The fracture strength developed between Fused-Deposition extruded roads is modeled in
terms of the wetting and thermally-driven diffusion bonding processes. Thermal histories at the
road-to-road interface are obtained from a heat transfer analysis and used to develop model
predictions based on reptation theory for the interdiffusion of long-chain polymer molecules.
Fracture toughness data on FD-ABS plastic specimens is used to quantify the model. The results
show that most of the fracture strength develops during the surface wetting stage of bonding and
that slower cooling rates during solidification promote stronger bonding between the roads.Mechanical Engineerin
