• International Journal of Precision Engineering and Manufacturing
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• v.4 no.3
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• pp.20-27
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• 2003

Compensation of probe radius is required for accurate measurement in metal working industry. Compensation involves correctly measuring data on the surface in the amount of radius of the touch probe with a Coordinate Measuring Machine (CMM). Mechanical parts with free-formed curves and surfaces are complex enough so that accurate measurement and compensation are indispensable. This paper presents necessary algorithms involved in the compensation of the probe radius for free-formed curves and surfaces. Application of pillar curve is the focus for the compensation.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.81-88
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• 1998

Measurement and inspection of freeform surfaces are required in reverse design processes. In the case of surface measurement using a touch probe, probe radius compensation affects measuring accuracy. But current industrial practice depends upon an operator's experience to compensate for probe radius. In this paper, an on-the-machine measuring and inspection system for freeform surfaces is studied. Probe radius compensation methodology is investigated by modeling of B-spline surfaces based on digitized data. The accuracy and reliability of the developed system is verified through various kinds of numerical simulations and on-the-machine experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.911-914
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• 1995

Measurement and inspection of freeform surface are required in reverse design process. In the case of surface measurement using a touch probe, probe radius compensation affects measuring accuracy But current industrial practice depends upon an operator's experience to compensate for probe radius. In this paper, an on-the-machine measuring and inspection system for freeform surfface was developed. Probe radius compensation methodology was studied via modeling of B-spline surfaces based on digitized data. The accuracy and reliability of the measurement system was confirmed through various kinds of experiments.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.2
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• pp.407-415
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• 1993

This report presents an automatic measurement method of 3-dimensional profiles of free-formed surfaces, by using a touch a touch-trigger contact probe along with a conventional coordinate measuring machine. The method proceeds in three steps; The surface profile under consideration is traced by the probe in an automatic manner, and then its measured data is compensated by considering the actual probe radius. Finally the compensated data is rearranged in the form suitable for the further processings of CAD/CAM applications. Some experimental results are discussed to verify the validity of the method suggested in this study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.71-76
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• 2001

In the surface measurement system using touch probe, probe radius compensation is a key factor for accuracy. In this paper we investigate methods for compensating probe radius so that the surface equation for an "unknown surface" can be efficiently derived. The developed algorithm derives the surface equation by the iterative procedure of estimation, verification, and modification . Since the procedure is applied only for the surface region exceeding the tolerance limit, an accurate surface equation can be obtained with less computation and measurement point. The validity and effectiveness of the algorithm was tested by numerical simulations. The results convinced us that the develop algorithm can be used for surface measurement and tool path planning for NC machining.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.6
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• pp.661-667
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• 2011

Kinematic contact trigger probes are widely used for feature inspection and measurement on coordinate measurement machines (CMMs) and computer numerically controlled (CNC) machine tools. Recently, the probing accuracy has become one of the most important factors in the improvement of product quality, as the accuracy of such machining centers and measuring machines is increasing. Although high-accuracy probes using strain gauge can achieve this requirement, in this paper we study the universal economic kinematic contact probe to prove its probing mechanism and errors, and to try to make the best use of its performance. Stylus-ball-radius and center-alignment errors are proved, and the probing error mechanism on the 3D measuring coordinate is analyzed using numerical expressions. Macro algorithms are developed for the compensation of these errors, and actual tests and verifications are performed with a kinematic contact trigger probe and reference sphere on a CNC machine tool.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.54-65
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• 1993

The paper describes and alternative method based on a new idea to measure the circular movement of machining centers. ISO has employed three testing methods for the acceptance tests of machine tools; the first is a rotating one-dimensional probe method, the second is a two-dimensional probe and a master circular ring, and the third is a kinematic ball bar. The last two methods were proposed and introduced by W. Knapp and J. B. Bryan, respectively. The newly developed method is superior to above two methods; the rotating angle can be detected and the rotating radius is variable. Circular movement errors of machining centers were investigated by the analysis of data measured by R- .THETA. method. Followint observations are obtained 1) The errors which depend on positions, i.e., periodical errors by the pitch of ball screws, errors by compensation of backlash and errors by perpendicularity of X and Y-axis, were analyzed. 2) The errors which depend on NC control system, i.e., errors by the unbalance of position-loop-gaians, errors by velocity-loop-gains and errors by feed speeds, were quantiatively analyzed. 3) The method of extracting error information, which uses moving technique of averaging angle and fourier's analysis data mesured by the R- .THETA. method, was proposed.