  Additive manufacturing parameters of high-performance polymers greatly affect
the thermal history and consequently quality of the end-part. For fused
deposition modeling (FDM), this may include printing speed, filament size,
nozzle, and chamber temperatures, as well as build plate temperature. In this
study, the effect of thermal convection inside a commercial 3D printer on
thermal history and crystalline morphology of polyetheretherketone (PEEK) was
investigated using a combined experimental and numerical approach. Using
digital scanning calorimetry (DSC) and polarized optical microscopy (POM),
crystallinity of PEEK samples was studied as a function of thermal history. In
addition, using finite element (FE) simulations of heat transfer, which were
calibrated using thermocouple measurements, thermal history of parts during
virtual 3D printing was evaluated. By correlating the experimental and
numerical results, the effect of printing parameters and convection on thermal
history and PEEK crystalline morphology was established. It was found that the
high melting temperature of PEEK, results in fast melt cooling rates followed
by short annealing times during printing, leading to relatively low degree of
crystallinity (DOC) and small crystalline morphology.
