Numerical and Experimental Investigation of Heat Transfer During Composite Fused Filament Fabrication

Abstract

Additive manufacturing of fiber-reinforced composite materials enables production of parts with high specific stiffness and strength. Several manufacturers have released their versions of composite 3D printers with the most popular being Markforged® which relies on fused filament fabrication (FFF) process. This paper focuses on numerical and experimental investigation of heat transfer in composite specimens produced via the FFF manufacturing process. The experimental setup combines the Markforged® Mark Twoâ„¢ composite 3D printer and the FLIR thermal camera. The camera is used to collect full field temperature history of a cylindrical composite specimen 12.7 ð‘šð‘š × 25.4 ð‘šð‘š (ð‘‘ð‘–ð‘Žð‘šð‘’ð‘¡ð‘’𑟠× â„Žð‘’ð‘–ð‘”â„Žð‘¡) manufactured using composite filament Onyxâ„¢ consisting of nylon matrix and chopped carbon fibers. The thermal data is used to validate three-dimensional finite element simulations of transient heat transfer during the filament deposition process. Two approaches are used for the numerical simulation: “element-by-element†in which elements are activated in sequence following a realistic deposition path, and “layer-by-layer†in which all elements of a layer are activated simultaneously and then allowed to cool. The latter approach is more computationally efficient. Micromechanical homogenization is used to estimate the effective conductivity values of the fiber-reinforced Onyxâ„¢ filament. Full-field temperature distribution and path plots are generated via both numerical approaches and from experimental data. The element-by-element approach appears to be capable of predicting the experimentally observed temperature distribution below the most recently deposited layer.