Simultaneous geometric error identification of rotary axis and tool setting in an ultra-precision 5-axis machine tool using on-machine measurement

2020 ◽  
Vol 63 ◽  
pp. 94-104 ◽  
Author(s):  
Sangjin Maeng ◽  
Sangkee Min
Keyword(s):  
Machine Tool ◽  
Geometric Error ◽  
Error Identification ◽  
Rotary Axis ◽  
Tool Setting ◽  
Ultra Precision

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.

R-Test Analysis Software for Error Calibration of Five-Axis Machine Tools – Application to a Five-Axis Machine Tool with Two Rotary Axes on the Tool Side –

2015 ◽  
Vol 9 (4) ◽  
pp. 387-395 ◽  
Author(s):  
Soichi Ibaraki ◽  
◽  
Yu Nagai ◽  
Hisashi Otsubo ◽  
Yasutaka Sakai ◽  
...  
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Three Dimensional ◽  
Geometric Error ◽  
Test Analysis ◽  
Rotary Axes ◽  
Rotary Axis ◽  
Displacement Sensors ◽  
Error Calibration ◽  
Five Axis

The R-test measures the three-dimensional displacement of a precision sphere, attached to a machine spindle, by using three displacement sensors fixed to the machine’s table. Its application to error calibration for five-axis machine tools has long been studied. This paper presents software for analyzing the measured R-test trajectories for error diagnosis and numerical compensation for rotary axis location errors and error motions. The developed software first graphically presents the measured R-test trajectories to help a user intuitively understand error motions of the rotary axes. It also numerically parameterizes the rotary axis geometric error parameters, and then generates a compensation table that can be implemented in some latest-generation commercial CNC systems. An actual demonstration of its application to a five-axis machine tool with a universal head (two rotary axes on the spindle side) is presented.

A Geometric Error Identification and Simulation Method Based on Laser Tracker for Large-Scale Multi-Axis NC Machine Tools

2012 ◽  
Vol 472-475 ◽  
pp. 556-560
Author(s):  
Ji Yang Ma ◽  
Fang Yu Peng ◽  
Rong Yan ◽  
Jing Wu
Keyword(s):  
Machine Tool ◽  
Coordinate System ◽  
Large Scale ◽  
Simulation Method ◽  
Geometric Error ◽  
Least Square ◽  
Laser Tracker ◽  
Profile Error ◽  
Error Identification ◽  
Nc Machine

To evaluate the profile error of manufacture mainly caused by geometric error of machine tool, this paper proposes a geometric error identification and profile error simulation method. The identify method measures each axis of machine tool based on laser tracker, then using the least square method to fit the axis, as a result the coordinate system of each axis can be built. The geometric error of machine tool can be gained by analysis of the coordinate system. Building the kinematics model of large-scale multi-axis NC machine tool considered the geometric error, then using MATLAB and UG second development to achieve simulation of profile error.

Fluctuation prediction of machining accuracy for multi-axis machine tool based on stochastic process theory

2014 ◽  
Vol 229 (14) ◽  
pp. 2534-2550 ◽  
Author(s):  
Qiang Cheng ◽  
Qiunan Feng ◽  
Zhifeng Liu ◽  
Peihua Gu ◽  
Ligang Cai
Keyword(s):  
Stochastic Process ◽  
Machine Tool ◽  
Significant Influence ◽  
Geometric Error ◽  
Error Modeling ◽  
Precision Machining ◽  
Machining Accuracy ◽  
Geometric Errors ◽  
Volumetric Error ◽  
Ultra Precision

Geometric error has significant influence on the processing results and reduces machining accuracy. Machine tool geometric errors can be interpreted as a deterministic value with an uncertain fluctuation of probabilistic distribution. Although, the uncertain fluctuation can not be compensated, it has extremely profound significance on the precision and ultra-precision machining to reduce the fluctuation range of machining accuracy as far as possible. In this paper, a typical 3-axis machine tool with high precision is selected and the fluctuations in machining accuracy are studied. The volumetric error modeling of machine tool is established by multi-body system (MBS) theory, which describes the topological structure of MBS in a simple and convenient matrix form. Based on the volumetric error model, the equivalent components of the errors for the three axes are established by reducing error terms. Then, the fluctuations of equivalent errors and the machining accuracy in working planes are depicted and predicted using the theory of stochastic process, whose range should be controlled within a certain confidence interval. Furthermore, the critical geometric errors that have significant influence on the machining accuracy fluctuation are identified. Based on the analysis results, some improvement in the machine tool parts introduced and the results for the modified machine show that the prediction allow for reduction in errors for the precision and ultra-precision machining.

Geometric Error Identification and Compensation for Rotation Axes of Five-Axis Machine Tools

2011 ◽  
Vol 338 ◽  
pp. 786-791 ◽  
Author(s):  
Wang Wei Chu ◽  
Shao Wei Zhu ◽  
Yu Peng ◽  
Guo Fu Ding
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Geometric Error ◽  
Machining Accuracy ◽  
Error Identification ◽  
Rotation Axes ◽  
Process System ◽  
Prototype Software ◽  
Multi Body ◽  
Five Axis

In NC machining, the precision of the final parts is affected by many factors, including geometric deviation of machine tool components and structures, deformation of process system caused by cutting force and cutting heat, servo delay, tool wear and so on. Among which geometric error of machine tool is one of the most important factors. This study focused on geometric error identification and compensation of rotation axes of five-axis machine tools. A new method was proposed to identify the 6 geometric error parameters of each rotation axes of five-axis machine tools based on a ball-bar system. Regarding the machine tool as a rigid multi-body system (MBS), a geometric error model was established based on homogeneous transfer matrix (HTM). Finally, the geometric errors were compensated by correcting NC codes by the prototype software system developed in this study. An experiment and an application were conducted and the results show that the proposed method is effective to improve the machining accuracy.

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