MANUFACTURED PART MODELING FOR CHARACTERIZATION OF GEOMETRIC VARIATIONS OF AUTOMOTIVE SPACEFRAME EXTRUSIONS

This article presents a method for characterizing geometric shape vari ations in manufactured automotive spaceframe extrusions using measurem ent data obtained by a Coordinate Measurement Machine (CMM). With a ma nufacturing perspective, a modeling scheme is proposed far representin g the actual shape of the extrusions. Systematic deviations in the geo metry of the parts front their theoretically perfect design descriptio n models are described by the critical parameters of their manufacture d part models (MPMs), which are constructed by fitting CMM data throug h an optimization. The manufactured part model can then be interpreted in a meaningful way for improving bending process as well as quantify ing the process capability. An application of the methodology is illus trated through the analysis of experimental data for rotary draw bent extrusions used in the aluminum intensive automobiles.