of α-lamellae. The higher micro-stress almost distributed at the interface of α-lamellae with a preferred orientation, while in randomly oriented grains, higher micro-stress distributed interior of some grains or local interface of α-lamellae. Moreover, the maximum micro-stress in randomly oriented grains is smaller than that of preferred orientation grains.

Abrasion performance of cement mortar by debris flow

Cement mortar detached from the concrete surface is one of the main damaged forms of concrete structures caused by debris flow. To enhance the abrasion resistance of cement mortar by improving its micropore structure and surface properties, the effects of hydrophobic treatments (integral treatment, surface coating), a dosage of hydrophobic agent (2 wt%, 4 wt%), and solid particle size (4.75–7, 7–9.5, 9.5–13.6 and 13.6–25 mm) on abrasion performance of cement mortar are investigated. The results show that the abrasion rate and abrasion depth of the mortar significantly increase with the increase of solid particle size of debris flow. At 120 h, the abrasion rate of the mortar increases by 85–151% under a solid particle size of 13.6–25 mm, compared to that of solid particle size of 4.75–7 mm. An experimental equation is proposed to describe the relationship between abrasion rate and solid particle size. The hydrophobic treatment does not show better abrasion resistance due to reduced mechanical strength. The abrasion mechanism caused by debris flow on cement mortar is mainly the collision and friction generated by the saltating and sliding solid particle. Moreover, the solid particle varies from a large irregular particle to a small smooth particle during the debris flow abrasion process. Debris flow abrasion shows a more significant effect on flexural strength, compared to compressive strength.

Correction to: Simulation of abrasive polishing process of single crystal silicon based on molecular dynamics

Correction to: Simulation of abrasive polishing process of single crystal silicon based on molecular dynamics

Influence of contact force and rubber wheel hardness on material removal in abrasive belt grinding investigated by physical simulator

The abrasive belt grinding process is applied to grind aero-engine blades benefiting from the elastic contact between the tool and workpiece. The local material removal is difficult to be accurately controlled, resulting in poor surface integrity. A better understanding of the relations between key process parameters and the material removal is needed. In this study, a physical simulator of the abrasive belt grinding process was developed. Different contact wheel hardnesses and contact forces were applied to grind the titanium alloys. A finite element model of multi-abrasive grinding was established to predict the material removal. The characteristics of the stress distribution on the rubber wheel under the dynamic contact state of abrasive belt grinding were obtained. The results show that the contact force has a significant effect on material removal when the contact force is less than a critical value. When the contact force exceeds the critical value, the hardness of the rubber wheel has a more significant effect. The changes on material removal obtained by the finite element model are consistent with the experimental results within the range of presented process conditions. This study provides a basis for selecting grinding contact force and contact wheel hardness.

Simulation of abrasive polishing process of single crystal silicon based on molecular dynamics

Simulation of abrasive polishing process of single crystal silicon based on molecular dynamics

Influence mechanism of abrasive belt wear on fatigue resistance of TC17 grinding surface

Abrasive belt grains morphology and wear process have direct effect on grinding surface quality and service performance of titanium alloys. In order to increase fundamental understanding of abrasive belt wear on service performance of grinding surfaces, further provide targeted guidance for anti-fatigue surface grinding, this paper analyzed the surface characteristics and fatigue failure mechanism of the TC17 samples ground before and after abrasive belt wear. Results showed that for zirconium corundum abrasive belt with relatively independent abrasive grains, the fatigue failure of machined surface before abrasive belt wear is dominated by roughness. After zirconium corundum abrasive belt was worn, grinding surface roughness is reduced and surface mechanical properties are strengthened, which promotes the initiation of fatigue cracks from the subsurface and the improvement of fatigue life. Although the wear of electroplated diamond abrasive belt can reduce the surface roughness of grinding surface, the embedding and accumulation of abrasive grains hindered the chip removal and heat dissipation in material removal process, making the grinding surface easy to form heterogeneous ablative layer, and fatigue cracks initiated from the subsurface ablation area. The heterogeneous areas formed by surface burns will exacerbate surface stress concentration, which in turn will greatly reduce surface fatigue performance, it needs to be avoided as much as possible. Sharp electroplated diamond belts and worn zirconium corundum belts have excellent advantages in improving surface anti-fatigue performance.

Optimization of wear and friction behaviour of AZ91D –B4C − Gr hybrid composite under dry sliding conditions

The tribological behaviour of AZ91D magnesium alloy bottom pouring stir cast with boron carbide (B4C) and graphite (Gr) was examined. The wear and frictional properties of AZ91D magnesium alloy, AZ91D-B4C composite, and AZ91D-B4C-Gr hybrid composite were investigated individually under dry sliding circumstances. To perform the studies, the L9 orthogonal array approach was adopted to investigate the effects of various sliding distances (0.5, 1, and 2 km) and applied load (5, 10 and 20N). When compared to AZ91D magnesium alloy and AZ91D- B4C composite, the wear loss for the AZ91D- B4C-Gr hybrid composite were reduced by 52.2% and 17.76% respectively at maximum load (20N) and sliding distance (2 km). Compared to AZ91D magnesium alloy, the hybrid composite had a higher hardness. SEM analysis of worn surfaces was performed to determine the significant abrasive wear process. The critical factors affecting the wear losses were generated using analysis of variance (ANOVA).

Application of Magnetic Abrasive Finishing Process Using Alternating Magnetic Field for Finishing Polychlorotrifluoroethylene Resin

In previous studies, it has been verified that the magnetic abrasive finishing process using alternating magnetic field can achieve higher finishing efficiency and surface quality, and nanolevel finishing of 5052 aluminum alloy material and SUS304 stainless steel material has been realized. In this study, the feasibility for ultra-precision finishing of polychlorotrifluoroethylene resin by this process was investigated, and the cutting mechanism of particles was discussed. As a result, the cutting depth of the particles is mainly affected by the size of the magnetic particles and abrasive particles. According to the experimental results, under optimized experimental conditions, the surface roughness of the workpiece can be improved from 112.83 nm Ra to 5 nm Ra within 15 minutes.

Taguchi’s design optimization for finishing of plane surface with diamond-based sintered magnetic abrasives

The magnetic field-assisted abrasive finishing parameters used in this study were the distance of the workpiece from the magnetic pole (D), amount of sintered magnetic abrasives (A), speed of rotation of the pole (R), grain size of the abrasive particles (S) and feed to the workpiece (F). The surface roughness percentage change (SRPC) and material removal rate (MRR) of the plane surface workpiece of aluminum are the response quantities. An orthogonal L16 array of the Taguchi method was constructed and is used in this study to analyze the influence of finishing parameters on the surface roughness percentage change of the workpiece. The analysis of variance (ANOVA) showed the extent to which finishing parameters are important. The experimental results showed that for SRPC, the best combination of levels for the given control factors is the distance of the workpiece from the magnetic pole (D) = 4 mm, the amount of sintered magnetic abrasive (A) = 16 g, the speed of rotation of the pole (R) = 600 rpm, the grain size of the abrasive particles (S) = 175 μm and the feed rate of the workpiece (F) = 1.5 m min−1. For MRR, the best combination of levels for the given control factors is the distance of the workpiece from the magnetic pole (D) = 4 mm, the amount of sintered magnetic abrasive (A) = 16 g, the speed of rotation of the pole (R) = 400 rpm, the grain size of the abrasive particles (S) = 175 μm and the feed rate of the workpiece (F) = 6.0 m min−1. The surface profiles and microscopic images of polished and unpolished workpieces show that the magnetic field-assisted abrasive finishing process is very effective in finishing aluminum surfaces.

Bioaccumulation and toxicity of polystyrene nanoplastics on marine and terrestrial organisms with possible remediation strategies: A review

Most of the things we see around are made up of plastics. From stores to homes, it has made its way into each economic sector. The most extensively used is polystyrene which has been widely used in the food industry, cutlery, industrial packaging, building insulation, medicinal equipment, toys, etc. Due to insufficient recycling and its non-biodegradable nature, these products end up in landfills and water bodies. Once introduced in the environment, polystyrene can undergo degradation and disintegration, mechanical abrasion and other processes that result in the formation of smaller sized microplastics that would eventually degrade into nanoplastics. Thus, these products are a significant source of polystyrene nanoplastics (PSNPs). Studies suggest that PSNPs penetrate living organisms through multiple routes via skin, respiratory and digestive tracts and consequently, their accumulation along the food chain takes place. Widespread research is going on to study the impact of polystyrene nanoplastics on different ecosystems and their species. The main focus of this review has been on the numerous sources of PSNPs, toxicity involving marine and terrestrial ecosystems and different remediation techniques such as photocatalysis, adsorption using biochar, flocculation, filtration, the electrospun membrane system and bioremediation measures that could be a possible solution to the major ecological crisis caused by PSNPs.

Finite element analysis of viscoelastic media used in abrasive flow machining process

The surface roughness of a part is the most important parameter in view of tribological applications and it also affects the working life of the part during application. The abrasive flow machining (AFM) process is an advanced non-conventional finishing process, used to deburr, polish, and to remove the recast layer from the surface as well as at the edges of the components. In AFM viscoelastic media is used to finish the workpiece with close dimensional tolerance and precision. The viscoelastic media used in the AFM process is laden with abrasive particles. In the present work, a finite element analysis of viscoelastic abrasive media is performed considering the AFM process. A mixture of polyborosiloxane and silicon carbide is used as viscoelastic abrasive media and the AFM process is modeled using ANSYS Polyflow. In the analysis, the flow of viscoelastic abrasive media is assumed to follow the Maxwell model of viscoelastic fluid. The simulations were performed for varying the extrusion pressure for the finishing of an internal cylindrical surface. The results of the simulations were validated with the experimental observation and found in good agreement.

Study of Temporal and Spatial changes in the Estuarine Area of the Mayangan River, West Java – Indonesia

The estuarine of the Mayangan River is an area confluence the Mayangan River with the Java Sea. Pondok Bali beach which is about a half kilometer from River mouth of the Mayangan River has undergone a severe abrasion process since 2006. Pondok Bali’s coastline changes are expected to affect the estuary area. It caused flooding and changes in water quality on the Mayangan water river area. This research was studied the factors that cause of river level rise and changes in water quality of the Mayangan River whether it has an impact of coastline geometry change. The results of hydrodynamic and water quality model simulations showed river water discharge and increase Sea level is a more influential factor compared to the change in coastline geometry or bathymetry of the river mouth. The increase in salinity at some observation points of the Mayangan River from 2006 to 2014 was only 0.2 ppt, from 2011 to 2014 the salinity increase was only 0.1 ppt, and from 2014 to 2020 only 0.03 ppt.

Stress state of the grinding tool loaded with tangential force

Purpose. Determining the interaction mechanism of discrete grains through material that binds them in a tool for abrasive material processing in the case of its loading with a tangentially directed cutting force. Methodology. Development and analytical solution to a mathematical model formulated on the basis of static equilibrium of an abrasive grain as a system element of tool grains bound with a material with excellent mechanical characteristics. Findings. A mathematical model has been developed and an algorithm has been formulated to analytically determine the stress-strain state parameters of a tool for abrasive processing of materials, which is loaded with a discrete cutting force, tangential to its working surface. The nature of the dependence of stresses and deformations on mechanical parameters, the quantity of grains and the material binding them in an abrasive tool, loaded with a unit tangential force, has been determined. Originality. The loading of the extreme grains leads to greater displacements, tangents of the shear angles of the material binding the grains. They decrease with increasing quantity of grain rows in the tool or with increasing quantity of grains to the nearest tool edge. Practical value. The distribution of interaction forces of grains and stresses in the material binding them has been determined. The found distribution allows one in the process of developing the tool and technology, in which it is involved, to comprehensively assess the influence of tangential load value of the tool working grain on its stress state and the material containing the grains. The determined stress state makes it possible to predict the number of loading cycles until the simultaneous rational wear of the grain and the destruction of that part of the material that contains it. The linear formulation of the problem makes it possible to take into account the mutual influence of the tangential loads of several grains on the stress-strain state of the tool as a whole.

A Magnetic Abrasive Finishing Process with an Auxiliary Magnetic Machining Tool for the Internal Surface Finishing of a Thick-Walled Tube

This paper proposes a novel magnetic abrasive finishing (MAF) process that uses an auxiliary magnetic machining tool for the internal surface finishing of a thick-walled tube. The auxiliary magnetic machining tool and external poles form a closed magnetic field circuit. Thus, a stronger magnetic force can be generated during the process. In the current study, we focus on analyzing the distribution of the magnetic field and magnetic flux density and investigating the finishing characteristics of a mixed magnetic abrasive finishing process and speed of relative revolutions. Based on the finishing characteristics, we also conduct a stage-by-stage finishing process by changing the combinations of the mixed magnetic abrasive finishing process. The finishing quality of the internal surface was mainly evaluated by the measured roundness and surface roughness. The experimental results show that the roundness and surface roughness Ra are affected when the total amount of WA abrasive and iron powder is too much; a better surface roughness could be obtained when the difference in the speed of relative revolutions is considerable, but the roundness is the worst. Furthermore, the original roundness measurement of 270 µm can reach 10 µm, and the surface roughness Ra can increase from an original surface roughness of 4.1 µm to reach 10 nm after 105 min of the stage-by-stage finishing process.

Influence of surface roughness on the sensitivity of a D-shaped optical fiber-based refractive index sensor

This paper presents the evaluation of the influence of surface roughness on the performance of a refractive index sensor based on a D-shaped optical fiber. In addition, the manufacturing process of D-shaped sections on standard silica single-mode optical fibers with different rms roughness values is described. The surface roughness morphology generated by the abrasive process is measured by processing microscopic images using the Gwyddion software. A model for the surface roughness, using the third order Weierstrass fractal function, is proposed and simulated with COMSOL Multiphysics. Experimental and simulation results are presented. The results show that the surface roughness increases the device insertion loss, as expected, but contributes positively to the sensitivity of the refractive index sensor, reaching sensitivity levels of 148.87 dB/RIU with a resolution of 10−4 RIU. The good agreement between the computational and experimental results is highlighted. Due to the good figures of merit obtained, the optical sensor has potential of application in biochemical sensing.

Surface Morphology Evaluation and Material Removal Mechanism Analysis by Single Abrasive Scratching of RB-SiC Ceramics

Reaction-Bonded Silicon Carbide (RB-SiC) ceramics possessing excellent mechanical and chemical properties, whose surface integrities have an essential effect on their performance and service life, have been widely used as substrates in the core parts of aerospace, optics and semiconductors industries. The single abrasive scratching test is considered as the effective way to provide the fundamental material removal mechanisms in the abrasive lapping and polishing of RB-SiC ceramics for the best surface finish. In this study, a novel single abrasive scratching test with an increasing scratching depth has been properly designed to represent the real abrasive lapping and polishing process and employed to experimentally investigate the surface integrity regarding different scratching speeds. Three typical and different material removal stages, including the ductile mode, ductile–brittle transition mode and brittle mode, can be clearly distinguished and it is found that in the ductile material removal stage by increasing the scratching speed would inhibit the plastic deformation and improve its surface integrity. It is also found that in the ductile–brittle transition and brittle material removal stages, to increase the scratching speed would inhibit the plastic deformation due to the fast scratching speed that limits the time of plastic deformation on the target, but it also results in the increased length of lateral cracks with the increased scratching speed which can reflect that the size of brittle chips, like brittle fractures and large grain fragmentations, increases as the scratching speed increases. It can provide the references for the optimization of the abrasive lapping and polishing of RB-SiC ceramics with high efficiency and surface quality.

OPTIMIZATION OF MAGNETIC ABRASIVE FINISHING PROCESS OF SS304 STAINLESS STEEL

With the advancement of the high-end industry, the demand for smooth surfaces has grown at an exorbitant rate. Magnetic abrasive finishing (MAF) is gaining wide attention these days as a popular finishing method to achieve smooth and high-quality surfaces. An alternative approach was used in the present work to produce a highly finished surface on stainless steel SS304 sheet using a magnetic abrasive finishing process. Response surface methodology (RSM) was applied to optimize the process parameters. Optimal results occur at a magnetic flux density (3100 Gauss), the rotational speed of the magnetic pole (250 rpm), grit size (250µm), and the percentage of abrasive particles (10%) for a percentage reduction in surface roughness (%∇Ra). Among the four factors, the grit size of the abrasives is the factor with the highest contribution (42.70%) and the rotation speed of the magnetic pole is the factor with the least contribution (0.79%) during the finishing process of the magnetic abrasive, which affects the percentage reduction in surface roughness (%∇Ra). To acquire a better understanding of the finishing mechanism, scanning electron microscope (SEM) images and surface profiles of the surface before and after magnetic abrasive finishing were also examined.

Effect of ceramic particle reinforcement type and process parameters on abrasive water jet processing of aluminum metal matrix composites fabricated by stir casting and hot rolling

In the present study, three AA6061 composites reinforced with 8% SiC, B4C, and Al2O3 were produced using the stir casting method. The composite specimens were molded in the thickness of 20 mm, and then the thicknesses of the samples were reduced to 7 mm by employing a hot rolling process at 450 °C. The effect of abrasive water jet cutting parameters such as nozzle speed (NS) and stand-off distance (SOD) on the kerf taper angle (KTA) and surface roughness (SR) were studied. The experiments were conducted based on the Taguchi L9 orthogonal array and the experimental results were analyzed by using the analysis of variance (ANOVA). The test results revealed that the most effective cutting variable on the KTA and SR was the type of reinforcement ceramic particle. The lowest KTA and the best SR values were recorded in the cutting of the Al2O3-reinforced composite specimen. The influence of the ceramic particle reinforcements on the SR and KTA was 60.6% and 65.1%, respectively. The effect ratio of the SOD, the second most effective process variable, to the SR is 28.1%, while the effect ratio to the KTA is 22.0%. Predictive models were developed for the KTA ( R2 = 93.29%) and SR ( R2 = 91.84) by the regression analysis. A close correlation with the ratio of 95.43% was achieved between the KTA and SR.