Geometric algorithms for rapidly reconfigurable mold manufacturing of free-form objects

This paper presents geometric algorithms for developing a re-configurable tooling system for fabrication of freeform objects. The proposed method involves a mold block, with n faces, in which the mold cavity is formed by moving a set of discrete pins on each face of the block. The part surfaces are approximated in the mold cavity using the pins from the suitable mold block faces. The geometric algorithms detailed in this paper analyze the part and determine the face of mold block from which the part model is approximated best. Further, the algorithms detect possible interference between pins from different faces, and suitably alter the approximating face to alleviate interferences. By moving these pins in and out of the mold block, the shape of the mold cavity is reconfigured rapidly to suit the changes in part geometry. Since, the proposed method approximates free-form objects with discrete pins, a surface-error calculation method is also developed to control the accuracy. Computer implementation and examples are also presented in this paper. q 2004 Elsevier Ltd. All rights reserved.