If you have a personal 3D printer, or are in the market for one, you are likely aware that the two most dominant printing materials are PLA and ABS filaments. Nearly every printer on the market prints in one or both of these materials and because of this you might want to know what differentiates the two and/or which material will be best for use by you.
This article will discuss the few similarities and many differences between the two most widely used plastic filaments for 3D printing.
Similarities Between ABS and PLA
While ABS and PLA filaments are the two most popular on the market, they are only two of many materials that are being explored and used in the 3D printing process. These two filaments can be categorized as thermoplastics in that they are soft and easily molded when heated up, and able to return to a strong solid when cooled down. In fact, many of the plastics you come into contact with on a daily basis are considered to be thermoplastics.
Though there are countless types of thermoplastics, this does not mean they are all viable for 3D printing. In order to be considered viable for 3D printing the material has to pass three basic tests; extrusion into a plastic filament, follow-up extrusion and binding during printing, and end-use application (does the final product fulfill its intended use?).
Being able to turn the plastic resin into plastic filament is the first and arguably most important test that these filaments must pass. Without the ability to be transformed from plastic powder to a plastic object the whole 3D printing process is put to a halt. As far as this test is concerned, both ABS and PLA filaments are more or less the same in that they are easily turned from resin into viable objects that are accurately printed, strong, and durable.
Though ABS and PLA filaments are highly similar when it comes to transforming them from resin state to hard plastic state, that is where the similarities more or less end.
When storing either ABS or PLA before use, it is always recommended that you harbor them in a place that avoids direct contact with the atmosphere as absorption of moisture from the air can negatively affect the filament’s quality.
If ABS filament is harmed in any way by moisture it tends to bubble and spray from the printing nozzle during production. This can affect the visual accuracy of the item you are printing as well as the accuracy of the object’s formation and can even clog the printing nozzle. You should be aware, however, that if your ABS filament does come in contact with moisture it can be easily dried by way of hot, dry air from something like a hair dryer or food processor.
PLA reacts differently to moisture in that it can negatively alter the color of the filament as well as reduce or change the properties of the item you are printing. While over-moisturized PLA filament can be dried in much that same way as ABS, it should be noted that drying it sometimes causes an alteration in the crystallinity ratio which can change the extrusion temperature and characteristics of the filament.
To be fair, both of these filaments have risen to their current status as being the best filaments in the industry because they are able to produce highly accurate objects. With that being said, however, there are a few things to look out for that can undesirably alter the end product.
ABS filaments are known to curl and become distorted when the hot plastic comes in contact with a cooler printing bed. While this is an obstacle encountered by many, having a heated printing bed that is clean, flat, and well-maintained works wonders when it comes to avoiding the curling of the edges of your final product.
Another aspect of ABS filament that causes problems with the end product is the occurrence of corners being rounded. If you are printing a creation that is intended to have sharply edged corners, any rounding can eliminate the product’s intended use, especially if your creation is comprised of moveable parts. While placing a fan or other cooling device near the printing nozzle can help eliminate rounding, people who do this run the risk of over-cooling the filament and thus taking away from its adhesive properties which can cause cracking of the final product.
PLA, on the other hand, experiences curling far less frequently than ABS does. In fact, the absence of a heated printing bed will not cause your end product to suffer any sort of deficiency like you often see with ABS filaments that come in contact with a non-heated printing bed.
PLA filament, when heated up, becomes much more of a liquid than ABS and for this reason it is able to create much sharper corners and edges without a high risk of wrapping or rounding.
General Properties of Final Product
Perhaps the most important quality of 3D printing filaments are their ability to produce a final product that is able to be used for its intended purpose.
ABS is able to take many shapes and form a wide variety of creations with all sorts of properties and features. Overall, ABS is a very strong material with a healthy amount of flexibility (when compared to PLA). Because this material is able to bend a bit, it is great for creations with inter-locking parts and pin pieces. Additionally, ABS does well with post-production and is able to be sanded, cut, and otherwise machined in order to fully customize and finalize your creation.
With the ability to flex and be machined, coupled with its strength, ABS filaments are often used by those who are making creations that have mechanical uses, such as gears.
PLA filament, which is comprised of a number of natural resources (corn, potatoes, etc.), is seen as more of an environmentally friendly filament when compared to the petroleum-based ABS filament. Its natural properties mean that any unused PLA filament can be composted at any commercial compost facility. The end-product is strong much like ABS-produced creations, though it is not nearly as flexible which makes working with interlocking parts a bit more difficult. PLA filament generally has a lower melting temperature than ABS and for this reason even sitting a PLA creation near a heater in the wintertime can cause the object to change shape and droop.
Because ABS filament is strong, flexible, and able to be worked on post-production, it is the favored plastic for those making creations with many moving and inter-locking parts. However, its one drawback is that printing ABS filament on a 3D printer which lacks a heating bed can bring about a plethora of unintended problems and misconfigurations that may be nearly impossible to correct by hand.
PLA is available in far more colors and shades than ABS making it the preferred filament for smaller household items and for work by artists. It is an eco-friendly material that can be returned to the earth by way of compost, thus lessening your carbon footprint. If you are able to cool this filament properly you will find that it can print faster, produce smaller, more precise layers, and even have sharper corners than a similar creation produced by way of ABS filament.