The Study of Reliability Modeling of Machining Center Based on Blocksim and Weibull++

There is often more than one failure at the same time when NC machine tools fails, but only one failure data is recorded which leads to that the reliability model of NC machine tools is not rational. In addition, the assumption of “repaired as good as new” for NC machine tools which consists of hydraulic, mechanic and other complicated subsystems is questionable and unreasonable. In this paper a method of reliability modeling using Blocksim and Weibull++ for NC machine tools is proposed. In the end, one example is provided and examined to show its potential applications and benefits. The result shows that the method of reliability modeling is more scientific and more in line with the practice.

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Reliability Modeling of NC Machine tools Based on Artificial Intelligence

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/435/1/012057 ◽

2018 ◽

Vol 435 ◽

pp. 012057

Author(s):

Guofa Li ◽

Hongxiang Zhu ◽

Jialong He ◽

Yongchao Huo ◽

Jiancheng Zhang

Keyword(s):

Artificial Intelligence ◽

Machine Tools ◽

Reliability Modeling ◽

Nc Machine ◽

Nc Machine Tools

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Enhancement of Motion Accuracy for Cone-Frustum Cutting Motion by Modified NC Program

Volume 4: Processes ◽

10.1115/msec2018-6557 ◽

2018 ◽

Author(s):

Kiichi Morishita ◽

Ryuta Sato ◽

Keiichi Shirase ◽

Isamu Nishida

Keyword(s):

Machine Tools ◽

Opposite Sign ◽

Accuracy Evaluation ◽

Error Vector ◽

Direction Error ◽

Dynamic Motion ◽

Machining Center ◽

Nc Program ◽

Nc Machine ◽

Nc Machine Tools

Motion accuracy of NC machine tools is directory copied onto the machined shape. However, it is known that the motion accuracy is deteriorated by several error courses; geometric and dynamic motion errors of feed axes. In this study, in order to enhance the motion accuracy of NC machine tools, a method that modifies the NC program based on the normal direction error at each command point on the designed path is developed. In the method, the error vector between the commanded and estimated machined shape is obtained. The NC program for the motion is modified by adding the obtained error vector with the opposite sign. In order to confirm the effectiveness of the proposed method, 5-axis motion tests for cone-frustum cutting which is widely applied to the accuracy evaluation of 5-axis machining centers are carried out. At the first, it is confirmed that the proposed method can compensate the dynamic synchronous errors based on the feedback positions and angles of the axes. In addition, it is also confirmed that the proposed method can compensate both of dynamic and geometric errors based on the tool center point trajectory measured by a ball-bar system. As the results, it is clarified that the proposed method can effectively enhance the motion accuracy of the 5-axis machining center.

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A Reliability Analysis of NC Machine Tools Based on the Weibull Distribution

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.741.763 ◽

2015 ◽

Vol 741 ◽

pp. 763-767

Author(s):

Hui Liang Li

Keyword(s):

Weibull Distribution ◽

Machine Tool ◽

Machine Tools ◽

Interval Estimation ◽

Point Estimation ◽

Numerical Control ◽

Control Machine Tool ◽

Failure Data ◽

Nc Machine ◽

Nc Machine Tools

In this paper, a series of numerical control machine tool truncated failure data collect.The data are assumed to be two parameter weibull distribution and related parameters is obtained and relevant inspection and test of hypothesis, it is concluded that the mathematical model of batch of nc machine tool failure interval time distribution.Relevant indicators to determine the reliability of nc machine tools, machine tool's observations, Machine tool observations, point estimation and interval estimation index value provide a theoretical basis for the research on reliability of machine tool.

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Study on Spindle Thermal Field Distribution and Thermal Errors of Horizontal Machine Tool

Materials Science Forum ◽

10.4028/www.scientific.net/msf.697-698.273 ◽

2011 ◽

Vol 697-698 ◽

pp. 273-276 ◽

Cited By ~ 1

Author(s):

X.B. Ma ◽

Jian Qiu ◽

Qi Wei Liu ◽

J.F. Lin

Keyword(s):

Temperature Distribution ◽

Field Distribution ◽

Machine Tools ◽

Thermal Field ◽

Infrared Imaging ◽

Positioning Error ◽

Thermal Errors ◽

Machining Center ◽

Nc Machine ◽

Nc Machine Tools

Research on thermal field and thermal errors of NC machine tools were carried on using infrared imaging and laser distance measurement technologies. It mainly focused on the analysis of thermal field distribution of a three-axis horizontal machining center and the relationships between thermal behaviors and their temperatures. It was found experimentally that spindle thermal errors is one of the main errors sources of NC machine tools, and spindle thermal errors has been observed to be closely linked to the temperature distribution of machine tools. There was a significant increase in the axis positioning error related to the spindle temperature increasing. The elongations on Z direction are much larger than the extensions of X and Y directions. Finally, a method by adjusting spindle temperature to control spindle thermal errors was taken.

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Reliability Analysis Based on Improved Bayes Method of AMSAA Model

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.482-484.2336 ◽

2012 ◽

Vol 482-484 ◽

pp. 2336-2340

Author(s):

Yang Qiang ◽

Lei Zhang ◽

Zhi Li Sun ◽

Yi Liu ◽

Xue Bin Bai

Keyword(s):

Reliability Analysis ◽

Machine Tools ◽

Interval Estimation ◽

Point Estimation ◽

Life Data ◽

Failure Data ◽

Amsaa Model ◽

Nc Machine ◽

Nc Machine Tools ◽

Five Axis

Aiming at the defects that failure samples of five-axis NC machine tools is small, traditional reliability analysis is not accurate, this paper presents reliability analysis mode based on improved Bayesian method for AMSAA model. Firstly, we obtain the failure model of NC machine tools meets the AMSAA model according to goodness-of-fit test, and in order to meet the requirements of simplifying engineering calculations, this paper adpots a method of Coefficient equivalent which converts failure Data into index-life data; then using Bayesian methods to estimate reliability parameters for the Index-life data; for the last we proceed point estimation and interval estimation for the MTBF of the machine. Take High-speed five-axis NC machine tools t of VMC650m for example, the result proved that the method can take advantage of a small sample of the equipment to proceed point estimation and interval estimation for MTBF failure data, and provide a reference for the optimization of maintenance strategies and Diagnostic work of the NC machine tools.

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Bayesian zero-failure reliability modeling and assessment method for multiple numerical control (NC) machine tools

Journal of Central South University ◽

10.1007/s11771-016-3349-9 ◽

2016 ◽

Vol 23 (11) ◽

pp. 2858-2866 ◽

Cited By ~ 6

Author(s):

Ying-nan Kan ◽

Zhao-jun Yang ◽

Guo-fa Li ◽

Jia-long He ◽

Yan-kun Wang ◽

...

Keyword(s):

Machine Tools ◽

Assessment Method ◽

Numerical Control ◽

Reliability Modeling ◽

Nc Machine ◽

Nc Machine Tools

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Reliability Modeling on Time between Failures of NC Machine Tools

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1028.145 ◽

2014 ◽

Vol 1028 ◽

pp. 145-150

Author(s):

Yu Xia Xue ◽

Wen Xu ◽

Jun Hong Li

Keyword(s):

Machine Tool ◽

Machine Tools ◽

Optimization Method ◽

Cnc Machine ◽

Reliability Modeling ◽

Nc Machine Tool ◽

Time Between Failures ◽

Nc Machine ◽

Coefficient Optimization ◽

Nc Machine Tools

A reliability modeling method is proposed based on the time between failures of NC machine tools. According to the field data of the time between failures of a certain type of NC machine tools, parameter estimation of reliability model is made by use of particle swarm optimization (PSO)-based correlation coefficient optimization method, and it is proved that time between failure of CNC machine tool obeyed mathematical model of 3-parameter Weibull distribution via hypothesis testing. This provides the basis for reliability assessment of NC machine tool as well as the development of maintenance strategy in the future. Meanwhile, it also provides a theoretical reference for the reliability prediction of the whole NC machine tool.

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Application of three-parameter Weibull mixture model for reliability assessment of NC machine tools: a case study

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406211404298 ◽

2011 ◽

Vol 225 (11) ◽

pp. 2718-2726 ◽

Cited By ~ 14

Author(s):

Z Wang ◽

J Yang ◽

G Wang ◽

G Zhang

Keyword(s):

Mixture Model ◽

Machine Tools ◽

Failure Modes ◽

Reliability Assessment ◽

Information Criterion ◽

Numerical Control ◽

Failure Data ◽

Nc Machine ◽

Nc Machine Tools

To analyse the reliability of numerical control (NC) machine tools, a three-parameter Weibull mixture model is proposed in this case study. Negative log-likelihood function is used as an optimal objective instead of solving complex system of equations; the problem of parameter estimation of mixture model is solved by a non-linear programming method. A comprehensive criteria, which include Akaike information criterion, Bayesian information criterion, and root mean squared error, is presented for selecting the number of components of mixture model. The field failure data of three NC machine tools are analysed and the results of reliability assessment, such as the reliability, maintainability, availability, etc., are all presented. The results show that the mixture model of three-parameter Weibull distribution, with advantages over other Weibull models, is suitable for modelling failure data of multiple NC machine tools with multiple failure modes and causes.

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