Manufactruability Analysis of Infeasible Features in Polygonal Models for Web-Based Rapid Prototyping

Web-based online submission of computer aided design (CAD) models for prototype parts is getting popular among service bureaus and gaining wider acceptance among rapid prototyping users. In the web based rapid prototyping (RP), an instant quote needs to be generated for an arbitrary polygonal model (usually in STL format). Hence the manufacturability analysis of polygonal models is critical in automating the instant quoting process. In this paper two common problems are addressed including: (1) small features that are infeasible to be made by a RP process, and (2) cost analysis of a given polygonal model. We present two methods based on the analysis of offsetting results: (i) a fast approach of identifying infeasible features in order to provide an instant feedback to users, and (ii) an accurate approach of calculating the information of infeasible features for a given tool size in order to facilitate cost analysis. The related data structures and algorithms are presented. Both 2-dimensional and 3-dimensional examples are provided to illustrate the effectiveness of our approach.