Strength and Interlayer Toughness of FDM PC , ABS , and PETG : Roles of Printing Speed and Environmental Temperature

ABSTRACT This work compares Polycarbonate (PC), Acrylonitrile–Butadiene–Styrene (ABS), and polyethylene terephthalate glycol (PETG) printed by fused deposition modeling (FDM) across speeds (50–150 mm/s) and test temperatures for mechanical characterization (tensile and delamination at 25/60/100°C), and interprets the results with a compact physics‐guided framework. Tensile and compact‐tension (CT) delamination tests, paired with Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR), link thermal transitions and chemistry to performance. PC consistently delivers the highest bulk tensile strength at all temperatures/speeds (high glass transition temperature ( T g ), strong thermal stability) but shows lower interlayer resistance than ABS and PETG at 25°C–60°C unless printing is tuned. PETG provides the strongest delamination toughness at 25°C–60°C, especially at higher speeds, yet loses load‐bearing capacity near 100°C as it softens above T g . ABS is intermediate, remaining stable to 60°C and dropping sharply at 100°C primarily from matrix softening, consistent with DSC/FTIR. A minimal model, composed of (i) a reptation‐controlled interlayer‐healing term driven by nozzle temperature and residence time (speed), (ii) a monotone tensile‐retention law versus reduced temperature ( T env – T g ), and (iii) cohesive‐zone parameters inferred from CT, captures these trends and yields material‐specific speed–temperature maps. Practically, PC suits hot‐service (~100°C) if interlayer bonding is enhanced; PETG is optimal at room‐to‐moderate temperatures when delamination resistance is critical; ABS offers a balanced option when service temperatures stay well below T g .