PLA, or poly (lactide), is one of the most popular materials used in FDM / FFF 3D printing technology, particularly liked by the less experienced 3D printer users. What is characteristic and what is worth knowing about it?
This material is a biopolymer classified as an aliphatic polyester. Corn starch or sugar cane are used for its production. In addition to FFF technology, it is used to manufacture various types of disposable packaging, it can also be a component of absorbable surgical threads, dressings, stents, orthopedic implants and scaffolds for tissue scaffolds due to its biocompatibility and degradation time not exceeding several years.
In the form of fibers and fabrics, we can meet him in the form of disposable clothes, upholstery, and hygiene products such as diapers. We can even find it in the composition of creams – whether as a carrier of nutrients or as a wrinkle filler. PLA is recyclable. It is considered biodegradable, although without providing special conditions – for example in a composting plant – its degradation lasts a very long time (hence, despite the media envelope of biodegradability, it is highly inadvisable to throw PLA packaging in the bushes. Or unsuccessful prints through the window).
Let’s return to 3D printing. Why is this material so popular? Well, mainly because:
- it’s easy to use and cheap
- material shrinkage is small, therefore it does not require a heated table
- it also does not require a heating chamber
- it is 3D printed at relatively low temperatures – in the range of 190-220°C
- it has quite good tensile strength and rigidity.
All this makes it an optimal choice for novice users, as well as those who want to easily get a large printout with good dimensional accuracy.
However, as might expect, PLA has its drawbacks. First of all: it is sensitive to high temperatures – it deforms already at a temperature of 50-60°C. As a result, it is excluded to use objects made of this material wherever they would be exposed to higher temperatures (such as hot water, hot spaces or dishwasher).
After prolonged contact with UV radiation, it will become brittle. PLA can be difficult to machine because of its rigidity and sensitivity to higher temperatures. This applies, for example, to grinding or drilling holes. It is also inadvisable to smooth the surface of prints with a solvent – PLA does not dissolve in acetone, it is sensitive to substances that are better not to be used outside of the extract in the laboratory (such as tetrahydrofuran and dichloromethane).
A nice smell is noticeable during 3D printing. Despite the lower temperatures reached in the 3D printer than those necessary for pyrolysis, i.e. about 300-400°C, volatile organic compounds with negative impact on health are emitted (such as polycyclic aromatic hydrocarbons). Although the concentrations of released substances are very low (and lower than in the case of 3D printing from ABS), it is advisable to use common sense not to stay in the room with the 3D printer working for a long time, or to ventilate it regularly.