ABS vs ASA shrinkage: which one shrinks more

ASA (acrylonitrile styrene acrylate) and ABS (acrylonitrile butadiene styrene) shrink by about the same amount. Every data sheet that lists both gives overlapping ranges, mostly 0.4 to 0.7%, and none shows ASA shrinking less. Compensate ASA the way you would ABS, then measure a test part.

Does ASA shrink less than ABS?

No, not by any published figure. INEOS Styrolution lists molding shrinkage of 0.4 to 0.7% for its Luran S ASA and at most 0.7% for its Terluran ABS. Purefil’s filament sheets give 0.4 to 0.7% for both. Sunlu’s table puts ASA at 0.4 to 0.9% and ABS at 0.4 to 0.8%.

Prusa’s knowledge base says ASA “warps less” than ABS but gives no shrinkage number for either. Warping is corners lifting off the bed. Shrinkage is the size a part loses as it cools, and no source here gives ASA a lower figure.

Some sheets list no figure at all. Polymaker’s ASA data sheet has none, and neither does Bambu Lab’s ABS sheet.

ABS vs ASA vs PETG vs PLA shrinkage

Each column comes from a different kind of test, so compare figures down a column, not across a row. PETG (polyethylene terephthalate glycol) and PLA (polylactic acid) are there for scale.

Material	Resin maker, molded	Purefil filament sheet	Sunlu filament sheet	Printed parts, X and Y (Binghamton)
ASA	0.4 to 0.7% (Luran S 777K)	0.4 to 0.7%	0.4 to 0.9%	not tested
ABS	up to 0.7% (Terluran GP-35)	0.4 to 0.7%	0.4 to 0.8%	0.59 to 0.69%
PETG	no figure	0.2 to 0.5%	0.1 to 0.5%	0.54 to 0.76%
PLA	0.4% (Ingeo 3052D)	no figure	0.1 to 0.3%	0.35 to 0.63%

What each column measures:

• Resin maker, molded. Injection-molded test specimens, measured against the mold. This is a property of the polymer, not of a printed part.
• Purefil. Also molded-specimen tests: ASTM D955 for ASA, ISO 294-4 and 2577 for ABS and PETG. Its PLA sheet leaves the field blank.
• Sunlu. One range per filament with no test method stated.
• Binghamton. Weiser et al. (2021) printed parts on one QIDI X-One2 and measured them with calipers. The study covered PLA, PETG and ABS only.

On ASA shrinkage vs PLA, the molded data put PLA at the bottom of ASA’s range, and Sunlu’s table puts it well below. In the printed study, PLA and ABS overlap. For PETG shrinkage vs ASA, both filament sheets list PETG lower. In the printed study, PETG shrank about as much as ABS.

How much does a 3D printed ASA part shrink?

No published study of printed parts gives ASA shrinkage by axis. The Binghamton paper tested PLA, PETG and ABS but not ASA. The only numbers come from molded specimens and filament sheets: about 0.4 to 0.7%, with Sunlu’s range reaching 0.9%.

Z is the bigger gap. In the Binghamton study, ABS parts shrank about 0.6% in X and Y but grew 0.92% in height. No source says whether ASA does the same. Molded figures have no Z value at all.

What shrinkage compensation to use for ASA

Start X and Y at the ABS printed value, 0.64% (the Binghamton mean of X and Y). Leave Z at no compensation until you have measured a part.

Where	Value for 0.64% in X and Y
Model scale	100.64%
OrcaSlicer, Shrinkage (XY)	99.36%
Bambu Studio, Shrinkage	99.36%
PrusaSlicer, Shrinkage compensation XY	0.64%

OrcaSlicer and Bambu Studio take the cooled size as a percentage of the design, which is why 0.64% becomes 99.36%. PrusaSlicer takes the shrinkage itself. The shrinkage compensation calculator also has an ASA preset at 0.55%, the midpoint of the molded range. The two starting points differ by 0.09 mm on a 100 mm part, so either works as a first value.

Then measure your own ASA:

1. Clear any shrinkage value in the filament profile and print a block about 100 mm long and 20 mm tall. Use your normal ASA settings, enclosure included.
2. Let it reach room temperature and measure X, Y and Z separately with calipers.
3. Shrinkage is (designed - measured) / designed. A 100 mm span that measures 99.45 mm has shrunk 0.55%.
4. Enter the designed and measured sizes in the calculator’s measure mode. It gives the value each slicer expects, by axis.

The guide to calibrating dimensional accuracy per material covers separating shrinkage from flow and wall-offset errors. A wall-offset error is a fixed amount on every part, while shrinkage grows with part size.