scholarly journals Reliability Evaluation of CNC Machine Tools Considering Competing Failures of Fault Failure Data and Machining Accuracy Degradation Data

2021 ◽  
Author(s):  
Cong Feng ◽  
Zhaojun Yang ◽  
Chuanhai Chen ◽  
Jinyan Guo ◽  
Jiangong Leng ◽  
...  
Keyword(s):  
Machine Tools ◽  
Failure Modes ◽  
Reliability Evaluation ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Failure Model ◽  
Cnc Machine ◽  
Failure Data ◽  
Degradation Data ◽  
Degradation Failure

Abstract Traditional reliability evaluation of CNC machine tools usually considers a single failure mode of fault failure or degradation failure, or considers fault failure and degradation failure to be independent of each other. However, in the actual working conditions, fault failure and degradation failure are mutually affected, and the reliability evaluation of the competing failure models of CNC machine tools by considering the two failure modes comprehensively can get more accurate evaluation results. Therefore, this paper proposes a reliability evaluation method for CNC machine tools considering fault failure data competing with machining accuracy degradation data. A fault failure model of CNC machine tools is established based on a non-homogeneous Poisson process. The fault failure model is updated according to the different effects of each maintenance result of the failure on machining accuracy. By integrating multiple geometric errors of CNC machine tools through multi-body system theory, the amount of machining accuracy degradation is extracted. A machining accuracy degradation failure model is established using the Wiener process. Considering the correlation between fault failure and degradation failure, a competing failure model based on the Coupla function is developed for evaluating the reliability of CNC machine tools. Finally, the effectiveness of the proposed method is verified by example analysis.

Applied Research on Reliability Evaluation of CNC Machine Tools Based on D-S Evidence Theory

2013 ◽  
Vol 446-447 ◽  
pp. 645-649
Author(s):  
Jie Yu ◽  
Wu Sheng Tang ◽  
Ting Ting Wang ◽  
Qiao Chan Li ◽  
Zhan Guo Li
Keyword(s):  
Machine Tools ◽  
Evidence Theory ◽  
Reliability Evaluation ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Production Cycle ◽  
Scientific Policy ◽  
Cnc Machine ◽  
Control Machine

Reliability is most important to the CNC machine tools and reliability estimation is a very important part of the reliability which has magnificence to allocate resources and put forward scientific policy. Reliability evaluation of computer numerical control machine tools can use all sorts of effective information to decrease the size of test samples and save the development costs and shorten the production cycle. The paper put forward to use D-S evidence theory and the information of experts system to decrease the uncertainty of the reliability evaluation of computer numerical control machine tools. The results show that the method can effectively decrease the uncertainty of the reliability evaluation of computer numerical control machine tools.

Reliability Analysis about A/C-Axis of Woodworking Five-Axis Milling Head

2014 ◽  
Vol 635-637 ◽  
pp. 407-410
Author(s):  
Shuang Yong Wang ◽  
Wei Zhang ◽  
Qian Wei Zhang ◽  
Jian Hua Yang ◽  
Peng Fei Zhang
Keyword(s):  
Theoretical Analysis ◽  
Reliability Analysis ◽  
Machine Tools ◽  
Theoretical Basis ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Cnc Machine ◽  
Core Feature ◽  
Drive Motor ◽  
Five Axis

As a core feature of high-end CNC machine tools, the torque carrying performance of five-axis milling head directly affects the machining accuracy and reliability. Through theoretical analysis and derivation, combining experimental prototype, the A/C-axis cutting torque formula of five-axis milling head on woodworking is obtained. The reliability analysis provides a theoretical basis for drive motor selection and five-axis milling head structural optimization and improvement.

Applied Research on Cmsr Method Used in Reliability Evaluation of the CNC Machine Tools

2013 ◽  
Vol 13 (22) ◽  
pp. 5284-5286 ◽  
Author(s):  
Jie Yu ◽  
Hai-Long Zhang ◽  
Wu-sheng Tang ◽  
Ting-ting Wang ◽  
Zhan-guo Li ◽  
...  
Keyword(s):  
Machine Tools ◽  
Applied Research ◽  
Reliability Evaluation ◽  
Cnc Machine Tools ◽  
Cnc Machine

scholarly journals Analysis of Nonlinear Error Caused by Motions of Rotation Axes for Five-Axis Machine Tools with Orthogonal Configuration

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Cong Geng ◽  
Yuhou Wu ◽  
Jian Qiu
Keyword(s):  
Machine Tools ◽  
Cnc Machine Tools ◽  
Reference Plane ◽  
Maximum Deviation ◽  
Machining Accuracy ◽  
Cnc Machine ◽  
Nonlinear Error ◽  
Rotation Axes ◽  
Five Axis ◽  
The Relationship

Since a nonlinear relationship exists between the position coordinates of the rotation axes and components of the tool orientation, the tool will deviate from the required plane, resulting in nonlinear errors and deterioration of machining accuracy. Few attempts have been made to obtain a general formula and common rules for nonlinear error because of the existence of various kinematic structures of machine tools with orthogonal configuration. This paper analyzes the relationship between the deviation of cutter location points and motion of tool orientations. Five-axis CNC machine tools are divided into two groups according to the configuration of the two rotational joints and the home position. Motions of the tool are regarded as a combination of translation and rotation. A model for error calculation is then built. The maximum deviation of the tool with respect to the reference plane generated by the initial and the final orientation is used to quantify the magnitude of the errors. General formulas are derived and common change rules are analyzed. Finally, machining experiment is conducted to validate the theoretical analysis. The research has important implications on the selection of a particular kinematic configuration that may achieve higher accuracy for a specific machining task.

Research of On-Line Monitoring Technology of Machining Accuracy of CNC Machine Tools

2013 ◽  
Vol 846-847 ◽  
pp. 268-273
Author(s):  
Rong Bo Shi ◽  
Zhi Ping Guo ◽  
Zhi Yong Song
Keyword(s):  
Neural Network ◽  
Machine Tools ◽  
Cnc Machine Tools ◽  
Frequency Domain Method ◽  
Machining Accuracy ◽  
Cnc Machine ◽  
Monitoring Technology ◽  
The Neural Network ◽  
Network Identification ◽  
On Line

This paper analyzes CNC machine tools machining error sources, put forward a kind of on-line monitoring technology of CNC machine tools machining accuracy based on online neural network. Through the establishment of CNC machine tools condition monitoring platform, collection sensor signal of the key components of CNC machine tools, using time domain and frequency domain method of the original signal processing, extract the characteristic related to machining accuracy change, input to the neural network, identification the changes of machining accuracy. The experimental results show that, the on-line monitoring technology based on neural network, can identify the changes of machining accuracy.

scholarly journals Accelerated Life Reliability Evaluation of Grating Ruler for CNC Machine Tools Based on Competing Risk Model and Incomplete Data

2021 ◽  
Author(s):  
Haiji Yang ◽  
Guofa Li ◽  
Jialong He ◽  
Yupeng Ma ◽  
Liding Wang ◽  
...  
Keyword(s):  
Incomplete Data ◽  
Machine Tools ◽  
Risk Model ◽  
Distribution Model ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Life Test ◽  
Life Distribution ◽  
Failure Data ◽  
Accelerated Life

Abstract Grating ruler is the high-precision linear displacement sensor used in the servo control system of CNC machine tools. It is one of the key components affecting the machining accuracy of CNC machine tools. Due to the long life-time of grating ruler, and it will cost a lot of time and resources to evaluate its reliability level by traditional life test. At the same time, there are some incomplete data in the failure data, which will cause inaccurate evaluation results. In this paper, an accelerated life reliability evaluation method of grating ruler based on competing risk model and incomplete data is proposed. Firstly, according to the characteristics of grating ruler, the life distribution model based on competitive risk is established, and the representation method and conversion method of failure data considering incomplete data are proposed. Secondly, the accelerated life test system which can apply temperature and humidity accelerated stress is built, and the reliability level of JFT series closed absolute grating ruler is evaluated by the proposed method. Finally, the proposed method is compared with the single life distribution model to verify the effectiveness.

scholarly journals Enhancing machining accuracy reliability of multi-axis CNC machine tools using an advanced importance sampling method

2021 ◽  
Vol 23 (3) ◽  
pp. 559-568
Author(s):  
Zhiming Wang ◽  
Hao Yuan
Keyword(s):  
Importance Sampling ◽  
Machine Tools ◽  
Sampling Method ◽  
Great Influence ◽  
Error Model ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Cnc Machine ◽  
Importance Sampling Method ◽  
Comprehensive Error Model

The purpose of this paper is to propose a general precision allocation method to improve machining performance of CNC machine tools based on certain design requirements. A comprehensive error model of machine tools is established by using the differential motion relation of coordinate frames. Based on the comprehensive error model, a reliability model is established by updating the primary reliability with an advanced importance sampling method, which is used to predict the machining accuracy reliability of machine tools. Besides, to identify and optimize geometric error parameters which have a great influence on machining accuracy reliability of machine tools, the sensitivity analysis of machining accuracy is carried out by improved first-order second-moment method. Taking a large CNC gantry guide rail grinder as an example, the optimization results show that the method is effective and can realize reliability optimization of machining accuracy.

scholarly journals The Use of Response Surface Methodology to Optimize Parameter Adjustments in CNC Machine Tools

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Shao-Hsien Chen ◽  
Wern-Dare Jehng ◽  
Yen-Sheng Chen
Keyword(s):  
Regression Analysis ◽  
Response Surface ◽  
Machine Tools ◽  
Cnc Machine Tools ◽  
Contour Plot ◽  
Machining Accuracy ◽  
Analysis Method ◽  
Cnc Machine ◽  
Acceleration And Deceleration ◽  
Feed Axis

This paper mainly covers a research intended to improve the circular accuracy of CNC machine tools and the adjustment and analysis of the main controller parameters applied to improve accuracy. In this study, controller analysis software was used to detect the adjustment status of the servo parameters of the feed axis. According to the FANUC parameter manual, the parameter address, frequency, response measurements, and the one-fourth corner acceleration and deceleration measurements of the machine tools were adjusted. The experimental design (DOE) was adopted in this study for taking circular measurements and engaging in the planning and selection of important parameter data. The Minitab R15 software was adopted to predict the experimental data analysis, while the seminormal probability map, Plato, and analysis of variance (ANOVA) were adopted to determine the impacts of the significant parameter factors and the interactions among them. Additionally, based on the response surface map and contour plot, the optimal values were obtained. In addition, comparison and verification were conducted through the Taguchi method, regression analysis to improved machining accuracy and efficiency. The unadjusted error was 7.8 μm; through the regression analysis method, the error was 5.8 μm and through the Taguchi analysis method, the error was 6.4 μm.

Sign in / Sign up

Export Citation Format

Share Document