An Improvement Geometric Error Identification Method of CNC Machine Tool Based on Double Ball Bar

2014 ◽  
Vol 496-500 ◽  
pp. 1516-1521
Author(s):  
Qiang Cheng ◽  
Zhuo Qi ◽  
Kai Li ◽  
Li Gang Cai ◽  
Dong Lu
Keyword(s):  
Machine Tool ◽  
Recognition Algorithm ◽  
Geometric Error ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Error Identification ◽  
Double Ball Bar ◽  
Ball Bar ◽  
Error Recognition ◽  
Better Than

The double ball bar is widely used because it can quickly, easily and cost-effectively detect and evaluate the accuracy of CNC machine tools. But since the error recognition algorithm based on the double ball bar ignores the quadratic item, its recognition accuracy would be reduced. In this paper, an improved CNC verticality error and position error identification formula, combined with the machine tool error model to deduce a new error recognition model of double ball bar measurement is proposed. It can be drawn that the accuracy of the model are better than the existing methods because it keeps the second item in the derivation process of the model.

scholarly journals A method for identifying  and predicting the geometric errors of a rotating axis

2020 ◽  
Author(s):  
Jinwei Fan ◽  
Peitong Wang ◽  
Haohao Tao ◽  
Zhongsheng Li ◽  
Jian Yin
Keyword(s):  
Machine Tool ◽  
Prediction Method ◽  
Geometric Error ◽  
Geometric Errors ◽  
Error Identification ◽  
Rotary Axis ◽  
Double Ball Bar ◽  
Ball Bar ◽  
Discrete Values ◽  
Identification Model

Abstract To improve the machine tool accuracy, an integrated geometric error identification and prediction method is proposed to eliminate the positioning inaccuracy of tool ball for a double ball bar (DBB) caused by the rotary axis’ geometric errors in a multi-axis machine tool. In traditional geometric errors identification model based on homogenous transformation matrices (HTM), the elements of position-dependent geometric errors(PDGEs) are defifined in the local frames attached to the axial displacement, which is inconvenient to do redundance analysis. Thus, this paper proposed an integrated geometric error identification and prediction method to solve the uncertainty problem of the PDGEs of rotary axis. First, based on homogeneous transform matrix (HTM) and multi-body system (MBS) theory, The transfer matrix only considering the rotary axes is derived to determine the tool point position error model. Then a geometric errors identification of rotary axis is introduced by measuring the error increment in three directions. Meanwhile the geometric errors of C-axis are described as position-dependent truncated Fourier polynomials caused by fitting discrete values. Thus, The geometric error identification is converted to the function coefficient. Finally, the proposed new prediction and identification model of PDGEs in the global frame are verified through simulation and experiments with double ball-bar tests.

Study on Checking and Measurement of Double-Ball Bar for Thermal Error of CNC Machine Tools

2008 ◽  
Vol 375-376 ◽  
pp. 544-548 ◽  
Author(s):  
Yong Xiang Li ◽  
Yu Yao Li ◽  
Hong Tao Cao ◽  
Yong Qiao Jin ◽  
Jian Guo Yang
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Thermal Error ◽  
Error Component ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Double Ball Bar ◽  
Basic Measurement ◽  
Ball Bar ◽  
Main Factors

Thermal errors of CNC machine tools was checked and measured by double-ball bar in this paper. Mathematical model of measuring thermal error of machine tools by DBB on the principle of its basic measurement was derived. Combining it with kinematics model of machine tool, the identification law of error component parameters was established when thermal error was checked and measured by DBB. Thus, all of the thermal error component would be separated from the synthetical error. Finally, the entire analysis was provided to adjust machine tool and actualize error compensation of machine tool through grasping main factors influencing the machining precision of machine tool.

scholarly journals New identification method for computer numerical control geometric errors

2021 ◽  
pp. 002029402110108
Author(s):  
Hongtao Yang ◽  
Mei Shen ◽  
Li Li ◽  
Yu Zhang ◽  
Qun Ma ◽  
...  
Keyword(s):  
Machine Tools ◽  
Geometric Error ◽  
Numerical Control ◽  
Identification Accuracy ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Cnc Machine ◽  
Identification Method ◽  
Double Ball Bar ◽  
Ball Bar

To address the problems of the low accuracy of geometric error identification and incomplete identification results of the linear axis detection of computer numerical control (CNC) machine tools, a new 21-item geometric error identification method based on double ball-bar measurement was proposed. The model between the double ball-bar reading and the geometric error term in each plane was obtained according to the three-plane arc trajectory measurement. The mathematical model of geometric error components of CNC machine tools is established, and the error fitting coefficients are solved through the beetle antennae search particle swarm optimization (BAS–PSO) algorithm, in which 21 geometric errors, including roll angle errors, were identified. Experiments were performed to compare the optimization effect of the BAS–PSO and PSO and BAS and genetic particle swarm optimization (GA–PSO) algorithms. Experimental results show that the PSO algorithm is trapped in the local optimum, and the BAS–PSO is superior to the other three algorithms in terms of convergence speed and stability, has higher identification accuracy, has better optimization performance, and is suitable for identifying the geometric error coefficient of CNC machine tools. The accuracy and validity of the identification results are verified by the comparison with the results of the individual geometric errors detected through laser interferometer experiments. The identification accuracy of the double ball-bar is below 2.7 µm. The proposed identification method is inexpensive, has a short processing time, is easy to operate, and possesses a reference value for the identification and compensation of the linear axes of machine tools.

scholarly journals Global Quantitative Sensitivity Analysis and Compensation of Geometric Errors of CNC Machine Tool

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Shijie Guo ◽  
Dongsheng Zhang ◽  
Yang Xi
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tool ◽  
Machine Tools ◽  
Geometric Error ◽  
Test Method ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Cnc Machine ◽  
Open Cnc ◽  
Open Cnc System

A quantitative analysis to identify the key geometric error elements and their coupling is the prerequisite and foundation for improving the precision of machine tools. The purpose of this paper is to identify key geometric error elements and compensate for geometric errors accordingly. The geometric error model of three-axis machine tool is built on the basis of multibody system theory; and the quantitative global sensitivity analysis (GSA) model of geometric error elements is constructed by using extended Fourier amplitude sensitivity test method. The crucial geometric errors are identified; and stochastic characteristics of geometric errors are taken into consideration in the formulation of building up the compensation strategy. The validity of geometric error compensation based on sensitivity analysis is verified on a high-precision three-axis machine tool with open CNC system. The experimental results show that the average compensation rates along theX,Y, andZdirections are 59.8%, 65.5%, and 73.5%, respectively. The methods of sensitivity analysis and geometric errors compensation presented in this paper are suitable for identifying the key geometric errors and improving the precision of CNC machine tools effectively.

Modeling and Analysis of Key Geometric Error for Gravity Deformation of Heavy-Duty CNC Machine Tool

2014 ◽  
Vol 552 ◽  
pp. 90-95
Author(s):  
Hong Ya Fu ◽  
Han Wang ◽  
Zhen Yu Han
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Geometric Error ◽  
Error Modeling ◽  
Influential Factor ◽  
Cnc Machine Tools ◽  
Heavy Duty ◽  
Cnc Machine ◽  
Modeling And Analysis ◽  
Huge Impact

Gravity has huge impact on the accuracy of heavy-duty machine tools. To investigate errors caused by gravity, it is essential to figure out the most influential factor. This paper presents a geometric error modeling for heavy-duty CNC machine tools. Regarding a machine tool as a rigid multi-body system (MBS), the geometric error model has been established by utilizing kinematics chain and homogeneous transfer matrix (HTM). By analyzing the Jacobi matrix, the influence of all the geometric error parameters has been calculated to find out the key geometric error that affect the accuracy most. It is revealed that gravity of beam and tool affect the accuracy of the machine tool most through the ANSYS simulation. It supports a theoretical basis for the further research on error compensation of the key component of a machine tool.

Influence Analysis of Machine Tool’s Turntable Angle Errors to the Roundness of Machined Hole

2014 ◽  
Vol 496-500 ◽  
pp. 816-822
Author(s):  
Qiang Cheng ◽  
Hong Wei Zhao ◽  
Li Gang Cai ◽  
Pei Hua Gu
Keyword(s):  
Machine Tool ◽  
Geometric Error ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Roundness Error ◽  
Machine Errors ◽  
Multi Body ◽  
The Mathematical Model

Machining accuracy has always been a key problem to machine tool. Machine errors are caused by a variety of error factors among which the geometric error is a key element. An accuracy model of the 3-axis CNC machine tool is established in this paper with multi-body system (MBS).And based on the accuracy model, the mathematical model of roundness error also built up. At last, the influence of CNC machine tools turntable angle error to roundness error of machined hole is analyzed.

scholarly journals A novel geometric error identification methodology for the tilting head of five-axis machine tools based on double ball bar

2018 ◽  
Vol 221 ◽  
pp. 04001
Author(s):  
Jinwei Fan ◽  
Changjun Wu ◽  
Zhongsheng Li
Keyword(s):  
Machine Tools ◽  
Relative Displacement ◽  
Geometric Error ◽  
Body System ◽  
Error Identification ◽  
Double Ball Bar ◽  
Motion Condition ◽  
Ball Bar ◽  
Multi Body ◽  
Five Axis

The paper proposes a novel geometric error identification methodology for the tilting head of five-axis machine tools using double ball bar(DBB).Firstly, based on the motion condition of the tilting head of five-axis machine tools, three measurement patterns in Y direction, X direction and Z direction are proposed respectively. Then, the relative displacement equations of two balls of DBB in three measurement patterns are established respectively on the basis of homogeneous transform matrix (HTM) and multi-body system (MBS) theory. Finally, the geometric error parameters of the tilting head are identified totally. The presented method is universal and provides a reference for the error identification for the tilting head of five-axis machine tools.

Sign in / Sign up

Export Citation Format

Share Document