scholarly journals A12 A Method of Geometric Error Identification with Cone Frustum Trajectories in Five-axis Controlled Machine Tool

2008 ◽  
Vol 2008.7 (0) ◽  
pp. 85-86
Author(s):  
Tetsuya MATSUSHITA ◽  
Tadahiro OKI ◽  
Atsushi MATSUBARA
2011 ◽  
Vol 338 ◽  
pp. 786-791 ◽  
Author(s):  
Wang Wei Chu ◽  
Shao Wei Zhu ◽  
Yu Peng ◽  
Guo Fu Ding

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.


2012 ◽  
Vol 271-272 ◽  
pp. 493-497
Author(s):  
Wei Qing Wang ◽  
Huan Qin Wu

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.


Author(s):  
Jennifer Creamer ◽  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers ◽  
Philip L. Freeman ◽  
...  

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.


2019 ◽  
Vol 10 (1) ◽  
pp. 100 ◽  
Author(s):  
Chuandong Li ◽  
Xianli Liu ◽  
Rongyi Li ◽  
Shi Wu ◽  
Houwang Song

This paper presents the design of a precise “ball-column” device to efficiently and accurately measure the geometric error terms of both rotary axes of the five-axis machine tool. A geometric error measurement method of spherical contact was proposed based on the influence of the geometric error term from a five-axis machine tool rotating axis on the integrated geometric error of the machine tool. A multiple degree of freedom, step-by-step contact method based on on-machine measure for measuring the spherical center point is proposed, and the solution formula of each geometric error term of the rotating axis is established, respectively. This method can identify 12 geometric errors based on the influence of one rotating axis on another rotating axis after long term operation. The spatial error field of the five-axis machine tool was constructed by analyzing the error law of the two rotating axes of machine tools based on various positions and postures. Finally, after the comparison of the experiment, the results showed that the accuracy of the developed error measurement device reached 91.8% and the detection time was as short as 30–40 min.


2015 ◽  
Vol 9 (4) ◽  
pp. 387-395 ◽  
Author(s):  
Soichi Ibaraki ◽  
◽  
Yu Nagai ◽  
Hisashi Otsubo ◽  
Yasutaka Sakai ◽  
...  

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.


2013 ◽  
Vol 420 ◽  
pp. 85-91 ◽  
Author(s):  
Li Gang Cai ◽  
Qiu Nan Feng ◽  
Qiang Cheng ◽  
Pei Hua Gu ◽  
Cui Zhang

The precision model of the 5-axis CNC machine tool can be built up based on the theory of kinematics for multi-body system (MBS). And then based on the precision model, the sensitivity analysis established with matrix differential is a method of identifying geometric error parameters for machine tool. And the geometric error factors of major parts that have relatively significant influence on comprehensive spatial error of the machine tool are identified. Finally, important theoretical basis for improving the titanium alloy Five-axis CNC machining center reasonably and for the error compensation can be provided.


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