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Keywords
Rapid prototyping, Anisotropy, Fused deposition modeling
Rapid Prototyping (RP) technologies provide the ability to fabricate initial prototypes from various model materials. Stratasys Fused Deposition Modeling (FDM) is a typical RP process that can fabricate prototypes out of ABS plastic. To predict the mechanical behavior of FDM parts, it is critical to understand the material properties of the raw FDM process material, and the effect that FDM build parameters have on anisotropic material properties. This paper characterizes the properties of ABS parts fabricated by the FDM 1650. Using a Design of Experiment (DOE) approach, the process parameters of FDM, such as raster orientation, air gap, bead width, color, and model temperature were examined. Tensile strengths and compressive strengths of directionally fabricated specimens were measured and compared with injection molded FDM ABS P400 material. For the FDM parts made with a 0.003 inch overlap between roads, the typical tensile strength ranged between 65 and 72 percent of the strength of injection molded ABS P400. The compressive strength ranged from 80 to 90 percent of the injection molded FDM ABS. Several build rules for designing FDM parts were formulated based on experimental results.
1. Introduction
Recent advances in the fields of Computer Aided Design (CAD) and Rapid Prototyping (RP) have given designers the tools to rapidly generate an initial prototype from concept. There are currently several different RP technologies available, each with its own unique set of competencies and limitations. The Fused Deposition Modeling (FDM) process from Stratasys produces prototype parts out of ABS plastic. FDM deposits a molten filament of ABS in a criss-cross manner resulting in direction dependant, or anisotropic, material properties. This paper seeks to characterize some of the anisotropic properties of ABS parts produced by the FDM process.
The FDM process works as follows. First, a three dimensional solid model must be created. This can be accomplished in many of the commonly available CAD packages. The model is then exported to the FDM Quickslice(TM) TI software using the stereolithography (STL) format. This format tessellates the part into a set of triangles. The advantage of the STL format is that most CAD systems support it, and it simplifies the part geometry by reducing it to its most basic components. The disadvantage...