Fused Deposition Modeling | Design Guide

Design Guideline: Fused Deposition Modeling (FDM)

These guidelines are to be used as a starting point in understanding the basic aspects of part design and preparation for Fused Deposition Modeling components. When designing a part to be built using FDM technology, build process must be considered. FDM is accomplished by extruding thin layers of molten thermoplastic layer by layer until a part is produced. Because FDM produces parts with specific characteristics and capabilities different from those of other prototyping processes, the systems have become increasingly used as a tool for producing manufactured products.

Part Design for FDM

These guidelines are to be used as a starting point in understanding the basic aspects of part design and preparation for FDM components. When designing a part to be built using FDM technology, build process must be considered. FDM is accomplished by extruding thin layers of molten thermoplastic layer by layer until a part is produced. Because FDM produces parts with specific characteristics and capabilities different from those of other prototyping processes, the systems have become increasingly used as a tool for producing manufactured products.

Size and Orientation

Stratasys Direct Manufacturing can make single FDM parts as large as 36 in. x 24 in. x 36 in. (X, Y, and Z). Designers should note that extruded plastic has its strongest strength in the tensile mode along the x-y plane. Since the layers are held together by “hot flow” across the strands (one strand is cooling while the other is laid upon it), the lowest strength is in the Z-direction for both tensile and shear modes. The Z-dimension brings another consideration to the FDM process. Overhanging non-supported features, such as the top of a closed box, require a foundation of support material to be built, which increases build time and material usage.