A Control-Oriented Model for Bead Cross-Sectional Geometry in Fused Deposition Modeling

Additive manufacturing (AM) is a digital manufacturing technology that manufactures a 3D object in a bottom-up and layer-by-layer fashion. Fused deposition modeling (FDM), also known as desktop 3D printing, is one of the most commonly used AM technologies with numerous applications in academia and industry. Some of the greatest challenges with FDM include poor repeatability and reliability of the process, leading to mid-process failures or out-of-spec final products. Closed-loop control applications for FDM have been proposed as a means of mitigating mid-process failures. However, no models currently exist to enable control of the bead cross-sectional dimensions for the extruded material. This work presents a control-oriented model describing the effect of process parameters on cross-sectional dimensions of the deposited beads in FDM. A geometric model is presented and a procedure to evaluate the unknown machine and material specific parameters in the model is provided by leveraging design of experiments. The proposed model is experimentally validated and the accuracy of the results is presented. The results show that the proposed model accurately represents the bead cross-sectional geometry and is suitable for closed-loop control applications.