PLA is very probably the most popular 3d printing filament around. There’s a good reason for that popularity. PLA is one of the easiest materials to work with, giving good results within a wider range of variables than the majority of other filaments on the market.
Good PLA filament is forgiving to print with and has excellent finish quality.
In this article, we’re going to take a closer look at PLA and show you how to get the best results possible when using it on your print jobs.
What is PLA?
PLA or Polylactic acid is thermoplastic polymer. Because it is derived from natural sources like corn and sometimes sugarcane, PLA is sometimes referred to a bioplastic. The majority of other thermoplastics are distilled from non-renewable resources like petroleum.
In addition, because it is a natural product, it is also biodegradable. This means that when discarded into a composting system, PLA will naturally break down into its constituent parts in about three to six months. Compare this to other thermoplastics which could take up to one thousand years to biodegrade.
If you’re new to 3d printing, it’s likely that you’ve already encountered PLA around your home. PLA is used to make many common objects, including food containers, disposable tableware and garbage bags.
Even though PLA is biodegradable it is still a strong and durable material. You will find PLA to be harder than other common thermoplastics like ABS. However, its lower tensile strength tends to make it more brittle.
Objects that are printed with PLA will hold up fine when used at room temperatures in a normal environment. It should be noted that PLA has a relatively low melting temperature, in the neighborhood of 170C upwards which makes it a poorer choice for objects that will be used in a higher temperature application.
Now that you know what PLA is and you have a general understanding of its strengths and weaknesses, let’s take a look at some of the things that you can do to get the most out of using PLA as a print material. In this regard, we’re going to look at three critical areas that can affect the success of any 3d printing job – temperature, adhesion and material storage.
Temperature and Speed
In any print job, it’s very important that you get the printing temperature just right if you want a good run. Printing with PLA is no exception to this rule. In general, PLA has an optimal printing range from about 185C to about 205C. If you’re using PLA with a width of 1.75mm your optimal temperature will be closer to the lower end of this temperature range. If you’re using 2.85mm filament, you might want to go closer to the higher end of the temperature range to compensate for the increased thickness of the material.
In any event, no matter what temperature you start with, you do want to adjust that temperature slightly upwards or downwards depending on the environment of the room you are printing in and the initial print conditions that you observe.
In general, it’s a good idea to start printing at about 190C and note how the material is being extruded, as well as the quality of the print layers being produced. If you note problems with the material, simply adjust the temperature up or down in 5C increments until the problem is no longer noticeable.
Your print temperature is probably too high if you notice that strings of material are occurring as your printer is moving between different parts of the print job. This “stringing” happens because the PLA loses too much viscosity due to being too hot. As a result, the material leaks out of the print nozzle as it moves.
Your print temperature is probably too low if you notice that the PLA is having trouble adhering to the print surface or to previous layers. Low temperature is also likely the cause of problems in the surface of the printed object like gaps, holes and missing layers.
This is an indication that the PLA is under extruding because of a higher material viscosity caused by a print temperature that is too low. In either case, dialing in the correct print temperature will increase the chances that you’ll end up with an object that is both useful and beautiful.
When it comes to print speed, every printer is different and optimum settings will depend on what type of printer you’re using. However, PLA generally prints well at a print speed between 30mm to 90mm/sec. For higher quality end results, a lower printer speed is more likely to get you the finished product that you want. As with temperature, the best speed for the object that you’re printing will need to be dialed in.
Getting your print material to adhere to your print surface is key to a successful print run. One of the things that make high quality PLA one of the easier materials to print with is that it somewhat easily adheres to a wide variety of surfaces with a minimum of fuss.
Problems with your PLA filament not sticking? Take a look at our article on build plate surfaces and adhesion to get an idea of what PLA build surfaces might work best for you.
One additional thing should be noted. PLA doesn't require a heated bed to print it as it's low warp, but you might want to use one as it can make those first few layers adhesion easier.
If your PLA does warp, you might want to take a look at our article “Warping – Why It Happens and How to Prevent It” which can be found here.
PLA, like a number of other thermoplastics is hydroscopic. This means that, over time, it naturally absorbs water from the air that surrounds it. When water builds up it PLA, it tends to break down or alter the molecular chains that hold the PLA together. When you print with PLA that has absorbed water, you will find that it is harder to get layers to bind together and those that do bind together tend to be distorted.
Is your PLA filament brittle or snapping? That's likely caused by (assuming it was good filament to start with) it having absorbed moisture.
The solution to this problem is in proper storage of your PLA when you’re not printing. Here at rigid.ink, this is the reason we provide metallic, sealable bags, along with desiccants, with every order we ship. It makes no sense to sell our customers the highest quality thermoplastics available and not give them the best means to protect those materials when they are not being used.
To get a better idea on just how much difference good quality PLA is over cheap PLA, check out Tom Sanladerer's video here:
It’s our goal to make sure that your print jobs are a success the first time, every time you print. When what you print is less than successful you not only waste material, you also waste time. Low cost filament seems like a bargain, but it’s not. Yes, you don’t pay as much upfront for your printing material. However, when design after design is ruined because of imperfections in the filament, the cost of buying replacement filament begins to add up.
As Tom says, our PLA printing filament is the best you’ll find. We carefully manufacture our PLA to super-tight tolerances of just +/-0.03mm either side of the diameter you purchase. This means that when you use our PLA you save time and money and get a successful print run, time after time.