this post was submitted on 06 Nov 2023
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33
Prusa MK3s+, PETG and a 0.6 nozzle (lemmy.world)
submitted 9 months ago* (last edited 9 months ago) by [email protected] to c/[email protected]
19 comments fedilink hide all child comments
 

Hey everyone.

I built an mk3s+ from its kit form successfully, tested a few PLA prints with the stock 0.4 nozzle.

I've set prusaslicer to use a 0.6 nozzle now that I've upgraded, and am using PETG. Prints look pretty bad, in spite of calibrating z-offset etc.

If you were doing something like this for the first time, what would your setup steps be like?

To be specific, using a diamondback 0.6 nozzle, matterhackers PETG at 235c.

Issues I'm seeing are a really bad loss of detail, lots of stringing, etc.

eta: added a photo of a moderately post-processed part. Notice how rough the top surface looks, there's a disconnect between perimeter loops, etc.

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[–] [email protected] 2 points 9 months ago (1 children)

Is there a nozzle setting in the printer too?

[–] [email protected] 1 points 9 months ago (1 children)

This is my guess based on OP not mentioning changing printer profiles or rerunning a wizard.

[–] [email protected] 3 points 9 months ago

It's been set to 0.6 on both printer and slicer during the setup process.

[–] [email protected] 2 points 9 months ago* (last edited 9 months ago) (1 children)

I got PETG working on my Mini clone by basically just switching to 0.6 nozzle profiles from the wizard and using the generic PETG profile.

But, if you’re new to PETG, know that it gets real moisture sensitive, real fast. Sounds like you might benefit from trying to dry the filament out, check the web for more on that.

After making sure the filament was dry and that my initial layer is good, because changing nozzles means you need to fine tune the z offset again, I would print a retraction tower test and dial in retraction length settings.

That a good basic troubleshooting list.

[–] [email protected] 1 points 9 months ago (1 children)

Z was recalibrated already. I'll try a 50c bake for a few hours to get rid of moisture.

Ordinarily, I'd expect to see evidence of bubbling/snapping at the nozzle as water boils out while laying down plastic. No obvious signs of that though.

[–] [email protected] 2 points 9 months ago* (last edited 9 months ago)

Stringing and nozzle buildup are the general signs I get with petg being damp, extreme cases it'll have noticeable bubble, I've found that I need to run 12+ hours at 54c to dry it sufficiently, even on relatively fresh spools depending on the supplier, age etc. I also recommend securing your spools if they're paper based, had the adhesive melt on one and the entire thing fall to pieces, I just rewound it onto an empty plastic spool I had.

Edit. I just looked at the pics, yeah it also looks like you have some overexrusion, I tend to slightly underextrude petg because of nozzle buildup. I'd start with the standard prusa profiles and tweak from there, generally had good luck modifying the prusament profiles to work with other filament.

[–] [email protected] 1 points 9 months ago* (last edited 9 months ago) (1 children)

You basically have to retune your profiles to match between the petg and the larger nozzle.

Recommend following this as well as you can: https://ellis3dp.com/Print-Tuning-Guide/

Oh yeah, and you're going to lose detail with the larger nozzle compared to a 0.4 but it's a trade-off

[–] [email protected] 1 points 9 months ago (1 children)

I know what you mean re: some detail loss, I'm talking about perimeter lines that just outright look like they were gouged out with an ice pick. It's really bad.

[–] [email protected] 1 points 9 months ago

Saw the pics and it honestly looks like over extrusion, especially that top surface

[–] [email protected] 1 points 9 months ago* (last edited 9 months ago) (1 children)

Make sure you change the specified nozzle size in the printer's settings (not just slicer settings). That matters for the stepper scaling.

Consider you are now extruding a larger volume of filament through a larger nozzle. The reduced amount neckdown from filament size, and larger volume of plastic to cool, means you also need to now print at a LOWER temperature than you would with a 0.4 nozzle, else the plastic will be too liquid and want to run out of the nozzle faster than the filament is pushing it. You also now have more plastic mass pushing against the surface tension, and the increase mass can also not solidify on the part surface fast enough and want to droop over the edge. Back it down to 230c, or even as low as 220c, as well as increase your part fan max speed. See if that improves things.

[–] [email protected] 1 points 9 months ago

It's matched on both printer and slicer.

I figured it might be a retraction issue, but I'll experiment with temp change as well while trying a retraction tower

[–] [email protected] 1 points 9 months ago (1 children)

With diamondback nozzles you need to reduce the printing temp compared to what you had on your brass nozzle. I have the same exact setup as you, mk3s with 0.6mm diamondback nozzle and it's working fine with stock settings but a bit lower temp . Stringing is really an issue for me though.

What layer height are you printing? I usually go for 0.4mm.

[–] [email protected] 1 points 9 months ago

Same, tried 0.35 too. Group consensus seems to point at the temperature.. I'll give that a shot. Thanks for your comment.

[–] [email protected] 0 points 9 months ago (1 children)

Two things I’d suggest:

Try another brand of PETG - I’ve heard weird things about MatterHackers PETG but never used it personally. Overture, Polymaker, Prusament, and Printed Solid PETG always behave consistently for me.

Take a look at your heatblock and make sure you’re not leaking anywhere. I tried a 0.8 nozzle when I first got my MK3S+ and got bad results b/c I was leaking out the top and it was stringing badly. I eventually went with a Revo nozzle because swapping is so much simpler.

[–] [email protected] 1 points 9 months ago

+1 for overture, I've had very good luck with it. That said, I'm pretty sure PETG needs to be very dry in general. Prints beautiful just out of the box, but I have terrible stringing even storing everything sealed in vacuum bags after a few prints.

[–] [email protected] -1 points 9 months ago (1 children)

PETG is very runny. Switch back to 0.4mm nozzle.

[–] [email protected] 1 points 9 months ago (1 children)

Laying down more material to speed prints as well as increase strength.

[–] [email protected] 1 points 9 months ago (1 children)

Then accept the fact that your prints won't look perfect.

[–] [email protected] 0 points 9 months ago

They don't need to be perfect. Reading skills, buddy. Use em.