PLA vs. ABS plastic filament

This post is about PLA vs ABS, two common thermoplastics used in 3D printers.  A thermoplastic is a polymer that becomes moldable above a specific temperature, and returns to its solid state when cooled.

Popular filament types:

PLA Polylactic Acid

ABS Acrylonitrile Butadiene Styrene

Made from plant material (soy, corn) Biodegradable (you can put it in city compost, but not in your backyard compost) PLA is liquid at about 190 C and burns at 230C Can be printed on blue tape on unheated printbed, although 50 C is recommended) Smells like waffles when heated. :) Shrinks / warps less than ABS Comes in rigid and rubbery grades Harder surface; shiny Easier to print than ABS Will fit the needs for about 90% of Printers (the person, not the actual printer) Comes in many, many colors

Made from petroleum Not biodegradable, but recyclable ABS is liquid at about 255C and gets nasty at about 305C Often printed on Kapton tape; requires heated print bed (we use 110 C) It releases unpleasant offgasses - people may complain of bad smell Deforms if you don't have a properly heated pad  Bendy  Can be machined afterwards Comes in many, many colors

Here is an older (2011) video that explains the basics of ABS, PLA and PVA quite well.  I would no longer say PLA is experimental, but I think the rest of the information is still accurate.

It's also worth mentioning there has been some preliminary research on emissions from 3D printers, which is worth investigating if you plan to use the material around kids. Many educators prefer using PLA over ABS for two reasons:

1. Starch-based PLA emits fewer ultrafine particles (UFP) and many people report it having less fumes than ABS.
2. ABS requires a heated build plate (more preheating time needed, often more expensive machines), while PLA does not require a heated build plate.

Here are some additional resources about these major types of plastic.

• Makerbot: About PLA
• 3Doodler: ABS vs. PLA
• MakerGeeks site (check out side bar for some of the very wide selection of filament types they sell)
• The 2014 MAKE magazine Ultimate Guide to 3D Printing has an excellent spread about filament types.

What about recycling filament?

MAKE reviewed the Filabot Wee and Filastuder, for folks who want to make their own filament by grinding up cheap plastic pellets (nurdles?!) that you can purchase online for ~$5/kg and extrude them into your own spool instead of purchasing pre-made filament spools at ~$40+/kg.   (Filabot plans are freely shareable under a CC license if you'd like to build your own.)

OmNom Project and Filabot’s Reclaimer grinder promise to allow you to actually recycle used filament (including failed prints!) into filament that can be fed back into the machine.  The only concern with this is that there is a high risk of contamination by dirt and everything else.

SLS does in fact feel like it is the future of reliable 3D printing and material recycling, since the unused powder can be reused in future prints.

Updated 2.27.14 by Luka.
Updated again 3.16.14 by C. Mytko.