Why is PLA commonly used in 3D printing?
Polylactic acid (PLA) is a biodegradable thermoplastic material made from renewable plant-based materials. It is a popular material for 3D printing for several reasons including:
- Ease of use: PLA is one of the easiest materials to work with in 3D printing. It has a low melting point, and it does not require a heated bed or a heated chamber for printing. This makes it a great material for beginners who are just starting with 3D printing.
- Biodegradability: PLA is a biodegradable material, which means it can be broken down by natural processes. This makes it an eco-friendly choice for 3D printing, as it reduces the environmental impact of discarded 3D printed parts.
- Low toxicity: PLA is non-toxic and does not produce any harmful fumes during printing. This makes it a safer material to work with compared to other 3D printing materials, such as ABS, which can produce harmful fumes when melted.
- Versatility: PLA is available in a variety of colors and finishes, making it a versatile material for 3D printing. It can be easily painted, sanded, and polished, giving the final printed object a professional finish.
- Cost-effective: PLA is one of the more affordable 3D printing materials making it a cost-effective option.
In summary, PLA is an excellent material for 3D printing due to its ease of use, biodegradability, low toxicity, versatility, and cost-effectiveness.
When should you consider a different plastic instead of PLA?
While PLA is a popular material for 3D printing, there are several instances where a different plastic material may be a better choice. Here are a few situations where you might want to consider using a different plastic:
- High-temperature applications: PLA has a low glass transition temperature, which means it can soften and deform at temperatures that are often reached in a car during the summer. If you need a 3D printed part that can withstand very high temperatures (hotter than anything you'd be comfortable in yourself), you may want to consider using a plastic material like acrylonitrile butadiene styrene (ABS) or polycarbonate (PC), which have higher temperature resistance.
- Chemical resistance: PLA is not highly resistant to chemicals, so if you need a 3D printed part that will be exposed to chemicals, you may want to consider using a material like polypropylene (PP).
- Mechanical toughness: PLA is a relatively brittle material, which means it can break easily under an impact (like glass or a ceramic) such as a hammer blow. If you need a 3D printed part that will be subject to significant and repeated force loads, you may want to consider using a material like nylon, which has higher toughness and greater maximum elongation.
- Water resistance: PLA is not highly water-resistant especially at higher temperatures. In fact, we dry our PLA pellets overnight before extruding them into filament to prevent hydrolytic degradation and ensure our PLA is of the highest quality. If you need a 3D printed part that will be exposed to water or moisture, you may want to consider using a material like PETG, which has higher water resistance.
- UV resistance: PLA is not highly UV resistant on paper, so if you need a 3D printed part that will be exposed to sunlight or other UV sources, you may want to consider using a material like ASA, which has higher UV resistance. With that said, our own personal experience has been that our PLA parts have survived for years outside even under load.
In summary, while PLA is a popular material for 3D printing, there are several cases where a different plastic may be better depending on the requirements and environments that your 3D printed part must survive.
How is PLA filament made?
The process of making PLA filament involves several steps that begin with sugar or starch typically from sugarcane or corn:
- Fermentation: The process begins with the fermentation of plant-based sugars. This is usually done using yeast, which breaks down the sugars into lactic acid.
- Purification: The lactic acid monomer (precursor to a polymer) is then cleansed into purified lactic acid.
- Polymerization: Next, the purified lactic acid is polymerized, which involves linking together many lactic acid molecules into long chains. This is typically done through a process called ring-opening polymerization, which involves opening up the cyclic lactide monomers and linking them together.
- Pelletization: The resulting polylactic acid is then processed into pellets or granules, which can be used for nearly all plastic processes.
- Extrusion: The final step is a typical plastic extrusion process where PLA pellets are melted then pushed and pulled through a circular die to result in filament of the perfect diameter for your 3D printer.
During the manufacturing process, the properties of the PLA can be adjusted by controlling the type and proportion of lactic acid used, the processing conditions, and by introducing additives such as colorants, copolymers, and plasticizers. This allows manufacturers to tailor the properties of the PLA for specific applications, such as improving its strength, appearance, heat resistance, or flexibility. Another very important property of our PLA is that is made in the USA from materials sourced in the USA!