July 28, 2021
For years PLA 3D filament has been the top dog in the 3D printing industry; it prints easily, is available in a huge variety of colors and effects, and can be printed on virtually any 3D printer. Being successful with PLA is an essential skill to develop as you are likely to stick with PLA for most of you're projects until you find yourself working on more demanding use cases. PLA is great for demonstration models, jigs, fixtures, your average around-the-office 3D print, or even full-body costumes, so let's jump into what you need to know to perform at your best.
PLA or Polylactic acid is a thermoplastic polyester. It is commonly derived from renewable resources, such as corn starch, tapioca roots or sugarcane. One of the most attractive things about PLA plastic is that it is industrially compostable, which means it can be broken down back into its base elements through industrial means, and not through a ten thousand year lifespan (note, composting in a compost bin is not the same as industrially compostable). It is important to point out that although PLA is compostable it is very robust when used in any normal application such as a 3D printed jig or a manufacturing prototype.
PLA plastic is used in many industries from food packaging to biodegradable medical implants such as sutures, tissue screws, and tacks. When used as a 3D printing material, it is almost always the introductory material as its printing properties make it well suited for a complete beginner. A majority of 3D printer users will have experience with PLA in one way or another, from end-use products to general prototyping.
PLA filament is an attractive material for newcomers as it's tough, available in a huge variety of colors, and be easy to print on basically an 3D printer. PLA is less thermally contractive which means it hardly ever warps and is very dimensionally stable, making it much easier to print big parts with and rely on the print being as close to the 3D model's dimensions as possible. The thing to consider is that being stiffer and harder also means that it is more brittle; if the part you're printing will be used where it might receive a lot of sudden impacts or sharp collisions, PLA has a tendency to shatter during failure.
The other important consideration when printing parts with PLA filament is knowing what sorts of temperatures the part will be subjected to. PLA plastic becomes soft as low as 50°C and will deform rather quickly in this rather limited heat. This is why you should avoid PLA when you have a design that will be exposed to heat, even as little as the heat inside a car on a summer day. At MatterHackers we generally use PLA filament for all our educational models, test-pieces, and quick-turnaround prototypes, as they aren't going to face any stressful scenarios, they just need to look beautiful.
As PLA is a rather undemanding filament, there isn't a lot you need to consider for your 3D printer to get it up and running and printing PLA. On average, 200°C is an excellent place to start printing PLA, but some brands and even colors may need you to adjust this hotter or cooler, depending on their individual makeup. Wood-filled PLA tends to clog easier when you have the temperature too high, so dropping it even as low as 180°C is a rational decision. Some black or white filaments use additives that take a bit more heat to flow nicely and may need as much as 220°C to print well. Essentially, start with 200°C and play around with 5°C higher or lower to find the ideal print quality for you.
With such a (relatively) low printing temperature, PLA does not require an all-metal hotend (a hotend that uses a thin walled heatbreak to keep heat in the heater block and away from the heatsink) and will work just fine with a PTFE-lined hotend (where the PTFE tube passes all the way through the heatsink and butts up against the nozzle). However, if your printer already has an all-metal hotend, don't worry as it's still perfectly compatible with PLA.
In general, PLA is non-abrasive, but once you start playing with additives it becomes a case-by-case basis. Sparkly filament isn't abrasive despite having non-PLA material in it, but glow-in-the-dark filament is abrasive as the additive that glows will wear away at your nozzle before you're through even one spool. Wood-filled PLA doesn't tend to abrade brass nozzles, but often a 0.6mm is necessary to prevent the wood particles from clogging the nozzle. An easy way to avoid these concerns is to swap over to an Olsson Ruby nozzle or a Nozzle X when you want to use these materials.
Layer cooling is a must for PLA, in fact, there's no such thing as "too much" cooling when it comes to PLA. Many other filaments' only requirement for the cooling fan is for it to be turned on for very short layers, but can stay off the rest of the time. PLA stays soft considerably longer than other materials so your fan will spend most of its time at 100% power, and even then some models print better when printed in pairs so there is enough time for the extruder to move away from the part and give it time to cool.
Right off the bat, PLA doesn't actually need a heated bed. Of course, having a heated bed will only makes things easier, but you can get by without one as long as you have the right bed surface. If you do have a heated bed, around 60°C is a good place to start and then you can adjust by 5°C in either direction to get the adhesion you need. Some bed materials need more heat than others for PLA to stick, so experiment until you feel happy with your results.
As for the bed surface itself, you have quite a few options to work with: glass, Buildtak, Buildtak PEI, GeckoTek, Wham Bam PEX, or LayerLock Powder-Coated PEI are all viable options for your 3D printer's bed surface, and keep in mind that's not an exhaustive list, just the big players. Let's take a look at each surface individually:
There are always new and exciting methods for bed adhesion being developed, so it's important to have a good grasp on what each method is best used for. You can check out our 3D Printing Essentials article about bed surfaces to fully understand the pros and cons of every bed surface you might come across while 3D printing.
In addition to build surface upgrades, there are also a wide variety of 3D printer adhesives that you can apply to your 3D printer's bed to get a great first layer. These adhesives are specifically developed for the 3D printing industry, so you can trust they have been tested to be tried and true 3D printer adhesives. Here are the best 3D printer adhesives that you can use to get the best first layer for PLA filament:
Most 3D printer bed adhesives have the same instructions for use: apply a thin layer to the build surface where your actively 3D printing. Then, wait for your part to cool before removing - waiting for your 3D printed part to cool makes it much easier to remove, and certain adhesives will sometimes even "pop" the part of the bed once cooled.
When switching between two PLA spools and colors:
The first layer is the most important part of any print - it sets the foundation that the entire print builds on. You can check out the in-depth article on how to get a perfect first layer here, or for a brief summary of what to consider below are the few things you need to do to get the first layer to stick well.
Below is a video from MatterHackers' 3D Printing Essentials series that will help guide you in the right direction for getting a stellar first layer. In this video, we'll walk you through the steps mentioned above in detail so you can succeed when 3D printing with PLA filament.
There are a few key things to check when your prints aren't working. But before we look at solutions we need to have a brief description of your symptoms.
"I can't tell if my printing temperature is right"What to Look for if you are having trouble getting your PLA filament temperature right:
"I can't get the first layer to stick."
"The part has bad internal layers and top surfaces."
"The outside edges of my parts have lots of little bumps on them."
"Tall sections of my prints look melted or squished together."
"My printer will not put out any material."
Thank you for reading How To Succeed When Printing In PLA.
If you have any comments or contributions, please drop us an email or give us a call. We are always looking for tips, and best practices - and would love to hear from you. Feel free to reach out with any specific questions on the MatterHackers Forum.
Happy Printing! - MatterHackers
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