Modeling the material grading and structures of heterogeneous objects for layered manufacturing

Abstract

The emphasis of this work is to discuss a scheme for modeling the material grading and structures of heterogeneous objects. To model the material grading of a heterogeneous object, a termed 'grading source' is defined. The grading sources are reference features, which specify the type and position of grading, and a material grading function for controlling the material variation within the geometric boundary of the objects. Within the proposed modeling scheme, a concept on representing objects, which are both heterogeneous in material and structure (e.g. composite laminates), will also be elaborated. For downstream layered manufacturing purposes, a contour sub-division algorithm on each layer arising from slicing a heterogeneous object is proposed. Within each slice, the material grading is decomposed into sub-contours according to the different grading variation. A parameter called 'grading step-width' is defined to control the number of sub-contours and resolution of the grading. With such discretization, it is, therefore, possible to build a heterogeneous object on layered manufacturing machines of different fabricating precision specification. © 2002 Elsevier Science Ltd. All rights reserved.