Title: Sampling scheme for locating two-dimensional parts

Authors: Dewi Rahardja, Yan D. Zhao

Addresses: Department of Mathematics and Computer Science, University of Indianapolis, Indianapolis, IN 46227, USA. ' Eli Lilly and Company, Indianapolis, IN 46285, USA

Abstract: Car manufacturers often need to compare and choose a car hood fixture that gives a good quality fitting between the hood and the body. The good quality hood fitting is usually defined as a constant-width gap from the car body and is typically evaluated from Coordinate Measuring Machine (CMM) data collected from the hood|s surface after placement. However, such CMM data are commonly obtained from arbitrary choice of CMM probe paths (thereafter referred to as a sampling scheme), which may not capture the hood shape well and thus make the fixture comparison inefficient. Hence, we recommend obtaining a sensible Sampling Scheme (SS) before collecting the actual data. To achieve this goal, we propose a figure of merit for comparing all possible SS(s) and use computational methods to get the optimum SS(s). We conclude from simulations that the probe paths in the optimum SS(s) will generally be located closest to the extremes of the part boundary in the two-dimensional (2D) case.

Keywords: statistical modelling; statistical sampling schemes; coordinate measuring machines; CMM data; probe paths; two-dimensional parts; 2D parts; automotive manufacturing; automobile industry; car hood fixtures.

DOI: 10.1504/IJMR.2007.015090

International Journal of Manufacturing Research, 2007 Vol.2 No.4, pp.484 - 498

Published online: 12 Sep 2007 *

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