ABS ABS (acrylonitrile butadiene styrene)

ABS is the plastic behind decades of injection-molded products: appliance housings, power-tool shells, automotive interior trim and the classic toy brick. It is a blend of three building blocks, and the rubbery butadiene part is what gives it a tough, slightly forgiving character instead of the glassy snap you get from PLA. For a printed part, that translates into a material that shrugs off knocks, can be drilled and tapped, and copes with warmer conditions than PLA or PETG.

The catch is that ABS is one of the harder everyday plastics to print well. It shrinks as it cools, so a large flat part wants to curl up at the corners and tall parts can split between layers if the air around them is cold. That is why we only print ABS in a closed, actively heated chamber. QIDI marks ABS as requiring a closed chamber in its filament guide, and our printers hold the chamber at up to 65 °C to keep the part warm while it builds.

Commercially, ABS sits in the middle of the range: a little more than PLA or PETG, much less than nylon or the fiber-filled materials. It is the right call when you need a part that looks and behaves like a real molded product, survives warm interiors, and can be sanded, painted or glued. If the part will live outdoors in sunlight, its close cousin ASA is usually a better choice, and we cover that below.

ABS is tough rather than ultra-strong. QIDI's comparison guide lists a bending strength of 77.5 MPa along the layers for its ABS Rapido, and Polymaker's PolyLite ABS sheet gives 33.4 MPa tensile strength along the layers. Those numbers are lower than PLA on paper, but ABS gives a little before it breaks, so it tends to crack or deform rather than shatter. Polymaker reports a notched Charpy impact strength of 18.0 kJ/m², which is a useful indicator of how it handles a sharp knock.

Like every FDM material, ABS is weaker between layers (the Z direction) than along them. QIDI lists 24.35 MPa tensile strength in Z for ABS Rapido, and Polymaker gives 29.7 MPa in Z against 33.4 MPa in XY. In practice this means the way a part is oriented on the bed matters: a hook printed standing up will split along a layer line far sooner than the same hook printed lying flat. Tell us how the part is loaded and we will orient it so the main stress runs along the layers, not across them.

ABS creeps less than PLA under a sustained load at room temperature, which makes it more trustworthy for clips and brackets that hold tension for months. It is still a plastic, so a part carrying a constant load in a warm space will slowly deform; design with generous margins and avoid long, thin cantilevers. Good layer bonding depends heavily on a warm chamber, which is one reason ABS printed in an open printer often disappoints.

Heat deflection temperature (HDT) is the temperature at which a standard test bar bends a set amount under a set load, so it is a practical guide to when a part starts to soften. QIDI lists 85 °C at 0.45 MPa for ABS Rapido and 92 °C at 0.45 MPa for its Odorless ABS, both as printed. Polymaker gives 100 °C at 0.45 MPa and 98 °C at 1.80 MPa for PolyLite ABS. Different brands land in different places, so treat these as a band, not a promise.

Those numbers put ABS clearly above PLA and PETG and below polycarbonate. QIDI does not generally recommend annealing ABS, and we do not anneal it. For a part that must stay stiff while hot and loaded, keep your working temperature well below the HDT, because a part under sustained stress will creep at lower temperatures than the test suggests.

ABS has fair weather resistance but poor long-term UV resistance. Sunlight breaks down the butadiene rubber phase, which is what makes ABS tough in the first place, so the surface chalks, yellows and becomes brittle. Prusa's guide describes ABS as lacking UV resistance compared with ASA.

For a part that sees occasional sun, such as a bracket inside a window, ABS is often fine for a season or two. For anything permanently outdoors, choose ASA, or plan to paint the ABS part with a UV-blocking finish and accept that the coating will need maintenance.

ABS dissolves in acetone, which is a feature for bonding and smoothing and a weakness if the part meets acetone-based nail polish remover or some paint thinners. It is also generally attacked by gasoline, many chlorinated solvents and strong acids, and can soften or stress-crack with some oils and cleaners. Polymaker rates its ABS as good against weak acids, weak alkalis and oils and greases, poor against strong acids and fair against strong alkalis.

Isopropyl alcohol (IPA) on a cloth for cleaning is generally fine for short contact, but long soaks are not recommended. Sunscreen and insect repellent can mark or soften styrenic plastics like ABS over time. If your part will meet a specific chemical, tell us which one and plan to test a sample before committing to a batch.

ABS is only mildly hygroscopic, meaning it absorbs a little water from the air. QIDI lists 0.3% saturated water absorption for its Odorless ABS and classes drying as optional, though it gives 70–80 °C for 4–6 hours if a spool has been open a long time. We dry ABS before demanding jobs so the surface is smooth and the layers bond well.

Once printed, ABS parts are dimensionally stable in normal humidity. They will not swell like nylon or turn brittle like damp PVA, so ABS is a safe choice for parts that live in a humid garage or bathroom, as long as they are out of the sun.

As printed, ABS has a satin, slightly matte surface with visible layer lines. It is less glossy than PETG and less crisp than PLA on sharp corners, because the material shrinks a little as it cools. Color range is good, and QIDI also offers a metallic-effect ABS for display parts.

Where ABS shines is in finishing. It sands easily, takes filler primer well and holds paint, so a well-prepared ABS part can be made to look like a molded product. It also bonds strongly with solvent cement, so larger parts can be printed in sections and joined.

Sanding and painting: ABS sands well wet or dry, according to Prusa's guide, and takes standard primers and acrylic or enamel paints. A coat of filler primer followed by light sanding hides layer lines on cosmetic faces. Ask for sanding or a primed finish on your quote if appearance matters.

Acetone welding: a small amount of acetone softens the surface of ABS, and two pieces pressed together fuse into a single, strong joint once the solvent evaporates. A slurry of ABS dissolved in acetone also fills gaps. This is how we join ABS parts that are bigger than the build volume, and it generally produces a stronger joint than most glues.

Vapor smoothing: exposing ABS to acetone vapor melts the outer skin into a glossy, almost molded-looking surface, as Prusa describes. It softens sharp edges and small details and changes dimensions slightly, so it is not suited to precise fits. We offer vapor smoothing only when it is listed as a finish on your quote; ask us if you want it.

Threads and inserts: ABS takes brass heat-set inserts very well and can also be tapped for coarse threads. For anything you will screw and unscrew repeatedly, heat-set inserts are the better option.

ABS shrinks more than PLA or PETG as it cools, so dimensions on large parts can be slightly smaller than the model and long flat faces can bow a little. A heated chamber reduces this a lot, but very large flat parts are still the riskiest shape. Prusa's guide names significant warping as one of ABS's main disadvantages.

Holes usually print slightly undersized in any FDM material, and ABS is no exception. For precise fits, either design holes a little larger, or let us print them close and ream or drill them to size afterwards. If you need a tolerance tighter than normal FDM, tell us which features matter so we can plan orientation and finishing.