Formulation of Influence of Machine Geometric Errors on Five-Axis On-Machine Scanning Measurement by Using a Laser Displacement Sensor

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Soichi Ibaraki ◽  
Yoshihiro Kimura ◽  
Yu Nagai ◽  
Shizuo Nishikawa
Keyword(s):  
Measurement Uncertainty ◽  
Spherical Surface ◽  
Uncertainty Assessment ◽  
Displacement Sensor ◽  
Experimental Comparison ◽  
Geometric Errors ◽  
Laser Displacement Sensor ◽  
Low Pass ◽  
Continuous Scanning ◽  
Five Axis

For on-machine measurement of workpiece position, orientation, and geometry on machine tools, five-axis continuous (scanning) measurement by using a laser displacement sensor has a strong advantage in its efficiency, compared to conventional discrete measurement using a touch-triggered contact probe. In any on-machine measurement schemes, major contributors to their measurement uncertainty are error motions of the machine tool itself. This paper formulates the influence of geometric errors of rotary axis average lines on the measurement uncertainty of the five-axis on-machine measurement by using a laser displacement sensor. To validate the present simulator, experimental comparison of measured and simulated trajectories is conducted on five-axis on-machine measurement of a precision sphere of the precalibrated geometry. For total 28 paths measured on the spherical surface, an error in the simulated trajectories from measured trajectories (properly low-pass filtered) was at maximum 5 μm. Uncertainty assessment demonstration for more practical application example of a turbine blade measurement is also presented.

A Calibration Device and Method to Calibrate the Beam’s Direction of the Point Laser Probe

2015 ◽  
Vol 799-800 ◽  
pp. 980-984
Author(s):  
Zhong Xing Xiong ◽  
Feng Li ◽  
Bin Li
Keyword(s):  
Laser Beam ◽  
Deflection Angle ◽  
Ccd Camera ◽  
Displacement Sensor ◽  
Cnc Machine Tools ◽  
Calibration Error ◽  
Laser Displacement Sensor ◽  
Cnc Machine ◽  
Calibration Device ◽  
Five Axis

When using the laser displacement sensor to measure distance, there is a deflection angle which exites between the direction of the laser beam and the direction of axis, this deflection angle has an impact on the final measurement result. This paper presented a calibration method of the laser beam’s direction, designed calibration device and ceramic calibration plate. In the process of calibrating, laser displacement sensor moves along Z-axis and Y-axis of machine, CCD camera takes the image of the spot projected by laser beam on the calibration plate, then calculate the laser beam’s direction based on the movement distance of laser displacement sensor and the spot’s position on calibration plate. Depend on the Mikron five-axis CNC machine tools, this paper describes the whole calibration process in details, the feasibility and accuracy of the method has been verified by experiment. Experimental results show that when the machine tool’s accuracy is within 0.002mm, the calibration error of laser beam’s direction can be controlled within the range of 0.05°.

Turning Dynamics: Part 1 — Experimental Analysis

2012 ◽  
Author(s):  
Eric B. Halfmann ◽  
C. Steve Suh ◽  
N. P. Hung
Keyword(s):  
Instantaneous Frequency ◽  
Period Doubling ◽  
Displacement Sensor ◽  
Laser Displacement Sensor ◽  
Turning Process ◽  
Time Frequency ◽  
Spectral Components ◽  
Tool Vibrations ◽  
Exact Moment ◽  
The Stability

The workpiece and tool vibrations in a lathe are experimentally studied to establish improved understanding of cutting dynamics that would support efforts in exceeding the current limits of the turning process. A Keyence laser displacement sensor is employed to monitor the workpiece and tool vibrations during chatter-free and chatter cutting. A procedure is developed that utilizes instantaneous frequency (IF) to identify the modes related to measurement noise and those innate of the cutting process. Instantaneous frequency is shown to thoroughly characterize the underlying turning dynamics and identify the exact moment in time when chatter fully developed. That IF provides the needed resolution for identifying the onset of chatter suggests that the stability of the process should be monitored in the time-frequency domain to effectively detect and characterize machining instability. It is determined that for the cutting tests performed chatters of the workpiece and tool are associated with the changing of the spectral components and more specifically period-doubling bifurcation. The analysis presented provides a view of the underlying dynamics of the lathe process which has not been experimentally observed before.

Vibration Test of Titanium Alloy Pipes

2012 ◽  
Vol 184-185 ◽  
pp. 701-706
Author(s):  
Ming Xing Qiu ◽  
Chuang Shao ◽  
Yong Zhou ◽  
Li Hua Yue
Keyword(s):  
Titanium Alloy ◽  
Failure Criteria ◽  
Fatigue Tests ◽  
Test Method ◽  
Displacement Sensor ◽  
Laser Displacement Sensor ◽  
New Findings ◽  
Vibration Fatigue ◽  
Welded Pipe ◽  
Test Result

In order to determine the fatigue limits of two kinds of titanium alloy pipes connected by welding and rolling, fatigue tests were carried out by the Aero-Criterion which gives vibration fatigue test method and failure criteria. A laser-displacement-sensor was used at the free end and a strain-gauge at the root of the pipe specimen. The test result shows that the fatigue limit of the welded pipe is higher than the rolled one. In the end some new findings are listed according to the test.

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.

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