Non-Contact R-Test for Error Calibration of Five-Axis Machine Tools

2012 ◽  
Author(s):  
Soichi Ibaraki ◽  
Cefu Hong
Keyword(s):  
Machine Tools ◽  
Three Dimensional ◽  
Target Surface ◽  
Test Device ◽  
Contact Type ◽  
Sphere Center ◽  
Displacement Sensors ◽  
New Instrument ◽  
Error Calibration ◽  
Five Axis

The R-test is a new instrument to measure three-dimensional displacement of a precision sphere attached to a spindle relative to a work table by using three displacement sensors. Its application to error calibration for five-axis machine tools has been studied in both academia and industry. For the simplicity in calculating the sphere center displacement, all conventional R-test devices use contact-type displacement sensors with a flat-ended probe. Conventional contact-type R-test may be potentially subject to the influence of the friction or the dynamics of supporting spring in displacement sensors particularly in dynamic measurement. This paper proposes a non-contact R-test with laser displacement sensors. A new algorithm was proposed to estimate the three-dimensional displacement of sphere center by using laser displacement sensors, It compensates the measurement uncertainty caused by the inclination of the target surface. Experimental case studies are presented to evaluate its measurement performance by comparing with the conventional contact-type R-test device.

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.

Error Calibration for Five-Axis Machine Tools by On-the-Machine Measurement Using a Touch-Trigger Probe

2014 ◽  
Vol 8 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Soichi Ibaraki ◽  
◽  
Yusuke Ota
Keyword(s):  
Machine Tool ◽  
Test Piece ◽  
Machine Tools ◽  
Experimental Demonstration ◽  
Arbitrary Geometry ◽  
Rotary Axes ◽  
Ball Bar ◽  
Touch Trigger Probe ◽  
Error Calibration ◽  
Five Axis

This paper presents a scheme to calibrate the error map of the rotary axes of a five-axis machine tool. This is done by means of on-the-machine measurement of a test piece using a contact-type touch-trigger probe. The present probing-based approach is more suitable for efficient and automated “self-calibration,” than conventional calibration schemes, such as ball bar tests or R-test. It is thus advantageous in the application to periodic checking of the error map, or periodic updating of its numerical compensation. In the present approach, a test piece of arbitrary geometry, e.g. a raw unmachined workpiece, can be used as the probing target. An experimental demonstration is presented.

scholarly journals Overall Profile Measurements of Tiny Parts with Complicated Features with the Cradle-Type Five-Axis System

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4609
Author(s):  
Lei Liu ◽  
Linlin Zhu ◽  
Li Miao ◽  
Chen Li ◽  
Changshuai Fang ◽  
...  
Keyword(s):  
Measurement Accuracy ◽  
Three Dimensional ◽  
System Construction ◽  
Actual Measurement ◽  
Measurement Capability ◽  
Error Calibration ◽  
Narrow Space ◽  
Complex Features ◽  
Five Axis ◽  
Industrial Problem

There are generally complex features with large curvature or narrow space on surfaces of complicated tiny parts, which makes high-precision measurements of their three-dimensional (3D) overall profiles a long-lasting industrial problem. This paper proposes a feasible measurement solution to this problem, by designing a cradle-type point-scanning five-axis measurement system. All the key technology of this system is also studied from the system construction to the actual measurement process, and the measurement accuracy is improved through error calibration and compensation. Finally, the feasibility is proved by engineering realization. The measurement capability of the system is verified by measuring workpieces such as cross cylinders and microtriangular pyramids.

A Study on Tool Position and Posture Measurement Device by Using Parallel Mechanism

2009 ◽  
Vol 3 (3) ◽  
pp. 271-276 ◽  
Author(s):  
Yukitoshi Ihara ◽  
◽  
Shozo Matsushita ◽  
Keyword(s):  
Machine Tools ◽  
Forward Kinematics ◽  
Parallel Kinematics ◽  
Test Device ◽  
Measuring Device ◽  
Multiaxis Machining ◽  
Displacement Sensors ◽  
Tool Position ◽  
Posture Measurement ◽  
Main Spindle

The main purpose of this study is to develop a measuring test device by parallel kinematics for measuring a motion accuracy of multiaxis machining centers. The initially developed measuring test device could measure only position of the spindle with three displacement sensors. With the 3DOF device the motion accuracy of machine tools with three-axis was measured. Since the mechanism of the joint was smooth and the sensor resolution was small enough, the measured result showed that the measuring device had an enough performance for the machining centers in normal accuracy. Then the 6DOF measuring test device was developed. It had six displacement sensors and it could measure both position and posture angle of the main spindle. Despite the adoption of parallel kinematics, forward kinematics calculation was possible due to the sophisticated arrangement of sensors, thus the hi-speed data acquisition could be possible.

scholarly journals Special Issue on Machine Accuracy Evaluation

2020 ◽  
Vol 14 (3) ◽  
pp. 359-359
Author(s):  
Soichi Ibaraki ◽  
Andreas Archenti
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Metrological Problem ◽  
Accuracy Evaluation ◽  
3D Measurement ◽  
Special Issue ◽  
Position Measurement ◽  
Machine Tool Accuracy ◽  
Error Calibration ◽  
Five Axis

The accuracy of a three-dimensional (3D) positioning system can ultimately be evaluated via measurement of a 3D vector between command and actual end-effector positions at arbitrary points over the entire workspace. This is a simple, yet challenging, metrological problem. The motion accuracy of a machine tool is traditionally evaluated on an axis-to-axis basis, with every error motion of every axis being independently measured as part of a one-dimensional measurement process in a different setup. Toward the ultimate goal of 3D position measurement over the entire workspace, research efforts have offered several new, practical measurement technologies. This special issue covers the technical and academic efforts regarding the evaluation of machine tool accuracy. The papers in this special issue clarify the latest research frontiers regarding machine tool accuracy from a metrological viewpoint. In the first paper, by Montavon et al., error calibration technologies and their management are reviewed within the Internet of production concept. Long-term accuracy monitoring and management are clearly among the most crucial technical challenges faced regarding machine tools, and the work by Xing et al. is related to them. Ibaraki et al. presented machining tests to evaluate the thermal distortion of a machine tool. Peukert et al. studied the dynamic interaction between machine tools and their foundations. Various 3D measurement schemes for determining machine error motions have been investigated by many researchers, and some have been implemented in industrial applications. Kenno et al. and Florussen et al. investigated 3D measurement using the R-test for five-axis machines. Miller et al. studied simultaneous measurement of six-degree-of-freedom error motions of a linear axis. Nagao et al. presented an error calibration method for a parallel kinematic machine tool. The editors appreciate the contributions of all the authors, as well as the work of the reviewers. We are confident that this special issue will further encourage research and engineering work for improving the accuracy and performance of machine tools.

scholarly journals Influence of Tool Length and Profile Errors on the Inaccuracy of Cubic-Machining Test Results

2021 ◽  
Vol 5 (2) ◽  
pp. 51
Author(s):  
Zongze Li ◽  
Hiroki Ogata ◽  
Ryuta Sato ◽  
Keiichi Shirase ◽  
Shigehiko Sakamoto
Keyword(s):  
Machine Tools ◽  
Test Accuracy ◽  
Test Results ◽  
Machining Error ◽  
Tool Profile ◽  
Machining Test ◽  
The Difference ◽  
Side Error ◽  
Profile Errors ◽  
Five Axis

A cubic-machining test has been proposed to evaluate the geometric errors of rotary axes in five-axis machine tools using a 3 × 3 zone area in the same plane with different tool postures. However, as only the height deviation among the machining zones is detected by evaluating the test results, the machining test results are expected to be affected by some error parameters of tool sides, such as tool length and profile errors, and there is no research investigation on how the tool side error influences the cubic-machining test accuracy. In this study, machining inaccuracies caused by tool length and tool profile errors were investigated. The machining error caused by tool length error was formulated, and an intentional tool length error was introduced in the simulations and actual machining tests. As a result, the formulated and simulated influence of tool length error agreed with the actual machining results. Moreover, it was confirmed that the difference between the simulation result and the actual machining result can be explained by the influence of the tool profile error. This indicates that the accuracy of the cubic-machining test is directly affected by tool side errors.

scholarly journals Study of Machining of Gears with Regular and Modified Outline Using CNC Machine Tools

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2913
Author(s):  
Rafał Gołębski ◽  
Piotr Boral
Keyword(s):  
Machine Tools ◽  
Coordinate Measuring Machine ◽  
Optical Microscope ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Cylindrical Gears ◽  
Measuring Machine ◽  
Five Axis

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.

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