Formulation of the influence of rotary axis geometric errors on five-axis on-machine optical scanning measurement—application to geometric error calibration by “chase-the-ball” test

2017 ◽  
Vol 92 (9-12) ◽  
pp. 4263-4273 ◽  
Author(s):  
Soichi Ibaraki ◽  
Yu Nagai
Keyword(s):  
Geometric Error ◽  
Geometric Errors ◽  
Optical Scanning ◽  
Rotary Axis ◽  
Error Calibration ◽  
Five Axis ◽  
Ball Test

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.

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.

Table-Based Volumetric Error Compensation of Large Five-Axis Machine Tools

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Jennifer Creamer ◽  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers ◽  
Philip L. Freeman ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Data Gathering ◽  
Measurement Data ◽  
Geometric Error ◽  
Compensation Method ◽  
Geometric Errors ◽  
Simultaneous Generation ◽  
Five Axis

This paper presents a geometric error compensation method for large five-axis machine tools. Compared to smaller machine tools, the longer axis travels and bigger structures of a large machine tool make them more susceptible to complicated, position-dependent geometric errors. The compensation method presented in this paper uses tool tip measurements recorded throughout the axis space to construct an explicit model of a machine tool's geometric errors from which a corresponding set of compensation tables are constructed. The measurements are taken using a laser tracker, permitting rapid error data gathering at most locations in the axis space. Two position-dependent geometric error models are considered in this paper. The first model utilizes a six degree-of-freedom kinematic error description at each axis. The second model is motivated by the structure of table compensation solutions and describes geometric errors as small perturbations to the axis commands. The parameters of both models are identified from the measurement data using a maximum likelihood estimator. Compensation tables are generated by projecting the error model onto the compensation space created by the compensation tables available in the machine tool controller. The first model provides a more intuitive accounting of simple geometric errors than the second; however, it also increases the complexity of projecting the errors onto compensation tables. Experimental results on a commercial five-axis machine tool are presented and analyzed. Despite significant differences in the machine tool error descriptions, both methods produce similar results, within the repeatability of the machine tool. Reasons for this result are discussed. Analysis of the models and compensation tables reveals significant complicated, and unexpected kinematic behavior in the experimental machine tool. A particular strength of the proposed methodology is the simultaneous generation of a complete set of compensation tables that accurately captures complicated kinematic errors independent of whether they arise from expected and unexpected sources.

A method to decouple the geometric errors for rotary axis in a five-axis CNC machine

2020 ◽  
Vol 31 (8) ◽  
pp. 085007
Author(s):  
Ruijun Liang ◽  
Wei Li ◽  
Zhiqiang Wang ◽  
Lei He
Keyword(s):  
Geometric Errors ◽  
Cnc Machine ◽  
Rotary Axis ◽  
Five Axis

Visual Measurement and Calibration of Geometric Errors of Rotating Axes for Five-axis Platform

2021 ◽  
Author(s):  
Song Yin ◽  
Haibo Zhou ◽  
Xia Ju ◽  
Zhiqiang Li
Keyword(s):  
Screw Theory ◽  
Coupling Mechanism ◽  
Geometric Errors ◽  
Visual Measurement ◽  
Decoupling Method ◽  
Vision Measurement ◽  
Rotation Axes ◽  
Error Terms ◽  
Error Calibration ◽  
Five Axis

Abstract In this paper, a method for identifying and decoupling geometric errors of rotation axes using vision measurement is proposed. Based on screw theory and exponential product formula, identification equations of position-dependent geometric errors (PDGEs) and position-independent geometric errors (PIGEs) of the rotation axes are established. The mapping relationships between the error twist and geometric errors are established. The error model provides the coupling mechanism of PDGEs and PIGEs. Furthermore, a progressive decoupling method is proposed to separate PDGEs and PIGEs without additional assumptions. The pose parameters, required for solving the identification equations, are obtained by visual measurement. Then, the error terms of PIGEs and PDGEs are determined. Lastly, the error calibration of the rotation axes is investigated, thus providing an average rotary table orientation error reduction of 28.1% compared to the situation before calibration.

Observation of Thermal Influence on Error Motions of Rotary Axes on a Five-Axis Machine Tool by Static R-Test

2012 ◽  
Vol 6 (2) ◽  
pp. 196-204 ◽  
Author(s):  
Cefu Hong ◽  
◽  
Soichi Ibaraki
Keyword(s):  
Machine Tools ◽  
Single Point ◽  
Geometric Errors ◽  
Thermal Tests ◽  
Thermally Induced ◽  
Rotary Axis ◽  
Spindle Rotation ◽  
Thermal Changes ◽  
Thermal Influence ◽  
Five Axis

Thermal distortions are regarded as one of the major error factors in machine tools. ISO 230-3 and ISO 10791-10 describe tests to evaluate the influence of thermal distortions caused by linear motion and spindle rotation on the Tool Center Position (TCP). However, for five-axis machine tools, no thermal test is described for a rotary axis. Therefore, in this paper, a method for observing thermally induced geometric errors of a rotary axis with a static R-test is proposed. Unlike conventional thermal tests in ISO 230-3 and ISO 10791-10, where the thermal influence on the positioning error at a single point is tested, the present test measures the thermal influence on the error motions of a rotary axis. The R-test measurement clarifies how the error motions of a rotary table change with the rotation of a swiveling axis and how they are influenced by thermal changes. The thermal influence on the error motions of a rotary axis is quantitatively parameterized by geometric errors that vary with time.

A Five-Axis Machining Error Simulator for Rotary-Axis Geometric Errors Using Commercial Machining Simulation Software

2017 ◽  
Vol 11 (2) ◽  
pp. 179-187 ◽  
Author(s):  
Soichi Ibaraki ◽  
◽  
Ibuki Yoshida ◽  
Keyword(s):  
Kinematic Model ◽  
Simulation Software ◽  
Geometric Errors ◽  
Machining Simulation ◽  
Machining Error ◽  
Rotary Axis ◽  
Tool Paths ◽  
Numerical Fitting ◽  
Machining Test ◽  
Five Axis

This paper presents a simulator that graphically presents the influence of rotary-axis geometric errors on the geometry of a finished workpiece. Commercial machining simulation software is employed for application to arbitrary five-axis tool paths. A five-axis kinematic model is implemented with the simulator to calculate the influence of rotary-axis geometric errors. The machining error simulation is demonstrated for 1) the cone frustum machining test described in ISO 10791-7:2015 [1], and 2) the pyramid-shaped machining test proposed by some of the authors in [2]. The influences of the possible geometric errors are simulated in advance. By comparing the measured geometry of the finished workpiece to the simulated profiles, major error causes are identified without numerical fitting to the machine’s kinematic model.

Geometric Error Compensation of Five-Axis Machining Centers Based on On-Machine Workpiece Measurement

2018 ◽  
Vol 12 (2) ◽  
pp. 230-237 ◽  
Author(s):  
Ryuta Sato ◽  
◽  
Keiichi Shirase
Keyword(s):  
Error Compensation ◽  
Geometric Error ◽  
Least Square ◽  
Geometric Errors ◽  
Rotary Axes ◽  
Cutting Test ◽  
Measurement Results ◽  
Simulation And Experiment ◽  
Five Axis ◽  
Least Square Matching

This study proposes an identification and compensation method for the geometric errors of the rotary axes in five-axis machining centers, based on the on-machine measurement results of the machined workpiece. Geometric errors can be identified from the shape geometry of the workpiece machined by five-axis motions because the influence of the errors appears on the shape geometry. An observation equation can be obtained based on the geometric error model and machined shape. The actual geometric errors can be identified by the least square matching of the measured and simulated machined shapes. In order to confirm the effectiveness of the proposed method, an actual cutting test and a simulation are performed. Based on their results, it is confirmed that the proposed method can successfully identify the geometric errors in the simulation. However, these errors cannot be identified in the experiments because a few of them do not have sufficient influences onto the machined shape. On the other hand, although the geometric errors cannot be correctly identified, it is confirmed that the they can be adequately compensated for based on the identified errors in both the simulation and experiment.

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