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ASA settings for the Prusa MK4

⚠ Possible with tweaks Advanced Engineering

These are hardware-tuned starting settings for printing ASA on the Prusa MK4. The Prusa MK4 pairs a direct-drive extruder with an all-metal hotend on an open frame, and tops out at 290°C hotend / 120°C bed. Against ASA's ideal range (240–260°C), that lands us at 250°C nozzle and 100°C bed. ASA is the UV-stable cousin of ABS and the better choice for parts left in the sun.

Quick answer: 250°C nozzle · 100°C bed · 63 mm/s · 1 mm retraction · 0% part fan. Change one setting at a time and validate with a small calibration model.
250°
Hotend
100°
Bed
63
mm/s
0%
Part fan

Recommended ASA profile

Hotend temperature250°C (tower 240–260°C)
Bed temperature100°C
Print speed63 mm/s
Retraction1 mm (direct drive)
Part cooling fan0%
Bed adhesionHot bed + enclosure; very similar to ABS.
NozzleBrass 0.4 mm is fine
First layer speed22–32 mm/s; same bed temp, verify Z offset
Flow / extrusion multiplierStart at 100%; calibrate flow before touching retraction
DryingDry if the spool pops, strings unusually, or the surface looks rough
⚠️ ASA warps without an enclosure and the Prusa MK4 is open-frame. Block drafts, raise the bed temp, add a brim, and consider a simple enclosure for tall parts.
💡 Best uses for ASA: outdoor parts, UV-resistant parts. Estimate the material cost of your next ASA print with the filament cost calculator.

How ASA behaves

StrengthFlexibilityHeatEaseDurabilityDetail

ASA property profile

Strength 72
Flexibility 35
Heat resistance 78
Ease of printing 40
Durability 85

Calibration order

  1. Dry the spool if it shows moisture symptoms, then confirm the nozzle and build plate are clean.
  2. Print a temperature tower inside the 240–260°C range; pick the lowest temperature with strong layer bonding and clean overhangs.
  3. Calibrate flow, then pressure/linear advance if your firmware supports it.
  4. Tune retraction last — more distance is not always better, especially on the direct-drive Prusa MK4.

ASA brands & what to expect

ASA behaves almost identically to ABS but is formulated for UV stability, so brands compete on colour-fastness outdoors. It usually wants a few degrees more heat than ABS and the same enclosed, draft-free chamber.

🔎 ASA is the right pick for anything that lives in the sun — ABS yellows and gets brittle under UV, ASA holds its colour for years. Everything you do to stop ABS warping applies to ASA too.

Popular ASA brands: Polymaker, Prusament, Bambu Lab.

Common ASA problems on the Prusa MK4

SymptomLikely causeFix
Warping / corner liftOpen frame or draftEnclose and pre-warm; brim + no part cooling.
Surface cracksRapid coolingKeep fan off, chamber warm and stable.

On the Prusa MK4 specifically: it is open-frame, so the warping fixes above are the ones that matter most — an enclosure or draft shield does more for ASA here than any slicer tweak.

ASA troubleshootingSymptoms, likely causes and a safe test orderCompare ASA across printersMaterial ranges and every per-printer profile

FAQ

What temperature should I print ASA on the Prusa MK4?
Start at 250°C for the hotend and 100°C for the bed, then run a temperature tower across 240–260°C to dial in your exact filament brand. Our temperature tower planner builds the tower for you.
What print speed works for ASA on the Prusa MK4?
Around 63 mm/s is a safe starting point. This printer can go faster once the profile is tuned, but start conservative for clean walls. Check your real speed ceiling with the max volumetric flow calculator.
What retraction should I use for ASA?
Use about 1 mm of retraction (direct drive needs very little). If you see stringing with ASA, raise retraction speed before distance and dry the filament first.
Do I need an enclosure for ASA on the Prusa MK4?
Yes — ASA really wants an enclosure and the Prusa MK4 is open, so expect warping on large parts without one.
Do I need a hardened nozzle for ASA?
No. ASA is not abrasive, so the stock brass 0.4 mm nozzle on the Prusa MK4 is fine.

Reviewed 2026-08-18. See how these starting settings are calculated. Numbers are conservative starting points, not lab measurements.