Torsional vibration analysis of lathe spindle system with unbalanced workpiece

For the purpose of analyzing the torsional vibration caused by the gravitational unbalance torque arisen in a spindle system when it is machining heavy work piece,a 10-DOF lumped parameter model was made for the machine tool spindle system with geared transmission.By using the elementary method and Runge-Kutta method in Matlab,the eigenvalue problem was solved and the pure torsional vibration responses were obtained and examined.The results show that the spindle system cannot operate in the desired constant rotating speed as far as the gravitational unbalance torque is engaged,so it may cause bad effect on machining accuracy.And the torsional vibration increases infinitely near the resonant frequencies,so the spindle system cannot operate normally during these spindle speed ranges.

Dynamic Response Analysis of Motorized Spindle System

As to motorized spindle system, this paper builds a simplified 3D model of spindle and bearing, performs structure modal analysis, reveals its dynamic characteristics under the free model; furthermore, modifies bearing radial stiffness and number of model and studies the change of modal parameters. On this basis, through the harmonic response analysis of the finite element model, dy- namic response characteristic caused by imbalance of monitored spindle system and law of vibration response to different amount of unbalance is analyzed.

Analysis on Failure Mode Severity of Machining Center Spindle System

According to the subjectivity and fuzziness of analysis on failure mode severity about spindle system of machining center,an analysis model of the failure mode severity of such a system is proposed based on the new fault severity index system, improved analytic hierarchy process( IAHP) and entropy-based fuzzy comprehensive evaluation. IAHP and entropy methods are adopted to determine the comprehensive failure severity index weight. The evaluation result is obtained after the factor set,comment set,weight set,and other parameters are determined,and then the level of risk degree and numerical value order of every spindle system failure mode is given. By taking an example,we verify that the proposed method can quantify the qualitative problem comprehensively,obtain more accurate analysis results,and provide the theoretical reference for mechanization and sequencing of failure mode effect analysis in reliability analysis. The calculation results can also serve as the basis of failure mode,effects,and criticality analysis in the subsequent step.

MECHANICAL-ELECTRIC COUPLING DYNAMICAL CHARACTERISTICS OF AN ULTRA-HIGH SPEED GRINDING MOTORIZED SPINDLE SYSTEM

On the basis of the traditional mechanical model of a grinding wheel rotor and the mechanical-electric coupling model with ideal sinusoidal supply, taking high-frequency converting current of inverter power switches into further consideration, a modified mechanical-electric coupling model is created. The created model consists of an inverter, a motorized spindle, a grinding wheel and grinding loads. Some typical non-stationary processes of the grinding system with two different supplies, including the starting, the speed rising and the break in grinding loads, are compared by making use of the created model. One supply is an ideal sinusoidal voltage source, the other is an inverter. The theoretical analysis of the high-order harmonic is also compared with the experimental result. The material strategy of suppressing high-order harmonic mechanical-electric coupling vibration by optimizing inverter operating parameters is proposed.

A DYNAMIC ANALYSIS OF THE SPINDLE SYSTEM FOR UNIVERSAL MILLING MACHINES

In this paper,the Riccati transfer matrix method and the modal parameter identification tech-nique are applied to the dynamic analysis of the spindle system of a machine tool,the X62Wknee-type universal milling machine.With-the help of a computer,the lowest three critical speedsare calculated and these are compared with the values measured by a 7T17S analyzer,showing afairly good agreement.

Myocardial metastasis from ZEB1-and TWIST-positive spindle cell carcinoma of the esophagus:A case report

BACKGROUND Metastatic cardiac tumors are known to occur more frequently than primary cardiac tumors,however,they often remain asymptomatic and are commonly dis-covered on autopsy.Malignant tumors with a relatively high frequency of cardiac metastasis include mesothelioma,melanoma,lung cancer,and breast cancer,whereas reports of esophageal cancer with cardiac metastasis are rare.CASE SUMMARY The case of a 60-year-old man who complained of dysphagia is presented.Upper gastrointestinal endoscopy showed a submucosal tumor-like elevated lesion in the esophagus causing stenosis.Contrast-enhanced computed tomography showed left atrial compression due to the esophageal tumor,multiple liver and lung metastases,and a left pleural effusion.Pathological examination of a biopsy speci-men from the esophageal tumor showed spindle-shaped cells,raising suspicion of esophageal sarcoma.The disease progressed rapidly,and systemic chemotherapy was deemed necessary,however,due to his poor general condition,adminis-tration of cytotoxic agents was considered difficult.Given his high Combined Positive Score,nivolumab was administered,however,the patient soon died from the disease.The autopsy confirmed spindle cell carcinoma(SCC)of the esophagus and cardiac metastasis with similar histological features.Cancer stem cell markers,ZEB1 and TWIST,were positive in both the primary tumor and the cardiac metastasis.CONCLUSION To the best of our knowledge,there have been no prior reports of cardiac metastasis of esophageal SCC.This case highlights our experience with a patient with esophageal SCC who progressed rapidly and died from the disease,with the autopsy examination showing cardiac metastasis.

MINITYPE MACHINING SYSTEM FOR DIAMOND LAPPING & POLISHING BY USING BRUSHLESS DIRECT CURRENT MOTOR AS PRECISE SPINDLE

A minitype precise spindle system which can machine precisely and stably in the process of diamond lapping and polishing is designed. In such minitype spindle system, the brushless DC spindle motor is used to drive the lapping finish table, which is built with fluid dynamic bearings. Some measures have been taken to make the lapping system dynamic balance, and a servo controller which can adjust the speed of motor from 1200 r/min to 5400 r/min is designed. Experiments show that the spindle system is reliable and stable for diamond polishing, and the detection results by atomic force microscope（AFM） show that the surfaces of diamond edge＇s Ra is 6.725 nm and whole diamond average Ra is 3.25 nm.

Research on the Dynamic Model of Spindle Rotation Induced Error Compensation System of Boring and its Simulation

In this paper we address the dynamics of compensation cutting process from both Laplace s frequency domain and the time domain of the first time, using the two computer aided analyzing softwares: MATLAB and SIMULINK. Theoretical analysis and simulation experiments firstly show that not only the systematical stiffness of workpiece, spindle and tools, but also the regenerated coefficient affects the compensation displacement effect. The results show that the SREC is practicable in reality to decease the spindle induced errors in many engineering applications such as hard boring through simulation and the preliminary experiment results.

Study of the thermal influence on the dynamic characteristics of the motorized spindle system

The severe internal heat generation of the motorized spindle system causes uneven temperature dis- tribution, and will affect the vibration characteristics of the system. Based on the thermal analysis about the motorized spindle by finite element method （FEM）, the thermal deformations of the spindle system are calculated by the thermal structure coupling simulation, and the thermal deformations of the rotor and the bearing units are extracted to analyze the bearing stiffness changes so that the modal characteristics of the rotor can be simulated in different thermal state conditions. And then the rotor thermal deformation experiment and the modal experiment of spindle by exciting with hammer are performed. The result shows that the thermal state of the motorized spindle system has a significant influence on the natural frequency of the rotor, which can be carefully treated when a spindle system is designed.

Improved thermal resistance network model of motorized spindle system considering temperature variation of cooling system

In the motorized spindle system of a computer numerical control (CNC) machine tool, internal heat sources are formed during high-speed rotation;these cause thermal errors and affect the machining accuracy. To address this problem, in this study, a thermal resistance network model of the motorized spindle system is established based on the heat transfer theory. The heat balance equations of the critical thermal nodes are established according to this model with Kirchhoffs law. Then, they are solved using the Newmark-β method to obtain the temperature of each main component, and steady thermal analysis and transient thermal analysis of the motorized spindle system are performed. In order to obtain accurate thermal characteristics of the spindle system, the thermal conduction resistance of each component and the thermalconvection resistance between the cooling system and the components of the spindle system are accurately obtained considering the effect of the heat exchanger on the temperature of the coolant in the cooling system. Simultaneously, high-precision magnetic temperature sensors are used to detect the temperature variation of the spindle in the CNC machining center at different rotational speeds. The experimental results demonstrate that the thermal resistance network model can predict the temperature field distribution in the spindle system with reasonable accuracy. In addition, the influences of the rotational speed and cooling conditions on the temperature increase of the main components of the spindle system are analyzed. Finally, a few recommendations are provided to improve the thermal performance of the spindle system under different operational conditions.

Optimization of Bearing Locations for Maximizing First Mode Natural Frequency of Motorized Spindle-Bearing Systems Using a Genetic Algorithm

This paper has developed a genetic algorithm (GA) optimization approach to search for the optimal locations to install bearings on the motorized spindle shaft to maximize its first-mode natural frequency (FMNF). First, a finite element method (FEM) dynamic model of the spindle-bearing system is formulated, and by solving the eigenvalue problem derived from the equations of motion, the natural frequencies of the spindle system can be acquired. Next, the mathematical model is built, which includes the objective function to maximize FMNF and the constraints to limit the locations of the bearings with respect to the geometrical boundaries of the segments they located and the spacings between adjacent bearings. Then, the Sequential Decoding Process (SDP) GA is designed to accommodate the dependent characteristics of the constraints in the mathematical model. To verify the proposed SDP-GA optimization approach, a four-bearing installation optimazation problem of an illustrative spindle system is investigated. The results show that the SDP-GA provides well convergence for the optimization searching process. By applying design of experiments and analysis of variance, the optimal values of GA parameters are determined under a certain number restriction in executing the eigenvalue calculation subroutine. A linear regression equation is derived also to estimate necessary calculation efforts with respect to the specific quality of the optimization solution. From the results of this illustrative example, we can conclude that the proposed SDP-GA optimization approach is effective and efficient.

Research on Control System of Spindle Drive for High Speed Spinning Machine

Through analyzing the principle of spindle drive of winding mechanism for high speed spinning machine,the article not only describes a kind of mode of spindle drive for take-up motion on the basis of control method of constant velocity winding, but also introduces the design technique of software and hardware for the control system of mechatronics of spindle drive mode for take- up motion on the basis of constant velocity winding for high speed spinning machine with single-chip microcomputer. The mathematical model to describe the spindle rotating speed is established. It is an important technology for high speed spinning machine and provides a feasible application way.

THE ROLE OF BRAIN-STEM DISCENDING INHIBITORY SYSTEM IN THE ANTINOCICEPTIVE EFFECT ELICITED BY MUSCLE SPINDLE AFFERENTS

Objective To analyse the antinociceptive effect of muscle spindle afferents and the involved mechanism.Methods The single unit of wide dynamic range neurons in the spinal cord dorsal horn were recorded extracelluarly.The effects of muscle spindle afferents elicited by intravenous administration of succinylcholine on nociceptive responses (C fibres evoked responses,C responses) of WDR neurons were observed before and after bilateral lesions of ventrolateral periaqueduct gray .And the effects of muscle spindle afferents on the spontaneous discharge of the tail flick related cell in the rostral ventro medial medulla and on the spontaneous discharge of the PAG neurons were observed.Results The C responses of WDR neurons were significantly inhibited by muscle spindle afferents,and the inhibitory effects were reduced by bilateral lesions of ventrolateral PAG.The spontaneous discharge of the off cell in the RVM was excited while the on cell was inhibited by intravenous administration of Sch.The spontaneous discharge of the PAG neurons were excited by muscle spindle afferents.Conclusion Muscle spindle afferents show a distinct effect of antinociception.PAG RVM descending inhibitory system may play an important role in this nociceptive modulative mechanism.

Research on A Master - slave Multi - microcomputers Control System for Hollow Spindle Fancy Yarn Spinning Machine

In this paper, a successfully studied and developed master - slave muld - microcomputers control system based on PC - BUS for hollow spindle fancy yarn spinning machine, mainly Its overall scheme, software and hardware construction, is introduced. Spinning experiments show that the system achieves satisfactory result. This system can solve the diftkultles of mechatronical fusion between domestic hollow splndk fancy yarn spuming muchine and its microcomputer control technology.

Ensemble Model for Spindle Thermal Displacement Prediction of Machine Tools

Numerous factors affect the increased temperature of a machine tool, including prolonged and high-intensity usage,tool-workpiece interaction, mechanical friction, and elevated ambient temperatures, among others. Consequently,spindle thermal displacement occurs, and machining precision suffers. To prevent the errors caused by thetemperature rise of the Spindle fromaffecting the accuracy during themachining process, typically, the factory willwarm up themachine before themanufacturing process.However, if there is noway to understand the tool spindle’sthermal deformation, the machining quality will be greatly affected. In order to solve the above problem, thisstudy aims to predict the thermal displacement of the machine tool by using intelligent algorithms. In the practicalapplication, only a few temperature sensors are used to input the information into the prediction model for realtimethermal displacement prediction. This approach has greatly improved the quality of tool processing.However,each algorithm has different performances in different environments. In this study, an ensemble model is used tointegrate Long Short-TermMemory (LSTM) with Support VectorMachine (SVM). The experimental results showthat the prediction performance of LSTM-SVM is higher than that of other machine learning algorithms.

An Efficient Sleep Spindle Detection Algorithm Based on MP and LSBoost

Sleep spindles are an electroencephalogram(EEG)biomarker of non-rapid eye movement(NREM)sleep and have important implications for clinical diagnosis and prognosis.However,it is challenging to accurately detect sleep spindles due to the complexity of the human brain and the uncertainty of neural mechanisms.To improve the reliability and objectivity of sleep spindle detection and to compensate for the limitations of manual annotation,this study proposes a new automatic detection algorithm based on Matching Pursuit(MP)and Least Squares Boosting(LSBoost),where the automatic sleep spindle detection algorithm can help reduce the visual annotation workload of sleep clinicians.Specifically,MP is a time-frequency analysis method suitable for extracting spindle wave characteristics,which can accurately locate spindle waves on a time-frequency plane.LSBoost is an ensemble learning classification method to deal with unbalanced data.Initially,theMP method is used to search for EEG segments that are possible spindle waves from the filtered raw EEG data.Then,the designed feature segments are thrown into the LSBoost classifier to further identify the real spindles from all candidates and output the final results.The proposed method is verified on the common public dataset DREAMS.The experiment results showthat the sensitivity and F1-scores based on the sample-based assessments achieve 68.2% and 55.4%,respectively.Furthermore,the Recall and F1-score based on the event assessments are 83.8% and 70.8%,respectively.These results show that the proposed algorithm is robust to the subject changes in the DREAMS dataset.In addition,it improves the quality of sleep spindle detection,which is expected to assist the manual marking of experts.

High spindle and kinetochore-associated complex subunit-3 expression predicts poor prognosis and correlates with adverse immune infiltration in hepatocellular carcinoma

BACKGROUND Spindle and kinetochore-associated complex subunit 3(SKA3)is a malignancyassociated gene that plays a critical role in the regulation of chromosome separation and cell division.However,the molecular mechanism through which SKA3 regulates tumor cell proliferation in hepatocellular carcinoma(HCC)has not been fully elucidated.AIM To investigate the molecular mechanisms underlying the role of SKA3 in HCC.METHODS SKA3 expression,clinicopathological,and survival analyses were performed using multiple public database platforms,and the results were verified by Western blot and immunohistochemistry staining using collected clinical samples.Functional enrichment analyses were performed to evaluate the biological functions and molecular mechanisms of SKA3 in HCC.Furthermore,the Tumor Immune Estimation Resource and single-sample Gene Set Enrichment Analysis(ssGSEA)algorithms were utilized to investigate the abundance of tumor-infiltrating immune cells in HCC.The response to chemotherapeutic drugs was evaluated by the R package“pRRophetic”.RESULTS We found that upregulated SKA3 expression was significantly correlated with poor prognosis in patients with HCC.Multivariable Cox regression analysis indicated that SKA3 was an independent risk factor for survival.GSEA revealed that SKA3 expression may facilitate proliferation and migratory processes by regulating the cell cycle and DNA repair.Moreover,patients with high SKA3 expression had significantly decreased ratios of CD8+T cells,natural killer cells,and dendritic cells.Drug sensitivity analysis showed that the high SKA3 group was more sensitive to sorafenib,sunitinib,paclitaxel,doxorubicin,gemcitabine,and vx-680.CONCLUSION High SKA3 expression led to poor prognosis in patients with HCC by enhancing HCC proliferation and repressing immune cell infiltration surrounding HCC.SKA3 may be used as a biomarker for poor prognosis and as a therapeutic target in HCC.

Managing spindle cell sarcoma with surgery and high-intensity focused ultrasound:A case report

BACKGROUND Undifferentiated pleomorphic sarcomas,also known as spindle cell sarcomas,are a relatively uncommon subtype of soft tissue sarcomas in clinical practice.CASE SUMMARY We present a case report of a 69-year-old female patient who was diagnosed with undifferentiated spindle cell soft tissue sarcoma on her left thigh.Surgical excision was initially performed,but the patient experienced a local recurrence following multiple surgeries and radioactive particle implantations.High-intensity focused ultrasound(HIFU)was subsequently administered,resulting in complete ablation of the sarcoma without any significant complications other than bone damage at the treated site.However,approximately four months later,the patient experienced a broken lesion at the original location.After further diagnostic workup,the patient underwent additional surgery and is currently stable with a good quality of life.CONCLUSION HIFU has shown positive outcomes in achieving local control of limb spindle cell sarcoma,making it an effective non-invasive treatment option.

Spindle-view系统在猪卵母细胞去核中的应用

应用Spindle—view对体外成熟培养36、42、44和45h的猪体外成熟卵母细胞减数分裂纺锤体进行去核操作，并与传统去核方法（McGrath—Solter去核法，挤压去核法）相比较，结果表明：①在42～48h之间利用Spindle—view得到的猪卵纺锤体影像与极体的相对位置没有明显的变化；②Spindle—view适合用于猪体外成熟卵母细胞减数分裂纺锤体的观察及去核；去核效率与其他两种方法相比差异极显著（95．5％，42.1％，74．2％，P〈0．01）；③纺锤体成像是否清晰可用于猪卵母细胞的质量监控。

AUTOMATIC CONTROL OF REGENERATIVE CUTTING CHATTER BASED ON OPTIMAL REGULATION OF SPINDLE SPEED

An applicable method to control regenerative cutting chatter automatically based on the optimal regulation of spindle speed is introduced. The optimal value of the phase shift angle of the regenerative chatter signal between the two successive cuts is 270°. The cutting process can be adjusted from the unstable region to stable one whenever regenerative chatter occurs if the phase shift angle is kept 270° by the optimal regulation of spindle speed. The theoretical analysis and the experimental results prove that the optimal regulation of spindle speed can effectively control regenerative cutting chatter. In addition, a reliablelly optimal control system of reliable spindle speed is presented. There is no need for system identification of the machine tool, and it is easy to put this regenerative chatter control method into practice, so the method has excellent application prospect.