An Algorithmic Approach for Designing Part Nests for Automotive Body Manufacturing

This paper presents an algorithmic approach for designing part nest fixtures used in the automotive industry for presenting sheet metal parts to robots for precision grasping. The algorithm receives the CAD model of the part to be nested and some user inputs and produces the CAD model of the part nest, complete with its functional elements like locating pins, side rests, bottom rests, and a frame to hold these elements together. To do this, the algorithm first orients the CAD solid from the as-modeled to the as-nested orientation, then identifies the locations of two points on the part's periphery that can optimally arrest CW and CW rotations, then identifies three, five, or eight points on the part's bottom-facing faces where bottom rests could be placed, and finally generates geometry of the locating pins, side rests, bottom rests, and the frame to hold them together. The algorithm is validated by applying it to four automotive sheet metal parts.