ABS

ABS (acrylonitrile butadiene styrene) is the plastic of LEGO bricks and appliance casings. Strong, impact-resistant, heat-resistant (~95–100 °C), but finicky to print: it warps heavily and gives off an unpleasant smell. In return, it can be acetone-smoothed to a gloss and machined.

What it is good for

• Functional parts under load and heat
• Electronics housings, under-hood automotive parts
• Items smoothed with acetone to a gloss
• Parts that need drilling, tapping, or gluing

Where NOT to use it

• Large flat parts without an enclosure — they will lift and warp
• Unventilated rooms — ABS emits VOCs (styrene)
• Outdoor parts in direct sun — yellows and weakens from UV (use ASA)
• When you have no enclosed printer or stable temperature

How to print

• Nozzle temperature: 230–250 °C
• Bed temperature: 90–110 °C
• Cooling: 0–20% — strong cooling = cracks and delamination
• Enclosure REQUIRED: chamber 40–50 °C, no drafts
• Adhesion: glue stick or ABS juice, wide brim
• Speed: 40–60 mm/s

Drying and storage

ABS is moderately hygroscopic. Wet ABS bubbles, hisses, and prints rough.

• Drying: 60–70 °C for 4–6 hours
• Storage: dry box with silica gel
• Signs of moisture: bubbling and hissing while printing, weakened layers

Pros and cons

• Strong and impact-resistant
• Heat-resistant (~95–100 °C)
• Acetone-smoothable, easy to machine
• Cheap

• Warps heavily — needs an enclosure
• Sharp toxic smell while printing
• Yellows in sunlight from UV
• Fussy about drafts and temperature swings