Ultrasonic Vibration-assisted Grinding Research Articles

Study on removal mechanism and surface quality of SiCf/SiC composites by longitudinal torsional ultrasonic vibration-assisted grinding

Study on removal mechanism and surface quality of SiCf/SiC composites by longitudinal torsional ultrasonic vibration-assisted grinding

Surface roughness model of ultrasonic vibration-assisted grinding GCr15SiMn bearing steel and surface topography evaluation

Surface roughness model of ultrasonic vibration-assisted grinding GCr15SiMn bearing steel and surface topography evaluation

Heterogeneous components removal mechanism and grinding force model from energy aspect in ultrasonic grinding continuous fiber reinforced metal matrix composites

Continuous fiber reinforced metal matrix composites (CFMMCs) offer higher specific strength, specific modulus, and operating temperature than matrix metals due to the unique enforcement mechanism of the one-to-one scale arrangement of matrix and reinforced phases. Due to the heterogeneous characteristics between the plastic matrix and brittle fibers, the removal mechanism of CFMMCs during processing is exceptionally complex. Ultrasonic vibration-assisted grinding (UVAG) shows great advantages in machining difficult-to-cut materials (i.e., ceramics and composites) by changing the motion trajectory between grains and workpieces, effectively reducing grinding force and improving machining quality. However, little is known about the removal mechanism of UVAG for CFMMCs composed of the ductile (i.e., matrix) and brittle (i.e., fiber) phases with highly anisotropic structure characteristics. This raises the question of how CFMMCs with heterogeneous components perform under abrasive processing and how to predict their processing forces. Hence, UVAG and conventional grinding (CG) experiments with single CBN grain were carried out on SiC fiber reinforced TC17 matrix composites (SiCf/TC17) in this work. A grinding force model considering both phases and materials structure was proposed. A theoretical model for suppressing SiC fiber damage has been proposed, which is expected to guide low-damage processing of brittle materials. According to the results, the removal models of CFMMCs are revealed including i) macro fracture of SiC fiber, ii) neat fracture of SiC fiber, and iii) TC17 matrix massive adhesion on the SiC fiber. Besides, no cracks crossing fibers are observed on the subsurface of SiC fiber under both UVAG and CG due to the good support effect of the TC17 matrix on SiC fibers. The grinding force predicted model error decreases as ap increases. When ap is 50 μm, the errors between predicted and experimental values are 7.8% and 9.1% for normal forces (Fn) and tangential forces (Ft), respectively. Ultrasound suppresses the severe wear behavior of grains, thereby improving the tool life. This paper aims to comprehensively reveal the characteristics of abrasive processing of CFMMCs from various aspects (surface morphology, subsurface features, grinding force prediction, and tool wear), which will promote the industrial application of CFMMCs.

Surface integrity characterization of third-generation nickel-based single crystal blade tenons after ultrasonic vibration-assisted grinding

Machined surface integrity of workpieces in harsh environments has a remarkable influence on their performance. However, the complexity of the new type of machining hinders a comprehensive understanding of machined surface integrity and its formation mechanism, thereby limiting the study of component performance. With increasing demands for high-quality machined workpieces in aerospace industry applications, researchers from academia and industry are increasingly focusing on post-machining surface characterization. The profile grinding test was conducted on a novel single-crystal superalloy to simulate the formation of blade tenons, and the obtained tenons were characterized for surface integrity elements under various operating conditions. Results revealed that ultrasonic vibration-assisted grinding (UVAG) led to multiple superpositions of abrasive grain trajectories, causing reduced surface roughness (an average reduction of approximately 29.6%) compared with conventional grinding. After examining the subsurface layer of UVAG using transmission electron microscopy, the results revealed that the single-crystal tenon grinding subsurface layer exhibited a gradient evolution from the near-surface to the substrate. This evolution was characterized by an equiaxed nanocrystalline layer measuring 0.34 μm, followed by a sub-microcrystalline grain-forming zone spanning 0.6 μm and finally, a constituent phase-twisted distorted deformation zone over 0.62 μm. Under normal grinding conditions, the tenon exhibited low surface hardening (not exceeding 15%), and residual compressive stresses were observed on its surface. In cases where grinding burns occurred, a white layer appeared on the tenon’s surface, which demonstrated varying thicknesses along the teeth from top to root due to thermal-force-structural coupling effects. Additionally, these burns introduced residual tensile stresses on the tenon’s surface, potentially substantially affecting its fatigue life. This paper enhances our understanding of UVAG processes and establishes a foundation for their application in manufacturing single-crystal turbine blades for next-generation aero-turbine engines.

Force model of ultrasonic empowered minimum quantity lubrication grinding CFRP

As a weight-reducing material in aerospace applications, carbon fiber reinforced polymer (CFRP) requires precision grinding to ensure the accuracy and assembly of mating positioning surfaces. However, achieving low-damage machining of CFRPs remains challenging. Flood cooling reduces the mechanical properties, while dry grinding deteriorates the surface integrity, making minimum quantity lubrication (MQL) a viable alternative. However, nanolubricants struggle to penetrate the grinding area due to gas barrier obstruction. Consequently, a new CFRP grinding approach using multiangle 2D ultrasonic vibration-empowered nanolubricant MQL was proposed. An analytical force model is crucial for optimizing machining strategies and adjusting parameters. The aim is to reveal grinding mechanics and develop a force model under different ultrasonic and lubrication-cooling conditions. First, a uniform random fiber distribution model and a grinding wheel model were established, and the mechanical properties of the interface were predicted. Then, the intermittent grinding behavior and dynamic stiffnesses of the multiangle 2D ultrasonic vibration-assisted grinding (UVAG) system were investigated based on the geometric kinematics of the grains' trajectory. Furthermore, based on the deformation deflection curve, bending fracture force models for 45°, 90°, and 135° fibers were established with different contact and boundary conditions. The material removal mechanisms of shear and tension-compression buckling in 0° CFRP grinding were revealed, and an elliptical contact normal force model was established. The interlayer shear in 45° CFRPs was analyzed. The longitudinal compressive matrix cracking and fiber shear fracture in the 90° CFRPs were elucidated. Fiber microbuckling and fiber bundle removal of 135° CFRPs were investigated. Finally, grinding force models with different fiber orientation angles (FOAs) were interconnected and experimentally assessed. Experimental assessments demonstrated that the grinding force model has acceptable estimation error and effectively captures the mechanics of CFRPs with different FOAs.

Wear behavior of white alumina and seeded gel abrasive wheels in ultrasonic vibration-assisted grinding of nickel-based single-crystal alloy

This study investigated the tool wear behavior of white alumina (WA) and seeded gel (SG) abrasive wheels in the ultrasonic vibration-assisted creep feed grinding (UVACFG) of nickel-based single-crystal alloy. The abrasive wheel wear characteristics were examined, and their effects on the grinding force, temperature, and surface quality were evaluated. Finally, the wheel wear mechanism in the UVACFG was discussed by analyzing the intermittent cutting behavior and wear patterns of a single grain. Experimental results indicated that the workpiece material adhesion and pore-clogging were the main wear patterns of abrasive wheels without ultrasonic vibration. In contrast, these were adequately mitigated after introducing ultrasonic vibration, and the main wear pattern for both wheels became the grain fracture. The WA wheel in the UVACFG experienced reduced radial wear by around 60.7 % in the initial wear state, 40.2 % in the stable wear state, and 25.3 % in the rapid wear stage, respectively, compared to the conventional grinding (CG). The intermittent cutting behavior of SG grains caused by high-frequency vibration promoted the micro-fracture capacity and ensured the coolant entered the grinding zone sufficiently, which reduced the grinding force and temperature by up to 63.2 % and 46.7 %, respectively, and meanwhile introduced the defects of high bulges and slight plastic deformation on the workpiece surface.

Effects of fiber orientations on removal behaviors in ultrasonic vibration-assisted grinding continuous fiber reinforced Ti matrix composite

Effects of fiber orientations on removal behaviors in ultrasonic vibration-assisted grinding continuous fiber reinforced Ti matrix composite

AAC theory for ultrasonic vibration-assisted grinding

AAC theory for ultrasonic vibration-assisted grinding

Atomic-scale simulation of ultrasonic vibration-assisted polishing process for graphene/GaN-layered composites

In the realm of semiconductor materials, the integration of graphene (Gr) and gallium nitride (GaN) has emerged as a promising avenue for enhancing device performance. In this study, a Gr/GaN layered nanocomposite was constructed using molecular dynamics simulation and the LAMMPS code. Diamond abrasive was pressed into the composite at a speed of 50 m/s at 300 K, followed by ultrasonic vibration-assisted polishing on the (0001) plane along the [01‾10] direction. By rigorously exploring various factors such as number of Gr layers, vibration amplitudes, vibration frequencies and grinding speeds, the study elucidates the intricate mechanisms governing material removal and subsurface damage. Key findings reveal optimal processing conditions, including three layers of Gr, an amplitude of 5 Å, a vibration frequency of 80 GHz and a grinding speed of 100 m/s, which result in enhanced material removal rates and improved surface quality. Additionally, the insertion of Gr layers within the GaN matrix demonstrates a remarkable reduction in friction and wear rates, highlighting the potential for enhancing device reliability and performance. This comprehensive investigation not only advances our understanding of ultrasonic vibration-assisted grinding processes but also underscores the transformative impact of Gr/GaN composites in semiconductor device fabrication.

Study on the material removal mechanism and the exit breakage of ultrasonic vibration-assisted grinding for microcrystalline glass

With the aim of solving problems such as exit breakage and surface microcracks during microcrystalline glass machining, an ellipsoidal erosion model is established by analyzing the motion trajectory and characteristics of single diamond grit in ultrasonic vibration-assisted grinding (UVAG), and the material removal volume of single diamond grit particles is obtained. A simulation model of UVAG of microcrystalline glass is established by the finite element method. The effect of process parameters such as rotational speed, grinding depth, feed rate on grinding force and workpiece edge stress has been investigated. The experiment of UVAG for microcrystalline glass is performed on a five-axis CNC machine with the same process parameters, and the surface morphology, surface roughness, and exit breakage sizes of microcrystalline glass are observed. The results show that with the increase in grinding depth, the average grinding force between the tool and the workpiece increases, and the proportion of material removal in a brittle fracture increases. As the rotational speed increases, the grinding force between the tool and the workpiece gradually decreases and results in an improvement in the surface quality of the workpiece. As the feed rate increases, the surface roughness increases by 16.76%, the width of the edge breakage increases by 109.19%, and the thickness of the edge breakage increases by 104.49%.

Ensemble learning with support vector machines algorithm for surface roughness prediction in longitudinal vibratory ultrasound-assisted grinding

It is critical to have an accurate prediction of surface roughness (Sa) in order to improve grinding productivity, reduce costs, and minimize the period of time required for trials and testing. Although many prediction methods have been developed, fewer studies have been conducted on the prediction of surface roughness in longitudinal ultrasonic vibration-assisted grinding (LUVAG). In this paper, a surface roughness prediction model algorithm based on ensemble learning of support vector machines (ELSVM) is proposed that can be used for surface roughness prediction of LUVAG alumina ceramics. This paper first details the development of the ELSVM surface roughness prediction model, which consists of four modules: the prepossessing module, the multi-algorithm regression module, the support vector machine algorithm (SVM) module, and the ensemble module. In addition, ELSVM was compared with four other machine learning methods based on experimental results for surface roughness prediction modeling. The error of ELSVM model was reduced by 6.3%, 7.9%, 8.9%, and 7.5%, respectively, compared to the individual prediction models such as I-AISPSO, I-AIS, SPSO, and KBaNN. Comparison results show that the ELSVM model has the lowest average ratio of Mean Absolute Error (MAE) for surface roughness prediction in LUVAG.

Intermittent cutting behavior and grinding force model in ultrasonic vibration-assisted grinding K4002 nickel-based superalloy

Intermittent cutting behavior and grinding force model in ultrasonic vibration-assisted grinding K4002 nickel-based superalloy

Undeformed chip thickness with composite ultrasonic vibration-assisted face grinding of silicon carbide: Modeling, computation and analysis

In order to achieve high efficiency and low damage processing of hard and brittle materials, composite ultrasonic vibration-assisted face grinding (CUVAFG) has been proposed by comprehensively combining the high efficiency of axial ultrasonic vibration grinding (UVAG) and the low damage of elliptic ultrasonic vibration grinding (EVAG). However, the three-dimensional ultrasonic vibration brings about a more complicated machining mechanism than the previous ultrasonic vibration-assisted grinding methodology. Hence, in order to explore the grinding mechanism in deep, this paper first developed a new model of undeformed chip thickness for CUVAFG from the perspectives of the kinematic mechanism and elastic-plastic deformation mechanism. Then the influences of different processing parameters on interference rate and undeformed chip thickness were further confirmed. Finally, CUVAFG experiments of silicon carbide (SiC) ceramics were conducted to study the relationship between the undeformed chip thickness and the resultant grinding forces, specific grinding energy, ground surface morphology and roughness, and subsurface damage. It is found from the experimental results that the critical chip thickness of brittle-ductile transition in CUVAFG is between 0.31 and 0.35 μm. As the undeformed chip thickness is less than the critical value, the grinding forces and the specific grinding energy increases with the undeformed chip thickness, but the ground surface roughness decreases with improved surface morphology and shallow subsurface damage. After exceeding the critical value, the grinding force remains unchanged, the specific grinding energy decreases, and ground surface roughness increases with deteriorated surface morphology and deepened subsurface damage. For the purpose of good machining surface integrity, it is essential to guarantee that the undeformed chip thickness is less than the critical value. The computational and experimental results have demonstrated the contribution of the developed undeformed chip thickness model to understanding the grinding performance of hard and brittle material by CUVAFG.

Research on the machining mechanism of AISI 304 ultrasonic vibration assisted grinding

Compared with conventional grinding (CG), ultrasonic vibration assisted grinding (UVAG) has more prospects and competitiveness in processing AISI 304. Due to the change of strength of materials, when the vibration is superimposed on the workpiece, the mechanism of ultrasonic assisted machining is different from that of tool ultrasonic assisted machining. Therefore, this article proposes a workpiece vibration grinding device suitable for UVAG to study the corresponding grinding mechanism. The vibration characteristics of workpiece ultrasonic generator were discussed based on finite element simulation and the vibration situation of the device was tested with instruments to verify the accuracy of the simulation. Meanwhile, the machining mechanism of workpiece ultrasonic vibration was studied through grinding comparative experiments. The experiment showed that the displacement curve of the output end of the ultrasonic vibration of AISI 304 with time could be approximated to a sine wave and there was no other clutter. As the amplitude percentage of the ultrasonic generator increased, the output amplitude of the transducer showed an increasing trend. The ultrasonic amplitude and the amplitude percentage of ultrasonic generator approximately follow a linear relationship. The grinding force decreased with the increase of spindle speed and amplitude, and increased with the increase of feed rate and grinding depth. Compared with conventional grinding force, the grinding force of tangential ultrasonic vibration assisted grinding (TUVAG) decreased by about 29 %, while the grinding force of radial ultrasonic vibration assisted grinding (RUVAG) decreased by about 28 %. Under the action of ultrasound, the workpiece obtained better surface morphology. Under processing conditions of vw = 25 mm/min, ap = 0.01 mm, n = 2000r/min, A = 8 μm, f = 20000 Hz, the minimum surface roughness Ra of TUVAG is 0.51, followed by RUVAG with Ra = 1.02, while the surface roughness Ra of CG is the worst at 1.56 due to grinding burns.

Experimental Investigation of Ultrasonic Vibration-Assisted Grinding of HVOF-Sprayed WC-10Co-4Cr Coating

WC-10Co-4Cr coating is highly valued for its corrosion resistance and wear resistance when applied using the high-velocity oxy-fuel (HVOF) spraying method. However, conventional grinding (CG) of this coating presents challenges, including substantial grinding forces and elevated surface temperatures. To address these concerns, our study proposed the utilization of ultrasonic vibration-assisted grinding (UVAG) as a means to enhance the machining properties of HVOF-sprayed WC-10Co-4Cr coatings. Comparative experiments were conducted to analyze the impacts of various factors on the grinding forces and surface roughness in UVAG and CG processes. Additionally, the topography of the ground surfaces was examined to gain insights into the material removal mechanism in UVAG. The experimental outcomes reveal significant reductions in tangential and normal grinding forces, amounting to 15.47% and 22.23%, respectively, in UVAG when compared with CG. Furthermore, UVAG led to a roughly 29.14% decrease in ground surface roughness compared with CG. Microscopic analysis of the ground surfaces using scanning electron microscopy (SEM) indicated that ductile removal was the predominant material removal mode in UVAG. Overall, UVAG was found to be effective in diminishing grinding forces, improving ground surface roughness, and enhancing surface integrity when contrasted with CG. These findings introduce a novel approach for processing WC-10Co-4Cr coatings.

Study on surface defect formation mechanism in ultrasonic vibration-assisted grinding of SiCp/Al composites

Study on surface defect formation mechanism in ultrasonic vibration-assisted grinding of SiCp/Al composites

Molecular dynamics simulations of ultrasonic vibration-assisted grinding of polycrystalline iron: Nanoscale plastic deformation mechanism and microstructural evolution

Ultrasonic vibration-assisted grinding (UVAG) has attracted plenty of attention to significantly improve surface integrity. However, existing research has not systematically investigated the effect of vibration directions during UVAG at atomic and nanoscales, limiting our understanding of the plastic deformation mechanisms and microstructural evolution of ultra-precision machining. To address this issue, we proposed an MD model for multi-abrasive UVAG of polycrystalline iron considering various vibration directions. We comprehensively analyzed atomic flow fields, surface atom distributions, temperature fields, grinding forces, stress distributions, crystal orientations, and dislocation distributions. The simulation results demonstrate that UVAG effectively reduces grinding force and results in instantaneous grinding forces greater than conventional grinding (CG), and the instantaneous load impact phenomenon of radial vibration is more obvious. In surface morphology, axial vibration contributes to reducing surface roughness, while radial vibration is detrimental to surface smoothness. Microstructural evolution is mainly induced by stress. The primary plastic deformation mechanisms in UVAG of polycrystalline iron involve lattice rotation and dislocation mediation. Compared to axial vibration-assisted grinding (AVAG), radial vibration-assisted grinding (RVAG) and elliptical vibration-assisted grinding (EVAG) exhibit finer grain refinement, with RVAG leading to the highest dislocation density.

Experimental study on ultrasonic vibration assisted grinding of GCr15SiMn bearing steel

Many problems of GCr15SiMn high-carbon chromium bearing steel have been found in the ordinary grinding (OG) process. Aiming at the problems of high grinding force, low residual compressive stress and low surface quality, ultrasonic machining technology is combined with OG. The test of ultrasonic vibration assisted grinding (UVAG) GCr15SiMn high carbon chromium bearing steel is carried out. The residual stress, surface roughness, grinding force, and surface morphology are analyzed by changing machining parameters. The research showed that as the grinding depth and feed speed become larger, the grinding force increased, when the spindle speed rises, the grinding force becomes smaller. In the test range, with the ultrasonic amplitude from small to large, the grinding force from large to small. The ultrasonic grinding force is 27.8% lower than that of OG. The surface roughness increases with increasing grinding depth and feed speed and decreases with increasing spindle speed and ultrasonic amplitude, and at an amplitude of 6 μm, the surface roughness is reduced by 27% compared to OG. When the feed speed and grinding depth are lowered or the ultrasonic amplitude is increased, the surface residual compressive stress is increased. Compared to OG, it is increased by more than 13.5% under the same parameters. At the same time, the phenomenon of burrs and surface tears can be reduced, and the surface quality of the workpiece becomes better.

Study on grinding performance during ultrasonic vibration-assisted grinding ultra-high strength steels

Study on grinding performance during ultrasonic vibration-assisted grinding ultra-high strength steels

Thermal analysis of ultrasonic vibration-assisted grinding with moment-triangle heat sources

AISI 9310 steel has garnered increasing attention for its superior mechanical properties in the manufacturing of transmission gears for helicopters and accessory transmission systems in aero-engines. The ultrasonic vibration-assisted grinding (UVAG) technique is a new potential method to machine tooth surface given the periodically changing trajectory between abrasive grains and the workpiece, contributing to enhancing heat transfer and thus solving sudden burns. The accurate prediction of grinding heat and the proposal of the associated control strategy are desired to ensure the machining quality. Combined with the separation coefficient model and the chip volume distribution of UVAG processes, a new moment-triangle (MT) heat source model was established. Subsequently, comparative analyses on grinding temperature with conventional grinding and UVAG process were performed using the conditional triangular heat source model and the proposed MT heat source model. Results show that the MT heat source model has a lower prediction error with an average error of 7.13%, which is improved by 7.33% compared with that of the triangular heat source model. The prediction accuracy for the maximum grinding temperature can be raised by 13.39% when the MT heat source model is applied in place of the other one under UVAG processes. In addition, the heat source model transits from triangular into uniform heat source gradually as the ultrasonic amplitude increases, and the transition rate is positively correlated with the ultrasonic amplitude. On this basis, the desired controlling strategy is proposed to enhance the machining performance of ultrasonic grinding processes and effectively reduce heat generations during grinding by increasing the ultrasonic amplitude, reducing the depth of cut and decreasing the workpiece speed.