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?
I've also had a fair amount of success sanding prints, giving them a coat of automotive filler primer, and using glossy spray paint.
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:
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.
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:
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.
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.
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:
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.
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:
This now dead link shows more images and say how it is done.