The Two Dimensional Microstage Used in Geometric Measurement of Rockwell Diamond Indenter

2015 ◽  
Vol 649 ◽  
pp. 90-96
Author(s):  
Sheau Shi Pan ◽  
I Chih Ni ◽  
Feng Yu Yang

The Primary Rockwell Hardness Standard System was set up in the Center for Measurement Standards since July 1996 till June 1997. During the period, a compact laser interferometer, HP10737R 3-axis interferometer system was used to measure the effect of pitch and yaw of the Rockwell Hardness standard machine. Considering to increase the performance of hardness measurement, the geometry of the diamond tip has to be determined. In this paper, we will present the results of indenter geometry by μ-CMM (Coordinate Measuring Machine) in CMS.

2014 ◽  
Vol 625 ◽  
pp. 42-46
Author(s):  
Qing Zhou Sun ◽  
Ji Zhao ◽  
Shi Jun Ji ◽  
Lei Zhang ◽  
Shu Hong Zhou

In this paper, a non-contact coordinate measuring machine with laser displacement sensor, which consists of three translational axes, is designed and built independently. In order to obtain the measuring precision, it needs to calibrate the coordinate measuring machine. Learning from the calibration method of contact coordinate measuring machine, a detection method is proposed for calibrating the precision of the non-contact coordinate measuring machine. Based on the homogeneous coordinate transformation theory, the error model of coordinate measuring machine is built under the condition that the positioning errors, angular errors, straightness errors and perpendicularity errors are taken into comprehensive consideration. The final error expressions of three axes can be calculated in the use of error model and homogeneous coordinate transformation theory. The final values of the errors are acquired through the analysis of the error curves, which can be obtained by using the laser interferometer system. The method proposed in this paper is using the two-dimensional ball plate to measure the errors. By locating three different positions of the ball plate in the space and using automatic centering procedure to measure the center position which is previously calibrated, the final errors of three axes can be detected directly. By comparing the two results, it testifies that the two-dimensional ball plate detection method is reasonable. Comparing with the laser interferometer method, the two-dimensional ball plate detection method reduces the workload of adjusting the optical path and the time of measuring errors, which has the vital significance in calibrating the precision of non-contact coordinate measuring machine.


2015 ◽  
Vol 4 (1) ◽  
pp. 125 ◽  
Author(s):  
Wilma Polini ◽  
Giovanni Moroni

Coordinate Measuring Machine (CMM) inspection planning is an activity performed by well-trained operators, but different measurement techniques, using the same data analysis algorithms yield in different measurement results. This is a well-recognized source of uncertainty in coordinate measurement. A CMM, provided with an automatic inspection planning (CAIP) system, permits to implement more accurate and efficient operating procedures and to fit higher quality assurance standards and tighter production timings.In this paper we present a frame of a CAIP system, able to deal with almost all the decisional stages of CMM inspection. Moreover, original approaches have been developed and presented in inspection feature selection, part set-up, probe configuration, and path planning.


2015 ◽  
Vol 9 (5) ◽  
pp. 541-545 ◽  
Author(s):  
Mariko Kajima ◽  
◽  
Tsukasa Watanabe ◽  
Makoto Abe ◽  
Toshiyuki Takatsuji

A calibrator for 2D grid plates have been developed. The calibrator was based on a commercial imaging coordinate measuring machine (imaging CMM). A laser interferometer for the calibration of the x-coordinate and two laser interferometers for the calibration of the y-coordinate were attached to the imaging CMM. By applying multistep measurement method for the calibration procedure, the geometrical error in the calibrator was reduced. The calibration of a precision 2D grid plate was demonstrated, and the expanded uncertainty was estimated to be 0.2 μm (k =2).


2008 ◽  
Vol 78 (3) ◽  
pp. 475-481 ◽  
Author(s):  
Ann Marie Owens ◽  
Ama Johal

Abstract Objectives: To test the hypothesis that there is no difference between the actual mesiodistal root angulation and the mesiodistal root angulation as measured on the panoramic radiograph. Materials and Methods: A typodont dentition was set up into a Class I occlusion. Wire struts were placed on the buccal surface of each tooth to represent their long axes. The dentition was fixed into a natural skull for imaging. The radiographic and true mesiodistal angulation of each tooth to a horizontal reference plane (the arch wire) was measured using a coordinate measuring machine (CMM). The mesiodistal root positions were then altered to a more mesial and then more distal position and the measurements were repeated. Results: Only 26.7% of the radiographic root angulations were within the clinically acceptable angular variation range of ±2.5°. The greatest variation in the upper arch occurred in the canine-premolar area where the roots were projected as being more divergent. The greatest variation in the lower arch occurred in the lateral incisor-canine region where these roots were projected as being more convergent. The extent of radiographic distortion is statistically greater in the lower arch than in the upper arch in the ideal (P ≤ .05) and distal (P ≤ .01) root positions. Conclusions: The hypothesis is rejected. There is a clinically significant variation between the radiographic and the true root angulations recorded. Caution is advised when interpreting mesiodistal root angulation using this radiograph.


2014 ◽  
Vol 1061-1062 ◽  
pp. 1162-1166
Author(s):  
Li Jie Chen ◽  
Hong Chao Wu

According to the standard definition of cylindricality error, set up any space surface cylindricality errors of least squares mathematics model. The coordinate origin of the model can be freely selected, nor equal angle interval among discrete sampling points. Analysis by computer simulation, results show that the model developed is right and pratical. On the basis of mathematical models, using four direct algorithm for unconstrained optimization, cylindricality errors can be evaluated in accordance with the minimum conditions. Mathematical models can be used for three-coordinate measuring machine and also available for other intelligent instrument for measuring parts of the cylindricality errors.


2012 ◽  
Vol 217-219 ◽  
pp. 2419-2422
Author(s):  
Li Jie Chen ◽  
Ping Zou

According to the standard definition of radial circular error, set up any space surface radial runout errors of least squares mathematics model. The coordinate origin of the model can be freely selected, nor equal angle interval among discrete sampling points. Analysis by computer simulation, results show that the model developed is right and pratical. On the basis of mathematical models, using four direct algorithm for unconstrained optimization, radial runout errors can be evaluated in accordance with the minimum conditions. Mathematical models can be used for three-coordinate measuring machine and also available for other intelligent instrument for measuring parts of the radial runout errors.


2012 ◽  
Vol 271-272 ◽  
pp. 1770-1775
Author(s):  
Qi Gao

The method used for measurement and calibration of machine tool errors should be general and efficient. With this method, the machine tool status can be completely identified and its accuracy can be enhanced by software error compensation. The point compensation method can be used as a means for modifying the nominal tool path and on-machine inspection where the machine tool is used as a coordinate measuring machine. The validity of the error calibration method proposed in this' paper was shown using a vertical 3-axis CNC machine with a laser interferometer and a ball bar technique.


Author(s):  
C H Liu ◽  
Y-R Jeng ◽  
W Y Jywe ◽  
S-Y Deng ◽  
T-H Hsu

In this paper a method is developed for straightness measurement of a linear guide by using a straightness self-compensating stage with an optical straightness measuring system, an eddy current sensor, and a cross-roller type compensation stage. Both the compensation stage and the optical straightness system were set up on a scanning stage to measure the straightness error of the scanning stage. The measured straightness error was fed back to the control system to compensate directly in real time. Thus, straightness of a linear guide without the added straightness error of the scanning stage could be measured. The Hewlett Packard laser straightness calibration system was used to verify the real-time compensated results. Straightness error of the scanning stage was compensated from the worst straightness error of 20 μm/150 mm to 0.9 μm/150 mm. The eddy current sensor measured straightness of the linear guide and the measured result matched the result obtained by the coordinate measuring machine.


ACTA IMEKO ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 250
Author(s):  
R. R. Machado ◽  
S. Low ◽  
A. Germak

This paper describes an overview of the capability of the NMIs that participated on the CCM Pilot Study measurement systems, conducted by the CIPM/CCM/Working Group on Hardness, to characterize the Rockwell hardness diamond indenter geometry, by measuring the included cone angle, the straightness of the generatrix, the spherical tip radius, the deviation of the local radius and the tilt angle. <br />Nine NMIs took part in this study: INMETRO (Brazil); INRiM (Italy); KRISS (South Korea); NIM/PR (China); NIMT (Thailand); NIST (USA); PTB (Germany); TUBITAK UME (Turkey); VNIIFTRI (Russia), where INMETRO (Brazil) served as pilot laboratory.


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