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Switching from PLA to ABS?  

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apemberton
(@apemberton)
Active Member
Switching from PLA to ABS?

I am designing and printing N scale (1:160) model railway items which I get nice detail on my MK3S+ with PLA and a 0.2 nozzle. So far, so good. Some of the items are quite fine and delicate at this scale.

I am finding that the PLA I am using (several different brands with their own peculiarities) is tending to go solid after a while which means that items that need to retain some springiness become too firm to do their duty. Not a major problem so far.

I am wondering:-

  • if a switch from PLA to ABS might overcome the change in PLA's hardening?
  • Would ABS prints be suitable for a fine (0.2mm) nozzle?
  • Would ABS produce such fine detail?
  • Are there any heatbed issues with the higher temperatures (apart from burning myself!)?
  • Is the ABS colour spectrum like PLA and are there any problems with fading?

Advice would be useful before ordering reels of ABS.

Thanks in advance, Tony

 

Posted : 22/10/2021 10:59 am
Dan Rogers
(@dan-rogers)
Noble Member
Try PETG for flexibility - ABS is stiff as stiff can be.

If you need flexibility, ABS is not the way to go.  It's hard - very hard - and has almost zero flex even in thin spots.  Also, you can do the .2mm nozzle with PLA because it is a low temp material.  ABS is printed at much higher temps - and will likely cause you heat dissipation related issues that you do not see in PLA.

 

Posted : 24/10/2021 11:16 am
BogdanH
(@bogdanh)
Honorable Member

Maybe you should try with PETG, which is more "flexible" than PLA -you can bend PETG a little (if part is thin enough). And btw. at least speaking for me, PETG is as easy to print as PLA. PETG doesn't need to be printed in enclosure (to prevent warping) and also doesn't produce smell during printing. I'm not paid for saying that, but I can really recommend Prusament PETG.

-I haven't tried smaller (than 0.4) nozzle, so I can't really say... some tuning would be necessary for sure. If I were you, I would try with 0.25 nozzle, because profile is already present in Prusa Slicer (that would make start easier).
-PETG is more prone to stringing than PLA, so details depend on good settings, I would say.
-for PETG, textured print sheet is recommended for optimal adhesion (I can confirm that) and bed temperature should be "only" 80-90°C.
-PETG exists in quite big varieties of colors (more that that's the case with ABS, I think).
-color fading... PLA, PETG and ABS aren't really UV resistant and they will fade over the time if exposed outside (I think PLA is the worst among these three). If UV resistance is important, then ASA should be used. Otherwise, ASA is similar to ABS -not flexible at all.

In short, you should give PETG a try anyway. It's very usable material for various applications, i.e better temperature resistance than PLA, is less brittle than PLA and doesn't require special measures during printing. Important: you need a dryer if you plan to use it! But then, that's true for every filament.
Just crossed my mind... if you paint your models, then that could be a problem with PETG (I've heard) -maybe you'd need some coating first.

[Mini+] [MK3S+BEAR]...
Posted : 24/10/2021 12:46 pm
apemberton
(@apemberton)
Active Member
Topic starter answered:
PETG it is then!

Thanks folks, I will order a small amount of PETG and give it a try. If it doesn't work, I won't have lost anything but if it does, I will then make the change for items that need to retain a modest amount of springiness. I could use any left over for spare parts for my older (discontinued!) non-Prusa printer. RAL7011 anyone?

 

Thanks again, Tony

 

Posted : 24/10/2021 7:57 pm
TerTerro
(@terterro)
Active Member
Petg does not paint well

PETG does not paint or glue well, so carefull here. 

You can try different pla like impact ir such. But for flex csn look into  Nylon maybe.

Posted : 27/10/2021 3:50 am
Dan Rogers
(@dan-rogers)
Noble Member
PETG and paint

No 3D print paints well until it is coated with a primer.  For PETG I use clear acrylic to seal the PETG print, let that dry and then it paints with ease (at least with acrylic air brush paints).  Tempra paint may not stick well 😉

 

Posted : 27/10/2021 8:31 am
apemberton
(@apemberton)
Active Member
Topic starter answered:
PETG and Paint

Thanks for your replies. Flex would not be rigid enough for the application I need. I am hoping that paint will not be necessary as the critical part for which I have ordered PETG comes in RAL7012. Glueing should not be necessary as the PETG parts should (hopefully) be a tight push fit into the slots provided as the PLA part is at present. Anyway I have to experiment. Hopefully a photo showing the object that needs a wee bit of springiness is at the lower left of the picture.

Tony

 

 

Posted : 27/10/2021 10:06 am
apemberton
(@apemberton)
Active Member
Topic starter answered:
Switching from PLA to PETG

I have performed my first prints of the delicate parts as photo above. I have had a problem with the filament jamming in the PTFE tube (again) but that is probably due to me using my existing PLA settings adapted (0.2 nozzle and higher temperatures). I have since used the default ultrafine 0.05 with generic PETG and the o.25 nozzle settings which was a success with full detail in the print. Fit into the existing PLA parts is good and the PETG shows more robustness, can be superglued and seems to have better 'springiness' than PLA.

Thanks for the advice PrusaPeople.

Tony

 

Posted : 02/11/2021 11:12 pm
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