Development of a data interface for rapid prototyping in STEP-NC
Layered manufacturing (LM) technologies, usually referred to as rapid prototyping (RP), have the ability to create a physical part directly from their computer model by adding materials on a layer-by-layer basis. Once a computer model is generated for a physical object, it needs to be communicated to other computer systems or LM machines to be further processed. Although it was developed specifically for the stereolithography process, a polygonal facet representation called stereolithography tessellation language (STL) has become the de facto industry standard for the transfer of geometric data to LM process planning system. However, STL has inevitable drawbacks such as redundancy, inaccuracy and lack of integrity. Furthermore, .STL file format is not compatible with high-level design information such as tolerance, mechanical properties and surface patterns, which will be indispensable for further design applications made by LM technologies. In this paper we propose an EXPRESS data model, an information exchange foundation of modeling operation, for the new data transfer scheme in LM community as one among STEP-NC (ISO 14649) modules.
lm rp iso 14649 cad information model step