Using multiple materials in additive manufacturing technologies is critical for building parts with functionally gradient geometries. In order to achieve a desired material gradient, an advanced process planning and control system is required. This paper details the development of a process planning method and control system for functionally graded material fabrication using a triple extruder Freeze-form Extrusion Fabrication (FEF) system including motion code generation, extruder dynamic modeling and control, and composition gradient control. The effect that extruding multiple materials from a single orifice via static mixing has on the time delay of the resulting mixture is taken into account for path planning, and this factor is incorporated into integrating motion codes with extrusion commands. The effectiveness of the proposed system is demonstrated by fabricating three-dimensional parts with desired gradient compositions using multiple materials.

Meeting Name

22nd Annual International Solid Freeform Fabrication Symposium -- An Additive Manufacturing Conference (2011: Aug. 8-10, Austin, TX)


Mechanical and Aerospace Engineering


This project is supported by NSF grant #CMMI-0856419, with participation and matching support of Boeing Company, through the Center for Aerospace Manufacturing Technologies at the Missouri University of Science and Technology, and by the Air Force Research Laboratory through Universal Technology Corporation (Contract #10-S568-0094-01- C1).

Document Type

Article - Conference proceedings

Document Version

Final Version

File Type




Publication Date

10 Aug 2011

Included in

Manufacturing Commons