What is PLA Filament and Why Use it?
Intro to PLA Filament
One of the fun parts about 3D printing is finding the perfect filament to use with your machine. There are seemingly hundreds of colors and materials to choose from and each one has different properties depending on what it's made of.
The most commonly used material for 3D printing at home is PLA, otherwise known as Polylactic Acid. PLA is relatively inexpensive, easy to work with, comes in a huge array of colors, and is even available in cool variants like metal or wood. Also, it's primarily made from renewable resources so it's lower impact to the environment over other materials. Essentially, it's a biodegradable plastic made of plants!
For Beginners: What is filament?
To start with the basics, what exactly is a 3D printing filament? Filament is basically a plastic wire wrapped around a spool that a 3D printer melts and pushes through a small nozzle. It's the raw material that you start with, and your machine converts it in to the printed model of your choice.
When ordering filament, there are a few considerations. In addition to the points about PLA we'll talk about in this article, also be sure you're ordering the correct size filament for your machine. Your printer's specifications will tell you what you need, but most likely you'll be looking for 1.75mm filament (if not, it's probably 3mm but that is very rare for modern 3D printers at home).
Why PLA is so Useful
It's Simple to Use!
PLA filament is so widely used because it's so easy to work with; but what exactly does that mean? The printer does all the work, right? Well, not exactly. There are a ton of factors when considering which filament to use and PLA checks the boxes on some important ones.
Lower melting temperature & less warping:
When compared to a material such as ABS, PLA has a lower melting temperature. For a comparison, PLA printing temperatures are usually around 205 degrees C (401 F) while ABS is about 230 degrees C (446 F). Not a massive jump, but still a very recognizable difference.
A benefit of these cooler temperatures, along with the general properties of PLA; is that when compared to ABS, PLA has a smaller amount of thermal expansion issues to deal with. What does that mean exactly? Bascially, as things get hot, they tend to expand, and as they cool down, they tend to contract.
The problem with this in 3D printing is if a print cools too much while being printed, it can lead to warping, potentially causing lots of problems. 3D printers are pretty precise machines, moving within microns along all directions to do the work they need to do. Now imagine if the surface the printer was trying to print on kept moving slightly because as the print cooled-down, the plastic that had already been printed is contracting slightly.
Each print layer becomes slightly more 'off' from the previous one. These minor differences add-up over time, eventually leading to an odd-shaped and 'smashed' part of a print at best, or a completely failed print at worst.
Using a heated bed and heated print chamber can help minimize this issue when using something like ABS, however with PLA, you don't have to worry about these extra precautions. While a heated bed is nearly essential for successful ABS prints, it's not required for PLA (but I still think it's helpful!). So overall, this lower temperature contributes to simpler printer operation, and less concerns over warping.
Safer to Use:
Adding to the simplicity of PLA filament, is the fact that it's much safer to use indoors vs. ABS. As explained in further detail in the next section, PLA is basically made from plants and is used in a variety of other 'green' applications. This is being put in the "easy to use" section though, because there are fewer considerations to worry about when using PLA in the average home. PLA in its pure form is considered non-toxic, and doesn't put out bad fumes when heated.
For example, ventilation is less of a concern. While you should always consider good ventilation wherever a 3D printer is, PLA is considered fairly safe to use indoors, where many desktop printers reside. No need to set up an elaborate exhaust fan and a chamber to help channel the fumes out the window like you would want to do for ABS. In this way, it's easier to get up and running with PLA than another material
Note: The safety of fumes can be up for debate. While PLA is pretty safe, various dyes & materials used to give color or other properties can be unknown. I use PLA indoors but always try to crack a window if it's going to be a big print. Make sure you're keeping yourself safe!
It's Green!(ish)
As touched-on earlier in the article, PLA filament is a plastic derived from renewable resources. PLA stands for Polylactic Acid and is considered a biodegradable material (and industrially compostable!). Meaning all of those prints that don't go as planned aren't adding a huge amount of permanent landfill waste when they're thrown out.
PLA is derived primarily from corn starch or sugarcane. That's right! PLA is, in the simplest sense, plastic made of corn. It's been in use in medical fields for a long time because it's safe, strong, and non-toxic. Over time, availability and the push for greener materials has created a PLA research boom. This has brought PLA to many more uses including affordable material for 3D printers.
It's Versatile!
Versatility as Printer Filament:
PLA filaments come in all different types. You can find nearly any color under the sun, transparent versions, and even what are called "composites".
Composite filaments are primarily PLA plastic, but have additional material mixed-in to the plastic to give it new properties or effects. You're still printing in plastic, but the small bits of other material mixed in can give you a world of options. Here is a short list of some cool composite PLA filaments I've come across so far:
Wood: Small bits of wood make this smell and act like wood once printed! It can be easily sanded and even will take-on a standard wood stain once printed. It's one of my favorite materials to work in since it's so unique and easy to work with. It's also a great conversation starter when you tell someone you 3D pritned wood!
Metals: Some manufacturers out there put small bits of metal shavings in to the PLA plastic material, giving the ability to print with a metal effect. These items can be sanded and polished, take on some rust, etc. With a little finishing work these can look pretty amazing.
Coffee: Yes, coffee! Definitely not something you'd want to toss in to your coffeemaker and use to make a cup, this PLA filament by Proto-pasta has bits of ground coffee throughout it. This means that as it prints, it leaves the scent of coffee in the air! (Limited release, may or may not be available at the time you read this!).
Other Uses of PLA Material
Not only is PLA a great when used as a 3D printer filament, it's also used in a wide variety of other items, some of which you might use every day without even realizing it! These are just a few highlights:
Food containers & plasticware. Ever see one of those cool "eco" plastic drink cups or set of disposable forks that claim to be biodegradable? Well it's most likely that it's made from a PLA plastic thanks to its food-safe nature, as well as the fact that it is biodegradable. Hopefully we see more of this over time to help reduce plastic waste.
Medical uses. PLA's biodegradable nature and non-toxicity in its pure form, means that it's a great material for items like screws or tissue scaffolding during medical procedures. The item can be implanted and slowly over time it will dissolve safely in the body; being replaced with materials the body creates. No need for a surgeon to go back in and remove something once the patient is healed!
Other uses. PLA is a cool material that's being used for new things all the time. Items such as plastic bags for groceries or potato chips, biodegradable tea pouches, or anything traditionally plastic and disposable has the potential to be replaced with PLA.
Disadvantages of PLA
While PLA does sound like the wonder material. there are a few downsides and reasons you may want to use another material.
Strength: When compared to ABS plastics, PLA is fairly brittle and can break easily, so it is not recommended for anything requiring some serious strength. A great example of this is a home-printed frame for a quadcopter drone. If printed in PLA, a bad crash would likely cause a part of the frame to break because the PLA is more likely to break than to bend and absorb the impact. If ABS was used to print the frame however, it's likely that the drone would flex and then pop back to its original shape, leaving no lasting damage.
Smooth-finishing: A technique often used to make ABS prints look smooth is by using acetone to slightly melt the plastic and fuse the layers, making the print appear smooth. PLA requires different techniques if you're looking for this effect, and can be more difficult or require more work to get the same results. This finishing method however, can cause a fair amount of bad fumes, so great ventilation or outdoor space is needed to do it safely.
Heat-resistance: As mentioned early in the article, PLA has a lower melting point. While it's plenty fine for sitting out on a desk, extreme temperatures, such as in a car in Florida on a hot summer day, can cause the print to weaken. So PLA is not recommended for areas where heat will be a factor.
The Bottom Line
Now it's easy to see why PLA is a material of choice when it comes to 3D printing at home. It's easy to work with, not as toxic as some other materials might be, it's fairly "green" because it's biodegradable, and it's extremely versatile!
In the end, PLA filament is perfect for most basic home uses, especially on any projects that don't require a super strong or flexible material. Desktop statues, storage boxes, small non-load bearing brackets, and toys can all be printed using PLA just fine. While PLA can be a bit brittle compared to ABS, unless you're expecting the part to experience high-impact or some serious forces, PLA is just fine. In fact, all of the useful things I have listed in my Top 10 Useful Prints article were printed in PLA filaments and I haven't had a single problem.
Don't forget to check out some of these sites that I visit often to see the latest and greatest in filaments:
https://www.proto-pasta.com/
https://hatchbox3d.com/
http://www.3dsolutech.com/