Bambu Lab ASA Aero Filament 1.75mm 1kg

A self-foaming ASA. As the filament passes through a hot nozzle it expands, so the printed part comes out full of fine closed cells rather than solid plastic. The result is dramatically lighter parts, with ASA's weather and UV resistance intact.

It exists mainly for one job: RC aircraft. Wings, fuselages, control surfaces — anything where every gram costs you flight time, and which also has to survive being left in the sun between flights.

You control the density with temperature. Hotter nozzle means more foaming, lower density and a lighter, weaker part. Bambu's range is 240–280°C, and the effect across that span is large. Expect to print test coupons and weigh them before committing to a full airframe.

Enclosure required, 0.4mm nozzle only, no AMS Lite. 45–60°C chamber as with all ASA. Bambu specify the 0.4mm nozzle for this filament and advise against every other size — the foaming behaviour is tuned around it.

At a glance

Density is adjustable for this one. As it is a foaming filament, you control how many voids you want and the part comes out lighter — control how much lighter using nozzle temperature.

What foaming costs you

Light parts are not free. Against plain ASA, every mechanical figure drops:

Heat resistance falls furthest. Vicat softening goes from 106°C to 80°C, and heat deflection from 92°C to 78°C. That is a big change — an ASA Aero part left in a closed car could soften where a plain ASA part would not. It resists UV and rain as well as ASA does, but not heat.

Stiffness and impact fall too — 2010 MPa against 2450, impact 32.0 against 41.0 kJ/m². Still tough for a foamed material, but not an engineering plastic any more.

The trade only makes sense when weight is the binding constraint. For a static outdoor part, plain ASA is better in every respect and half the price.

Printing it well

Smooth PEI plate with glue. That is Bambu's recommendation for this filament specifically; the Cool Plate SuperTack is not compatible.

Design out the travel moves. Foaming filament is highly fluid and expands as it leaves the nozzle, so long travels ooze badly. Bambu advise against models with lots of travel paths, and publish a ready-made X1C 0.4mm profile you can import in Bambu Studio as a starting point.

Layer bonding is very weak. Impact across layers is 3.4 kJ/m² against 32.0 in plane, and bending strength 24 MPa against 58. For a wing, that means orienting so the spar loads run along the layers — a Z-loaded foamed part will snap easily.

Turn supports on, and print slowly — the 150 mm/s ceiling is well below plain ASA's 250 mm/s.

Storage

Bambu specifies under 20% RH, sealed with desiccant, and 80°C for 8 hours to dry.

This one absorbs more water than any other ASA at 0.80%, and moisture interferes directly with the foaming — damp filament foams unevenly, so density varies through the print. For a material bought specifically for controlled weight, drying is not optional.

Bambu's usage guide has a dedicated section on foamed filament, including the downloadable preset: ABS / ASA / PC Usage Guide