scholarly journals Identification Method of Error Motions and Geometric Errors of a Rotary Axis by R-Test

2020 ◽  
Vol 14 (3) ◽  
pp. 399-408
Author(s):  
Takaaki Kenno ◽  
Ryuta Sato ◽  
Keiichi Shirase ◽  
Shigemasa Natsume ◽  
Henny Spaan ◽  
...  
Keyword(s):  
High Precision ◽  
Machine Tools ◽  
Geometric Errors ◽  
Rotary Table ◽  
Test Device ◽  
Motion Error ◽  
Rotary Axis ◽  
Measurement Results ◽  
Reference Sphere ◽  
Precision Machine Tools

While evaluating the accuracy of high-precision machine tools, it is critical to reduce the error factors contributing to the measured results as much as possible. This study aims to evaluate both the error motions and geometric errors of the rotary axis without considering the influence of motion error of the linear axis. In this study, only the rotary axis is moved considering two different settings of a reference sphere, and the linear axes are not moved. The motion accuracy of the rotary axis is measured using the R-test device, both the error motions and geometric errors of the rotary axis are identified from the measurement results. Moreover, the identified geometric errors are verified for correctness via measurement with an intentional angular error. The results clarify that the proposed method can identify the error motions and geometric errors of a rotary axis correctly. The method proposed in this study can thus be effective for evaluating the motion accuracy of the rotary axis and can contribute to further improvement of the accuracy of the rotary table.

Sensitivity Analysis of Error Motions and Geometric Errors in the Case of Sphere-Shaped Workpiece

2020 ◽  
Author(s):  
Zongze Li ◽  
Ryuta Sato ◽  
Keiichi Shirase
Keyword(s):  
Sensitivity Analysis ◽  
Machine Tools ◽  
End Milling ◽  
Geometric Errors ◽  
Machined Surface ◽  
Error Sources ◽  
Motion Error ◽  
Machining Center ◽  
Machining Errors ◽  
Five Axis

Abstract Motion error of machine tool feed axes influences the machined workpiece accuracy. However, the influences of each error sources are not identical; some errors do not influence the machined surface although some error have significant influences. In addition, five-axis machine tools have more error source than conventional three-axis machine tools, and it is very tough to predict the geometric errors of the machined surface. This study proposes a method to analyze the relationships between the each error sources and the error of the machined surface. In this study, a kind of sphere-shaped workpiece is taken as a sample to explain how the sensitivity analysis makes sense in ball-end milling. The results show that the method can be applied for the axial errors, such as motion reversal errors, to make it clearer to obverse the extent of each errors. In addition, the results also show that the presented sensitivity analysis is useful to investigate that how the geometric errors influence the sphere surface accuracy. It can be proved that the presented method can help the five-axis machining center users to predict the machining errors on the designed surface of each axes error motions.

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.

Development of High-Speed, High-Precision 5-Axis Integrated Machine Tools

2007 ◽  
Vol 1 (2) ◽  
pp. 103-107 ◽  
Author(s):  
Masahiko Mori ◽  
◽  
Hidehito Ota ◽  
Makoto Fujishima
Keyword(s):  
High Precision ◽  
Machine Tools ◽  
High Speed ◽  
Direct Drive ◽  
Machining Performance ◽  
Rotary Axis ◽  
Rotary Actuator

This paper describes the development of high-speed, high-precision 5-axis machine tools which can be used for both milling and turning. Conventional 5-axis machine tools are generally difficult to operate because the visibility is poor. Moreover, their precision is inadequate and the rotary axis speed is insufficient for turning. To deal with these factors, we developed a simple, high-precision 2-axis rotary actuator with high-speed direct drive motors. We studied the machining performance of 5-axis machining centers equipped with such direct drive motors.

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