Using MATLAB to Compute Heat Transfer in Free Form Extrusion

Abstract

Rapid Prototyping (RP) is a group of techniques used to quickly fabricate a scale model of a part or assembly using three-dimensional computer aided design (CAD) data (Marsan, Dutta, 2000). A large number of RP technologies have been developed to manufacture polymer, metal, or ceramic parts, without any mould, namely Stereolithography (SL), Laminated Object Manufacturing (LOM), Selected Laser Sintering (SLS), Ink-jet Printing (3DP) and Fused Deposition Modeling (FDM). In Fused Deposition Modelling (developed by Stratasys Inc in U.S.A.), a plastic or wax filament is fed through a nozzle and deposited onto the support (Perez, 2002; Ahn, 2002; Ziemian & Crawn, 2001) as a series of 2D slices of a 3D part. The nozzle moves in the X–Y plane to create one slice of the part. Then, the support moves vertically (Z direction) so that the nozzle deposits a new layer on top of the previous one. Since the filament is extruded as a melt, the newly deposited material fuses with the last deposited material. Free Form Extrusion (FFE) is a variant of FDM (Figure 1), where the material is melted and deposited by an extruder & die (Agarwala, Jamalabad, Langrana, Safari, Whalen & Danthord, 1996; Bellini, Shor & Guceri, 2005). FFE enables the use of a wide variety of polymer systems (e.g., filled compounds, polymer blends, composites, nanocomposites, foams), thus yielding parts with superior performance. Moreover, the adoption of coextrusion or sequential extrusion techniques confers the possibility to combine different materials for specific properties, such as soft/hard zones or transparent/opaque effects.