How To Succeed When Printing In PLA
Posted on May 17, 2013 by MatterHackers
Let's dive into the details of 3D printing with PLA filament. We will discuss what PLA is and how to make it work with your printer, how to find the right temperature and what surfaces to print on.

PLA is a wonderful material for 3D printing. It is a renewable, biodegradable resource.  It is non-toxic and has a pleasant smell when printing.  PLA filament comes in a wide range of colors and because of its thermal characteristics, is particularly easy to get great prints with.

WHAT IS PLA

Strawberries in PLA containers


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 is that it naturally degrades when exposed to the environment.  For example, an item made of PLA in the ocean has a degradation time on the order of six months to two years.  Compare this to conventional plastics, which take from 500 to 1,000 years to degrade.  It is important to point out that although PLA will degrade in an exposed natural environment it is very robust when used in any normal application such as a printed toy or a critical piece of a printer.  In that respect you can think of it as being similar to iron.  If you were to expose it to continuous moisture or leave it outside, it would "rust" and become unusable in short order.  But if you had it in your home you would expect it to last nearly indefinitely.

PLA is used in many industries from food packaging (like the pictured strawberry containers) to biodegradable medical implants such as sutures, tissue screws, and tacks.  PLA comes in a number of grades; scientific, medical, food safe, and then to the type of PLA used in consumer 3D printing.  PLA's natural melting temperature is around 80C but it is mixed with other plastics to make it suitable for 3D printing. 

If you have printed with ABS, you will find PLA to be harder, wear more slowly, and be easier to get a nice flat part with.  PLA is less thermally contractive and much easier to print big parts with. 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 banging or sharp collisions, PLA may not be the best material.

The other important consideration when printing parts in PLA is knowing what sorts of temperatures they will be subjected to.  PLA becomes soft at 70c - 80c and will deform if used in environments that remain above those temperatures for any prolonged time. This is why you should use ABS or some other material near the extruder.  At MatterHackers we generally use PLA for all our printer parts except those that are directly around the extruder (such as the x-carriage, mounting plate and extruder block) which we print in ABS.

Spooled PLA Ready for Printing


Getting the First Layer Right

The first layer is the most important part of any print.  There are a few things you need to do to get the first layer to stick well.  

  1. You need the print bed (or print surface) to be level.
  2. You need the extruder to be homed to the correct height from the bed.
  3. You need a good base material for your PLA to adhere to.

 

PRINTING ON BLUE TAPE

Blue Tape, or Painters Tape, is one of the easiest and fastest ways to get a great print from PLA.  Here is a quick checklist of things you want to make sure you are doing.

  1. Check that the Blue Tape creates an even layer. Don't miss any spots.  Don't overlap the edges.
  2. Don't heat the bed when using Blue Tape, it will not stick well to your PLA
  3. Replace any tape strips that get damage when removing parts.
  4. Replace the tape after 5-10 prints or when parts stop sticking.
  5. If your first layer is not sticking - make sure the print head is close enough to make a nice squished line of PLA. If that doesn't take care of your problem, you may want to increase the 'first layer temperature' 5 to 10 degrees (start with 5 and increase if necessary).

Blue Tape is not perfect but it is very easy to use and generally gives great results.  However, sometimes your parts can pull the tape up off the glass during printing, and you will see some warping when that happens. To reduce the Blue Tape from pulling up, we have had great results putting Blue Tape on top of PET tape, but that's just crazy :).

NOTE: PLA will not stick well to Blue Tape when it is warm.  You do not want to heat the bed if you plan to print on Blue Tape.  Also, the surface of the Blue Tape will lose its ability to hold onto a part with use.  You should replace the tape when you start to see the adhesion degrading (usually somewhere between 5-10 prints on the same spot). 

Printing On Blue Tape


PRINTING ON GLASS WITH A HEATED BED

When you have a temperature controlled bed, printing directly on glass can be a great option.  The recommended bed temperature for PLA is 70C.

  1. Having your bed level and extruder at the right height is extremely important when printing on glass.  If your extruder is too far from the glass your PLA will not stick AT ALL, if it is too low the glass will completely block the extrusion of material and it will not stick AT ALL.
  2. If your first layer is not sticking
    1. Make sure the bed is level.
    2. Make sure the print head is close enough to make a nice squished first layer.
    3. Make sure you run the extruder enough before your print starts so there is filament going onto the bed during the entire first layer.  In slic3r you can turn the number of loops up to 4 or 5 or more depending on the part.
    4. Clean the glass with denatured alcohol

When you can get it working well, glass is the absolute best way to print PLA.  It make a great shiny bottom layer and the heated bed ensures that parts stay nice and flat.

Printing Directly On Glass


OTHER PRINTING SURFACES

Printing on Kapton Tape

Many people have had success printing on Kapton Tape. To print PLA on Kapton Tape you need to have a heated bed.  We used to print on Kapton Tape on a heated bed, but after mastering printing on glass we no longer recommend printing on Kapton tape as a first option.  The procedure for printing on Kapton tape is nearly identical to printing on glass but involves more setup and clean up.  If you have advice on other benefits of Kapton Tape please let us know.  We are always working to improve our process.

Printing on Polycarbonate

We have experimented briefly with Polycarbonate, oiling it slightly with vegetable oil.  Polycarbonate did work, and the print came out fine.  However the part was difficult to remove and the benefit was not readily apparent.  We feel this method deserves more investigation and we'll update this section as we learn more. For now we recommend sticking with Blue Tape.

Getting The Temperature Right

When working with a new roll of filament for the first time, we generally like to start out printing at about 200c and then adjusting the temperature up or down by 5 degree increments until we get the quality of the print, and the strength of the part, to be in good balance with each other.

What to Look for:

If the temperature is too high

You will see more strings between the separate parts of your print and you may notice that the extruder leaks out a lot of plastic while moving between separate areas of the print.  If this happens you should try to incrementally lower the temperature by 5 degrees until the extruder is not leaking so much material.  

Sometimes you will have a material that is simply less viscous than other PLA and will leak more even at lower temperatures.  We recommend you increase the retraction a few millimeters (3-4 seems like a good number for most every PLA we have tried).

If the temperature is too cold

You will either see that the filament is not sticking to the previous layer and you are getting a rough surface (like the picture below), or you will get a part that is not strong and can be pulled apart easily.  In either case, you should increase the temperature by 5 degrees and try again until you get good line segments on every layer and have a strong part when done printing.

Extruded Filament Not Hot Enough


Changing Filament

When switching PLA colors:

  1. While the extruder is cold set the heat to 80c and wait for it to heat up.
  2. When you reach 80c remove the current filament from the extruder.  You may be able to back it out by hand or you may need to reverse the extruder.
  3. If you are having trouble removing the filament, increase the temperature to 100c and try again.
  4. Increase the heat and load the new filament normally.
  5. Run the new color through the extruder until it runs clean and the new color is all that is coming out of the extruder. If you are switching from a dark color (such as black) to a light color (like white or natural) run a while longer to be sure you don't have any dark contamination:
    1. Clean the extruder gear and blow out any particles from the extruder entrance.
    2. Print something that you don't care if it has bits of the previous color in it, or run the extruder for several minutes.  It may take as much as 10 to 15 minutes of extrusion before you can have confidence that there won't be dark material mixed with lighter material.

Note: We recommended removing the filament when soft rather than when fully melted so that there is less possibility of depositing melted material onto the extruder drive gear or leaving meterial high up the melt chamber entrance.  Both of which can cause jamming and are hard to clean out.  Soft removal also helps ensure that you get everything out of the extruder tip.

PRINTING WITH A MAKERBOT REPLICATOR

The Makerbot Replicators extruder is not quite as powerful as some of the RepRap geared extruders so here are some extra tips that can really help get great results.

  1. Make sure your bed is absolutely flawlessly leveled.
  2. Measure the filament with calipers. Take 5 measurments, throw out the bottom and top values and average the remaining 3.  Put this number in for the filament diameter.
  3. Clean the extruder.  If you been having problems you probably need to do this.
  4. Clean the teeth of the drive gear.
  5. AND THE BIGGIE! Use a tiny drop of canola oil on the end of the filament during the filament change. We got this tip from a customer and it has been AMAZING, not a single filament jam since!

MatterHackers PLA Temperature Quick Reference

Color Recommended Temperature Recommended Range
Black 195c 190c - 210c
Glow-In-The-Dark 190c 185c - 205c
All Other Colors 210c 205c - 220c

Note: You may need to experiment with the temperature that will print the best on your printer.  Ambient temperature, humidity and the calibration and uniqueness of your printer all play a part in how your prints will turn out.

What to do When Things go Wrong

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 get the first layer to stick."

  1. Make sure the extruder is at the right height. Adjust the limit switch or extruder 0 height
  2. Make sure the print bed is level. Level the bed

"The part has bad internal layers and top surfaces."

  1. Check the extrusion temperature (you may need to increase it by 5 degree bumps)
  2. Check the filament tension.
  3. Clean the filament drive gear

"The outside edges of my parts have lots of little bumps on them."

  1. Make sure your printer is getting enough data. If printing from a computer, ensure that the computer is not too busy to feed the printer commands. If the printer is pausing it is usually due to the printer being too busy.
  2. Print from SD cardOn some printers you can try and print from SD card.  This often helps the printer have enough data to run more smoothly.
  3. Source better PLA.  We have found that the quality of your print material can have a big impact on the quality of your part.  Getting better PLA can help you get better parts.  However, don't be too quick to assume the problem is in your PLA.  With the right settings and patience hobbyists have succeeded in printing all sorts of materials many of which have very low viscosity and inconsistency.  You should be able to get at least usable parts even with some lower quality filament.

"Tall sections of my prints look melted or squished together."

  1. Turn on "Cooling". If your printer has a fan you should enable "cooling" in the print settings.
  2. Get a small fan. If your printer does not have an integrated fan you should look into getting a small desk fan.  This can help dramatically with tall sections of your print or when "bridging" (printing top layers that span gaps).

"My printer will not put out any material."

  1. Make sure your hot end is getting hot. Check that the hot end is heating at all.  If it is not you need to have your printer serviced.  It is likely that you have a loose connection or your electronics have been fried (assuming the printer is still connected and responding to your host software :).
  2. Clean the drive gear and adjust tension. The first thing we are going to do is clean the filament touching drive gear and ensure that we have proper tension against the filament.  Usually improper tension or a clogged drive gear will make the print look more like the picture we have for low temperature filament, but it sometimes does prevent extrusion all together.  Clean the pinch wheel with a wire brush, and make sure your tension is good and solid (too much can also prevent extrusion and is more common with direct drives [the motor is directly connected to the drive gear] but less common with geared drives).
  3. Remove the current filament. It may be that you have a small particle in your extruder tip jamming the plastic.  Use the change filament technique described above to pull out any particles that are in the extruder tip.
  4. Check for and remove jams between the extruder and hot end. This is the most extreme type of problem because now it is time to take things apart.  Sometimes heat can creep up the filament in the extruder and cause a bulge that then cools and prevents any further extrusion.  This is usually at the junction between the extruder and hot end.  Take off the extruder and remove all the PLA you can (you may need the hot end hot  (80c-100c) to get all the material out.  If you can't get out all the filament by pulling it out you may need to try and drive it down through the hot end. We usually use a small allen wrench.  If this fails you can try and drill out the extruder or hot end but you may need to replace parts.  Be sure to take precautions against being shocked or burned.  If you are not qualified to do this work find someone who is, rather than risk injury.



Thank you for reading 'How To Succeed When Printing In PLA'.

If you have any comments, corrections, 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.

Sincerely,

MatterHackers


P.S. Check out our Filament Comparison Guide to get the scoop on all the latest and greatest filaments! Or browse the MatterHackers Store for all your fun filament needs.

28 Comments

Great article. I am printing black PLA directly on heated glass. Only problem is I have is that the part is very difficult to remove from the glass and have even broken parts trying to do so!

CAFrap - September 18th, 2013 at 5:24p.m.

If you wait until the part fully cools you should be able to remove it easily, in fact it usually just falls off the glass.

LarsBrubaker [Moderator] - September 18th, 2013 at 5:26p.m.

Very helpful. I had one layer coming out ok then the rest was full of bits then nothing, i have noticed that my Robo3D printer heater switches off but it took me 3 days to notice that.

I have never managed to print anything on this machine since i bought it, now i know why.

Guest - October 2nd, 2013 at 4:02a.m.

After cleaning glass with acetone I put some lemon juice on to the glass print bed while it is warming up. It is probably just the sugar content but it seems to help the filament to grip and the finish is a little nicer.

Tony3D - October 7th, 2013 at 3:51p.m.

Great article. Although a bit more detail on getting that first layer to stick to the glass would be helpful. I'm using the heated glass, which helped a bit, but still hitting problems. How does extrusion temperature affect the first layer? It seems the strand of filament is too thin for me to see if it's "squished" or not as it comes out, and because it doesn't stick, it's even harder. Instead, it gets gummed up in the underside of the hot end, which snags on stuff when it does eventually start sticking. Maybe some pictures of the different problems would also help, or breaking down more specifically the problems. Am I extruding fast enough? Too fast? So many settings for a newbie...

Agrabren - November 6th, 2013 at 8:13p.m.

Agrabren, It sounds like you're printing with the nozzle too cold.

Max Tepermeister - November 8th, 2013 at 4:28p.m.

I have also had a terrible time getting anything to print on my Robo3D printer. One thing to note, I ordered mine assembled and calibrated. It was missing parts, not completely assembled, and not in the slightest calibrated. It is worth looking into your bed leveling, mine was extremely unlevel and is requiring a lot of work to get it set up right.

Guest - November 15th, 2013 at 8:16a.m.

the main problem I'm getting is in my makerbot replicator 2X is the filament skipping, im not sure, only happens on quick short sections when the filament has long straight lines it comes out ok.

there's a clicking sound and it stops extruding I've printed from 80'-90' all the way to 230' dagrees. prints great with ABS no prob, at this point I hate PLA.

Any suggestions?

Ion Popian - December 22nd, 2013 at 12:29p.m.

Ion, have you gotten the upgraded drive block Makerbot released this summer? My Rep2 had this issue before the upgrade.

cselph [Moderator] - December 23rd, 2013 at 4:54p.m.

Awesome got the PLA down, and looks great. tightened the screw on the drive, and slowed down the mm/s speed. thanks for the article.

New question, Im trying to support with water soluble plastic and print with ABS, one melts at 230, the other at 100-120 how can I heat one nozzle at one temp and the other and a different temp, because they are both running a default temp of 230 and the PVA comes out water and not very good

PVA and PLA work great at the same temps.

same question would be applicable for PLA and ABS to get nice different shininess in one go

thanks. :)

Guest - December 26th, 2013 at 6:54p.m.

Yes! MakerWare has a roundabout way of achieving this, but you can definitely set the extruder temperatures to be different.

When you're exporting your STL in MakerWare, select "Create Profile" instead of "Use Defaults". A window will prompt you to name the profile. After you do that the window will close and you'll see an option for "Edit Profile". Your default text editor will open a file with all the slice settings for your custom profile. If you scroll down a tad you'll see:

"extruderTemp0": 230,
"extruderTemp1": 230,
"platformTemp": 110,

You can edit the temp, save the profile, and your extruders should then print with the settings you input.

cselph [Moderator] - January 2nd, 2014 at 4:44p.m.

I have found that lightly sanding the blue painters tape with medium grit paper before printing with PLA helps to ensure a good first layer adhesion. I've had problems with thin edges or points (like all the snowflakes I printed this season) curling up and this stops that. Usually it sticks so well that I have to re-apply the painters tape to the print platform.

Jershanlon - January 6th, 2014 at 3:55p.m.

wow, hot temps, i've been running PLA at 160-175 and cursing the bad infill, first time i saw a pic of that despite a lot of looking.
Increased PLA temp now to 190c with a strong 80mm fan blowing in the print. Looks way better! :)

Now if bridges would be good as well..

I like ABS better tho, even tho it doesn't stick to bed as well, many parts even if corners lifted up ends up usable.

PulsedMedia - January 11th, 2014 at 6:15p.m.

I use a thin layer of molassis and water mix. I'm guessing it is around a 15 parts water to 1 part molassis. I dry it with a 60C bed temp. The dry layer has to be very thin or it won't stick at all.

slashthedragon - February 3rd, 2014 at 2:32a.m.

For those of you with Robo3ds: I also got mine assembled and calibrated. And it was calibrated, for the first few prints. One thing nobody considers is the belts are under tension for the first time, and of course they will stretch a bit, just like new cables on a bike, you will have to tighten them after the initial setup.
Additionally, Getting your Z axis zeroed correctly takes time. It took me multiple revisions and a few weeks of tinkering to get it so the extruder head was only a sheet of paper's thickness from the blue tape every time I told it to go to the home position. Once you get the Z axis properly tuned getting your PLA to stick to the printer bed is no longer an issue. At that point it's fine tuning the extruder temperature to each particular spool of PLA you have. I generally run a 5mm calibration cube at 5 degree intervals, along with a long, wide flat print that is about 5mm deep to check how each temp works with the infill pattern and surface texture.

Baron - February 13th, 2014 at 3:05p.m.

When it comes to getting PLA to stick to glass, there is nothing comparable to glue sticks.
Use a thin layer and print. It is easy to apply and remove, it is cheap, it doesn't require the bed to be perfectly leveled and it is easy to remove the print after it is done.

Also, another pro tip for PLA printing is to apply a dab of Canola oil to the tip of the filament. (Google for it). Specially if you are using clear PLA or low quality PLA, the environment is dusty, extruder isn't super strong or hot-end isn't of the best quality. The oil will make jams go away.

Franklin Dattein - February 17th, 2014 at 5:29a.m.

WHEN I PRINT PLA, I HEAT MY BED TO 60C AND EXTRUDER TO 210C ITS A GOOD STARTING POINT. I USE GLASS AND I SPRAY SUAVE HAIR SPRAY GET IT FROM MENARDS PINK/RED CAN AND ITS CHEEP. I HAVNT HAD AS OOD OF RESULTS FROM THE GLUE STICK METHOD. LEVEL BED IS THE MOST CRUTIAL PART!!!

MIKE D - February 23rd, 2014 at 12:03p.m.

for better abs sticking I am using UP printer's PCB perfboard build platform with 9000 holes on it. dia:0,8mm pitch 2,5mm, slicer advanced setting - first layer 500%, rafting - 1 layer. Try.

Guest - February 25th, 2014 at 8:40a.m.

after finishing printing ,
put some water near the object and it will easily or automatic to take off..
it really usefull

Guest - March 17th, 2014 at 4:29a.m.

After each PLA print on my M2 I clean the bed with Windex on a paper towel and the polish the glass with a micro-fiber cloth. I run the bed at 60-65' and the extruder at 215'. I never have any adhesion problems and once the bed cools, the print all but falls off the plate.

Guest - April 22nd, 2014 at 11:11p.m.

Thank you for the temperature hint. I was printing PLA @ 180-190 deg (as suggested by reprap site) with bad results. Thank to this article I tried with 210 deg and now I have pretty decent prints.

heron - June 6th, 2014 at 8:32a.m.

Thanks for such clear comments and help.
In may 2014, I purchased my first 3D printer, a TAZ 4. Up until recently I have only been doing abs prints which, after many startup issues (level bed, pinch roller tension, and setting nozzle height 1st layer) are now resolved.
I was using the PET tape on my heated bed and found it was to good, I was having to use enough force to remove some prints that I was scratching them with my tools. Yes, I let them cool down even overnight. I finally tried using hairspray as so many are suggesting and found it to work great. After my heated bed cooled down, I could actually hear when the print was 'unsticking'. Then a little tap and my prints came off easily.
I recently changed over to black PLA with some success. Small prints less than an inch in height come out well. My biggest problem right now,after many hours of printing and when my print reaches a height of more than about 2", the filament stops coming out of the nozzle. The nozzle temperature still reads 185 (as recommend). The pinch roller is still turning (and eating a notch in the filament). When I release the pinch roller on the filament, the filament is stuck quite hard between the pinch roller and nozzle. Its difficult but can be pulled out.
My first layer is sticking well, and the other layers look good until the filament stops coming out.
I'm running into this problem with several prints of different types. Some of which printed perfectly using abs.
Any help anyone can provide would be great. And I have a couple specific questions:
Shouldn't PLA take less tension than ABS on the same printer?
From observation, I believe you need to position the nozzle a little closer to the table on the first layer when printing directly on glass (instead of PET tape).

Dean - June 30th, 2014 at 2:54p.m.

@Dean, I would recommend bumping up your temperature a bit, to maybe 195-200Cº. 185Cº works with some PLA, but most of it requires that you print a bit hotter. Which also might be why your filament stops extruding after extended prints. (Because the filament is not feeding quickly enough.)

GriffinKahnke [Moderator] - June 30th, 2014 at 3:49p.m.

@Dean, I had the same problem on a TAZ 3 and solved it completely with a 6" desk fan blowing toward the part and print head. The fins above the print head need some air movement through them to prevent the heat from soaking into the parts above the nozzle. If those parts get too hot, they heat the filament that is above the nozzle. That makes it yield and expand radially as it is being pushed down into the nozzle. If the filament expands enough to drag on the bore, it will jam. With the fan, I have not had a single feed jam after printing about 20 kg of PLA.

The only down side to a desk fan is that on a cool day, the platen can't heat up enough before the print starts. So, I have to turn the fan off, wait for the print to start, then turn the fan back on.

The other thing that I had to do to make the printer run reliably was add a UPS power supply. Even an extremely brief change in power to the house would make the printer stop. In my case, I think those power blips are coming from my solar panel system. With the fan and UPS, it has been 100% reliable as a production unit.

fireballs - July 11th, 2014 at 8:46a.m.

I'm a newbie and just started using Simplify 3d. Love it btw. It gives default profiles for many of the printers out there, mine included. My point here is it sets my extruder to 220c and my bed to 60c. I seem to get good results from those settings. But after reading this post I can't help but wonder if my head temp is too high and my bed temp is too low? Anybody have thoughts on these settings? I can of course change them ,but wanted some experienced opinions first.

Pete - July 21st, 2014 at 2:50a.m.

@Pete, if 220c is working for you then I would leave it there. If you are having any problems then the best direction to start in is down, 220 is a bit high for the recommended PLA temps.

The same with the bed. If you are getting good adhesion at 60, then keep it. 70c is closer to PLAs transition temp and will keep it softer but the goal is really about finding something that works in your situation. Also, every printer and environment is a bit different.

LarsBrubaker [Moderator] - July 24th, 2014 at 9:37a.m.

I just want to say Thank you for your great information.!!! And do you have any suggestion about Pla filament brand?

Guest - August 9th, 2014 at 5:43a.m.

Thanks! We stand by all of the PLA available on the site. The PRO Series in particular is our favorite when it comes to internal prints.

kevin.pope [Moderator] - August 9th, 2014 at 10:47a.m.

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