Fused filament fabrication of polyetheretherketone in vacuum: the influence of high vacuum on layer adhesion in z-orientation

The application of fused filament fabrication (FFF) in vacuum changes the heat transfer of the process. This work investigates the influence of the working ambient pressure conditions in FFF-based 3D printing of polyetheretherketone (PEEK) specimens, and its impact on the resulting part strength. Layer adhesion drastically improves with decreasing pressure, maximum layer adhesion is reached for ambient pressure below \(10^{-3}\) ${10}^{-3}$ mbar. We show that simple and low-cost vacuum equipment is sufficient to achieve such pressure conditions, making this process interesting for the general processing of high-temperature polymers using FFF.