Development of predictive models for the coalescence of fused deposition modeling fibers

Abstract

Fused deposition modeling (FDM) is the prominent manufacturing method for fabricating end-use parts due to the ability to build complicated structures. In order to be used confidentially in the industry requires a thorough understanding of mechanical behavior of FDM parts under working conditions. The strength of FDM parts is negatively influenced by the insufficient bond strength achieved between fibers, the weakest links in the FDM parts are the weak inter-layer bonds and intra-layer bonds. The aim of this study is to create models that can accurately predict bond length and bond strength between fibers. Analytical equations describing the sintering processes and heat transfer between FDM fibers and surrounding environment are developed and presented. By comparing the predicted value to the actual bond length, the models are found to be moderately accurate. To validate the relation between bond length and bond strength and also determine the process parameters that affect the bond strength, design of experiments (DOE) and analysis of variance (ANOVA) were applied. The result showed that the extrusion temperature to be statistically significant. Further research is recommended to take in to account more factors that could affect the cooling and sintering process that will help improve the precision of predictive models.