3D printing is a revolution for many sectors, making it possible to create complex objects from digital models. Many materials can be used depending on the application. Among the most used in FDM 3D printing, PLA occupies a prominent place.
In this article, we will present PLA, its applications, its properties, recommended printing parameters, usable support materials, adhesives suitable for this material, as well as its advantages and disadvantages compared to other leading 3D printing materials.
What is PLA?
In 1932, Wallace Carothers created a low molecular weight product by heating lactic acid under vacuum; PLA, polylactic acid, was born. This polymer belongs to the aliphatic polyester family, composed solely of carbon, hydrogen, and oxygen atoms (C, H, and O). It is considered compostable under industrial conditions.
This is a thermoplastic derived from annually renewable resources, such as corn starch, potato starch, beet sugar or cane sugar, etc.
In which applications can it be found?
PLA is used in many sectors, depending on the processes and grades used. It can be found:
- In food packaging, as PLA is approved by the FDA. In addition, its ability to degrade rapidly can reduce its impact on the planet.
- In the medical sector for biocompatible or resorbable implants, to create tissues or membranes. It has high biocompatibility.
N.B. Not all PLA grades are medical grade; specific materials are required. - In textiles, as PLA is a polyester.
- In 3D printing. It is the most popular polymer because it is bio-sourced and very easy to print. It can be combined with many materials to create different effects and textures. In 3D printing, it can be used for functional prototyping, aesthetic parts, and tooling or machine parts with no or low stress.
PLA properties for 3D printing
Key properties and performance:
- Not resistant to bases, hydrocarbons, ketones and ethers
- Resistant to water, salts and oils
- Good layer adhesion
- Rigid, brittle, and inflexible
- Deformation at temperatures as low as 40°C
- Good level of detail
- Low shrinkage, not subject to warping
- Easy post-processing for sanding and painting. Smoothing is more difficult.
- Suitable for food contact
- Low UV resistance
How to print PLA?
To optimize printing:
- PLA is hygroscopic, so it is advisable to store it in a dry place.
- It is not essential to use the heated bed, but it can allow for better adhesion and is recommended for large parts.
- For large volume parts, it is advisable to use an adhesion solution such as hairspray.
- From a safety point of view, PLA is non-toxic, but potential additives must be taken into account.
What supports should I use with PLA?
- PVA (Polyvinyl Alcohol), water-soluble
- BVOH (Butanediol vinyl alcohol copolymer), water-soluble
- Breakaway filament is a non-soluble filament that is easy to break to remove supports.
What adhesives can be used for PLA?
- Cyanoacrylate glue (super glue type), which works with most conventional polymers, is a popular option for bonding PLA, providing a fast hold and good adhesion.
- Two-part epoxy glue is a good option for bonding PLA and offers durable adhesion. However, mixing the two components can be a deterrent.
To optimize any bonding, always ensure surfaces are clean. This will allow better adhesion of the glue to the material.
PLA is a relatively easy material to glue, but it is sensitive to heat. It is therefore not recommended to use glues that require high temperatures to cure, as this could damage or deform the PLA parts.
If the PLA needs to be glued to another material, ensure that the glue is also compatible.
