FDM_PRINTING_101
ZERO-TO-FIRST-PRINT ▸ THE FUNDAMENTALS OF FUSED DEPOSITION MODELING
Anycubic Kobra Max — inbound, ETA Jun 2026 — Large-format. Bed: 450×400×400mm. 180mm/s max.
> WHAT_IT_IS
FDM (Fused Deposition Modeling) melts plastic filament and extrudes it layer by layer through a heated nozzle. Think of it as a computer-controlled hot glue gun that builds objects from the bottom up, one thin layer at a time.
Core components: Hotend (heats filament to melting point), extruder (gears that push filament), heated bed (keeps first layers stuck), motion system (CoreXY on the S1 — fast and accurate).
> LAYER_HEIGHT
Thinner layers = smoother surface, longer print. Thicker layers = faster, visible lines. Our standard is 0.16–0.20mm unless the job calls for otherwise.
> FIRST_LAYER_IS_EVERYTHING
If the first layer doesn't stick, the print fails. Bed must be level, clean, and at the right temperature. PLA bed ~60°C. ASA bed ~100°C in an enclosure. Watch the first layer go down before walking away.
The distance between nozzle and bed at Z=0. Too high = filament doesn't stick, curls up. Too low = nozzle digs into bed, no filament comes out. A sheet of paper should drag slightly between nozzle and bed. Calibrate when changing nozzles or after a failed print.
> MATERIALS
> INFILL
Interior structure density. 0% = hollow, 100% = solid. 15–20% grid/gyroid for most parts. Higher for structural/load-bearing parts. Gyroid pattern is strongest for weight.
Key insight: 3 walls + 15% infill is usually stronger than 1 wall + 50% infill. Wall count matters more than infill percentage.
> SUPPORTS
Overhangs > 45° need support material underneath. Supports break away after printing. Tree/organic supports (PrusaSlicer) are easier to remove than grid supports. Design parts to minimize overhangs when possible.
> FILAMENT_STORAGE
PLA absorbs moisture slowly — keep in sealed bag with desiccant. ASA is less hygroscopic but still benefits. Nylon and PC MUST be dried before printing — they absorb water from the air and will bubble/steam/pop during extrusion. A filament dryer is not optional for engineering materials.
> COMMON_FAILURES
> POST-PROCESSING
Remove supports → sand if needed (start 120 grit, work up) → optional: primer + paint, vapor smooth (ASA only — acetone vapor), or leave as-printed.
Sanding note: PLA sands poorly (it gums). ASA and PC sand cleanly. For display-quality PLA, skip sanding and go straight to filler primer + wet sand.