Geometric Errors Sensitivity Analysis of Precision Vertical Machining Center Based on Multi-Body System Theory

2011 ◽  
Vol 108 ◽  
pp. 61-66 ◽  
Author(s):  
Qiang Cheng ◽  
Dong Sheng Xuan ◽  
Jie Sun ◽  
Zhi Feng Liu
Keyword(s):  
System Theory ◽  
Sensitivity Analysis ◽  
Machine Tool ◽  
Great Influence ◽  
Geometric Error ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Body System ◽  
Machining Center ◽  
Multi Body

Parts of geometric error coupled into space error is the main reason that affects machining accuracy of machine tools; therefore, how to determine the effect of geometric error to the machining accuracy and then assigning geometry precision of parts economically is a difficult problem in machine tool designing process. Therefore, based on multi-body system theory, a sensitivity analysis method of geometric error is put forward in this paper. Let’s take precision vertical machining center for an example. Firstly, an accuracy model of machining center is established based on multi-body system theory, and with 21 geometric errors obtained through experimental verification, key error sources affecting the machining accuracy are finally identified by sensitivity analysis. The example analysis shows that the proposed method can effectively identify the main geometric errors of parts that have great influence on volumetric error of machine tool, and thus provides important theoretical basis to improve the accuracy of machine tool economically.

Sensitivity Analysis of Geometric Errors for Five-Axis CNC Machine Tool Based on Multi-Body System Theory

2012 ◽  
Vol 271-272 ◽  
pp. 493-497
Author(s):  
Wei Qing Wang ◽  
Huan Qin Wu
Keyword(s):  
System Theory ◽  
Sensitivity Analysis ◽  
Machine Tool ◽  
Geometric Error ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Body System ◽  
Cnc Machine ◽  
Multi Body ◽  
Five Axis

Abstract: In order to determine that the effect of geometric error to the machining accuracy is an important premise for the error compensation, a sensitivity analysis method of geometric error is presented based on multi-body system theory in this paper. An accuracy model of five-axis machine tool is established based on multi-body system theory, and with 37 geometric errors obtained through experimental verification, key error sources affecting the machining accuracy are finally identified by sensitivity analysis. The analysis result shows that the presented method can identify the important geometric errors having large influence on volumetric error of machine tool and is of help to improve the accuracy of machine tool economically.

The Effect of Geometric Error on Machining Accuracy for Machining Center

2013 ◽  
Vol 690-693 ◽  
pp. 3244-3248
Author(s):  
Gui Qiang Liang ◽  
Ai Rong Zhang ◽  
Ting Ting Guo
Keyword(s):  
Great Influence ◽  
Geometric Error ◽  
Linear Displacement ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Lower Body ◽  
Body System ◽  
Research Results ◽  
Machining Center ◽  
Multi Body

In order to improve machining accuracy of machining center, the effect of geometric error on machining accuracy was researched by multi-body system theory. Taking a vertical machining center as example, topological structure of the machining center was described by lower body array. Geometric errors of the bodies in the multi-body system were expressed by homogeneous coordinate transformation. Error model for machining accuracy was deduced and geometric errors having great influence on the machining accuracy were identified. The research results show that, straightness errors and linear displacement errors in three directions have direct influence on machining accuracy, and the effect on machining accuracy caused by angle errors are related to the dimensions of the machining center and travel distance of the three axes. The research results provide guidance for analysis on sensitivity of geometric errors.

Geometric Error Modeling of a Vertical Machining Center

2013 ◽  
Vol 694-697 ◽  
pp. 1842-1845
Author(s):  
Gui Qiang Liang ◽  
Jun Xian Zhang ◽  
Fei Fei Zhao
Keyword(s):  
Coordinate Transformation ◽  
Transformation Method ◽  
Geometric Error ◽  
Error Modeling ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Lower Body ◽  
Body System ◽  
Machining Center ◽  
Multi Body

The effect of geometric error on machining accuracy was researched by multi-body system theory, as well as homogeneous coordinate transformation method. Taking a vertical machining center as example, topological structure of the machine tool was described by lower body array. Lower body array of the machining center, motion freedom between adjacent bodies and geometric errors of the vertical machining center were analyzed. Geometric errors of the bodies in the multi-body system were expressed by homogeneous coordinate transformation. Error model for machining accuracy was deduced and geometric errors having influence on the machining accuracy were identified. The research results provide guidance for analyze of geometric errors on machining accuracy.

4-Axis Machine Tool Geometric Error Modeling and Measurement

2012 ◽  
Vol 152-154 ◽  
pp. 788-795 ◽  
Author(s):  
Fang Yu Pan ◽  
Ming Li ◽  
Chang Kai Xu
Keyword(s):  
System Theory ◽  
Machine Tool ◽  
Geometric Error ◽  
Error Modeling ◽  
Laser Doppler ◽  
Geometric Errors ◽  
Body System ◽  
Machining Precision ◽  
The Matrix ◽  
Multi Body

To improve the machining precision and reduce the geometric errors for 4-axis machine tool, multi-body system theory is introduced . Based on of the theory, ,through analysing the matrix of the position transformation and the displacement transformation, a model for the machine tool is put forth. By the laser Doppler displacement measurement, test is done and value of the errors is achieved which will benefit for later compensation.

Geometric Error Identification of a Three-Axis Machining Center

2013 ◽  
Vol 694-697 ◽  
pp. 1803-1807
Author(s):  
Gui Qiang Liang ◽  
Jun Xian Zhang ◽  
Fei Fei Zhao
Keyword(s):  
Working Conditions ◽  
Laser Interferometer ◽  
Great Influence ◽  
Geometric Error ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Positioning Errors ◽  
Machining Center ◽  
Influence Effect ◽  
Squareness Errors

Geometric errors of a machining center can cause great influence on machining accuracy, and these geometric errors should be identified and compensated in the actual working conditions. Taking a three-axis vertical machining center as example, 21 geometric errors of the machine tool were solved. By using the 12-line method based on a laser interferometer, identification principle of the positioning errors, straightness errors, pitch errors, yaw errors, roll errors and squareness errors are presented, and all of the 21 geometric errors of the machining center were identified. Geometric errors having great influence effect on machining accuracy can be identified. The research results provide guidance for analyze of geometric errors of machining center.

An Optimization Method for Geometric Error of Machine Tool Based on NSGA-II

2013 ◽  
Vol 418 ◽  
pp. 180-186
Author(s):  
Li Gang Cai ◽  
Cui Zhang ◽  
Qiang Cheng ◽  
Pei Hua Gu ◽  
Hong Ying Wang
Keyword(s):  
Machine Tool ◽  
Optimization Method ◽  
Geometric Error ◽  
Machining Accuracy ◽  
Body System ◽  
Critical Problem ◽  
Nsga Ii ◽  
Allocation Method ◽  
The Cost ◽  
Multi Body

Balancing the cost and processing precision of machine tool by the method of error allocation without affecting the machining performances is a critical problem in the Machine tool industry. In this paper, a new accuracy allocation method for multi-axis machine tool based on Multi-body system theory, manufacturing and quality loss costs and relationship between tolerances and accuracy parameters of components is proposed. This optimization method is performed with Non-Dominated Sorting Genetic Algorithm II algorithm using Isight and Matlab software. A three-axis vertical machine tool is taken as an example to demonstrate the method, and the optimization results show that the accuracy allocation method proposed is feasible in the optimization of geometric errors on the premise of satisfying machining accuracy requirements.

Sensitivity Analysis of Tool Axis Errors in Large Mill-Turn Machine Tools

2014 ◽  
Vol 487 ◽  
pp. 337-342
Author(s):  
Pan Pan Sun ◽  
Fang Yu Peng ◽  
Shuai Yuan ◽  
Rong Yan ◽  
Zhuang Min
Keyword(s):  
System Theory ◽  
Sensitivity Analysis ◽  
Machine Tools ◽  
Kinematic Model ◽  
Orthogonal Test ◽  
Geometric Errors ◽  
Body System ◽  
Range Analysis ◽  
Tool Axis ◽  
Multi Body

This paper proposes an approach to carry out sensitivity analysis of tool axis errors caused by component geometric errors, in order to meet the high precision requirement in holes series machining with mill-turn machine tools. Firstly, ideal kinematic model and real kinematic model considering geometric errors of the mill-turn machine tools are built respectively based on homogeneous transfer matrix and multi-body system theory. Secondly, tool axis errors caused by component geometric errors are simulated using an orthogonal test. Finally, sensitivity analysis of tool axis errors is implemented by means of range analysis and variance analysis.

Geometric accuracy allocation for multi-axis CNC machine tools based on sensitivity analysis and reliability theory

2014 ◽  
Vol 229 (6) ◽  
pp. 1134-1149 ◽  
Author(s):  
Qiang Cheng ◽  
Ziling Zhang ◽  
Guojun Zhang ◽  
Peihua Gu ◽  
Ligang Cai
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tool ◽  
Operating Conditions ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Volumetric Error ◽  
The Cost ◽  
Five Axis

Machining accuracy of a machine tool is influenced by geometric errors produced by each part and component. Different errors have varying influence on the machining accuracy of a tool. The aim of this study is to optimize errors to get a desired performance for a numerical control machine tool. Applying multi-body system theory, a volumetric error model was constructed to track and compensate effects of errors during operation of the machine, and to relate the functional specifications on volumetric accuracy to the permissible errors on the joints and links of the machine. Error sensitivity analysis was used to identify the influence of different errors (especially the errors which have large influences) on volumetric error. Based on First Order and Second Moment theory, an error allocation approach was developed to optimize allocation of manufacturing and assembly tolerances along with specifying the operating conditions to determine the optimal level of these errors so that the cost of controlling them and the cost of failure to meet the specifications is minimized. The approach developed was implemented in software and an example of the geometric errors budgeting for a five-axis machine was discussed. It is identified that the different optimal standard deviations reflect the cost-weighted influences of the respective parameters in the equations of the functional requirements. This study suggests that it is possible to determine the coupling relationships between these errors and optimize the allowable error budgeting between these sources.

scholarly journals A geometric error tracing method based on the Monte Carlo theory of the five-axis gantry machining center

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770764 ◽  
Author(s):  
Jinwei Fan ◽  
Yuhang Tang ◽  
Dongju Chen ◽  
Changjun Wu
Keyword(s):  
Monte Carlo ◽  
Machine Tool ◽  
Test Piece ◽  
Great Influence ◽  
Numerical Control ◽  
Geometric Errors ◽  
Machining Center ◽  
Machining Errors ◽  
Five Axis ◽  
Tracing Method

This article proposes a tracing method to identify key geometric errors for a computer numerical control machine tool by cutting an S-shaped test piece. Adjacent part relationships and machine tool errors transform relationships are described by topology of the machining center. Global sensitivity analysis method based on quasi-Monte Carlo was used to analyze machining errors. Using this method, key geometric errors with significant influence on machining errors were obtained. Compensation of the key errors was used to experimentally improve machining errors for the S-shaped test piece. This method fundamentally determines the inherent connection and influence between geometric errors and machining errors. Key geometric errors that have great influence on machining errors can be determined quickly with this method. Thus, the proposed tracing method could provide effective guidance for the design and use of machine tools.

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