The Difference Between ABS & PLA
If you've got a 3D Printer that can print both ABS and PLA. We’ve compiled short article to understand some of the key differences between ABS and PLA filament. There are also some excellent tips that are well worth the read and may save you hours of frustration.
|Extrude at ~225°C||Extrude at ~180-200°C|
|Requires heated bed||Benefits from heated bed|
|Works reasonably well without cooling||Benefits greatly from cooling while printing|
|Adheres best to polyimide tape||Adheres well to a variety of surfaces|
|Filament tolerances are usually tighter||Finer feature detail possible on a well calibrated machine|
|Prone to cracking, delamination, and warping||Prone to curling of corners and overhangs|
|More flexible||More brittle|
|Can be bonded using adhesives or solvents (Acetone or MEK)||Can be bonded using adhesives|
|Fumes are unpleasant in enclosed areas||More pleasant smell when extruded|
|Oil Based||Plant Based|
Both ABS and PLA filament are capable of creating dimensionally accurate parts. However, there are some key differences.
ABS - There will often be a slight rounding of the corner for fine features on parts involving sharp corners, such as gears. Using a fan to provide a small amount of active cooling around the nozzle can improve corners but also risks introducing too much cooling and reducing adhesion between layers, eventually leading to cracks in the finished part.
The single greatest challenge for accurate parts in ABS will be a curling or peeling upwards of the first layer in direct contact with the 3D Printer's print bed. To see our adhesion Tips page, CLICK HERE.
PLA - Compared to ABS, PLA demonstrates much less part warping. For this reason it is possible to successfully print without a heated bed and use more commonly available "Blue" painters tape as a print surface. Ironically, totally removing the heated bed can still allow the plastic to curl up slightly on large parts, though not always.
PLA undergoes more of a phase-change when heated and becomes much more liquid. If actively cooled, much sharper details can be seen on printed corners without the risk of cracking or warp. The increased flow can also lead to stronger binding between layers, improving the strength of the printed part.
ABS & PLA General Material Properties
ABS - ABS as a polymer can take many forms and can be engineered to have many properties. In general, it is a strong plastic with mild flexibility (compared to PLA). Natural ABS before colorants have been added is a soft milky beige. The flexibility of ABS makes creating interlocking pieces or pin connected pieces easier to work with. It is easily sanded and machined. Notably, ABS is soluble in Acetone allowing one to weld parts together with a drop or two, or smooth and create high gloss by brushing or dipping full pieces in Acetone. Compared to PLA, it is much easier to recycle ABS.
Its strength, flexibility, machinability, and higher temperature resistance make it often a preferred plastic by engineers and those with mechanical uses in mind.
PLA - Created from processing any number of plant products including corn, potatoes or sugar-beets, PLA is considered a more 'earth friendly' plastic compared to petroleum based ABS. Used primarily in food packaging and containers, PLA can be composted at commercial compost facilities. It won't bio-degrade in your backyard or home compost pile however. It is naturally transparent and can be colored to various degrees of translucency and opacity. Also strong, and more rigid than ABS, it is occasionally more difficult to work with in complicated interlocking assemblies and pin-joints. Printed objects will generally have a glossier look and feel than ABS. With a little more work, PLA can also be sanded and machined. The lower melting temperature of PLA makes it unsuitable for many applications as even parts spending the day in a hot car can droop and deform.
While ABS Filament is a petroleum based plastic, PLA Filament is made from nature plants rich in starch like corn, beets and wheat. PLA Filament is both compostable and biodegradable.
PLA has a lower melting temperature compared to ABS. As a material, PLA has much less warping versus ABS. Additionally a heated bed is not required to print it. PLA generally enjoys sharper details and corners compared to ABS without the risk of cracking or warping. PLA can also be printed at higher throughput speeds.
PLA is created from processing a number of plant products and can be composted at commercial facilities unlike ABS which is derived from fossil fuels. PLA plastic is stronger and more rigid than ABS. and in general the printed objects will have a more glossy look and feel compared to ABS.
Different from ABS, PLA has a firm glass transition temperature, around 60 °C to 65°C , and requires a lower extruder temperature, around 180 °C to 200 °C . As for mechanical performance, PLA is dimensionally stable so that a heat bed can be eliminated, but PLA has a higher coefficient of friction at the same time so more adjustment is needed to avoid extruder jams. Due to the different temperature requirements, make sure the extruder temperature is in the right range when shifting between ABS and PLA.
Both ABS and PLA do best if, before use or when stored long term, they are sealed off from the atmosphere to prevent the absorption of moisture from the air. This does not mean your plastic will be ruined by a week of sitting on a bench in the shop, but long term exposure to a humid environment can have detrimental effects, both to the printing process and to the quality of finished parts.
ABS - Moisture laden ABS will tend to bubble and spurt from the tip of the nozzle when printing; reducing the visual quality of the part, part accuracy, strength and introducing the risk of a stripping or clogging in the nozzle. ABS can be easily dried using a source of hot (preferably dry) air such as a food dehydrator.
PLA - PLA responds somewhat differently to moisture, in addition to bubbles or spurting at the nozzle, you may see discoloration and a reduction in 3D printed part properties as PLA can react with water at high temperatures and undergo de-polymerization. While PLA can also be dried using something as simple as a food dehydrator, it is important to note that this can alter the crystallinity ratio in the PLA and will possibly lead to changes in extrusion temperature and other extrusion characteristics. For many 3D Printers, this need not be of much concern.
ABS - While printing ABS, there is often a notable smell of hot plastic. While some complain of the smell, there are many who either do not notice it or do not find it to be particularly unbearable. Ensuring proper ventilation in small rooms, that the ABS used is pure and free of contaminants and heated to the proper temperature in a reliable extruder can go a long way in reducing the smell.
PLA - PLA on the other hand, being derived from sugar gives off a smell similar to a semi-sweet cooking oil. While it certainly won't bring back fond memories of home-cooked meals, it is considered by many an improvement over hot plastic.
ABS - Its strength, flexibility, machinability, and higher temperature resistance make it often a preferred plastic for engineers, and professional applications. The hot plastic smell deter some as does the plastics petroleum based origin. The additional requirement of a heated print bed means there are some printers simply incapable of printing ABS with any reliability.
PLA - The wide range of available colors and translucencies and glossy feel often attract those who print for display or small household uses. Many appreciate the plant based origins and prefer the semi-sweet smell over ABS. When properly cooled, PLA seems to have higher maximum printing speeds, lower layer heights, and sharper printed corners. Combining this with low warping on parts make it a popular plastic for home printers, hobbyists, and schools.