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The surfaces of my printed parts using PLA plastic look rough and uneven.

Would changing filament to a better one make any difference?

If not, what kind of methods can I use to achieve a smoother finish for my for 3D-printed objects?

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PLA parts can be finished with a coat of epoxy like XTC-3D from Smooth-On. This will smooth out the part and give it a pretty nice shine.

I've also had a fair amount of success sanding prints, giving them a coat of automotive filler primer, and using glossy spray paint.

You can also get great results with an acetone vapor finish if you're willing to switch to ABS. Though that will require a heated bed and can be a bit more finicky to work with than PLA.

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    $\begingroup$ XTC-3D is more of a resin coat. It works as intended, and looks really good if primed, painted, and sanded, but do know your model will be a little thicker as a result. $\endgroup$ – Kirbinator Apr 20 '16 at 18:12
  • $\begingroup$ +1 for mentioning a filler primer. Just make sure to get an actual filler primer. I have found that Rustoleum's typical Paint/Primer does not have the same properties as a filler. The filler dries much faster and fills in print lines way better. $\endgroup$ – Josh B. Dec 26 '18 at 6:09
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Acetone vaporing is a great way to smooth ABS prints. For PLA, however, acetone smoothing does not work. An article about smoothing PLA says:

This is a pity, since PLA is much easier to work with than ABS. We found some solutions for smoothing PLA, but most involve rather dangerous-sounding chemicals such as Tetrahydrofuran and Dichloromethane. The one exception we found is Ethyl Acetate which seems to give good results and is (relatively) safe.

Other article mentioned MEK Substitute, which is Ethyl Acetate as well. You could also try some kind of polisher manufactured for 3D print results, such as XTC-3D. Here is a real photo of XTC-3D on PLA:

XTC-3D on PLA, image courtesy of tiskni3ddoma.cz

Ultimaker also suggests using chloroform for smoothing PLA prints.

If your parts are really uneven, it might be a symptom of something bad going on with your print(er), you might want to read Taxonomy of Z axis artifacts in extrusion-based 3d printing.

The most recognizeable cause of this problem is Z-wobble. It is caused by the misalignment of layers in a repeating pattern with a period equal to the Z thread pitch (technically the lead, but this is the same as the pitch unless you are using a multi-start thread), and was a famous problem of the original Makebot, the CupcakeCNC.

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It takes quite an effort to make PLA shiny, and it's not as simple as ABS and acetone.

You have to sand down the print with sandpaper with different grit sizes (start with grit P100, then P240, P400, P600, P1500 and P2000).

To make the shining result you have to polish the print with plastic finish compound. Alternatively you can apply XTC-3D Print Coating.

See these posts:

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Your two easiest options are dipping your print in acetone or giving it an acetone vapor bath. Note this process generally only works with ABS not PLA, with the exception of some brands. There are many articles online where you can learn more about the process.

Aside from finishing, you will generally get a smoother looking end result by lowering the layer thickness, and removing any hysteresis/wobble in your print head making sure it's well calibrated.

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    $\begingroup$ For a question that asks about smoothing PLA an answer that only addresses smoothing ABS doesn't seem very useful. Calibration is a nice starting point, but won't achieve "shiny smooth". $\endgroup$ – Tom van der Zanden Jan 13 '16 at 10:24
  • $\begingroup$ @Tom van der Zanden, It's pretty clearly addressing PLA specifying that the acetone method will in fact work for some brands. Provided links are for PLA. All other answers in this thread echo similar points. $\endgroup$ – ZachNag Jan 13 '16 at 23:47
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    $\begingroup$ Acetone does not work for any brand of PLA. The article you linked to doesn't use acetone, they use another solvent. $\endgroup$ – Tom van der Zanden Jan 14 '16 at 6:52
  • $\begingroup$ Not trying to be argumentative, just factual. The third link in the post (ultimaker.com/en/community/10412-acetone-finishing-on-pla) which you might have missed due to the way I formatted it, contains information on how one person was able to use acetone finishing with Colorfabb PLA. The reason is because they include a small percentage dissolvable plastics in their formulation, which is what allows this process to work, although marginally. $\endgroup$ – ZachNag Jan 14 '16 at 23:55
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Make sure your printer is properly calibrated and that there are no jams as this can cause blobs or other defects on the object. Printing at a higher resolution would also make the object smoother, as there would also be less difference between each layer.

The filament that you are using could be a cause for the rough look as well. Make sure you play around with the temperature to find the right range for a specific brand of filament. I have noticed different brands tend to print better at different temperatures, and if it too low could cause flow issues.

Also leaving PLA out in the air tends to have it absorb moisture which is also no good. If you are not going to use it for a while put the filament back in a resealable bag with a desiccant to help keep moisture out.

If you don't want to see the printed layers you could also try melting the surface again with a heat gun to smooth out the object. Be careful not to overheat the object, because could you could discoloring or cause drooping.

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  • $\begingroup$ Thank you for mentioning proper printer setup. Surprisingly, it seems that you're the first person to bring this up. So +1 for providing an insightful answer! $\endgroup$ – tbm0115 Apr 8 '16 at 21:37
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It is called Acetone Finishing

Basically the 3D printed part stays in acetone vapor and the outer shell turns to smooth surface. I have heard that it works better with ABS.

This article shows how with videos:

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    $\begingroup$ It is worth noting here that acetone finishing works very well with ABS and (at very least) not as well with PLA. $\endgroup$ – kaine Jan 12 '16 at 19:42
  • $\begingroup$ Note that this particular method only works for certain brands of PLA. In most cases there is a good chance that the acetone will do little if anything at all to the PLA. $\endgroup$ – Dani Epstein Jan 12 '16 at 19:44
  • $\begingroup$ I have heard that Acetone isn't effective with PLA, but it certainly is for ABS. One place to get acetone is in nail polish removers. Some stores and salons sell 100% acetone variants, while others can be 70% or even as low as 20%, the stronger they are the quicker they will act. $\endgroup$ – Chase Cromwell Jan 12 '16 at 22:18
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    $\begingroup$ This answer is incorrect. The question asks specifically about PLA, and acetone does absolutely nothing to PLA. You need something really nasty like MEK to affect PLA. $\endgroup$ – Tom van der Zanden Jan 13 '16 at 10:20
  • $\begingroup$ Because this answer is based on the wrong filament, it has extremely low quality and should be removed. $\endgroup$ – Trish May 13 '19 at 16:21
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So we know what doesn't work but what does work (but not well) is alcohol! Only isopropyl alcohol 90% (and up) will work! Also at Walmart you can get stuff called Goo Gone or even better is Oops!

What you're doing is melting the plastic chemically. Since PLA is made from corn (more or less) the same chemicals won't work on this kind of bio plastic that PLA is. ABS is an oil based product so that's why acetone works.

I use those two mentioned products because they are made to remove glues and waxes and don't immediately evaporate so it has time to do its job and dissolve the plastic. Alcohol will evaporate, especially with less water content, and I absolutely positively don't want anyone doing this in a bedroom or kitchen especially do not do it without ventilation! The vapors are flammable and will build up fast at room temp and takes little to set off and it's just bad!

With alcohol I dip and soak the parts till I see them looking kind of soft like having a skin or depending on the PLA used silky. I print hotter than recommended with hot bed little to no fan and more feed because what happens is it gets denser past a certain temp and will look like its messing up and not print right like its clogged or not being fed fast enough and it's true but if you increase the feed rate to say 108 or 115 it compensates for the shrinkage and you get the same fill.

Now that being said your going to get smoother prints because it becomes like watery but with faster speed and or little fan snaps it in place but the hot bed will keep it from getting too hard for the next pass of the hot end and new layer so the next layer wont go on a cold surface and can easily get squished and fused to the last layer and now two 0.15 mm layers act like three but denser and smoother.

Then with the Oops! chemical or alcohol I just take what's left of the imperfections off. I take a dustless cloth and apply the solution onto it and wiping in the same direction with very little pressure till it feels like the cloth is getting stuck or its biting then I leave it alone for 15 seconds and wash it off by dunking it in a bucket of cold soapy water then rinse with fresh water and repeat if necessary. It's best if you use string to hold or suspend the parts because it's easy to leave prints behind.

Also even better (and I don't offer this because any liquid when atomized can be flammable - besides water) is to use spray bottles instead and lightly spray the same process on and dip-and-dunk to take it off - instead of wiping and risking leaving prints with marks on the finished parts.

There is sanding. Lots of sanding is another way to smooth parts.

I also tried conformal coating my parts which works but gets messy when trying to apply over a pre applied coat.

Then there's body filler or if you use paint I recommend either automotive paint with filler primer or a paint in the automotive section specifically for plastic and vinyl or heavy thick paints but not latex but lacquer paint that is heavy and fills in imperfections but lays flat when dried! There are Lexan paints for RC and model plastics but need primer.

But your best bet is make sure that your printer is running 100 % print in as fine detail with no bigger than 0.4 mm nozzle and make sure your slicer profile is setup to work perfectly with how your machine works like your stepper numbers and everything because all that matters first and foremost your first layer determines the rest of the print! Level bed and clean level surface! New nozzle every few dozen prints makes a difference unless you get a high end tip!

Keeping your Bowden tube fresh also makes a big difference! Get yourself feeler gauges and use them to level your bed instead of paper and it will be exact every time! And print the same speed and make as few adjustments as possible through the whole print and it will come out uniform. Taller prints if you need hot bed add heat as the print gets taller or nozzle temp because the print will lose heat as it gets higher up and won't print the same as the bottom layers.

I hope this helps or was the answers you were looking for! I was just passing through and hate useless answers that done have anything to do with the question asked! People like to just talk I guess.

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  • $\begingroup$ Isopropylic alcohol does not solve PLA - I have had parts exposed to it for weeks and not soften at all. Further it has nothing to do with the origin in what a plastic is soluble but the chemical composition only. $\endgroup$ – Trish May 13 '19 at 16:19
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    $\begingroup$ This post is very hard to read as it is one big wall of text. Please consider improving the formatting. $\endgroup$ – Tom van der Zanden May 13 '19 at 18:31
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For a cheap method to smooth out your prints, you can use clear nail polish. It will act as a resin-like coat.

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    $\begingroup$ Hi Logan, and welcome to SE 3D Printing! Whilst your answer may be technically correct, it is rather terse, and, as such, it has been recommended for deletion, unfortunately. If you could expand it then you may get a more positive response. I would recommend that in addition to reading some highly voted answers to gauge the standard expected, that you take a look at the help section relating to answering questions, in particular How to Answer, and take the tour for more information on how stack exchange works. Thanks :-) $\endgroup$ – Greenonline May 14 '19 at 19:41
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I suggest using XTC-3D since your prints are small also you can add some UVO pigments in. It's difficult to use in large prints because has small working time. Anyway here is a print I did for a friend:

Example print

This now dead link shows more images and say how it is done.

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    $\begingroup$ This answer does not add anything over other answers (XTC 3D is already mentioned by a fair few of them). While there might be useful information hidden behind your link, we discourage answers where the main content is a link, as they may become invalidated if the linked content changes or becomes unavailable. Moreover, since the linked site is your own this is a bit of a grey area concerning self-promotion. We're trying to build a repository of questions and answers here, we're not looking to build a repository of questions and people saying "look, you can find the answer on my website". $\endgroup$ – Tom van der Zanden Jan 7 '17 at 10:04
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    $\begingroup$ I think Tom gives a nice analysis of your answers quality - we generally don't like link-only answers. I would recommend you to take the Stack Exchange Tour, in order to get more familiar with our site. :-) Also, welcome! $\endgroup$ – Tormod Haugene Jan 21 '17 at 12:32
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    $\begingroup$ Your link has died and as you included no information from the link in your post, your post is effectively useless. $\endgroup$ – Greenonline Jul 4 '18 at 9:50
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    $\begingroup$ because of the explanation of @TomvanderZanden I vote to delete this as superfluous and contentless. $\endgroup$ – Trish May 13 '19 at 16:20
  • $\begingroup$ The only additional information that I can see in this answer is the use of UVO pigments. $\endgroup$ – Greenonline May 13 '19 at 21:15

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