How is PLA different from ABS material?

Question

What are the main differences when using ABS over PLA and vice versa?

Answer 1

Paraphrasing this site. Feel free to add suggestions in the form of comments and I will try to incorporate them.

Summary

• ABS: Stronger, machinable, more flexible, and more temperature resistant than PLA. Typically printed on a heated bed. Warping is a common problem when printing ABS.
• PLA: Wider range of filaments available, easier and in some cases faster to print. Not as strong as ABS and the fact that its biodegradable could be seen as both a benefit and a drawback.

Material Properties:

• ABS: Strong plastic with mild flexibility. Naturally beige in color. Can be filled and sanded. Higher temperature. Easy to recycle.
• PLA: Not as strong as ABS but more rigid. Naturally transparent. More difficult to fill and sand. Can sag in hot temperatures. Sourced from organic matter so it can be broken down in commercial compost facilities.

Part Accuracy:

• ABS: Part warping is a significant issue. Sharp corners will often be rounded.
• PLA: Less heat required contributes to less warping. Becomes more liquid at common extruder temperatures so finer details can be printed.

Safety and Handling:

• ABS: Strong burning/melting plastic smell is present when printing ABS. Health concerns have been raised regarding airborne ultrafine particles generated while printing with ABS (ref). ABS will absorb moisture causing popping when the moisture enters the hot end. This leads to discontinuities in the print job.
• PLA: Doesn't smell as strongly when printing due to its organic nature. Moisture can also be absorbed into PLA and can irreversibly damage it.

Answer 2

The problem is that it's almost impossible to answer the PLA/ABS question just by looking at the material characteristics as it is so dependent on the application and even the specific object you're printing.

The decision guide in this infographic covers the following points that usually should be involved when deciding between ABS and PLA:

Ventilation - I wouldn't recommend putting your nose into the printer with any material, but being exposed to ABS fumes is likely a lot worse.

Heated Bed - This is an easy one: Without one, PLA should be your choice. If you do have one though, it might improve adhesion of PLA as well (set to ~60C instead of 90C-110C for ABS)

Exposure to Heat or Mechanical Stress - ABS would be the preferred choice as PLA melts at lower temperatures (it might start to deform when left in your car in the summer) and ABS can endure more bend before breaking.

Of course even ABS has upper limits and you might want to consider other materials like Polycarbonate for extreme applications.

On the other hand there are newer materials that share many PLA features (biodegradable, no heat bed required) but are more similar to ABS in their mechanical properties (e.g. BioFila Linen) and temperature stability (e.g. Advanced PLA, ExcelFil EVO).

Printer Enclosure - Not a must-have for using ABS, but especially objects with large footprints are susceptible to warping when they cool too fast. A fully enclosed printer ensures a slow and even cooling process.

Post Processing - Often an afterthought, but ABS has a slight advantage here as it is a little easier to sand and you have the option of working with acetone (which I personally wouldn't mess with unless you REALLY need to).

Print Temperature - Roughly 190C-220C for PLA and 220C-240C for ABS, so be sure that your printer can go high enough to extrude ABS.

Biodegradability - PLA is biodegradable (under specific circumstances) which is a consideration when printing test objects, prototypes and other objects that will be discarded.

Answer 3

PLA/ABS general and thermal properties

Answer 4

PLA (polylactic acid) melts at a lower temp and does not warp AS BADLY when cooled. It is non-toxic (in USA it comes from cornstarch, beets in some countries, or tapioca root) It is less flexible than ABS, could rip or crumble.

ABS (Acrylonitrile Butadiene Styrene) is a harder and more sturdy plastic. (What Legos are made of). A heated bed is used to keep it from cooling too fast, as warping can be a problem is you cool it too fast (being close to an exterior door or an air vent) An enclosed printer helps regulate temp and avoids SOME of this problem. Some people get headaches from the smell of molten ABS over a prolonged time. It flexes better than PLA. Can be sanded or cut easily and maintain integrity.

Beware of CHEAP ABS as it may contain a higher amount of HCN (Hydrogen Cyanide) that can be released when used (but usually around 1 part per million, about one fourth the dangerous limit.)

"GOOD" ABS CAN contain HCN as well, but it is not released by "normal" printing temperatures. (avoid burning ABS or Nylon)

so, all in all: PLA is safe/non-toxic, biodegradable, uses less energy to print, less flexible.

ABS is harder, sturdier, will last nearly forever (if not bent or stressed or frozen). Somewhat flexible and will snap back.

Answer 5

Basic facts and tips for using and choosing ABS and PLA materials:

Made from:

ABS: Petroleum based

PLA: Corn or other plants

Smell:

ABS: smell of hot plastic, 

PLA: gives off a smell similar to a semi-sweet cooking oil. Less intense smell than ABS. 

Part Accuracy:

Both PLA and ABS are capable of building dimensionally accurate parts. However, there are characteristics that we need to memorized. ABS: will be curling upwards of the surface in direct contact with the 3D printer’s print bed. for fine and delicate features on parts involving sharp corners, such as gears, there will often be a slight rounding of the corner. PLA: much less part warping. but it undergoes more of a phase-change when heated and becomes much more liquid. The increased flow can also lead to stronger binding between layer.

Recycling:

ABS: Recycling number 7, most local recycling programs do not accept ABS. It generally being recycled into plastic lumber. PLA: it biodegrades, however the process takes a long time when outside of an industrial composting facility Why we provide a vacuum sealed package for ABS and PLA products? long term exposure to a humid environment without sealed package may result in detrimental effects, both to the printing process and to the quality of finished parts.

ABS: will tend to bubble and spurt from the tip of the nozzle when printing, part accuracy, strength are reduced. Raises the risk of clogging the nozzle. ABS can be easily dried by using dry or hot air. PLA: bubbles or sporting at the nozzle, also discoloration and a reduction in 3D printed part are found when in long term moisture environment. Improving the printing outcomes （Blue tape and Kapton tape pictures) PLA: printing temperature approximately: 190°C - 240°C ABS: printing temperature approximately: 225°C - 250°C (recommend to use a heated print bed)

A good first layer adhesion is of the utmost importance in obtaining the best results for the prints.

Using Blue Tape or Kapton Tape. Hairspray the print bed. To attain optimal result for the prints, you need to consider variables such as nozzel diameter, printing speed, and layer height. Summary: ABS: A preferred filament for the prints with engineering and professional purposes with its strength, machinability, flexibility, and higher temperature resistance. The bad plastic smell is due to the petroleum based origin. Required a heated print bed to attain ABS printing reliability. PLA: Wide range of available colors, provide translucencies and glossy feel of the prints. Plant based and semi-sweet corn like smelling are appreciated over ABS. When properly cooled, PLA seems to perform higher maximum printing speeds, and sharper printed corners. Combining this with low warping on parts make it a popular plastic for household uses, toys, hobbyists, and educational purposes. to know more please visit abs vs pla