Modeling for silicone foam material extrusion with liquid rope coiling

Abstract

This research demonstrates a Modeling idea using parametric Modeling and considering the process to predict coiling patterns effectively in open-cell foams material extrusion (MEX) with liquid rope coiling (LRC) effect. The model consists of three sub-models, including pneumatic extrusion model, liquid rope coiling model, and geometric model, considering material properties, material extrusion, falling, LRC, pattern formation process and device structure. The model uses four MEX process parameters (back pressure, moving speed, inner nozzle diameter, and nozzle height) to predict three geometric parameters of the coiling pattern. The capability to predict pattern shape (period length, width, and loop length) accurately is validated by comparing the fit of predicted and experimental values when adjusting the process parameters, with R-squared coefficients up to 0.957. Then, application value is demonstrated by printing silicone open-cell foams under the guidance of the proposed model and studying the compression properties of these foams. The obtained three-region stress-strain curves indicate the feasibility of variable stiffness foam fabrication by adjusting the process parameters according to the proposed model during the printing process. Based on the results, the proposed model demonstrates accuracy in predicting geometric parameters of translational coiling pattern, makes predictable manufacturing of complex cellular structures available, and provides a foundation for design and fabrication of load-based variable stiffness silicone open-cell foam.