Waste block issues with PETG  

Re: Waste block issues with PETG

You can tweak the purge block with the Loading speed in filament settings, and with the Ramming settings.

I print only with PETG and I noticed if the Loading speed is reduced I had to increase the Total ramming time,

The settings that works for me with PETG :
Loading speed at the start 3 mm/s
Loading speed 28 mm/s or a little less,
Unloading speed at the start 100 mm/s
Unloading speed 90 mm/s
Total ramming time 2.5 or 3 s
Ramming line spacing 100 or 110 % (default 140 % doesn't work for me)

Re: Waste block issues with PETG

Thanks a ton for this advice, I’ll try that tonight!

Re: Waste block issues with PETG

Thanks a ton for this advice, I’ll try that tonight!

You're welcome,

Keep in mind the settings needs perhaps to be adjusted from one brand to an other, I use these settings for INNOFIL PET, but it works also for other brands I'm using, FormFutura, DailyFil PETG.

Before printing with a new filament I did first a little test with a two color object to ensure my settings are working.

Re: Waste block issues with PETG

Testing now, looks considerably better. Thanks again for pointing this out. When I looked at the filament settings I found that the advanced settings for my PETG filaments showed up set to PLA somehow, so I think that explains my problem--the purge block was acting like PLA which explains the under-extrusion. You are awesome!

Re: Waste block issues with PETG

Hm, maybe I celebrated too soon. The block seems to still get messy because it seems like maybe the nozzle is cooling down or something, and when it purges on a color switch it doesn't lay down material for a few lines sometimes, especially on the first switch. And then it seems maybe pressure builds up and a bunch comes out. I'm not sure what's happening.

Re: Waste block issues with PETG

Hi Robert

I forgot something, I change also the extra loading distance in the advanced printer settings (default -13, actually I set it to -2) this setting affect also the purging block.

Personally I started to have purging block problems when I changed the Loading speeds, many peoples recommend to set Loading speed at start to 19mm/s and Loading speed to 20mm/s, but I have to increase ramming time to 4,5 second so I go back to the default settings for PETG.

But first of all is the nozzle temp not too low for your filament ?, are you sure you don't have some unmelted debris in the nozzle, doing a "cold pull" from time to time can help.

Anyway printing PETG with the MMU2 is tricky, some times ago I published a post on this forum, take a look, but since I've done some other hardware changes. https://shop.prusa3d.com/forum/general-discussion-announcements-and-releases-f53/progress-in-printing-petg-with-the-mmu2-t25417.html#p117090