Printing PLA at 265°C? How does printing temperature affect strength?

Printing PLA at 265°C? How does printing temperature affect strength?


Have you ever asked yourself how the printing
temperature influences the strength of your 3D printed parts? I printed and tested almost 50 specimens and
will give you an answer to that question. Guten Tag everybody and welcome to CNC kitchen. So if you are already following the channel
for a bit you might know that I built myself a tensile testing machine which I use to assess
the strength of various 3D printed materials and methods. I already got a couple of requests to tests
how the printing temperature changes the properties and strength of your 3D printed parts. So that’s I exactly what I did! I focused my tests on PLA because that’s
the material which is probably most commonly used in FDM 3D printers these days. Please let me know if you want to see other
materials as well! I wanted to do these tests with quality material
and since I already did tests with Prusas PLA I went with this brand. I am very sure that the results will differ
depending on the brand you are using but the general trend should be the same. Even though the base material is always PLA
the different manufacturers modify it to be more suitable for FDM printing. And depending on these modifications or even
blendings with other polymers the material properties will differ in the end. So at first I needed to define the temperature
range and since you won’t be able to use printing temperatures that result in good
properties but produce horrible print results I printed some temperature test towers which
can be found on Thingiverse. Prusa recommends temperatures from 190°C
to 220°C for their PLA. Since my test part was designed for 5 different
temperatures I went from 230°C to 190°C in 10°C decrements. Keep in mind that these temperatures are specific
for my printer and my Prusa i3 MK2, at least at ambient temperature, shows slightly elevated
values. Both bed and heater temperature are usually
around 5°C higher than ambient. Does anybody else also have this problem? My Mendel90 is pretty accurate at ambient
temperature. I used Simplify3D to create this temperature
test. This gives you the possibility to set different
temperatures at different heights by using so called processes. You just duplicate your initial process, set
the temperature for each section and then adjust the start and end printing height. This is a great method to play around with
different setting when you don’t want to constantly restart your printer. A small tip on the side. I had to figure out what the height steps
of the test model were. Fusion 360 offers a measuring tool which lets
you measure distances not only on proper geometry but also imported stls. Just use the measure tool and select two points
on the model. By activating “XYZ Delta” Fusion will
also show the XYZ components of the measured distance which is mostly of interest. The first testprint showed that there was
barely a difference in print quality in my 230°C to 190°C temperature range. Bridging was fine, no stringing, small details
and overhangs printed without any issue! The overhangs probably look the best at 220°C
but the rest was totally equal! And trust me, I doublechecked if the temperatures
were really altered. So in order to see a difference I increased
the temperature range from 240°C down to 180°C in 15°C decrements. This print still looks fine but you are able
to see a little bit of bubbeling at the highest temperature and some small printing defects
at 180°C. I still wasn’t 100% satisfied so I printed
a third test at temperatures from 240°C to 270°C. My guess was that higher print temperatures
might be better for layer adhesion so I wanted to know how far I can go. So just like before 240°C was still fine
but starting at 250°C lots of bubbling started to show and small junks of PLA appeared at
the start and endpoints of the extrusion. The bubbling is probably due to moisture in
the material. I have to say that I opened this of material
5 months ago. Using brand new or dried material might enable
you to print PLA at these high temperatures but realistically I guess 240°C should be
the maximum. Also it started to smell quite a bit at these
temperatures. Okay, so Prusas PLA seem to handle different
printing temperatures quite well and the moisture absorption seems to be very low. From my printing experience this is not always
the case. I used to print with Amazons cheapest NuNus
filament on my Mendel90 and this material was much more sensitive to moisture and temperature. But working with a proper quality material
for this test makes more sense I guess, so I stuck to Prusas PLA. For the first run (I’m going to tell you
later why I had to do a second) I used a temperature range from 180°C to 265°C in 15°C increments
with a 60°C heated bed. For each temperature, I printed two specimens
which were lying on the print bed which tests the bulk material strength and two upright
specimens which give us information about the layer adhesion. Since I didn’t want to create a separate
print job for each temperature I again used Simplify 3Ds processes. If you have several processes, Simplify 3D
will ask you if you want to print layer by layer or sequential. For our test tower I used layer by layer before
but that wouldn’t work properly with the specimens. Instead I used sequential printing. If the parts are separated far enough from
each other so they don’t interfere with the hotend, they will be printed one by one. So now the temperature is fixed for each set
of specimens and will only be changed if the next row is started. Let’s take a look at the results. The strength of the lying specimens was quite
constant and wasn’t influenced too much by the print temperature. The specimens printed at 180°C were a little
bit stronger and they did not show a brittle failure like the others, but if you take a
look at the fracture surface you can see that the material did not perfectly fuse together
so some filament strands are still visible. The specimens which were printed at 265°C
has a slightly smaller strength probably because the material already degenerates at these
temperatures and the forming bubbles create weak points. All of the other ones were pretty much the
same with fracture surfaces becoming more and more homogeneous with higher temperatures
which shows that everything is fusing together with more heat. The more interesting datapoints are from the
standing specimens. These ones nicely show that the layer adhesion
is worse at lower temperatures, stays quite constant starting from around 210°C and then
drops off again for the maximum temperature. So this proves that you need a minimum temperature
so that the layers stick together well even though the print results look good. If you want to get the best layer adhesion
you need to increase the print temperature up to the point before you notice printing
problems. These problems usually are not only the bubbles
but also stringing, drooping, warping and so on. I also tested the strength of bqs white PLA
for 180°C and 240°C which showed a very similar behavior. The interesting thing with this material was
that it performed way worse at my temperature tower test. 240°C showed horrible bridging and stringing
and even at 225°C the print wasn’t perfectly good. So there you see that even though you might
get better strength at higher temperatures the material itself is just not suitable for
temperatures above 220°C. But wait! I said that I tested Prusas PLA twice. How come? So I was reading some papers about annealing
of PLA last weekend. Annealing means that you put your printed
part in an oven at temperatures from 60°C up to something like 100°C which increases
the crystallinity of the material and therefore increases the temperature resistance of your
parts. More on that in another video. So they showed that annealing can already
be done at temperatures of around 60°C, which takes longer but still changes the characteristics
of the material. 60°C is the temperature of my PEI print bed,
so my lying specimens were loaded with this temperature for quite a while. Damn! The upright specimens should not be affected
by this problem since the areas under test are decently far away from the heat bed. So I reprinted the laying specimens without
the heater on which is actually not so easy. I had to use quite a lot of glue stick to
get them to stick to the building plate. The Ultimate Tensile Strength of these were
not too different from the other ones. The only thing which really changed was the
failure mode. The ones printed on the 60°C bed failed brittle
whereas the ones printed on the cold bed strained and necked before they broke, which makes
them more robust. This doesn’t change my conclusion but shows
me that I need to investigate heat treating PLA soon in more details! So we have seen, that Prusas PLA is usable
in quite a vast temperature range and doesn’t start to degenerate before 250°C. This is not true for all PLAs because for
example bqs PLA had to be printed at much lower temperatures. The bulk strength of the laying specimens
wasn’t greatly affected by the print temperature but the layer adhesion constantly increased
up to the point when the material started to degenerate. So if you want to get better layer adhesion
increase your printing temperature maybe a little bit. The default printing temperature in Prusas
Slic3r Edition is 205°C for example. Looking at these results I would increase
that value to around 220°C because I have seen that the print quality should stay the
same but the layer adhesion is a little bit better which is good for parts which are mechanically
loaded. Thanks for watching everybody! I hope you liked this video! Please give it a thumbs up if you did and
appreciate the efforts I’m doing. Please consider subscribing if you want to
see more of this. Auf wiedersehen and I’ll see you next time!

100 thoughts on “Printing PLA at 265°C? How does printing temperature affect strength?”

  • I don't understand PLA temperatures… I bought a Tevo Tarantula 1 month ago and made a few temperature tests, but for me, the best prints were made on 240°C. At 210 it wasn't flowing well and at 190°C it didn't even work… What could be the problem? It's a filament issue?

  • I have run hundreds of pla jobs and i agree that 210-220 is the sweet spot. really 210 for most brands.

  • Prusa PLA filament is horrible quality, I got bubbling at day one it comes with loads of kinks and the size is not uniform, Chinese PLA is by far better

  • Great test and very interesting, thanks I am new to 3D printing and this was very informative as there are so many variables in the process of printing. Subscribed and thumbs up 🙂 Keep up the good work.

  • Could I by chance get a link to that temperature test file? Would love to use it myself. (Didn't see it in the description)

  • In simplify3d control k will bring up a menu where you can find where the heights are so you can do it all in one program.

  • If you're only varying temperature, you can go to the "Temperature" tab and simply set multiple set points instead of making whole new processes altogether 🙂

  • That's actually nice to see, that PLAs tensile strength peaks at aprox 230 degrees. Im looking for a stressable, more eco-friendly type of material that works with HIPS (230°C) to support structures (ABS and HIPS are the commonly – if not the only – mentioned combination). The printing results, as shown, are quite good also. Valueable information that brings me closer to a buying decision. thanks

  • I'm a rookie, so I don't know much. Anyways, I began printing on tape, ditched that mess, and now am using mirror tile (no surface additives) glass.

    Printing PLA (value-priced varieties). Slicer: Cura. Temps: filament 210°, bed 70• (I'm aware most everyone claims PLA doesn't really need a heated bed). The 1st few layers print speed ~20-25, fan speed 0. I've had zero adhesion issues. Admittedly, I don't the strength of the prints, albeit appearance is good.

    Sorry for the long intro to my question… what's (where can I find) the 'whys and why nots' concepts of bed temperatures? Thx!

  • Hi There. Love your videos! I'm a bit of a scientist at heart and your methods for testing the tensile strength of printed plastics is much better than I was expecting from a simple youtube video.

    I'm very interesting in the annealing process and I've watched loads of videos but no-one tests the strength of the plastics like you do. Would you mind doing a follow up video to this one where you print a number of PLA specimens and anneal them under different conditions with the aim of finding the best conditions that yield the maximum strength.

  • I print at 260°C but at 80mm/s for prototyping, works OK if you have a strong fan.
    What speeds have you used?

  • You measure with Fusion 360!!! kidding??
    In S3d, Tools, Variable Settings Wizard
    With visualisation, you can set heights and split processes.

  • at 2;02 you had cardboard to help level the base plate..I hate being a year short and $202 dollars late

  • Good investigation! I had terrible bed adhesion a week after building my Prusa mk3 i3. None of the forum advice or manual suggestions worked. It was by chance that I downloaded a user made calibration model for the mk3 and that had a print temp of 235 for the pla. Bed adhesion was perfect. So I started setting 235 for the first layer on my own designs and the bed adhesion is perfect. I should also say that the bottom layer of my models showed separate filament lines and the detail was always bad on first layer regardless of how many times I recalibrated. Since setting 235 for first layer the bottom of the print model is perfect.

  • Don't forget that print orientation also affects part strength! I realize you printed 10 test bars on the print bed at once, but ideally for max strength you should probably print these at a 45 degree angle to the X-Y axes: http://www.sparxeng.com/blog/mechanical/3d-print-orientation-effect-part-strength

  • 2:30 Tip about simplify 3d you can actually figure out the height steps by clicking on view>cross section. the slider will show you in preview the exact height of each slice.

  • I see a lot of test on Prusa printers for the money it seems like you can get more printer for your $ . I got a Chinese printer on Amazon. The BIBO 3D i am still tuning it. Just wanted your thoughts on the difference?

  • Printing those parts on a bed at 60 degC should have little effect on annealing, according to your graph, and even then would affect only the parts that were on the bed the longest.

  • you can also ramp up the temperatur at specified layers within one process, so you can accomplish a heat tower within one process

  • Re inaccurate temperature readings.. YES.. My Ender 5 is consistently 5-8 degrees off of what's reported on the screen, and my printer bed temperature varies as much as 10 degrees C in different spots, with the hottest areas being in the center, with the coolest areas naturally being along the outter-most perimeter. Personally, I think this is a result of the print bed being designed using a single uniform thickness throughout. I believe this is ALSO the exact same reason why so many people experience print beds which are warped in the center and tend to "pucker" up around the outter edges. The outside edges have more surface area and the heaters don't reach to the edges of the bed, so the heat is more easily dissipated along the edges of the bed, because they act like a natural heatsink. Another drawback to this design is that as the bed heats and cools, it causes the puckering. They could potentially solve this by using a thicker piece of aluminum, but they could also machine a structural "rim" into the underside, leaving the bed thicker around the outside edges. This would allow the bed to have more strength and the thicker aluminum would retain more heat, causing overall more even heating across the entire surface of the bed.

    Also, just because of the nature of thermodynamics and how heat radiates and soaks through a single piece of aluminum.. I think it would be beneficial to make the print bed circular, and slightly thicker around the outside edges. If the thickness was machined into the bottom of the bed in "steps" (as opposed to a gradual, smooth, transition from thin to thick, it would give the bed more rigidity, preventing warping, buckling, or puckering, and applying a spiral shaped heating element would allow the bed to evenly heat acrossed it's entire surface as well. A circuit bed with 3 leveling points also makes for a nicer, more even bed that's much easier to level, since a circle with 3 points levels in a curved fashion instead of the current 4 point system which naturally causes a biaxial linear motion to occur when leveling.

  • You should make video similar to this but with fan speed. It efetcts both layer adhesion and print quality so it is very important to get it right!

  • I've already had overheating issues while printing at 195°c on my monoprice mini delta. If I need a very strong part, I think I'll print at 210 degrees with a fan blowing on the print and the printer runing very slowly. I'll also anneal the part. For now, I don't need such a part, but this video has provided very valuable info in case I do ever need such strength in a 3d print.

  • Nice video man, I managed to print with my 16€/kg eBay PLA some good Zstrength things but I'm sure that a good PLA would print the same thing but with at least 10°C less, that's were a good PLA spool differ from mine.

    Also turning off the cooling did the trick, did you have any video test or chart about that? Keep up the good work.

  • Did anyone try Geeetech Pla filament? I like it but maybe I haven't tried enough different filaments to tell if it's really good

  • Is the test really relevant ? I mean this method of tensile test works for isotropic material and is normalized for that (calculation in the software and so modulus you find)
    Since this is a layer per layer fabrication I'm not really sure that the values you obtain means a lot. I could be wrong but any other view on this ?

  • I would love to see this with ABS since it's just as commonly used as PLA! Thank you for the great info!

  • I go between 205-215 for all my pla. most it doesn't matter but some brands like a bit lower or higher.

  • Thank you for the great video's Stefan. Question…are you running a cooling fan on the hot end when printing? (especially at the 240 degrees) if so what percentage? Regards, Mario

  • Very interesting, great not to have to do the test by ourselves, you just compare all variables!

  • In symplify3D you can set temps for each layer in one process, no need to make 6 of them for 6 temps, I do this to print the first layer hotter for better platform adhesion.

  • Hy , i have an ender 3 pro with some modifies, and i get a nice looking surface , hood extrusion but the extern wall , i think it is thin wall , with green in cura, it dont stick to the printed part , there i a gap betwen that wall and the inside print , what can i do ?

  • Love this video.
    It's the first time I've seen a tensile test and some results with PLA.
    BTW I love your tensile testing machine, I presume you did it yourself, do you have the plans available and a video with it?.
    Regards.

  • Simplify3d has variable settings wizard, which allows you to split process on one or several heights, which can be selected visually. No need to manually input and edit heights.

  • https://youtu.be/mwS_2R2mIvo?t=407
    At 6:47 you say "So this proves that you need a minimum temperature so that the layers stick together well. It's not what you meant, right?
    I actually had to watch the video again because I was confused after watching it the first time.

  • I love this channel! All of the information I wonder about but do not have the time or spare filament to test for myself! I want to print a MPCNC now I know how to make it as strong as possible.

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