Reliability Analysis Based on Improved Bayes Method of AMSAA Model

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.

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

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.

scholarly journals Reliability Parameter Interval Estimation of NC Machine Tools considering Working Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Li Hongzhou ◽  
Sun Lixia
Keyword(s):  
Working Conditions ◽  
Machine Tools ◽  
Estimation Method ◽  
Interval Estimation ◽  
Point Estimation ◽  
Test Field ◽  
Reliability Parameter ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Parameter Interval

Aiming at the problem that the parameter interval estimation of NC machine tool’s reliability model considering working conditions established by Hongzhou is difficult to implement, given that it has several independent variables, an improved interval estimation method based on Bootstrap is proposed. Firstly, the two-step estimation method was used to calculate the point estimation of NC machine tool’s reliability parameter in test field, based on which B resamplings are generated based on the point estimation. The reliability parameter’s point estimation of the resamplings was obtained by maximum likelihood estimation. Permutation of B point estimations was made in ascending order and the interval estimations were obtained by the α quantile of the permutation. Case study indicated that the location and length of the interval estimation of NC machine tools’ reliability parameter, under different levels of working condition covariates, vary obviously.

scholarly journals Development of Motion Accuracy Measurement Method of Five Axis NC Machine Tools with ISO230-4

2006 ◽  
Vol 72 (7) ◽  
pp. 873-877
Author(s):  
Masaki USHIO ◽  
Norifumi KURMAE ◽  
Masahide KOUYA ◽  
Hiroyuki NARAHARA ◽  
Hiroyuki KORESAWA ◽  
...  
Keyword(s):  
Machine Tools ◽  
Measurement Method ◽  
Accuracy Measurement ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Five Axis

A novel approach to calculating the dynamic error reflected on an S-shaped test piece

2020 ◽  
pp. 095440622096215
Author(s):  
Weiwei He ◽  
Liping Wang ◽  
Liwen Guan
Keyword(s):  
Test Piece ◽  
Machine Tools ◽  
Dynamic Error ◽  
Dynamic Performance ◽  
Error Distribution ◽  
Feed System ◽  
Test Pieces ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Five Axis

This paper proposes a novel approach to calculating the dynamic error distribution reflected on an S-shaped test piece. First, a numerical model of an S-shaped test piece is established, and the distribution characteristics for the twist angle and curvature are analysed. Second, a delay continuous method (DCM), which can transform the discrete input into a delayed step input, is presented to express the single-axis dynamic error affected by the input quantitatively in the form of a mathematical expression. Based on the sinusoidal input, the feasibility of the DCM is verified by comparing the experimental results of a Simulink simulation model and a mathematical expression derived by the DCM. Third, according to a new three-point tangential (NTPT) positioning algorithm and the DCM, this article makes the first attempt to investigate the quantitative calculation method of the influence of the dynamic performance of a servo feed system for five-axis numerical control (NC) machine tools on the dynamic error distribution for S-shaped test pieces after processing. Parameter p, representing the dynamic characteristic of the servo feed system, is varied to compare the difference of the dynamic error distribution law on S-shaped test pieces. The calculation results show that the parameter p can be adjusted to reduce the dynamic error of the final machined test pieces. It is important to improve the dynamic performance of servo feed systems for five-axis NC machine tools and enhance the machining quality of test pieces. In addition, compared with the calculation results of the dynamic error distribution for an NAS979 test piece, the S-shaped test piece can reflect the dynamic performance of the servo feed system for five-axis NC machine tools more accurately and effectively. Finally, the effectiveness of the proposed calculation method is verified through processing experiments on a five-axis NC machine tool.

Optimizing of Integral Impeller NC Program Based on the Material Removal Rate

2014 ◽  
Vol 1030-1032 ◽  
pp. 1305-1308
Author(s):  
Shi Chao Li ◽  
Song Lin Wu ◽  
Yan Kun Liang
Keyword(s):  
Material Removal Rate ◽  
Machine Tools ◽  
Material Removal ◽  
Removal Rate ◽  
Cnc Machining ◽  
Machining Process ◽  
Machining Accuracy ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Five Axis

It is a general processing technology that multi-axis NC machine tools is used for machining impeller at present. In order to improve the machining accuracy of the five-axis NC machine tools, the paper analyzes the computing interpolation error of the Multi-axis CNC system in detail. Some of the measures of tools selection have been proposed in purpose of diminishing the accumulative error of the system. The paper also establishes the optimized objective function to optimize the process parameters of the CNC machining based on the material removal rate. All these measures will improve the machining efficiency significantly and increase the stationary of the machining process.

Analysis on Geometry Error Software Compensation Technology Model of Gantry Five-Axis NC Machine Tool

2012 ◽  
Vol 241-244 ◽  
pp. 1470-1474 ◽  
Author(s):  
Hua Gang Han ◽  
Xiao Lin Hu ◽  
Ying Chun Li ◽  
Feng Shou Shang Guan
Keyword(s):  
Error Compensation ◽  
Machine Tools ◽  
Body System ◽  
Nc Machine Tool ◽  
Result Show ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Multi Body ◽  
Geometry Error ◽  
Five Axis

Based on multi-body system, the error model of gantry five-axis NC machine tools was discussed. The calculate method of precision process equation and NC instruction has been derived out. Based the above research works，make a emulate by using of geometry error compensation soft-ware. The result show machining precision can be improved through the error compensation method which is concluded in this paper.

Motion Accuracy Enhancement of Five-Axis Machine Tools by Modified CL-Data

2018 ◽  
Vol 12 (5) ◽  
pp. 699-706 ◽  
Author(s):  
Ryuta Sato ◽  
Shogo Hasegawa ◽  
Keiichi Shirase ◽  
Masanobu Hasegawa ◽  
Akira Saito ◽  
...  
Keyword(s):  
Machine Tools ◽  
Numerical Control ◽  
Geometrical Shape ◽  
Motion Trajectories ◽  
Shape Errors ◽  
Nc Machine ◽  
Nc Machine Tools ◽  
Simulation And Experiment ◽  
Profile Machining ◽  
Five Axis

The motion trajectories of machine tools directly influence the geometrical shape of machined workpieces. Hence, improvement in their motion accuracy is required. It is known that machined shape errors occurring in numerical control (NC) machine tools can be compensated for by modifying the CL-data, based on the amount of error calculated by the measurement results of the machined shape of the workpiece. However, by using this method the shape errors cannot be compensated accurately in five-axis machining, because the final machining shape may not reflect the motion trajectory of a tool owing to the motion errors of the translational and rotary axes. In this study, a modification method of the cutter location (CL)-data, based on the amount of motion errors of the tool center-point trajectory during the machining motion, is newly proposed. The simulation and experiment of a wing profile machining motion is performed, to confirm the effectiveness of the proposed method. From the results, we confirm that the motion accuracy can be significantly improved by applying the proposed method.

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