ABS and ASA

ABS and ASA are strong, heat-tolerant filaments for functional parts, but they punish uneven cooling: drafts and too much fan cause warping and layer splitting. Pick ASA when the part will live outdoors (better UV resistance), and plan your setup around keeping the whole print warm and stable—often an enclosure matters more than tiny slicer tweaks.

TL;DR

ABS/ASA punish uneven cooling. Print warm and draft-free (ideally enclosed) with a hot bed and very little fan, or you’ll see corner warp and layer splits. Pick ASA for outdoor sun/weather; pick ABS for indoor functional parts and acetone-based bonding/smoothing (with proper ventilation and handling).

ABS vs ASA: what to choose and what to controlTopic-specific diagram for the concept, checks, and tradeoffs in this lesson.String controlCompare tradeoffs before choosingBed adhesionCompare tradeoffs before choosingFlex + toughnessCompare tradeoffs before choosingDry storageCompare tradeoffs before choosing
This diagram highlights the two main choices: environment control and outdoor UV exposure.

What ABS and ASA are (and why prints go wrong)

ABS is strong and heat-tolerant compared with PLA, but it shrinks more as it cools. That shrinkage builds internal stress. If one area cools faster than another, corners lift (warping) and taller parts can crack between layers. ASA prints much like ABS, but it’s commonly picked for outdoor parts because it typically holds up to UV/sunlight better and stays looking nicer over time.

Choose ABS when…

  • The part is mainly indoors but may get warm (electronics enclosures, motor mounts, car interior parts)
  • You want a tough part that can flex a bit instead of snapping
  • You want acetone-based bonding or smoothing (with strong ventilation and careful handling)

Choose ASA when…

  • The part will live in sun and weather (outdoor mounts, brackets, covers)
  • You want ABS-like strength and heat behavior with typically better UV resistance
  • Outdoor appearance over time matters more than the cheapest filament option

Start-point settings (typical ranges)

Nozzle temperature
Often 240–270 C (follow your spool guidance). Too low weakens layer bonding; too high increases stringing/blobs and can worsen surface quality.
Bed temperature
Commonly 90–110 C. A warmer bed usually improves first-layer grip and reduces warping, especially on wide parts.
Cooling fan
Usually low or off for most of the print. Use the minimum airflow needed for bridges/overhangs, then drop back to low.
Enclosure / draft control
Strongly recommended for medium/large parts. Stop drafts from hitting the print, and let the part cool down slowly after the job finishes.
Drying and storage
Store sealed with desiccant. If you hear popping/steam or see rough, foamy extrusion, dry the filament before you start tweaking slicer settings.

Common ABS/ASA print problems and first fixes

Corners lifting (warping)

Likely cause: Edges cool and shrink faster than the center until they overpower bed adhesion

Fix: Block drafts/use an enclosure, raise bed temp within spec, clean the build surface, and add a brim (or mouse ears on sharp corners).

Layer cracks or splits (tall parts)

Likely cause: Upper layers cool too much during the print, so new plastic can’t fuse well to the layer below

Fix: Reduce fan, raise nozzle temperature slightly, and keep the enclosure warmer and more stable (avoid opening doors or blasting cold air).

Droopy overhangs or mushy detail

Likely cause: Cooling is too low for the geometry at your current speed/temperature

Fix: Slow down overhangs/bridges and add minimal, targeted fan for those sections; if adhesion stays solid, lower nozzle temp slightly.

Stringing and blobs

Likely cause: Nozzle temperature is too high, filament is wet, or retraction isn’t right for your extruder

Fix: Dry the filament first, then lower nozzle temperature in small steps and tune retraction for your specific extruder and path.

A quick proof test before a long print

Before a big job, print a small test that includes: (1) a sharp corner to show warping, (2) a tall thin wall to show layer splitting, and (3) a simple overhang/bridge to check cooling. Change one variable at a time (enclosure/draft control, bed temp, fan behavior, nozzle temp), then rerun the same test so you can see exactly which change fixed the failure.