Grinding Method Research Articles

Kinematics modeling and trajectory optimization for precision grinding of variable-parameter helical grooves

End mills with variable helix angles in a certain range can suppress the cutting vibration, and the change of the core radius can improve the cutting rigidity and realize the best match between the rigidity and the chip removal performance. However, the existing process cannot accurately realize the continuous variable helix angle along the cutting edge. Moreover, the change in helix angle and core radius increases the difficulty of calculating the grinding trajectory and makes it difficult to control the rake angle accurately, and that results in the performance of this end mill cannot be accurately guaranteed. Therefore, this paper proposed a kinematics modeling and trajectory optimization method for the precision grinding of variable-parameter helical grooves. Firstly, a general grinding kinematics model is established by geometric analysis. Secondly, with the rake angle, helix angle, and core radius as constraints, models are constructed to solve the location and direction parameters of the grinding wheel. Then, the calculation and optimization method of the grinding trajectory for variable-parameter helical grooves is developed. Finally, the experimental verification is carried out and the results show that the maximum rake angle error is 0.09°, the maximum helix angle error is 0.08°, and the maximum core radius error is 0.053 mm. It indicates the grinding kinematics model and the trajectory optimization are correct. This process can also be used to grind complex helical grooves on custom cutting tools such as drills and screw taps.

Hydrogen-as-a-probe applied to investigate the influence of extraction and preparation methods on TDS spectra of 13CrMo4-5 samples

AbstractThermal desorption spectroscopy (TDS) provides rich information on the desorbed hydrogen flow rate activated at different heat energy levels, supporting high-resolution assessment of small-scale features that are preferential trapping sites. TDS spectra are also highly sensitive to hydrogen uptake from the sample’s extraction and preparation methods, whose influence requires further evaluation. In this research, hydrogen-as-a-probe is applied to evaluate the influence of extraction, surface grinding, dwelling time, plate thickness, and sample thickness on TDS spectra of 13CrMo4-5 steel. Validation of TDS results confirms that all hydrogen present in the sample before the TDS measurement, including metallurgical hydrogen and hydrogen uptake from the studied methods, is desorbed during the first heating cycle. Results indicate that peaks 1 and 3 are negligibly influenced by the studied methods. Peak 2 and total hydrogen concentration are significantly influenced by sample extraction and surface grinding methods, which provide the main outcomes of this work. Methods based on severe solid-state distortion, like machine cutting and grit P320, present an increased total hydrogen content of 99% and 142%, respectively. Dwelling time and plate thickness have small influence on hydrogen content. Reducing the sample thickness results in less total hydrogen concentration at a rate of 5.7 at.ppm/mm.

Phytochemical properties and antioxidative activities of ginseng superfine powders prepared by wet grinding method with high-pressure homogenization

Phytochemical properties and antioxidative activities of ginseng superfine powders prepared by wet grinding method with high-pressure homogenization

Visible Light-Driven Selective Oxidative Transformation of Vicinal Diols Using ZnS-Based Photocatalyst in the Presence of Molecular Oxygen

The heterogeneous photocatalysis for the oxidative cleavage of C-C bond is significant to the transformation of biomass feedstock. In this work, a heterojunction photocatalyst based on the conductor ZnS and g-C3N4 (CN) material is prepared and employed in the aerobic oxidative cleavage reaction of vicinal diol under visible light irradiations. As a result, it is found that 3ZnS/CN catalyst obtained by a mechanical grinding method shows a high photocatalytic activity. In the photocatalytic oxidative cleavage process of 1-phenyl-1, 2-glycol, more than 98.7% conversion of substrate with a 96.2% selectivity of benzaldehyde was attained using O2 as oxidant. In addition, the photocatalyst recycling experiments exhibited that the 3ZnS/CN catalyst still kept a good activity and stability even after being recycled for 5 times. Finally, the active reaction intermediates are investigated by the control experiments and the relative EPR detection. According to the obtained results and photocatalytic principle, the mechanism for the selective oxidative transformatioin of 1-phenyl-1, 2-glycol has been proposed. It gives a promising approach for the catalytic utilization of biomass-based lignin and cellulose.

Using the Cocrystal Approach as a Promising Drug Delivery System to Enhance the Dissolution and Bioavailability of Formononetin Using an Imidazole Coformer

Background: Natural isoflavones are recognized for their diverse pharmacological activities; however, their low aqueous solubility presents a significant challenge for further development. Here, we aimed to develop a cocrystal of formononetin (FMN) to improve its solubility. Methods: The formononetin-imidazole (FMN-IMD) cocrystal was prepared using liquid-assisted grinding method. The prepared cocrystal was identified through a thermal analysis of physical mixtures with various coformers. FTIR and solid-state NMR confirmed the presence of hydrogen bonds and π-π interactions in the FMN-IMD cocrystal. Results: The solubility of FMN-IMD was two to three times higher than that of crystalline FMN. The FMN-IMD cocrystal showed a 4.93-fold increase in the Cmax value and a 3.58-fold increase in the AUC compared to FMN after oral administration in rats. There were no changes in the PXRD of the FMN-IMD cocrystal after six months of storage at 40 °C. Conclusions: Thus, the FMN-IMD cocrystal is proposed as an effective solid form for oral delivery, offering enhanced solubility and physical stability.

Study of Luminescence Phenomena of Tb (III) Containing Fluroquinoline for Application in Optoelectronic Devices.

This study presents a series of six vivid green Tb(III) complexes, denoted by the general formula [Tb(L)3.secondary sensitizers], where L represents 1-cyclopropyl-7-(4-ethylpiperazin-1-yl)-6-fluoro-4-oxoquinoline-3-carboxylic acid and secondary sensitizers consist of heterocyclic N-donor aromatic systems. The synthesis of these complexes were achieved through a solvent-assisted grinding method, and their characterization involved various techniques such as CHN analysis, FTIR, NMR, UV, XRD, and NIR spectroscopy. These analyses confirmed the successful synthesis of complexes with coordination between the quinoline moiety and the metal ion. Photoluminescence studies were conducted in solid and solution phases, revealing excellent luminescence properties. The bright green color emitted by the complexes upon exposure to UV rays was attributed to the hypersensitive 5D4 → 7F5 transition. J-O analysis indicated an asymmetrical coordination environment around in the complexes. Additionally, various radiative properties (Ared, Anred, η, βexp, σs) and band gap values were determined, highlighting the potential applications of these complexes in diverse optoelectronic fields. Chromaticity evaluation demonstrated high color purity in both solid and solution phases. Furthermore, the CCT value identified the solid complexes as a cool light source. Overall, the analyses supported the exceptional luminosity of synthesized complexes, positioning them as promising luminescent materials for a wide range of devices.

Intelligent Grinding System for Medium/Thick Plate Welding Seams in Construction Machinery Using 3D Laser Measurement and Deep Learning

With the rapid development of the construction machinery industry, thick plate welds are increasingly needing efficient, accurate, and intelligent processing. This study proposes an intelligent grinding system using 3D line laser measurement and deep learning algorithms to solve the problems of inefficiency and inaccuracy existing in traditional weld grinding methods. This study makes use of 3D line laser measurement technology and deep learning algorithms in tandem, which perform automated 3D measurement and analysis to extract key parameters of the weld seam, in conjunction with deep learning algorithms applied on image data of the weld seam for the automatic classification, positioning, and segmentation of the weld seam. The entire work is divided into the following: image acquisition, motion control, and image processing. Based on various weld seam detection algorithms, the selected model was MNet-based DeepLab-V3. An intelligent trimming system for welding seams based on deep learning was constructed. Experiments were conducted to verify the feasibility and accuracy of the 3D line laser measurement technology for weld seam inspections, and that the deep learning algorithm can effectively identify the type and location of the weld seam, thus predicting the trimming strategy. With an accuracy far superior to conventionally based methods in accurate detection and regrinding of weld surface defects, the system proves advantageous for improved weld regrinding productivity and quality. It was determined that the system presents significant advantages in reinforcing weld regrinding when it comes to efficiency and quality, thus initiating a paradigm of using intelligent treatments for medium/thick plate welds in the construction machinery industry.

Effect of Water Content in Semidry Grinding on the Quality of Glutinous Rice Flour.

The grinding process is one of the key factors affecting the quality of glutinous rice flour (GRF). As an emerging grinding method, semidry grinding aims to solve the problems of the high yield of wastewater in traditional wet grinding and the high content of damaged starch in dry grinding, in which the water content has a great influence on the quality of GRF. However, semidry grinding has not yet been formally put into production due to limitations such as the long time required to adjust the water content of rice grains. Therefore, this work was carried out to shorten the soaking time of glutinous rice (GR) by hot air pretreatment, and to conduct a systematic and in-depth study of the effect of water content on the quality of GRF, including water distribution, water hydration properties, thermal properties, rheological properties, and microstructure. The results showed that the GRF with higher water content had lower water solubility and higher enthalpy of pasting, which were due to the low content of damaged starch and the high degree of crystallization. The particle size of the GRF became smaller as the interaction between water and starch was enhanced and the GR was softened. In addition, the viscosity and elasticity of the GRF were also improved with an increase in water content. This work provides theoretical guidance for the improvement of semidry grinding to a certain extent.

Development of a MOF-5/g-C3N4 nanocomposite: an effective type 2 heterojunction photocatalyst for rhodamine B dye degradation.

The field of environmental and water remediation faces a significant challenge in removing organic dyes from wastewater, particularly Rhodamine B (RhB), a stubborn dye used in various industries. Traditional treatment methods struggle with its resistance to decomposition, posing risks to water quality, human health, and aquatic life. This study demonstrates a novel approach to enhance photocatalytic efficiency for RhB degradation by constructing a MOF-5/g-C3N4 composite through a facile mechanical grinding method, which is unprecedented. The composite addresses the limitations of g-C3N4, such as rapid recombination of electron-hole pairs, low electron transfer rates, and small surface area, by forming a heterojunction with MOF-5. The composite exhibits enhanced photocatalytic efficiency for the degradation of RhB under sunlight, with a degradation of 91.5% achieved within 90min. Optimization studies highlight the importance of pH and catalyst dosage in the degradation process. The reusability test shows consistent performance over five successive cycles, maintaining a degradation efficiency of over 90%. Total organic carbon (TOC) analyses confirm the mineralization of the dye solution to 82.05% after 90min of irradiation, demonstrating the environmental benignity of the composite. Trapping experiments suggest the involvement of superoxide radicals, electrons, and holes in the photocatalytic mechanism. This study introduces a promising strategy for addressing challenges in dye degradation through innovative composite materials.

Investigating the efficacy of naphthalene-thiazole hybrid hydrazones as α-glucosidase inhibitors

In this study, a series of hydrazone derivatives containing naphthalene and thiazole hybrids were synthesized through the condensation of (E)-4-methyl-2-(2-(naphthalen-1-ylmethylene)hydrazineyl) thiazole-5-carbohydrazide with various carbonyl compounds, including aldehydes and ketones, whether carbocyclic aromatic or heterocyclic, using a grinding method with drops of acetic acid. The elucidation of the structures of the synthesized hydrazone derivatives was achieved through the analysis of NMR, IR, and mass spectrometry data. All the newly prepared compounds were assessed for their in vitro α-glucosidase inhibition profiles and the results revealed a diverse range of inhibitory potentials, ranging from 9.3 ± 1.0 to 70.5 ± 1.8 μM, in contrast to the reference acarbose (with an IC50 value of 45.2 ± 1.3 μM). In an attempt to explain the observed inhibitions of synthesized naphthalene containing thiazole compounds, molecular docking was performed to determine the binding modes between the synthesized compounds from one side and the active residues of α-glucosidase from the other side. Compounds 4d, 4e, 4c, and 8 demonstrated the strongest binding affinities, with binding energies of -10.5, -9.8, -9.6, and -9.5 kcal/mol, respectively.

Acoustic road surface maintenance on low noise asphalts in Switzerland with grinding

This study investigates the effectiveness of grinding techniques on special low-noise pavements as well as conventional asphalt surfaces in order to restore or enhance their noise-reducing properties. This study analyzes 17 different test tracks where grinding techniques were applied, featuring various surface types and stages of aging. The research employs Close-Proximity-Measurements (CPX) and additional methods to evaluate surface characteristics. Initial results reveal significant acoustic improvements from grinding, especially on surfaces with 4- and 8-mm maximum aggregate size. However, the durability of these measures varies, with 4~mm surfaces returning to baseline after 2-4 years, while 8 mm surfaces benefit for approximately 4 years. The study demonstrates that grinding methods can enhance acoustics through surface texture improvement and partially reactivating previously clogged pore spaces. The effectiveness depends on the initial acoustic state and grinding depth, emphasizing the importance of setting clear objectives for optimal results. In summary, this study underscores the effectiveness of grinding in enhancing the acoustic quality of low-noise road surfaces. Moreover, its integration into road surface maintenance strategies is a new tool for extending the functional and acoustic lifespan of low-noise road surfaces.

Cocrystal screening in minutes by solution-mediated phase transformation (SMPT): Preparation and characterization of ketoconazole cocrystals with nine aliphatic dicarboxylic acids

The rapid and efficient cocrystal screening, based on solution-mediated phase transformation (SMPT), was applied to the screening of cocrystals between ketoconazole (KTZ) and nine aliphatic dicarboxylic acids. Cocrystals formed successfully, in minutes, with a change of suspension characteristics, either a cake formation or the formation of large particles. Bulk cocrystals were characterized by powder X-ray diffraction, thermal analysis, and Raman spectroscopy. Single crystals were grown, and molecular structures were determined. Three previously reported cocrystals were reproduced, and six new cocrystals were discovered, including one that was reported as a failure in literature by solution or grinding method. Two hydrogen-bonded motifs are observed in these nine cocrystals: Most cocrystals form hydrogen bonded discrete tetramer with two KTZ and two acids molecules; while two cocrystals form infinite chain. This study demonstrated the high efficacy of cocrystal generation using the slurry screening method. It should be fully utilized in future cocrystal screening.

Determination of a standard efficiency using the ISOCS uncertainty estimator for calculating the activity concentration of 226Ra, 232Th, and 40K in concrete

The Activity Concentration Index (ACI) requires knowledge of the activity concentrations of 226Ra, 232Th (212Pb), and 40K, typically determined through gamma spectrometry. The inherent heterogeneity of concrete makes the determination of gamma counting efficiency a complex problem. For this reason, this study employed the ISOCS Uncertainty Estimator (IUE), which allows for probabilistic calculations based on variations in parameters affecting counting efficiency, such as dimensions, density, and composition. The IUE enabled the estimation of a representative efficiency for a standard concrete configuration applicable to concrete specimens and samples from existing structures. The results obtained with the proposed efficiency for natural radionuclides of the uranium and thorium series, along with 40K, compared to the classical material grinding method, showed no significant differences in the mean and variance. The maximum differences observed when applying regression analysis were less than 16 %, thus validating the representative efficiency obtained with the IUE.

Формообразование задней поверхности многогранных твердосплавных пластин на шлифовально-заточных станках с ЧПУ

The purpose of the work is to obtain a mathematical expression for calculating the coordinates of the workpiece center in relative movements in accordance with the third shap ing scheme. A certain algorithm for modeling the third kinematic scheme of forming a part with a tool can be implemented by means of an automatic design system. It is noted that the main shaping movements – translational in the direction of the X axis, rotational around the B and C axes are controlled by a numerical control system. This method of grinding makes it possible to process the rear surfaces of plates of any shape, including plates with a clearance angle on the edges and tops. The models of the tool I and the workpiece are shown in the ini tial II and one of the intermediate positions III, the models of the workpiece and the tool for their various relative positions. A relationship has been established between the corresponding translational and rotational motion of the workpiece. The obtained dependences were used in the preparation of control programs on the VZ-700F4 machine tool for grinding multifaceted carbide inserts along the contour.

Effect of superfine grinding mulberry leaves (Morus alba Linn.) powder on biscuit properties

SummarySuperfine and regular grinding methods were used to mill mulberry leaves (ML), and the chemical composition and physical characteristics of the powders were investigated. Compared to regular grinding, superfine grinding reduced particle size from 121.44 μm to 18.69 μm. Compared to coarse mulberry leaf (CML), the fine mulberry leaf (FML) powder had a greater water solubility index, soluble dietary fibre content and 1‐deoxynojirimycin (DNJ) content. Both types of ML powders were substituted for flour at various percentages (3%, 6%, 9% and 12%), and their effects on the biscuits' textural qualities and sensory assessment were examined. The adhesiveness, cohesiveness and springiness of biscuit doughs were all reduced by ML powder addition, while their hardness was raised. The inclusion of ML powders increased the hardness of the biscuits significantly, whereas only the addition of FML powders decreased their fracturability. Additionally, the DNJ contents in FML biscuits were significantly higher than that in CML biscuits. The sensory assessment revealed that biscuits containing 9% FML powder received the best rating.

Enhanced temperature sensing in lead-free Cs3Bi2Cl9 perovskite co-doping Yb3+/Er3+ for optical thermometry application

A simple and rapid grinding method for preparing Er3+-doped and Er3+/Yb3+co-doped Cs3Bi2Cl9 upconversion phosphors was developed. We avoid to employ strong acids as reaction solvents, aligning with the principles of green chemistry. By controlling the thermal treatment temperature and adding BiCl3, a reversible phase transformation process between Cs3Bi2Cl9 and Cs3BiCl6 perovskite phosphors was achieved. The Er3+/Yb3+ co-doped Cs3Bi2Cl9 phosphors emit green light under 980 nm excitation, whereas Cs3BiCl6 phosphors emit red light. Their temperature sensing performance was tested through variable-temperature processes. Compared to Er3+-doped Cs3Bi2Cl9 phosphors, the co-doped Er3+/Yb3+ phosphors have a higher relative sensitivity of 1.60 % K−1. Compared to previously reported materials, Cs3Bi2Cl9 phosphors show enhanced sensitivity in temperature sensing. The study demonstrates that lead-free halide perovskites’ unique color-tunability not only underscores the innovativeness of this synthetic strategy but also provides a significant technological foundation for temperature sensing applications. Given their environmental friendliness and facile preparation process, these phosphors possess notable advantages for industrial production and hold promise as potential candidates for next-generation high-performance phosphor materials.

Impact Mill

An impact mill has been developed to produce powders from shavings of refractory metals using impact grinding method for reuse in electrometallurgy in devices with screw feed, for example, in 3D printers. The proposed device provides high uniformity of grinding with a minimum content of dust fraction and impurity content at low technical and economic costs. The result is achieved by using a Laval nozzle, which operates in the supersonic jet formation mode. In the area of the first Mach disk there are rod fenders arranged in a cascade, and the impact plate is located in the turbulence zone and is equipped with winglets with holes for separating crushed metal.

Surface roughness and fracture cracks of Al2O3/TiO2 composite coating by wet chemical mechanical grinding with structured abrasives pad

In the fields of wind power, and other industries, the Al2O3/TiO2 coating is prepared and ground on the bearing ring, in order to obtain the insulation resisting the electrical erosion for the motors at high voltage. A novel wet chemical mechanical grinding (WCMG) method is proposed to finish this hard-brittle composite material, utilizing the structured diamond abrasives pad and the NaOH solution. The softened workpiece's surface under the chemical reaction was demonstrated by means of Raman spectrum, indentation and scratching tests. The analytical model of surface roughness and fracture cracks is established based on the synthesis of geometry and kinematics, contact mechanics, material removal and indentation fracture mechanics. The surface roughness of coating was reduced from initial Sa 3.293 μm down to final Sa 0.049 μm in the WCMG process with grain size 3 μm and pH 12.01, mostly attributed to the ductile removal of chemically softened coating surface.

Computerized generation, deviation correction and rapid tooth contact analysis of helical face gear

This paper delves into the generation of helical face gears using a grinding worm. It investigates the computerized generation process and explores the inherent geometric constraints associated with the application of a grinding worm for helical face gears. An approximate grinding method, tailored for helical face gears featuring large helix angles, is proposed, with an evaluation of the resulting theoretical deviations. Furthermore, a novel rapid computational approach for determining the bearing contact of helical face gear pairs is introduced and validated through Finite Element Analysis (FEA). The subsequent analysis comprehensively examines the effects of the machine tool positioning errors on tooth flank deviations, bearing contact, and transmission errors. A sensitivity matrix is developed to elucidate the relationship between machine tool positioning errors and the tooth flank deviations, leading to the proposition of a correction method for theoretical generating deviations. Finally, the paper introduces a tooth flank modification method for helical face gears and the meshing performance is highly improved.

Linking the size of hard carbon particles with electrochemical response in sodium ion storage

Hard carbon is considered to be one of the most promising anodes for sodium-ion batteries (SIBs) owing to its high capacity and abundant resources. However, the role of particle size on sodium ion storage is unclear, which leads to low capacity and initial coulombic efficiency (ICE) in practical application. In this work, a series of hard carbons with different particle sizes were prepared by an “up to down” strategy using simple grinding and ball-milling method to investigate the effect of particle size on electrochemical response of sodium ion storage. The particle size of hard carbon has negligible effect on initial specific capacity. However, it has a strong effect on the ICE and rate capability. The ICE reduces as the particle size decreases, but the rate performance in reverse. Moreover, impedance analysis and electrochemical kinetics show huge differences for different particle sizes. In-situ Raman technique was also adopted to further illustrate the sodium ion storage mechanism of hard carbon, and an “adsorption-intercalation-pore filling” mechanism is proposed. This work could provide a new perspective for the design of hard carbon materials with suitable structure for efficient sodium ion storage, helping to develop high performance SIBs.