## Instructions - First layer decides everything: trammed bed, correct Z-offset (squished lines, no gaps, no ridges), clean PEI sheet (dish soap, not fingers). 90% of "adhesion problems" are Z-offset. - Calibrate in order: E-steps → flow → temperature tower → retraction → pressure advance. Each builds on the last; skipping ahead wastes filament. - Materials: PLA for everything structural indoors (easy, strong enough); PETG for heat/outdoor (stringy — dry it); TPU flexibles slow with no retraction; ABS/ASA only enclosed (fumes + warp). - Slicing: 0.2mm layers default, 3-4 walls before more infill (walls carry strength; 15-20% gyroid infill is plenty), orient layer lines across expected stress, supports only where overhangs exceed ~60°. - Wet filament (popping, stringing, rough surface): dry it — most "bad rolls" are just damp. - Never leave the first layer unattended; a failed print caught at layer 2 saves hours and a nozzle. - Bed adhesion stack: clean PEI (dish soap + hot water, monthly IPA wipe is NOT enough) → correct Z-offset (live-adjust while printing a skirt) → right plate per material (textured PEI for PLA/PETG, smooth + glue for TPU) — skip any layer and blame nothing else. - Filament storage: dry boxes (silica + hygrometer, <30% RH) for PETG/TPU/nylon; PLA tolerates room air for weeks, not months; weigh spools (1kg nominal − spool weight = remaining) before long prints. - Print orientation is engineering: layer lines are the weak axis — orient so expected loads compress layers, never peel them; chamfers beat fillets for FDM overhangs. - Speed vs quality: 0.2mm/60mm-s default, outer walls 30–40mm/s for cosmetics, infill fast; input shaping + pressure advance tuned before chasing speed records. - Farm hygiene: nozzle wipe + bed check every print, brass brush for the nozzle (cold), spare nozzles/thermistors/heaters on the shelf — downtime costs more than parts. ## Examples - Functional bracket: PETG, 4 walls, 20% infill, oriented so load crosses layers not along them. - Cosmetic figure: 0.12mm layers, dry PLA, slow outer walls. - Enclosure clip (PETG, heat-adjacent): 5 walls, 40% gyroid, annealed? No — PETG creeps under sustained load, use ASA for engine-bay heat. ## Workflows 1. Model check (manifold?) → orient → supports → slice preview layer-by-layer → print first layer → walk away. 2. Failed print: photograph, identify layer/event, change ONE variable. 3. New filament roll: temperature tower → retraction test → pressure-advance line → flow cube → record profile `MAT_NOZZLE_LAYER` before real parts. 4. Functional part: print test coupon (hole tolerances, thread fit) in the same material/settings before the full part. ## Templates - Slicer profile naming: MATERIAL_NOZZLE_LAYER (e.g. PLA_04_20) so profiles stay comparable. - Pre-flight checklist: plate clean? correct plate? filament dry + right type? Z-offset verified on skirt? purge line good? camera/timelapse on for long prints? - Calibration log row: `date / filament brand+batch / temps / retraction / PA value / flow % / notes` — one line per roll, no surprises on reorder. - Support rules: overhangs >60° need support; organic/tree supports for figures, rectilinear for flat bridges; 0.2mm Z-gap + 75% XY for removable PETG supports. ```text # Slicer baseline (PLA, 0.4 nozzle — tune per roll from here) # Layer 0.2 / walls 3 / top-bottom 4 / infill 15% gyroid # Nozzle 210C first layer, 205C rest / bed 60C / fan 100% after layer 2 # Speeds: inner 60 / outer 35 / infill 80 / travel 150 mm/s # Retraction: direct 0.8mm@40mm/s, Bowden 4mm@45mm/s (temp tower first) ``` ```bash # cold pull (clears partial clogs without disassembly) # heat to 90C PLA / 120C PETG, push cleaning filament, cool to 60C, yank firmly ``` ## Tools - SARAH file tools for tracking calibration results and filament inventory notes. - OrcaSlicer/Bambu Studio/PrusaSlicer calibration menu (temp tower, PA pattern, flow rate) — run in that order. - OctoPrint/Mainsail for remote monitor + timelapse; spaghetti detective plugins for unattended long prints. ## Advanced - Pressure advance / input shaping: PA pattern per filament (direct-drive ~0.02–0.08, Bowden ~0.4–0.8), input-shaper resonance test per printer placement (moving the printer invalidates it). - Multi-material: purge volumes tuned per color pair (dark→light needs 2x), prime towers only when ooze is proven, filament-buffer discipline so tangles don't fake as clogs. - Tolerances: horizontal expansion −0.05 to −0.1mm for press fits, test holes 6/8/10mm printed vertically vs horizontally differ — design per orientation; threads: print oversize + chase with a tap, never trust printed threads under M6 load. - Annealing PLA (body-safe heat deflection +30%): 80–90°C oven 30–60min on supported jigs (warps unsupported), dimensions shift ~2% — scale models before, not after. - Troubleshooting: stringing → wet filament first (dry 6h), then retraction + temp −5°C; layer shifts → belt tension + grub screws + crash (obstruction), not flow; warping corners → enclosure/draft check + brim 8mm + plate 5°C up; clicking extruder → partial clog (cold pull) or heat-creep (fan duct + retraction <4mm Bowden); first layer ridges → Z too low (raise 0.02 steps); gaps → Z too high or under-extrusion (E-steps then flow). - First-layer microscope: lines merged but distinct = perfect; translucent ridges = too low; round separated strands = too high; adjust live in 0.02mm steps while the skirt prints. - Clog ladder: cold pull (nylon/cleaning filament) → needle from below at temp → nozzle swap (cheap, fast) → PTFE-tube check (degraded tube narrows = recurring clogs) → extruder-gear clean. - Belt tension by ear: plucked belts hum ~80–120Hz (phone tuner app works); too loose = ringing/ghosting, too tight = premature bearing wear + layer shifts from missed steps. - Wet-filament test: snap test (brittle PLA/PETG snaps clean = wet), print a 20mm cube — popping sounds + rough top = dry 6h at 55°C (PLA) / 65°C (PETG). ## Templates ```text # Filament profile card (one per roll, taped to the dry box) # Brand/batch: ______ Type: PLA/PETG/TPU/ASA Color: ______ # Nozzle: ___C Bed: ___C Chamber: open/enclosed # Retraction: __mm @ __mm/s PA: __ Flow: __% Max volumetric: __mm3/s # Dried: date ___ @ ___C ___h Notes: ______ ``` ## Documentation - Teaching Tech calibration guide, CNC Kitchen (strength science). - OrcaSlicer calibration: https://github.com/SoftFever/OrcaSlicer/wiki/Calibration - Filament drying guide: https://wiki.bambulab.com/en/filament-acc/filament/dry-filament