Unanswered PETG Print Issues

Hey guys - I've printed with PETG several times, but the last couple of days I seem to be having issues. The PETG I am using is Inland (eSun) PETG. I was printing with the green I have had for a couple of months. Came out great with no issues. My print settings were 215/80. I decided to shift to the new boxes I got. Blue and Yellow. They are also Inland and both were bought a couple of weeks ago and were sealed.

When I tried printing the yellow, it clogged/jammed twice. Same thing with the blue. I was printing up to 220C. So I decided I probably needed to up the temp. I just started trying to print again with the blue and we'll see how it goes, printing at 230 now. So here are my specific questions:

1 - I noticed it would get a filament booger on the nozzle - especially at the first few layers. What causes that? Overextrusion? If so, I assume I just lower the extrusion multiplier - correct?
2 - Is there a safe point below which I shouldn't put the extrusion multiplier? I.e. I am at 96 now - what's the lowest I can reliably go - or doesn't it matter?
3 - What is the difference between Extrusion Multiplier in S3D and "flow" on he LCD controller? Which takes precedence? I ask because I had the Extrusion Multiplier set at 98 but the LCD shows Flow at 100 when it is printing.
4 - For stringing should I be adjusting the retraction more? I am afraid to lower the temp too much because it clogged at 220 and I am only printing at 230 now. I am getting minor stringing at 230.

Thanks!

 

Thanks Geof!

 

Yeah mess with your reaction. I print petg at 244 and 80 and have printed 3lbs of it (one print) without boogers or warping. Never noticed much by adjusting extrusion but when I turned up the temp it stopped sticking to my nozzle

 

Thanks guys - I printed at 230 and got the entire print done. It was an 8 hour print and came out pretty good, but it still has the bumps/zits. I'll take pictures and post later, but reducing the extrusion multiplier fixed most of the blobbing - though there were still a couple of boogers I found on the print. I watched it and I see that the bumps/zits are occurring at the end of the layer when it stops printing and goes to reposition. The S3D troubleshooting guide says to adjust the coast setting - so I think I will try that. Going to try a few test prints and change the retraction/coast settings to see if I can get the zits to go away. I'll also try to up it to 240 - though I did get some stringing so I don't know if raising the temp will help or hurt that.

 

Ok - I have reached new heights of frustration. I have literally tried almost every setting, read every article on the web, and searched every forum for a way to fix these blobs/zits. The best I have been able to do is to set the layer on optimize instead of random, which gives me a a seam down the print. Extremely frustrating. There has got to be a way to fix this.

I tried coast all the way up to 5mm. Started negatively affecting layer adhesion, but bumps were still there. Tried wipe, but all it did was leave a spiral in my print where the wipe action was. Tried lowering extrusion to as low as 91% with no luck. Printed slower, printed faster (30mm-50mm). Turned on retract between layers, turned on retract only between islands, etc. Same issue.

It's definitely not retraction related. It happens at the end of a layer when the nozzle moves to the next layer. I am now at the point where I might have to just accept the crappy seam... But it shouldn't be that way.

Any thoughts?