Quasisteady models for weld temperatures in fused filament fabrication

Abstract

During fused filament fabrication (FFF), strands of hot extruded polymer are layered onto a cooler substrate. The bond strength between layers is related to the weld temperature at the polymer/substrate interface, and hence understanding temperature evolution is of keen interest. A series of increasingly sophisticated models is presented: a standard heat equation, an unsteady fin equation and a fin equation with a heat-loss jump condition. Each is analytically tractable and uses a quasisteady approximation for the temperature in the growing substrate. The jump condition introduces the complication of a non-self-adjoint problem, but fits the experimental data very well.