A proposed ISO 10303 (STEP)-based approach for representing heterogeneous objects for layered manufacturing

Solid modeling of objects forms an important task in design and manufacturing. Recent developments in the field of layered manufacturing (LM) have shown potential for the physical realization of heterogeneous (multi-material) objects. Thus, there is a need to represent material information as an integral part of the CAD model data. Slicing of the CAD model is an inherent part of process planning for LM. There is a need for a neutral 2D slice format to transfer data from the CAD system (slicing is done on the 3D CAD model) to the commercial LM machine. This can also be used as a file format to demonstrate inter-operability among LM machines having comparable layer thickness specifications. To fabricate heterogeneous objects, the slice format should be capable of representing both material and geometry information. Information models for the representation of product data are being developed as an international standard (ISO 10303) informally called STEP. However, the current application protocols focus on the representation of homogeneous objects only. This paper suggests an information model to represent heterogeneous objects using the information modeling methodology developed for ISO 10303. The information model Address all correspondence to this author