High-speed Grinding Research Articles

Design and Development of a High-Speed Precision Internal Grinding Machine and the Associated Grinding Processes

In order to meet the P2-grade bearing grinding requirements, we designed a high-speed internal grinding machine to be used for grinding bearing raceways and inner circles. The machine has a T-type layout and a four-axis numerical control linkage. It is supported by hydrostatic pressure and driven directly by a torque motor. In addition, it is equipped with a high-speed hydrostatic grinding wheel spindle. Our design includes a hydrostatic workpiece shaft and hydrostatic turntable, and the process has a good engineering application value. Finally, the designed precision grinding machine was used to grind a P2-grade bearing raceway.

Preface

The 2022 2nd International Conference on Mechatronics, Automation and Intelligent Control (MAIC 2022) was successfully held on September 16-18, 2022 in Wuhan, China (virtual conference). MAIC 2022 focused on the latest research results in advanced intelligent control of automation systems, including both theoretical advances and practical implementations, which are becoming more and more popular in industry and in our daily lives.We had the honor of having invited Prof. Peng Zhao from Zhejiang University, China to serve as our Committee General Chair. The conference was composed of keynote speeches, oral presentations, and online Q & A discussion, attracting 100 delegates worldwide. Firstly, keynote speakers are each allocated 30-45 minutes to hold their speeches. Then in the next part, oral presentations, the excellent papers selected are presented by their authors one by one.During the conference, three distinguished professors invited address their keynote speeches. For a start, Prof. Yajun Liu from South China University of Technology, China performed a thought-provoking speech on A Novel Signal Processing Method of Coriolis Mass Flowmeter Based on SVR and Hilbert Transform. To improve the measurement accuracy of mass flow and reduce the impact of noise, a novel signal processing method for Coriolis mass flowmeter based on SVR and Hilbert transform was proposed in this study. Ad then, Prof. Li Guo from Hunan University, China made a speech on the Research on Acoustic Emission Intelligent Monitoring in Grinding Engineering Ceramics. He studied the relationship between the acoustic emission signal of high speed grinding of engineering ceramics and grinding force, grinding temperature, and carried out a high precision AE monitoring of diamond grinding wheel wear in engineering ceramics grinding, solving the problem of acoustic emission monitoring in engineering ceramics grinding. Lastly, Prof. Heming Jia from Sanming University, China made a report on Swarm Intelligence Optimization: Advances in Algorithms and Applications. He introduced the current popular SIOAs and a novel technique called Remora Optimization Algorithm (ROA) and analyzed their search mechanism and existing limitations in different optimization tasks. Their brilliant speeches had triggered heated discussion. And every participant praised this conference for disseminating useful and insightful knowledge.The proceedings of MAIC 2022 are a compilation of the accepted papers and represent an interesting outcome of the conference. These papers feature but are not limited to the following topics: Advanced Motion Control, Electric Automation, Artificial Intelligence, Modeling and Design, Unmanned Vehicle, etc. All the papers have been checked through rigorous review and processes to meet the requirements of publication.We would like to express our sincere gratitude to all the keynote speakers, peer reviewers, and all the participants who supported and contributed to MAIC 2022. Particularly, our special thanks go to the Journal of Physics: Conference Series, for all the efforts of its colleague in publishing this paper volume. We firmly believe that MAIC 2022 had turned out to be a forum for excellent discussions that enable new ideas to come about, promoting collaborative research.The Committee of MAIC 2022List of titles Committee member, Conference General Chair, Technical Program Committee Chairs, Local Organizing Committees, Technical Program Committees are available in this Pdf.

Investigating the Effect of Grinding Time on High-Speed Grinding of Rails by a Passive Grinding Test Machine.

High-speed rail grinding is a unique passive grinding maintenance strategy that differs from conventional grinding techniques. Its grinding behavior is dependent on the relative motion between the grinding wheel and rail; hence, it possesses great speed and efficiency. In this study, the effects of the duration of grinding time and the increase in the number of grinding passes on the grinding of high-speed rails were investigated using passive grinding tests with a single grinding time of 10 s and 30 s and grinding passes of once, twice, and three times, respectively. The results show that when the total grinding time was the same, the rail removal, grinding ratio of grinding wheels, rail grinding effect, grinding force, and grinding temperature were better in three passes of 10 s grinding than in one pass of 30 s grinding, indicating that the short-time and multi-pass grinding scheme is not only conducive to improving the grinding efficiency and grinding quality in the high-speed rail grinding but can also extend the service life of the grinding wheels. Moreover, when the single grinding times were 10 s and 30 s, respectively, the grinding removal, grinding efficiency, grinding marks depth, and surface roughness of rail increased with the number of grinding passes, implying that the desired rail grinding objective can be achieved by extending the grinding time via the multi-pass grinding strategy. The results and theoretical analysis of this study will contribute to re-conceptualizing the practical operation of high-speed rail grinding and provide references for the development of the grinding process and grinding technology.

Experimental study on residual stress in high-speed grinding of noncircular equidistant profile

To explore the formation mechanism of residual stress in the high-speed grinding of noncircular equidistant profiles, orthogonal experiments of three grinding parameters—the grinding wheel speed, workpiece speed, and grinding depth—were designed. A ceramic bond CBN grinding wheel was used for the high-speed grinding of noncircular equidistant profile by the X-C axis linkage. The effects of the grinding parameters on the grinding temperature, surface roughness, and residual stress were analyzed. The results show that with the increase of grinding wheel speed, the grinding temperature and residual stress increase, and the surface roughness decreases. With the increase of workpiece speed, the grinding temperature and residual stress decrease, and the surface roughness increases. With the increase of grinding depth, the grinding temperature, residual stress, and surface roughness increase. Besides, the grinding depth has the greatest influence on the residual stress, followed by the grinding wheel speed and workpiece speed.

Predicting the efficiency of high-speed diamond grinding of superhard materials using 3D models of macro- and micro-levels

Predicting the efficiency of high-speed diamond grinding of superhard materials using 3D models of macro- and micro-levels

Material removal and surface damage in high-speed grinding of enamel

Although high-speed grinding of the enamel surface is often required in restorative dentistry, the knowledge of grinding mechanics, material removal, and fracture damage mechanism related to this process is still relatively limited; therefore, it is important to perform relevant scientific and theoretical research. As per the occlusal surface and the buccal/lingual surface of the teeth, the experimental scheme of high-speed grinding of the enamel surface using a diamond grinding bur was designed, and the grinding force, force ratio, grinding temperature, chips, surface morphology, surface damage, and other important characteristics were tested and analyzed. Furthermore, the grinding geometry model, grinding mechanics, material fracture, and removal mechanism associated with the high-speed grinding of an enamel surface were considered. The results show that the grinding force, friction coefficient, grinding temperature, and surface damage achieved through buccal/lingual surface grinding are considerably greater, and the grinding quality is worse than that obtained via occlusal surface grinding under the same grinding conditions. With the increase in the feed rate, grinding force, friction coefficient, grinding temperature, and surface damage obviously increase, and the surface quality decreases. The embrittlement effect and the ironing mechanism are present during the process of high-speed grinding of enamel. Regardless of the feed rate, the three types of material fracture modes of the buccal/lingual surface are more serious than those of the occlusal surface (making it more likely to produce unstable large chips or tearing chips); moreover, the brittle fracture and damage of the final machined surface are more obvious. The cutting mechanics and cutting mechanism identified in this study will provide scientific guidance for dental grinding operations.

Numerical simulations of grinding force and surface morphology during precision grinding of leucite glass ceramics

• A force model of grinding of leucite glass ceramics is developed. • A surface morphology model of grinding of leucite glass ceramics is developed. • Elastic-to-plastic and brittle-to-ductile transitions are considered in the models. • The predicted errors of two models are within 10% and 15%. Leucite glass ceramics are high-performance denture materials due to their high mechanical strength, excellent light transmittance, and excellent biocompatibility. Glass-ceramic denture must be processed using precision grinding technology to achieve a satisfactory surface integrity. To understand the contact interaction between the abrasives and workpiece, a theoretical model of grinding force during grinding of leucite glass ceramics was developed by considering elastic-to-ductile transition depth, brittle-to-ductile transition depth, strain rate effect, and random distributions of the abrasive position and size. In addition, a surface morphology model was developed to understand the material removal and deformation behaviors during grinding of leucite glass ceramics, which considered the brittle-to-ductile transition depth, elastic recovery, and random distributions of the abrasive position and size. The mechanical properties of leucite glass ceramics used in the models were measured by nanoindentation and nanoscratch tests. Grinding experiments of leucite glass ceramics were performed to verify the accuracy of the models, and the results showed that the predicted errors of the force and surface morphology models were within 10% and 15%, respectively. Both theoretical and experimental results demonstrated that small abrasive size, low feed speed, small grinding depth, and high grinding speed were beneficial to improving the surface quality, and large abrasive size, low feed speed, small grinding depth, and high grinding speed were beneficial to decreasing the grinding force. The results will provide a theoretical guidance for optimizing process parameters during high-efficiency and precision grinding of hard and brittle solids. Graphical Abstract .

High-speed grinding fracture mechanism of Cf/SiC composite considering interfacial strength and anisotropy

Cf/SiC composite is connected through the bonding interface to achieve the toughening effect, which makes the fiber direction and interface strength in the material directly affect the composite properties and grinding quality. Aiming at the high-quality processing of Cf/SiC composite, a single abrasive particle model is built to reveal the variation law of grinding force in the process and the surface damage phenomena such as interface debonding, fiber fracture and matrix fracture. Based on the constitutive relationship among matrix, reinforcement and interface phase, the constitutive model of composite was established. However, Cf/SiC composite is a typical hard brittle material. Low grinding speed cannot yield to good machining quality. Thus, to improve the output quality, high speed grinding is applied in this paper. Meanwhile, by considering the heterogeneous structure characteristics of composite materials, the two-dimensional simulation of grinding of single abrasive particle grinding, based on FEM (Finite Element Model) method, is realized. Finally, composite fracture behavior is analyzed by observing microstructure in the grinding process. The effects of fiber orientation, surface strength, grinding speed, and grinding depth on the surface properties and the quality of Cf/SiC composite are studied by grinding force and surface analysis. The mechanism of high-speed grinding of ceramic matrix composites, as well as the practical approach and theoretical underpinnings of grinding process optimization, are examined.

Optimization of high-speed grinding parameters for anti-fatigue performance of 20CrMnTi steel

Optimization of high-speed grinding parameters for anti-fatigue performance of 20CrMnTi steel

High Speed Grinding of EN31 Steel with Alumina Nanofluid Coolant

Grinding is a choice for obtaining high surface quality and closer dimensional tolerance. For meeting this objective economically, the material removal rate (MRR) must be sacrificed to certain extent. The MRR could be increased by either increase in wheel speed, depth of cut, and feed rate. An increase in MRR increases the surface temperature leading to thermal defects on surfaces. Improving the MRR without compromising the surface quality is a challenging objective. Many investigations are progressing for machining various materials under different cooling environments to meet such challenges. This experimental novel aim is to investigate the performance of Al2O3 nanofluid in high-speed grinding of EN31 steel under flood cooling method for reduction of surface roughness and cutting zone temperature. Taguchi’s full factorial design was employed for experimental investigation. The factors such as feed, depth of cut and cutting fluid environment were considered for analysing the responses of cutting zone temperature and surface roughness. The thermal analysis on the work piece was carried out with experimental values by the finite element analysis method. The nanofluids outperform in terms of reduction of surface roughness and downsizing cutting zone temperature. The proposed nanofluid-based grinding significantly reduced the surface roughness and cutting zone temperature.

Improving the grinding performance of high-speed rail grinding stone via mixed granularity of zirconia corundum

High-speed rail grinding stones (GS) were fabricated using zirconia alumina (ZA) with five mass ratios of F16 to F30 to explore the regulatory mechanism of abrasives with mixed granularity on the grinding performance. With the decrease of abrasive grit size, the enhanced abrasive crushing strength can control the grinding behaviors of GS. GS with low mass ratio of F16 to F 30 gave the largest grinding amount (4.0 g) and grinding ratio (46.2), and the largest amounts of scratches on the rail surface, evincing that the fiercest grinding actions were realized via the mixed granularity, the improved strength and grinding capacity. A grinding equilibrium state was achieved via attrition-wear/micro-fracture of F16 and attrition-wear/pulled-out of F30, thus offering the best self-sharpness of GS.

Subsurface residual stress and damaged layer in high-speed grinding considering thermo-mechanical coupling influence

Subsurface residual stress and damaged layer play a vital role in determining the accuracy maintenance and fatigue performance of parts. Due to the advantages of machining quality and efficiency, high-speed grinding technology is being applied to the machining of precision parts. At present, the influence of high-speed grinding on the damaged layers generation and residual stress distribution has not been completely recognized, and there has been little quantitative research on the mechanism of thermo-mechanical coupling influence on the distribution of residual stress generated in the high-speed grinding process. In this study, a finite-element model comprehensively considering grinding force and thermal field was proposed to investigate the subsurface residual stress and heat influenced layer of AISI 52,100 bearing steel. The subsurface damaged layer and residual stress fields were measured to validate the analytical results. Mathematical models were proposed to quantitatively analyze the thermo-mechanical coupling influence on the distribution characteristics of subsurface residual stress. The theoretical and experimental results demonstrate that when the grinding speed surpasses the critical value of 45 m/s, the depth of residual stress and damaged layer decrease simultaneously with the increase of grinding speed. Higher grinding speeds exceeding 60 m/s are supposed to restrain the maximum value of both the tensile and compressive residual stress, which helps to enhance the precision retention and fatigue performance of components. Base on this study, the performance of the subsurface can be controlled by selecting the proper grinding speed in the high-speed range.

Optimization of High-speed Dry Milling Process Parameters Based on Improved ELM and Genetic Algorithm

High-speed dry grinding has the characteristics of high processing efficiency and clean environment. The high-speed dry grinding method meets the requirements of the green and efficient development of the national manufacturing industry. However, inappropriate cutting parameters seriously affect the surface quality of the workpiece and cause the workpiece to be scrapped. Therefore, this paper proposed an optimization method based on the combination of the improved extreme learning machine neural network (ELM) for high-speed dry milling surface roughness prediction model and genetic algorithm (GA). The Taguchi orthogonal experiment results show that the surface roughness of high-speed dry milling can be accurately predicted by the improved ELM and thereafter the optimal cutting parameter combination can be determined by GA.

Effect of process parameters on hardness and microstructure of 18CrNiMo7-6 carburized steel in high-speed cylindrical grinding

Effect of process parameters on hardness and microstructure of 18CrNiMo7-6 carburized steel in high-speed cylindrical grinding

Development of expert system for the process of high-speed diamond grinding of superhard materials based on macro- and microscale 3D models

Development of expert system for the process of high-speed diamond grinding of superhard materials based on macro- and microscale 3D models

Simultaneous quantification of 106 drugs or their metabolites in nail samples by UPLC-MS/MS with high-throughput sample preparation: Application to 294 real cases

The nail is an alternative matrix to complement hair analysis in proving drug intake over several months in forensic toxicology investigations. However, because of the high hardness and toughness of nails, the existing pretreatment procedures for nails have the disadvantages of either a high degree of time consumption (from hours to days), or low extraction recoveries. This study aims to propose a high-throughput nail sample preparation method and provide a quantitative analytical method for 106 drugs and their metabolites present in nail. We developed cryogenic grinding, coupled with high-speed grinding in the extraction solvent method, which could improve the extraction recovery by thoroughly destroying the nail keratin for approximately 18 min. Subsequently, an ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed for the identification and quantification of 34 synthetic cannabinoids, 26 fentanyls, 18 synthetic cathinones, 10 phenylethylamines, eight opioids, three phencyclidine, two tryptamines, two piperazine, cocaine, benzoylecgonine, and tetrahydrocannabinol (THC). Nail samples were collected from people with a history of drug abuse from five different regions of China. The analysis of 294 authentic samples resulted in 213 detected samples, and showed a broad concentration range including 5.04–67.26 pg/mg for nine synthetic cannabinoids, 109.29–250.29 pg/mg for a synthetic cathinone, 5.06–434291 pg/mg for four phenylethylamines, 5.06–464278 pg/mg for three phencyclidine, 5.50–192195 pg/mg for six opioids, 19.44–36.11 pg/mg for cocaine, and 50.53 pg/mg for THC in nail. Furthermore, up to 10 different compounds were detected in a single nail sample. This nail analysis method serves as a useful tool for the large-scale surveillance of illicit drugs abuse.

Surface integrity and material removal mechanisms in high-speed grinding of Al/SiCp metal matrix composites

SiC particle reinforced Al metal matrix composites (Al/SiCp MMCs) are typical difficult-to-machine materials due to the heterogeneous constituent. Poor surface integrity is commonly caused in conventional machining methods. To explore material removal mechanisms in high-speed grinding, this study carries out high-speed grinding (HSG) on an Al/SiCp MMC at a grinding speed from 30.4 m/s to 307.0 m/s, and assesses surface integrity including surface damage and subsurface damage (SSD) to explore how different grinding speeds take effect therein. The results reveal that improved surface quality is attained in HSG in which continuous and discontinuous dynamic recrystallization mechanisms govern Al grain refinement, and the latter is inclined to occur in the upper part of the ground surface. The distribution of the O-rich zone is closely associated with subsurface cracks. The workpiece ground at a higher grinding speed is with less damage than at a lower grinding speed due to the reduced O-rich zone. Three different layers in the subsurface below ground workpiece are identified based on various features, which are relatively narrower compared to that in low-speed grinding. The range of plastic deformation of the Al alloy matrix is suppressed in HSG because of larger Al grains and a reduced depth of lateral cracks in Al alloy matrix. Distinctly denser dislocation kinks formed at the boundary of SiC particles in HSG indicate the increased ductility of SiC particles. In HSG of Al/SiCp MMCs, strain-rate effect prevails for Al alloy matrix as a result of reduced ductility, and size effect plays the dominant role for SiC particles due to increased ductility, which facilitate reducing the property discrepancies between these two very different components. Therefore, an improved surface integrity of the Al/SiCp MMCs is realized through HSG. This study enhances the understanding of the surface and subsurface formation and material removal mechanisms in HSG of Al/SiCp MMCs, which can provide a theoretical basis and practical reference for achieving better surface quality for Al/SiCp MMCs and other composites machined by HSG.

Exploring the Efficiencies of Spectral Isolation for Intelligent Wear Monitoring of Micro Drill Bit Automatic Regrinding In-Line Systems

Despite the increasing digitalization of equipment diagnostic/condition monitoring systems, it remains a challenge to accurately harness discriminant information from multiple sensors with unique spectral (and transient) behaviors. High-precision systems such as the automatic regrinding in-line equipment provide intelligent regrinding of micro drill bits; however, immediate monitoring of the grinder during the grinding process has become necessary because ignoring it directly affects the drill bit’s life and the equipment’s overall utility. Vibration signals from the frame and the high-speed grinding wheels reflect the different health stages of the grinding wheel and can be exploited for intelligent condition monitoring. The spectral isolation technique as a preprocessing tool ensures that only the critical spectral segments of the inputs are retained for improved diagnostic accuracy at reduced computational costs. This study explores artificial intelligence-based models for learning the discriminant spectral information stored in the vibration signals and considers the accuracy and cost implications of spectral isolation of the critical spectral segments of the signals for accurate equipment monitoring. Results from one-dimensional convolutional neural networks (1D-CNN) and multi-layer perceptron (MLP) neural networks, respectively, reveal that spectral isolation offers a higher condition monitoring accuracy at reduced computational costs. Experimental results using different 1D-CNN and MLP architectures reveal 4.6% and 7.5% improved diagnostic accuracy by the 1D-CNNs and MLPs, respectively, at about 1.3% and 5.71% reduced computational costs, respectively.

High-entropy rare-earth zirconate ceramics with low thermal conductivity for advanced thermal-barrier coatings

The high-entropy rare-earth zirconate ((La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7, 5RE2Zr2O7 HEREZs) ceramics were successfully prepared by a new high-speed positive grinding strategy combined with solid-state reaction method. The microstructure, crystal structure, phase composition, and thermophysical and mechanical properties of the samples were systematically investigated through various methods. Results indicate that the samples have a single-phase defect fluorite-type crystal structure with excellent high-temperature thermal stability. The as-prepared samples also demonstrate low thermal conductivity (0.9–1.72 W·m−1·K−1 at 273–1273 K) and high coefficient of thermal expansion (CTE, 10.9 × 10−6 K−1 at 1273 K), as well as outstanding mechanical properties including large Young’s modulus (E = 186–257 GPa) and high fracture toughness (KIC). Furthermore, the formation possibility of the as-prepared samples was verified through the first-principles calculations, which suggested the feasibility to form the 5RE2Zr2O7 HE-REZs in the thermodynamic direction. Therefore, in view of the excellent multifunctional properties exhibited by the as-prepared 5RE2Zr2O7 HE-REZs, they have great potential applications in next-generation thermal-barrier coatings (TBCs).

Micro-fracture behavior of a single-aggregated cBN grain and its relation to material removal in high-speed grinding of Ti–6Al–4V alloys

Aggregated cubic boron nitride (cBN) abrasive grains were developed using high-temperature liquid phase sintering processes and then the single-grain scratching trial was conducted to study the grain wear behavior and material removal characteristics. Characterizations of grain wear evolutions and related surface scratches grinded by aggregated and monocrystalline cBN grains are performed, respectively. The evaluations of wear-resistance and self-sharpening abilities of both abrasive grains are carried out based on the proposed indicators of volumetric pile-up ratio, volumetric groove removal rate, and grain grinding ratio. Compared to the monocrystalline cBN grain, the as-developed aggregated cBN grain exhibits the more stable grinding process, excellent self-sharpening ability as well as a higher material removal volume provided by the dynamic balance between microfracture and partial macrofracture of multi-layer micro cBN particles.