Every material in this family is the same idea executed three ways: a hard, glassy styrene-based matrix with a soft rubbery phase dispersed through it as microscopic droplets. The matrix supplies rigidity and heat resistance; the rubber droplets stop a crack travelling, which is what turns brittle polystyrene into something you can drop.
Two composition questions separate the three members, and knowing them is enough to choose without reading further.
The two questions
Which rubber? ABS and HIPS use polybutadiene, whose backbone carries the double bonds that ultraviolet light attacks. ASA uses an acrylic ester rubber with no such bonds. That is why one of these three survives outdoors and two do not.
Is acrylonitrile present? ABS and ASA contain it and gain chemical resistance and hardness from it. HIPS does not, which is why HIPS is softer, weaker and dissolves in a solvent the other two shrug off.
| Material | Rubber phase | Choose it for |
|---|---|---|
| ABS | polybutadiene | indoor parts needing heat resistance and acetone smoothing |
| ASA | acrylic ester | anything that will live in sunlight |
| HIPS | polybutadiene, no acrylonitrile | limonene-soluble support for ABS, and lightweight model work |
When to reach for this family at all
Three requirements bring people here, and only three:
- Heat. Deflection temperatures of 80 to 105 °C across the family, well beyond what any PLA or copolyester offers. A part that has to survive a parked car in summer belongs here.
- Solvent smoothing. Acetone dissolves the styrene matrix, so a finished part can be vapour-smoothed to a moulded gloss and sealed against water at the same time. Nothing else on this site does that.
- Weathering, specifically in ASA. Years of sun rather than months.
If none of those is your requirement, a copolyester will do the job with no enclosure, no smell and far less risk. That is not a criticism of the styrenics; it is the honest boundary of where they earn their difficulty.
What the whole family costs you
Everything here shares the same three demands, and none of them is optional.
An enclosure. All three contract 0.4% to 0.8% as they cool, which is enough to peel a print off the plate or split it horizontally on any part with a footprint. The individual pages set out why chamber temperature rather than bed temperature is the lever; at family level, treat an enclosure as part of the cost of entry rather than as an upgrade.
Ventilation. These are styrenics and they smell like it. An enclosure that vents outside or filters through activated carbon is proportionate; printing them overnight in a bedroom is not.
Lowered expectations about strength. Tensile figures across the family run from 20 to 50 MPa, which puts all three below PLA. Whatever brought you to this shelf, it was not raw pulling strength — and if that is what your part needs, the shelf is wrong.
Settings the three share
The settings cluster tightly: nozzle 230 to 265 °C, bed 90 to 110 °C, part cooling essentially off, and a hot plate with a release-and-grip layer such as a glue-stick film. That third item is the one people get wrong, because the reflex to run the fan hard is carried over from PLA and it is exactly backwards here — a large share of first attempts fail on that setting alone.
Drying is a shared requirement rather than a per-member one: all three sit at 65 °C for a few hours. Styrenics are far less thirsty than a polyamide, but damp ones print hazy and rough and crack along their layers.
Picking one in ten seconds
Going outside? ASA. Staying inside and going in the acetone jar? ABS. Printing soluble support alongside ABS, or building something light that will be sanded and painted? HIPS.
If the part is simply functional, lives indoors and never gets hot, none of the above — that is a job for the copolyesters, and you will finish it on the first attempt.