Chatter prevention and improved finish of workpiece for a milling process

2009 ◽  
Vol 224 (4) ◽  
pp. 579-588 ◽  
Author(s):  
N-C Tsai ◽  
D-C Chen ◽  
R-M Lee
Keyword(s):  
Real Time ◽  
Acoustic Signal ◽  
Milling Process ◽  
Spindle Motor ◽  
Spindle Speed ◽  
Feedback Signal ◽  
Motor Speed ◽  
Acoustic Feedback ◽  
The Stability ◽  
Milling Chatter

This paper presents how real-time chatter prevention can be realized by feedback of an acoustic cutting signal. The efficacy of the proposed adaptive spindle speed tuning algorithm is verified by intensive experimental simulations. A pair of microphones, perpendicular to each other, is used to acquire the acoustic cutting signal resulting from milling chatter. A real-time feedback control loop is constructed for spindle speed compensation in such a way to ensure that the milling process is within the stability zone of the stability lobe diagram. The acoustic chatter signal index (ACSI) and the spindle speed compensation strategy (SSCS) are proposed to quantify the acoustic signal and actively to tune the spindle speed respectively. By converting the acoustic feedback signal into the ACSI, an appropriate spindle speed compensation rate (SSCR) can be determined by the SSCS based on a real-time chatter level or the ACSI. Accordingly, the compensation command, referred to as added-on voltage (AOV), is applied to increase/decrease the spindle motor speed. By employing the commercial software MATLAB/Simulink and the dSpace DS1104 interface module to implement the controller, the proposed chatter prevention algorithm is practically verified by intensive experiments. By inspection on the precision and quality of the workpiece surface after milling, the efficacy of the real-time chatter prevention strategy via acoustic signal feedback is further assured.

scholarly journals Stability Analysis of Milling Process with Variable Spindle Speed and Pitch Angle considering Helix Angle and Process Phase Difference

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Gang Jin ◽  
Haotian Jiang ◽  
Jianxin Han ◽  
Zhanjie Li ◽  
Hua Li ◽  
...  
Keyword(s):  
Phase Difference ◽  
Pitch Angle ◽  
High Speed ◽  
Helix Angle ◽  
Stability Domain ◽  
Milling Process ◽  
Spindle Speed ◽  
The Stability ◽  
The Time Domain ◽  
Milling Chatter

Suppression of milling chatter by disrupting regenerative effect is a well-known method to obtain higher cutting stability domain. In this paper, a dynamic model of the milling process with variable spindle speed and pitch angle considering helix angle and process phase difference is presented. Then, an updated semidiscretization method is applied to obtain the stability chart. After the effectiveness of the proposed method is confirmed by comparisons with the previously published works and the time-domain simulations, lots of analyses are conducted to deeply evaluate the influence of the helix angle, the process phase difference, and feed per tooth on milling stability. Results show that the change of helix angle can result in significant stability discrepancies for both high-speed and low-speed regions. Though the process phase difference has the randomness and immeasurability in the practical application, it has an important influence on the stability and will result in a periodic evolution of the stability with a period π. Also, its recommended values are given for the practical milling process.

The Dynamic Analysis of Micro-Scale Edge in the Process of Micromilling

2013 ◽  
Vol 797 ◽  
pp. 628-637
Author(s):  
Ya Dong Gong ◽  
Jin Feng Zhang ◽  
Jun Cheng ◽  
Xue Long Wen ◽  
Chao Wang ◽  
...  
Keyword(s):  
Fourier Method ◽  
Milling Process ◽  
Spindle Speed ◽  
Micro Milling ◽  
Theoretical Research ◽  
Actual Case ◽  
Micro Scale ◽  
Machined Parts ◽  
Micro Tool ◽  
Milling Chatter

The micro-processing technology has gradually become a hot topic problem, especially in micro-scale milling chatter prevention with the development of the information age. In allusion to the actual case of micro-milling, the dynamic theoretical research is analyzed in-depth about the Fourier method and the average tooth angle method. Compared to two ways, the former is close to the actual processing requirements. The lobes are obtained use the two ways. Micro milling parameters are selected in the stable area and unstable region. Stable and non-stable curve and surface quality of machined parts are obtained after micro-milling test. The chatter points, non-chatter point and uncertain point are obtained in the high spindle speed, which are consistent with theoretical analysis. In contrast, the distribution of chatter points in the low-speed spindle speed. The reason is that the damping effect is produced in the micro-scale milling process. The research of micro-scale milling chatter, which has a certain significance to improve parts of precision machined parts, reduce the wear and tear of the micro-milling blade and extend micro-tool life.

Time Domain Simulation of Milling Chatter Stability

2016 ◽  
Vol 836-837 ◽  
pp. 94-98 ◽  
Author(s):  
Ying Chao Ma ◽  
Min Wan ◽  
Wei Hong Zhang
Keyword(s):  
Time Domain ◽  
Chip Thickness ◽  
Time Algorithm ◽  
Milling Process ◽  
Time Domain Simulation ◽  
Chatter Stability ◽  
Stability Lobe ◽  
Machining System ◽  
The Stability ◽  
Milling Chatter

In this paper, time domain simulation has been carried out to study the chatter stability of milling process. Dynamic chip thickness is calculated by analyzing the kinematics of the cutter, and thus dynamic governing equation revealing the dynamic behaviors between the cutter and workpiece is established. Solving framework is constructed by using the Simulink module and S-Function of Matlab software, and dynamic deflection is achieved with the four-order Runge-Kutta algorithm. With the simulated cutting forces, a criterion for the construction of the stability lobe is suggested. At the same time, algorithm for the prediction of the surface topography involving the dynamic response of the machining system is developed.

Investigation on Adaptive Filter for On-Line Detection and Active Control of Chatter Vibration in Milling Process

2019 ◽  
Author(s):  
Shaoke Wan ◽  
Xiaohu Li ◽  
Wenjun Su ◽  
Jun Hong
Keyword(s):  
Active Control ◽  
Adaptive Filter ◽  
Rotation Frequency ◽  
Milling Process ◽  
Spindle Speed ◽  
Line Detection ◽  
Spindle Rotation ◽  
On Line ◽  
Milling Chatter ◽  
Periodic Components

Abstract On-line detection and active control of chatter vibration have always been important issues in milling process respectively. To some extent, the signals obtained with sensors determine the performance of on-line detection and active control of chatter. However, due to the characteristics of milling process, the obtained signals are mainly consisted with spindle rotation frequency and its harmonics, and the chatter components are usually submerged by these stable harmonics, imposing negative effects for the detection and active control of milling chatter. Then, it is highly needed to design a real-time filter to filter out the spindle rotation frequency and its harmonics. In this paper, an adaptive filter is designed to filter out the spindle speed related components. Moving average (MR) model and adaptive filter theory is utilized to estimate these periodic components. The influence of filter order and step size factor on the filter characteristics are also analyzed. Considering that the filter order needs to be adjusted under different cutting conditions, which will alter the filter’s performance, an improved adaptive filter is proposed. Experiments are also performed and the experimental results show that, not only the spindle speed related components can be filtered out effectively, but the chatter frequency components are amplified with appropriate initial step factor, which is beneficial for the detection of milling chatter at early stage. Meanwhile, the periodic components caused by the installation error and the other spindle speed related components can be effectively filtered out real-timely, preventing the saturation of actuator caused by these stable components.

Study on Online Intelligent Control of Cutting Vibration in Milling Process

2011 ◽  
Vol 42 (10) ◽  
pp. 75-80
Author(s):  
Fu Hongya ◽  
Li Maoyue ◽  
Liu Yuan ◽  
Han Zhenyu
Keyword(s):  
Real Time ◽  
Vibration Amplitude ◽  
Milling Process ◽  
Spindle Speed ◽  
Open Architecture ◽  
Work Piece ◽  
Machining Parameters ◽  
Constraint Condition ◽  
Cutting Vibration ◽  
The Right

To realize online and real-time suppressing vibration amplitude in milling, an open architecture intelligent controller is designed and developed, which is modular and can achieve machining parameters' online adjustment based on acceleration constraint condition. According to the idea of the velocity control, a spindle speed control model is constructed. This controller can realize both the right codes translation and assume the effective coordination and synchronization among the thread of adaptive control, interface display and interpolation and so on. A series of fuzzy control rules have been designed to reduce the vibration amplitude about stepped-weir work-piece, and some actual experiments based on acceleration constraints have been also completed. The results show the open architecture variable spindle speed controller can be used in the practical machining, and the spindle speed can realize online real-time adjustment based on the acceleration constraint condition. All these technologies can effectively suppress the cutting vibration, which protect the machine and work-piece tool system.

Stability Analysis of a Variable Spindle Speed Milling Process

2005 ◽  
Author(s):  
X.-H. Long ◽  
B. Balachandran
Keyword(s):  
Milling Process ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Infinite Dimensional ◽  
Dimensional Matrix ◽  
Finite Dimensional ◽  
Milling Operations ◽  
Milling Operation ◽  
The Stability ◽  
Delay Differential

In this effort, a stability treatment is presented for a milling process with a variable spindle speed (VSS). This variation is caused by superimposing a sinusoidal modulation on a nominal spindle speed. The dynamics of the VSS milling process is described by a set of delay differential equations (DDEs) with time varying periodic coefficients and a time delay. A semi-discretization scheme is used to discretize the system over one period, and the infinite dimensional transition matrix is converted to a finite dimensional matrix over this period. The eigenvalues of this finite dimensional matrix are used to determine the stability of the VSS milling operation with respect to selected control parameters, such as the axis depth of cut and the nominal spindle speed. The benefits of VSS milling operations are discussed by comparing the stability charts obtained for VSS milling operations with those obtained for constant spindle speed (CSS) milling operations.

Stability Prediction in High-Speed Milling Process Considering the Milling Force Coefficients Dependent on the Spindle Speed

2014 ◽  
Vol 13 (04) ◽  
pp. 247-255 ◽  
Author(s):  
Kunlong Wen ◽  
Houjun Qi ◽  
Gang Jin
Keyword(s):  
High Speed ◽  
Milling Process ◽  
Spindle Speed ◽  
Chatter Vibration ◽  
Milling Force ◽  
High Speed Milling ◽  
Force Coefficients ◽  
Stability Lobe ◽  
Vibration Model ◽  
The Stability

In order to further research the chatter vibration in high-speed milling, in this paper, a new regenerative chatter vibration model, considering the effect of milling force coefficients dependent on the spindle speed (MFCDSS) on the stability of high-speed milling process is proposed, and then milling stability lobe diagram is obtained, based on full-discretization method (FDM). The variable tendency of the stability of milling system is analyzed by comparisons in case of different radial immersion ratios in low-speed and high-speed milling regions, respectively. It is found that great stability predicting differences occur, especially in high-speed region when the MFCDSS is considered. This model can further supplement the theory of stability of high-speed milling process, it has certain engineering guidance significance in the selection of high-speed milling parameters.

scholarly journals Stability of Milling Process with Variable Spindle Speed Using Runge–Kutta-Based Complete Method

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shujie Lv ◽  
Yang Zhao
Keyword(s):  
Removal Rate ◽  
Modulation Frequency ◽  
Milling Process ◽  
Spindle Speed ◽  
Calculation Time ◽  
Time Varying Delay ◽  
Speed Modulation ◽  
Runge Kutta ◽  
The Stability ◽  
Delay Differential

The variable-spindle-speed (VSS) technique is effective in preventing regenerative chatter in milling processes. However, spindle-speed-modulation parameters should be deliberately selected to augment the material removal rate. Stability-prediction algorithms of stability predicting play an important role in this respect, as they allow the prediction of stability for all ranges of a given spindle speed. The increase in calculation time in variable-spindle-speed milling, which is caused by the modulation frequency, hinders its practical use in the workshop. In this paper, a Runge–Kutta-based complete discretization method (RKCDM) is presented to predict the stability of milling with variable spindle speeds, which is described by a set of delay differential equations (DDEs) with time-periodic coefficients and time-varying delay. The convergence and calculation efficiency are compared with those of the semidiscretization method (SDM) under different testing configurations and milling conditions. Results show that RKCDM is more accurate and saves at least 50% of the calculation time of SDM. The effects of modulation parameters on the stability of VSS milling are explored through stability lobe diagrams produced from RKCDM.

RPS24c Isoform Facilitates Tumor Angiogenesis Via Promoting the Stability of MVIH in Colorectal Cancer

2020 ◽  
Vol 20 (5) ◽  
pp. 388-395 ◽  
Author(s):  
Yue Wang ◽  
Youjun Wu ◽  
Kun Xiao ◽  
Yingjie Zhao ◽  
Gang Lv ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Ribosomal Protein ◽  
Real Time ◽  
Tumor Angiogenesis ◽  
Real Time Pcr ◽  
Molecular Mechanisms ◽  
Migration And Invasion ◽  
Binding Interaction ◽  
Tubule Formation ◽  
The Stability

Background: Colorectal cancer (CRC) is the second leading cause of death worldwide, and distant metastasis is responsible for the poor prognosis in patients with advanced-stage CRC. RPS24 (ribosomal protein S24) as a ribosomal protein, multiple transcript variant encoding different isoforms have been found for this gene. Our previous studies have demonstrated that RPS24 is overexpressed in CRC. However, the mechanisms underlying the role of RPS24 in tumor development have not been fully defined. Methods: Expression of RPS24 isoforms and lncRNA MVIH in CRC tissues and cell lines were quantified by real-time PCR or western blotting assay. Endothelial tube formation assay was performed to determine the effect of RPS24 on tumor angiogenesis. The cell viability of HUVEC was determined by MTT assay, and the migration and invasion ability of HUVEC were detected by transwell assay. PGK1 secretion was tested with a specific ELISA kit. Results: Here, we found that RPS24c isoform was a major contributor to tumor angiogenesis, a vital process in tumor growth and metastasis. Real-time PCR revealed that RPS24c isoform was highly expressed in CRC tissues, while other isoforms are present in both normal and CRC tissues with no statistical difference. Moreover the change of RPS24 protein level is mainly due to the fluctuation of RPS24c. Furthermore, we observed that silencing RPS24c could decrease angiogenesis by inhibiting tubule formation, HUVEC cell proliferation and migration. Additionally, we investigated the molecular mechanisms and demonstrated that RPS24c mRNA interacted with lncRNA MVIH, the binding-interaction enhanced the stability of each other, thereby activated angiogenesis by inhibiting the secretion of PGK1. Conclusion: RPS24c facilitates tumor angiogenesis via the RPS24c/MVIH/PGK1 pathway in CRC. RPS24c inhibition may be a novel option for anti-vascular treatment in CRC.

scholarly journals Underground Microseismic Event Monitoring and Localization within Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2830
Author(s):  
Sili Wang ◽  
Mark P. Panning ◽  
Steven D. Vance ◽  
Wenzhan Song
Keyword(s):  
Sensor Networks ◽  
Real Time ◽  
Information Needs ◽  
Localization Algorithm ◽  
Distributed Sensors ◽  
Distributed Sensor ◽  
Microseismic Events ◽  
The Stability ◽  
Stability And Accuracy

Locating underground microseismic events is important for monitoring subsurface activity and understanding the planetary subsurface evolution. Due to bandwidth limitations, especially in applications involving planetarily-distributed sensor networks, networks should be designed to perform the localization algorithm in-situ, so that only the source location information needs to be sent out, not the raw data. In this paper, we propose a decentralized Gaussian beam time-reverse imaging (GB-TRI) algorithm that can be incorporated to the distributed sensors to detect and locate underground microseismic events with reduced usage of computational resources and communication bandwidth of the network. After the in-situ distributed computation, the final real-time location result is generated and delivered. We used a real-time simulation platform to test the performance of the system. We also evaluated the stability and accuracy of our proposed GB-TRI localization algorithm using extensive experiments and tests.

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