Causes of buildup on the nozzle?  

RE: Causes of buildup on the nozzle?

I keep a soft brass brush about the size and shape of a toothbrush next to my printer. I clean the nozzle off before every print when the nozzle gets close to the target temperature.

PETG tends to be a bit sticky and sometimes leaves some residue on the nozzle after a print. Just force of habit on my part to try to minimize the random blob in the print.

Good luck.

RE: Causes of buildup on the nozzle?

PETg is most definitely oozy, and I too use the brass wire brushes to keep the nozzle clean.  I get a bag of them from Amazon every so often.

Now leakage around the hot end can be a cause of buildup of filament residue, and that's a more serious issue, usually caused by the hot end having loose parts or else being assembled improperly.

RE: Causes of buildup on the nozzle?

Thanks for the replies, but the problem isn't merely buildup. The problem is buildup on the nozzle that is then coming off during a print, resulting in thick strings or blobs on the print that have to be cleaned up post print.  It's also not the nozzle leaking anywhere.  Normal PETG filament doesn't build up; it's just one specific brand of carbon fiber PETG (Paramount) that shows this buildup.  I have another brand of CF PETG that does not build up either (Atomic).  But for various reasons I need the other properties of the Paramount that the Atomic doesn't have.

I have tried so many different settings to try and eliminate this (increasing/decreasing nozzle temp, slowing down/speeding up the print speeds, raising the live adjust Z height and others that I don't remember).  But nothing seems to make much of a difference.  

RE: Causes of buildup on the nozzle?

Have you tried printing a temperature tower? That may help isolate the best temperature range for the material you’re trying to print.

You will likely have to tweak retraction settings, extrusion multiplier, and some others.

Hopefully, someone with experience printing this material will chime in with some solid direction.

RE: Causes of buildup on the nozzle?

Thanks for the suggestion.  I should do that (temp tower).  

I have tried different extrusion multipliers, but haven't touched retraction yet.  I'll start experimenting with retraction.

RE: Causes of buildup on the nozzle?

You get this figured out?    I’m also using the paramount cf PETG, and dealing with this buildup…. It comes off randomly during the print causing nasty artifacts, and also causes layer shifts, because the next time the extruder comes around, it hits it, causing the pei build sheet to slide/shift…. Is really a pita..  like you, I’ve tried adjusting the temp, speeds, retraction, retraction speed, z height, and nothing seems to stop it….

I’ve ordered some of the e3d socks, that cover the entire nozzle, with just the veeeery tip sticking out, and I’m gonna try that once they come in..  

I hate to have to switch filaments… I’ve already printed 2/3’s of the roll, and have about half my parts printed..  I’ve had to re-print 80% of the prints, due to the hardened blobs that come off the nozzle, being hit by the extruder on the next pass, causing the plate to slide, inducing layer shifts.

RE:

This tends to be an issue with the brass nozzles.

You just always get some buildup on brass nozzles, especially when printing PETG.  Even on genuine E3D brass nozzles.

I have switched to copper plated nozzles (genuine E3D), I think they are coated with nickel. They are a lot better in this regard, PETG doesn't stick to that material at all.

RE: Causes of buildup on the nozzle?

Posted by: @lethxl

You get this figured out?    

I have not fully figured this out, but I have improved the situation.  The only thing that seemed to make any difference was increasing the retraction to 4mm and lift z to 0.2mm.  I still get a fair bit of stringing but the buildup on the nozzle is far less.  I would also suggest slowing down your print speeds if you haven't already.  

Posted by: @mpothmann

This tends to be an issue with the brass nozzles. 

I am using a Micro Swiss plated wear resistant nozzle, which does work much better than the standard brass nozzles. 

RE: Causes of buildup on the nozzle?

Posted by: @buckeyestargazer

Posted by: @lethxl

You get this figured out?    

I have not fully figured this out, but I have improved the situation.  The only thing that seemed to make any difference was increasing the retraction to 4mm and lift z to 0.2mm.  I still get a fair bit of stringing but the buildup on the nozzle is far less.  I would also suggest slowing down your print speeds if you haven't already.  

Posted by: @mpothmann

This tends to be an issue with the brass nozzles. 

I am using a Micro Swiss plated wear resistant nozzle, which does work much better than the standard brass nozzles. 

Well, Im using standard e3d brass nozzles.. and I’ve fixed mine, for the moment..    I didn’t realize it, as it was happening, and I’ve always heard that cf filaments are abrasive and will wear your nozzle, but I remember having to change my live z throughout that roll, started at -1.565… ended up at -1.700.. well, nothing was working, and was like, let me change the nozzle, cuz I have some coated hardened steel nozzles from my ender5 plus, but I didn’t like the way they looked, it seemed the threads were not long enough for the v6 hotend, and I didn’t wanna put em in there..  but now that I had the nozzle out, I put it beside a new e3d v6 brass one, and you could tell, immediately, without calipers, that the nozzle was worn..  on the conical shape leading down to the tip, the small flat of the tip, was indistinguishable.. it was rounded off, uneven, and visibly shorter than the new nozzle..   

I don’t have another new nozzle to show in comparison, but you can clearly see the wear, and that’s what was causing my print inconsistencies, and was causing the cf PETG to creep up and gather on the nozzle…  since I changed the nozzle tonight, I’m on the 3rd print, and there’s no filament accumulation on the nozzle, and print quality has increased dramatically…  and by that I mean there’s no random blobs causing artifacts and causing layer shifts..

I realize, your using a different nozzle, but this solved the issue for me.

I should note, that before the nozzle change, I swapped filaments and ran a print with just regular PETG, and even with the old worn nozzle, it didn’t act like it did with the cf PETG..  I was able to complete that print, with no accumulation of filament on the nozzle, and as fair quality as you can expect with a nozzle in that kind of shape.. so, that paramount 3D cf-PETG is just some finicky stuff…  but, when it turns out.. it turns out..

RE: Causes of buildup on the nozzle?

Yesterday I made a few minor changes that seemed to help considerably.  In the filament settings tab I changed the Lift Z from 0.2mm to 0.5mm, and I also enabled Deretraction Speed and set it to 25mm/s  (note that this is slower than the retraction speed which is 40mm/s).  

That print came out quite well with just a few strings and bits and no buildup on the nozzle.  That's far better than when I first started printing with this filament.

RE: Causes of buildup on the nozzle?

I’ll add that to that filament profile as well.  Thx

RE: Causes of buildup on the nozzle?

One final update.  I enabled "Wipe while retracting" in the filament settings and that virtually eliminated stringing and bits on the print.  It came out very clean.  

RE: Causes of buildup on the nozzle?

Posted by: @buckeyestargazer

One final update.  I enabled "Wipe while retracting" in the filament settings and that virtually eliminated stringing and bits on the print.  It came out very clean.  

Ahh yea, I have that turned on for every profile. It is great for that, no doubt.

i failed to mention before, that, that nozzle, was brand new when I started that roll of paramount cF PETG.. so, it ruined that nozzle, in a half of a spool..  which is crazy because I’ve printed cf PLA on my ender5, nearly 3 spools of it, and went on to print a lot of non abrasive afterwards.. it never wore the nozzle like that..

so, that stuff is harsh on standard brass nozzles..  I ordered some of those nozzles with the stainless steel screw on replacement tips to print cf PETG and cf PC from now on.

the reasoning there, instead of hardened steel nozzles, is because, from what I’ve read, filament doesn’t stick to stainless, and although still not as hard as hardened steel, stainless is harder than brass for abrasives.. and I get to keep the heat conductivity of the brass, as it’s still mostly brass.. AND, those tips are longer, and pointy, almost needle-like, so as to also help keep filament off the nozzle.. and of course, I can unscrew and replace the tips..

RE: Causes of buildup on the nozzle?

I know this is a very late response, but I recently got some of this CF-PETG steampunk gray from paramount and had the same issues. It is such a gorgeous filament, but I kept having really bad delamination and build-up on the nozzle as well. 

I played around for a while trying to dial it in so I could actually use it and this is how I got it to print MUCH better:

• Nozzle temp: 270°C (I know that is really high for PETG, but it works for this particular one) 
• Bed Temp: 80°C
• Print Speed: 35mm/s (including supports, infill and inner walls. Used 30mm/s outer walls and 20mm/s for first layer)

This is a very tricky filament. Much more so than any other PETG i've ever used. But these settings are what worked. It takes a long while to print anything, but it works. At least for me. 

Hope this helps!