Functionally Gradient Material Representation by Volumetric Multi-Texturing for Solid Freeform Fabrication 350

In order to fabricate parts from Functionally Gradient Materials (FGM) by layered manufacturing methods, the SFF community needs a method to represent material distributions in solid models. Gradient material distribution requires accurate and systematic representation, and must be compatible with existing geometric data. This paper presents a method, called Volumetric Multi Texturing, to represent a three dimensional density gradient by exploiting hypertexturing and volumetric density functions. This method utilizes procedural and implicit methods to design/acquire density information. The implicit procedural approach, as opposed to an input database, allows users to interactively create and modify the design patterns without explicitly changing the values stored in the database. Further, it promises convenience in process planning, and efficiency in data storage and computation time. The theoretical approach, design procedure, and tool path generation for fabrication of an example part are presented in the paper. The design procedure presented is based on specifying the material gradient by surface modification.