Evaluation Method for Behavior of Rotary Axis Around Motion Direction Changing

2017 ◽  
Vol 11 (2) ◽  
pp. 171-178 ◽  
Author(s):  
Tadahiro Nishiguchi ◽  
◽  
Shogo Hasegawa ◽  
Ryuta Sato ◽  
Keiichi Shirase ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Motion Trajectory ◽  
Machined Surface ◽  
Motion Direction ◽  
Motion Error ◽  
Rotary Axes ◽  
Rotary Axis ◽  
Synchronous Motion ◽  
Five Axis

Several methods for evaluating the motion accuracy of the rotary axes in five-axis machining centers have been proposed till date. As it is known that particular motion errors exist around the motion direction changing points, it is important to evaluate the behavior of the rotary axes around these points. However, the influence of the motion error in the translational axes is included in the conventional evaluation results, as the translational axes reverse at the motion direction changing points about the rotary axes. In this study, an evaluation method which can assess the behavior of a rotary axis around motion direction changes by synchronous motion of translational and rotary axes is proposed. In this method, the direction of translational axes does not change when the motion direction of a rotary axis changes. A measurement test and actual cutting tests are carried out to clarify the influence of the behaviors of rotary axes on the motion trajectory and machined surface, caused by the change in the motion direction of the rotary axis. Simulations of the motion are also carried out to discuss the causes of inaccuracy.

scholarly journals Influence of Motion Error of Translational and Rotary Axes onto Machined Surface Generated by Simultaneous Five-axis Motion

Procedia CIRP ◽  
2014 ◽  
Vol 14 ◽  
pp. 269-274 ◽  
Author(s):  
Ryuta Sato ◽  
Kentaro Nishio ◽  
Keiichi Shirase ◽  
Gianni Campatelli ◽  
Antonio Scippa
Keyword(s):  
Machined Surface ◽  
Motion Error ◽  
Rotary Axes ◽  
Five Axis

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.

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.

scholarly journals Ball Bar Measurement on Machine Tools with Rotary Axes

2012 ◽  
Vol 6 (2) ◽  
pp. 180-187 ◽  
Author(s):  
Yukitoshi Ihara ◽  
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Industrial Robots ◽  
Error Sources ◽  
Rotary Axes ◽  
Rotary Axis ◽  
Test Conditions ◽  
Ball Bar ◽  
Articulated Robots ◽  
Five Axis

A ball bar is a very convenient device for measuring the motion accuracy of machine tools. Some trials have also been done for measuring motion accuracy of industrial robots. Nowadays, multi-axis machines such as five-axis machining centers are very popular, and therefore, there is increased demand for checking their accuracy. This paper introduces an idea for checking the motion accuracy of five-axis machining centers and diagnosing error sources by reviewing trial measurements on articulated industrial robots. There are two problems. The first problem is that the ball bar can measure only distances, and the second problem is that the ball bar is a linear device and therefore not suitable for the rotary axis motion of 5-axis machines and articulated robots. Finally, the test conditions for the measurement of the motion accuracy of a machine tool showing conical motion, by using the ball bar and ISO/DIS 10791-6 (which is currently being edited) are reviewed and verified.

scholarly journals Improved Method for Synchronizing Motion Accuracy of Linear and Rotary Axes Under Constant Feed Speed Vector at End Milling Point – Investigation of Motion Error Under NC-Commanded Motion –

2019 ◽  
Vol 13 (5) ◽  
pp. 679-690 ◽  
Author(s):  
Takamaru Suzuki ◽  
Kazuki Yoshikawa ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Takakazu Ikegami ◽  
...  
Keyword(s):  
End Milling ◽  
Research Work ◽  
Free Form ◽  
Machining Accuracy ◽  
Feed Speed ◽  
Shape Error ◽  
Control Coefficient ◽  
Machined Surface ◽  
Motion Error ◽  
Rotary Axis

A 5-axis machining center (5MC) is noted for its synchronous control capability, making it a feasible tool for quickly and accurately machining complicated three-dimensional surfaces such as propellers and hypoid gears as it is equipped with a direct-drive (DD) motor in the rotary axis. The current research work identified the necessity of improving both the accuracy of the machined shape and the consistency of the free-form machined surface. A method for maintaining the feed speed vector at the milling point by controlling two linear axes and the rotary axis of a 5MC to improve the quality of the machined surface was investigated. Additionally, a method was proposed for reducing the shape error of machined workpieces by considering differences in the servo characteristics of the three axes. The shape error was significantly reduced by applying the proposed method using a precedent control coefficient determined via calculations. To maintain the feed speed vector at the milling point in the machining of complex shapes, rapid velocity change in each axis is often required, leading to inaccuracy caused by torque saturation at a DD motor in the rotary axis. The results of this study indicate that torque saturation can be evaluated via simulation and that the machining accuracy and consistency can be improved by accounting for these errors using the proposed precedent control coefficient method.

Sign in / Sign up

Export Citation Format

Share Document