Vibratory Mill Research Articles

Vibration monitoring and analysis of strip rolling mill based on the digital twin model

A vibration monitoring method of strip rolling mill based on the digital twin model was proposed which could effectively reduce the structure complexity and test cost of the traditional monitoring system. Firstly, the coupling vibration mechanism model of the dynamic characteristics of roll system and bearings of four-high mill was established. Secondly, the digital twin model of strip rolling mill vibration was built based on the mechanism model. At the same time, the traditional monitoring test of the rolling mill was carried out to verify the accuracy of the digital twin model. Through analyzing the experimental results, it could be found that the roll system is vibrating intensely with the increase of rolling force obvious fluctuation. Finally, based on the above research results, the corresponding measures were put forward to suppress the rolling mill vibration. In conclusion, the rolling mill vibration monitoring theory based on the digital twin model provided the technical support and theoretical basis for improving equipment operation stability and reducing testing costs.

Multiscale mathematical modelling of drug activation by co-grinding

Since the 1980s, drug activation by grinding or co-grinding has evolved considerably, allowing the conversion of microcrystals into nanocrystals or amorphous phases, whose increased solubility brings a significant improvement in drug bioavailability. This has prompted many researchers to investigate and understand the entire grinding/co-grinding process. Therefore, the present work focuses on the multiscale mathematical modelling of these three aspects to establish a rational relationship between the mill setting and the properties of the milled drug. Based on the developed model, it was possible to correctly interpret and describe the experimental data obtained when we ground two poorly water-soluble drugs (nifedipine and nimesulide) with a stabiliser (cross-linked polymer; polyvinylpyrrolidone) in two mills (vibrational and planetary mills). Interestingly, despite the complexity of the whole phenomenon, the implementation of the model only required the use of a Microsoft Excel sheet in which a suitable user-defined function was embedded.

Stability analysis of milling process for multi-hardness splicing die

The tool bears the impact load and the alternating force load caused by the sudden change of hardness in the milling process of automobile panel splicing die, which aggravates the milling vibration and reduces the accuracy of die surface. According to the machining characteristics of automobile panel splicing die, the dynamic equation considering the impact of through-seam is established. The state item, the time-delay item and the periodic coefficient item in the state space form of dynamic equation were discretized by multi-order Lagrangian interpolation, and a fourth-order complete discretization method is proposed. Based on the proposed fourth-order complete discretization method, the multi-period milling stability lobe was obtained, and the milling stability lobe band in the splicing region was obtained by combining the maximum and minimum envelope method. The correctness of the dynamic model was verified by the time-frequency domain method such as Fourier transform and milling vibration and milling force data collected from the machining process. The research results can provide theoretical support for the selection and optimization of milling process parameters of splicing die.

Correction to: Experimental study on a two‑dimensional ultrasonic vibration platform and milling of Ti2AlNb intermetallic alloy

Correction to: Experimental study on a two‑dimensional ultrasonic vibration platform and milling of Ti2AlNb intermetallic alloy

Chatter Detection in Robotic Milling Using Entropy Features

Chatter detection in robotic milling is a difficult issue due to the complex dynamic behavior of robots. In this paper, a novel approach to detecting chatter in the robotic milling process is proposed. The method of improved complete ensemble empirical mode decomposition with adaptive noise is introduced for decomposing the milling vibration signals into a series of intrinsic mode functions (IMFs). The effective IMFs are chosen according to the correlation between the original signals and each IMF. Signal reconstruction is conducted using the selected IMFs. The weighted refined composite multiscale dispersion entropy is extracted from the reconstructed signals in order to characterize the chatter states. Then, a classification model is established for chatter detection. Experimental results prove that the proposed method is feasible for chatter detection in the robotic milling process under different robot configurations and machining parameters.

Ternary and Quaternary Nanocrystalline Cu-Based Sulfides as Perspective Antibacterial Materials Mechanochemically Synthesized in a Scalable Fashion.

Twelve Cu-based ternary (Cu–Me1–S, Me1 = Fe, Sn, or Sb) and quaternary (Cu–Me2–Sn–S, Me2 = Fe, Zn, or V) nanocrystalline sulfides are shown as perspective antibacterial materials here. They were prepared from elemental precursors by a one-step solvent-free mechanochemical synthesis in a 100 g batch using scalable eccentric vibratory ball milling. Most of the products have shown strong antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. For instance, stannite Cu2FeSnS4 and mohite Cu2SnS3 were the most active against E. coli, whereas kesterite Cu2ZnSnS4 and rhodostannite Cu2FeSn3S8 exhibited the highest antibacterial activity against S. aureus. In general, stannite has shown the best antibacterial properties out of all the studied samples. Five out of twelve products have been prepared using mechanochemical synthesis for the first time in a scalable fashion here. The presented synthetic approach is a promising alternative to traditional syntheses of nanomaterials suitable for biological applications and shows ternary and quaternary sulfides as potential candidates for the next-generation antibacterial agents.

Solvent-Free Synthesis of Core-Functionalised Naphthalene Diimides by Using a Vibratory Ball Mill: Suzuki, Sonogashira and Buchwald-Hartwig Reactions.

Solvent‐free synthesis by using a vibratory ball mill (VBM) offers the chance to access new chemical reactivity, whilst reducing solvent waste and minimising reaction times. Herein, we report the core functionalisation of N,N’‐bis(2‐ethylhexyl)‐2,6‐dibromo‐1,4,5,8‐naphthalenetetracarboxylic acid (Br2‐NDI) by using Suzuki, Sonogashira and Buchwald–Hartwig coupling reactions. The products of these reactions are important building blocks in many areas of organic electronics including organic light‐emitting diodes (OLEDs), organic field‐effect transistors (OFETs) and organic photovoltaic cells (OPVCs). The reactions proceed in as little as 1 h, use commercially available palladium sources (frequently Pd(OAc)2) and are tolerant to air and atmospheric moisture. Furthermore, the real‐world potential of this green VBM protocol is demonstrated by the double Suzuki coupling of a monobromo(NDI) residue to a bis(thiophene) pinacol ester. The resulting dimeric NDI species has been demonstrated to behave as an electron acceptor in functioning OPVCs.

Vibration mill-assisted complex enzyme hydrolysis for flavoring of freeze-dried sea cucumber powder.

This study aims to analyze the flavor differences of freeze-dried sea cucumber powder, processed for different time intervals, under vibration mill-assisted complex enzyme hydrolysis using electronic nose (E-nose) and gas chromatography-ion mobility spectrometry (GC-IMS). The results of principal component analysis by E-nose showed distinction among the four groups of freeze-dried sea cucumber powder (papain-neutral protease (PN) and flavorzyme-neutral protease (FN), processed for 60 and 80 min). The GC-IMS revealed 35 volatile compounds. Subsequently, based on the fingerprint and heat map results, the flavor differences among the samples were clearly distinguished. When compared to the other three groups, the 60-FN group exhibited a greater variety and quantity of volatile compounds such as octanal, heptanal, hexanal, (E, Z)-2,6-nonadienal, and nonanal. The 80-PN group exhibited high amounts of 2-propanone, ethylbenzene, ethyl acetate, and 2,5-dimethylpyrazine. In addition, the vibration mill technique was considered to be a mild enzyme-assisted method. PRACTICAL APPLICATIONS: This study found that different enzyme types and physical technology operation time can affect the different volatile flavor compounds of freeze-dried sea cucumber powder, which can be quickly and effectively be identified by E-nose and GC-IMS technology to improve the flavor and quality of the product, while facilitating the rapid adjustment and development of the industry. Meanwhile, the results of the study could provide a reference for the deep processing and flavor improvement of the sea cucumber industry and make an important contribution to the related literature. In addition, this could also promote the development and application of non-thermal processing technologies such as vibratory mill in the freeze-dried sea cucumber powder industry.

Experimental study on a two-dimensional ultrasonic vibration platform and milling of Ti2AlNb intermetallic alloy

Experimental study on a two-dimensional ultrasonic vibration platform and milling of Ti2AlNb intermetallic alloy

Vibration prediction and analysis of strip rolling mill based on XGBoost and Bayesian optimization

The stable operation of strip rolling mill is the key factor to ensure the stability of product quality. The design capability of existing domestic imported and self-developed strip rolling mills cannot be fully developed, and the frequent occurrence of mill vibration and operation instability problems seriously restrict the equipment capacity and the production of high-end strip products. The vibration prediction analysis method for hot strip mill based on eXtreme gradient boosting (XGBoost) and Bayesian optimization (BO) is proposed. First, an XGBoost prediction model is developed based on a self-built data set to construct a complex functional relationship between process parameters and rolling mill vibration. Second, the important hyperparameters and parameters of XGBoost are optimized using Bayesian optimization algorithm to improve the prediction accuracy, computational efficiency, and stability of the model. Third, a comprehensive comparison is made between the prediction model in this paper and other well-known machine learning benchmark models. Finally, the prediction results of the model are interpreted using the SHapley Additive exPlanations (SHAP) method. The proposed model outperforms existing models in terms of prediction accuracy, computational speed and stability. At the same time, the degree of influence of each feature on rolling mill vibration is also obtained.

Photoluminescence of Y3NbO7:Eu3+ powders

Y3NbO7:xEu3+ powders (x = 0.25, 0.5, 0.75, 2, 3, 5, 10 at%) were synthesized by a two-step vibrational milling, alternating with annealing. All the samples crystallize as fluorite-type structure (space group Fm3‾m), with crystallite size 50–60 nm and show a strong orange/red luminescence with an excited state lifetime around 1.2 ms. Photoluminescence excitation and emission spectra show rapid intensity decline after 3 at% of Eu3+ content, indicating this concentration as critical for the concentration quenching, and we predicted multipolar interaction as the dominant mechanism behind it. Judd–Ofelt intensity parameters (Ω2 = 0.941∙10−20 cm2, Ω4 = 0.277∙10−20 cm2, Ω6 = 0.277∙10−20 cm2) were obtained from the excitation spectrum of Y3NbO7:3 at%Eu3+. The emission of this luminescent powder is characterized by radiative and nonradiative lifetimes of 2.3 ms and 2.4 ms, respectively, and an intrinsic quantum yield of 51.5%.

Reduced deactivation of mechanochemically delaminated hierarchical zeolite MCM-22 catalysts during 4-propylphenol cracking

The delamination of MCM-22 using shear forces in a vibratory ball mill, rather than chemical surfactants and sonication, is illustrated. The resulting material has comparable or improved physical properties compared to chemically delaminated MCM-22 without a significant loss of acid sites. The mechanical treatment affected the initial rate of 4-propylphenol cracking to phenol and propylene, a model reaction for lignin-derived aromatics, much less than chemical delamination. It also shows improved deactivation resistance for this reaction known to experience fast deactivation by pore blockage.

Grey correlation analysis of milling temperature and milling vibration of TC4 titanium alloy

In this paper, a synchronous acquisition system of milling temperature and milling vibration was established to measure the data of milling temperature and milling vibration. Based on grey correlation theory, the influence of milling parameters and milling vibration on milling temperature was analyzed. It is found that the grey correlation degree between milling temperature and milling parameters and vibration is above 0.70, indicating that milling parameters and vibration have great influence on temperature. In addition, the GM (0, N) grey prediction model of milling temperature on milling parameters and milling vibration was established, and the correlation coefficient of the model was above 0.8, indicating that the reliability of the model was high, and the correlation between milling temperature and milling vibration signal was high.

Design of a damped vibration absorber to control the resonant vibration of roll

Strip rolling is currently the main steel production process. The vertical vibration of the rolling mill caused by the large reduction ratio and high rolling speed reduces the qualification rate of strip products, and even damages the rolling equipment. In this paper, a new particle damping absorber (PDA) is designed to suppress the vertical vibration of the mill. The adaptive genetic algorithm (AGA) is used to optimize the basic parameters of PDA. Considering the nonlinear stiffness between the roll and the rolling stock, a four-degree-of-freedom vertical vibration model of the roll system with the PDA is established. The amplitude-frequency characteristic equations of the primary resonance and the internal resonance are solved by using the multi-scale method. The static bifurcation of the primary resonance of the system is investigated based on the singularity theory. The effects of parameters on vibration are analyzed. The control effect of the vibration absorber is investigated experimentally, and it is found that the experimental results are basically consistent with the theoretical analysis, which verifies the reliability of the established vibration model. The results show that the PDA can effectively suppress the vertical vibration of the roll. It provides some theoretical guidance for the research on vibration suppression of rolling mills.

Study on Surface Integrity and Surface Roughness Model of Titanium Alloy TC21 Milling Considering Tool Vibration

Due to its excellent strength, plasticity, and fracture toughness, titanium alloy has been widely used in the aerospace field. The specificity of its application environment places high demands on the surface quality of titanium alloy. In this paper, we study the effects of different lubrication methods on the microscopic topography, surface roughness, and microhardness of titanium alloy TC21 during the milling process. The lubrication methods include dry, high-pressure air cooling, and minimum quantity lubrication (MQL). Compared with dry milling and high-pressure air cooling conditions, the MQL environment can effectively suppress plastic deformation and surface defects of titanium alloy TC21. MQL is significant for improving the milling process of titanium alloy TC21. In addition, a surface roughness model considering milling vibration is developed. According to the results of orthogonal experiments, the prediction accuracy of the surface roughness model is acceptable, and the prediction errors are all below 20%.

ПОЛУЧЕНИЕ ВЯЖУЩИХ КОМПОЗИЦИЙ ОПТИМАЛЬНЫХ СОСТАВОВ НА ОСНОВЕ ПОРТЛАНДЦЕМЕНТА И ОТХОДОВ БОЯ КЕРАМИЧЕСКОГО КИРПИЧА

When developing composite binders of a certain functional purpose, it is necessary to rationally select raw materials, taking into account their chemical, mineral and granulometric composition. The use of mechanical activation with the choice of the most suitable grinding unit affects the creation of binder compositions, the functional additives used have a significant impact on the properties of composite binders.
 The article presents the results of obtaining binder compositions of optimal composition based on Portland cement and broken ceramic bricks. Experimental studies of the granulometric composition have been carried out, the results of tests of binder compositions of the compositions: cement – broken ceramic bricks prepared in a mill are given. Compositions of binder compositions with a wide range of use of ceramic cullet waste – brick production waste have been developed and installed.
 Using the method of electron microscopy, the features of the microstructure of chips of cement stones synthesized on the basis of Portland cement and various content of mineral filler – ceramic brick slaughter waste, mechanically activated in a vibration mill, were studied. It is noted that the open pores of cement stone chips, synthesized binders, are densely overgrown with various neoplasms of various sizes.
 It has been established that the microstructure of hydrated binder compositions is marked by a dense structure due to the use of powdered brick cullet, which compact the structure of the composite, and it is also noted that grains of calcium hydrosilicates grow on the mineral particles of the filler, compacting the overall structure of the composite.

Experimental Study on Ultrasonic-Assisted End Milling Forces in 2195 Aluminum-Lithium Alloy.

To achieve high-quality machining of the 2195 aluminum-lithium alloy, this paper presents an experimental study on the effect of milling processing parameters on milling forces and surface topography, during which conventional milling and longitudinal-torsional ultrasonic vibration milling of the 2195 Al-Li alloy were performed. The characterization of the tool tip trajectory illustrates some of the advantages of ultrasonic machining, which include variable depth of cut and tool chip pulling. The differences in milling forces between conventional milling and longitudinal-torsional ultrasonic vibration machining were compared using orthogonal tests, and the effect of ultrasonic vibration on milling forces was investigated in detail. The maximum reduction of milling force Fy in the feed direction under the influence of torsional vibration is 62% and 54% for larger feed per tooth and cutting depth, respectively. The high-frequency impact generated by the longitudinal vibration not only reduces the chip accumulation on the surface, but also smooths out the tool-tooth scratches and creates a regular surface profile. In addition, the characteristics of the milling force signals of the two machining methods were analyzed, and the analysis of the spectrum of the collected milling forces revealed that the ultrasonic vibration caused the high-frequency components of the milling forces Fy and Fz. The orthogonal result analysis and single-factor result analysis verified the superiority of ultrasonic machining, provided parameter selection for subsequent aluminum-lithium alloy machining, and bridged the gap of longitudinal torsional ultrasonic vibration machining of 2195 aluminum-lithium alloy in the study of milling force.

Roughness Scaling Extraction Accelerated by Dichotomy-Binary Strategy and Its Application to Milling Vibration Signal

Fractal algorithms for signal analysis are developed from geometric fractals and can be used to describe various complex signals in nature. A roughness scaling extraction algorithm with first-order flattening (RSE-f1) was shown in our previous studies to have a high accuracy, strong noise resistance, and a unique capacity to recognize the complexity of non-fractals that are common in signals. In this study, its disadvantage of a long calculation duration was addressed by using a dichotomy-binary strategy. The accelerated RSE-f1 algorithm (A-RSE-f1) retains the three above-mentioned advantages of the original algorithm according to theoretical analysis and artificial signal testing, while its calculation speed is significantly accelerated by 13 fold, which also makes it faster than the typical Higuchi algorithm. Afterwards, the vibration signals of the milling process are analyzed using the A-RSE-f1 algorithm, demonstrating the ability to distinguish different machining statuses (idle, stable, and chatter) effectively. The results of this study demonstrate that the RSE algorithm has been improved to meet the requirements of practical engineering with both a fast speed and a high performance.

Recycling of Broken Waste Glass as Polyethylene Nanofiller for Electrical Insulating System

This work focuses on the preparation of a high-quality glass powder from the broken windowpane. The expected glass powder must show a high amount of silicon dioxide with fine particle size. The processing technique used in this work is coarse grinding and high-speed vibratory milling under a variety of conditions to get the best quality of glass powder. The particle size and particle size distribution were examined by using DLS technique. The chemical composition was examined by EDX together with FT-IR and XRF spectroscopies. The results showed that the wide range of particle size distribution occurred in all milling conditions, which approximately ranged from 0.3 to 7 µm, and the 270 min-milling time showed the smallest particle size of glass powder. The chemical analysis showed that the glass powder is rich in silica which contained about 70.47% of SiO2. After that, the various ratios of the glass powder/HDPE composites were formed by using the traditional casting method. The physical and electrical properties were investigated for all composites. The results showed that after adding glass powder into the HDPE matrix, the εr value significantly drops due to the inorganic filler suppressed polarization within the systems. For the resistivity, the ρ value significantly increases after adding glass powder to the HDPE matrix for all compositions because this filler promotes the hinder of electric current flow. Finally, it can conclude that the waste glass powder can use as a filler in the HDPE-based composite as better as the commercial SiO2 powder for the electrical insulting application.

Properties of biomass powders resulting from the fine comminution of lignocellulosic feedstocks by three types of ball-mill set-up.

Background: Lignocellulosic biomass has many functionalities that hold huge potential for material, energy or chemistry applications. To support advanced applications, the biomass must be milled into ultrafine powder to increase reactivity. This milling unit operation needs to be fully mastered to deliver high-quality standard end-products. Here we studied the relationship between the characteristics of the starting lignocellulosic plant material and the properties of the resulting ultrafine powder in different ball-mill process routes. Methods: Two lignocellulosic biomasses (pine bark and wheat straw) with contrasted compositional and mechanical properties were milled using three ball-mill set-ups delivering different balances of impact force and attrition force. The resulting powders were analysed for particle characteristics (size, agglomeration extent, shape) and powder flow properties (compressibility, cohesion) using a dynamic powder rheometer. Results: Pine bark is more amenable to a fast particle size reduction than the fibrous wheat straw. The resulting pine bark powders appear less compressible but much more cohesive than the straw powders due to particle shape, density and composition factors. The mill set-up working by attrition as dominant mechanical force (vibratory ball mill) produced a mix of large, elongated particles and higher amounts of fines as it acts mainly by erosion, the resulting powder being more prone to agglomerate due to the abundance of fines. The mill set-up working by impact as dominant mechanical force (rotary ball mill) produced more evenly distributed particle sizes and shapes. The resulting powder is less prone to agglomerate due to a preferential fragmentation mechanism. Conclusions: The attrition-dominant mill yields powders with dispersed particle sizes and shapes and the poorest flow properties, while the impact-dominant mill yields more agglomeration-prone powders. The mill set-up working with impact and attrition as concomitant mechanical forces (stirred ball mill) produces powders with better reactivity and flow properties compared to rotary and vibratory mills.