Infrared preheating to improve interlayer strength of big area additive manufacturing (BAAM) components

The Big Area Additive Manufacturing (BAAM) system can print structures on the order of several meters at high extrusion rates, thereby having the potential to significantly impact automotive, aerospace and energy sectors. The functional use of such parts, however, may be limited by mechanical anisotropy, in which the strength of printed parts across successive layers in the build direction (z-direction) can be significantly lower than the corresponding in-plane strength (x-y directions). This has been primarily attributed to poor bonding between printed layers since the lower layers cool below the glass transition temperature (Tg) before the next layer is deposited. Therefore, the potential of using infrared heating is considered for increasing the surface temperature of the printed layer just prior to deposition of new material to improve the interlayer strength of the components. This study found significant improvements in bond strength for the deposition of acrylonitrile butadiene styrene (ABS) reinforced with 20% chopped carbon fiber when the surface temperature of the substrate material was increased from below Tg to close to or above Tg using infrared heating.