Retraction Issues

[rock75]

for some reason I can only include 3 attachments so here are a couple more screen shots of my settings.

[rock75]

[rock75]

ok, last set LOL

[bpopilek]

So, just when I think I have everything close to working correctly, I realize that I am still having retraction issues! AAARRRGGGHHH!!!!

So if I have a print that has lots of short moves, with many retractions, the hot end seems to lose it's prime and then I get under extrusion in those areas. This ends up with the print failing. Prime example is the baby Groot that everyone has been printing. It was going great until it got to the top of the head with the small spiky areas. It was a complete mess. I realized that this is also the same problem that I was having while trying to print the new fan bracket. So I guess it is back to the drawing board for the settings...

Additionally, I changed a couple of real minor settings, and now I am getting filament grinding when trying to print a large item. The only change that I made before the grinding started was to change the layer height. I am prototyping a large part, and I changed it to 0.4 for less resolution and a faster print time. Prior to this I had no issues with grinding. I will try the next iteration back at 0.2 to see if that makes any difference. I know I have tried 0.1 layer heights on previous prints with this printer, and I have had no grinding issues. Is it just trying to push filament out too fast and the hot end should be hotter? I am using PETG, and the temp stays a consistent 239-240C throughout the print.

Andrew, do you have any plans to make an optional direct drive extruder for this printer? So far, I really dislike the Bowden setup. I understand that there may be a learning curve with it, but it is a very frustrating one. Your last two printers, with direct drive extruders, always worked perfectly and I never had any of these types of retraction issues. Any suggestions are welcomed and appreciated!

[3DprintedLife]

Hey Brian,
Sorry you're still having trouble with the bowden system! My unit seems to be working just fine in bowden, there is some very slight stringing but other than that I don't have any issues..have you tried printing with the provided cura config just to narrow down your problem to be either hardware or software? It may be possible that your e3d hotend was assembled too loosely so it oozes or something like that, a problem which would probably not show up at all in direct drive systems but bowden really amplifies it.

I don't have any official plans to make a direct drive setup, but I'd say the best option would be to make an L bracket that sits on top of the extruder carriage which you can attach the extruder to, then just run a shorter length of ptfe tubing and keep the original e3d mounting method (someone else described something similar on another post). Another option would be to totally redesign the extruder carriage and just replace the metal plate with one big 3d printed piece designed around a direct drive extruder. I'm not sure how rigid you could get the hotend with this setup, but it would probably work reasonably well.

[bpopilek]

I was sure that it was not the hot end being too loose and leaking, but I did it check anyways. This is the third one that I have assembled from scratch, not counting all the previous E3D tear downs and rebuilds on my other printers.

I'm still confused as to why changing the layer height would cause filament grinding though. Unless I inadvertently changed something else that I don't remember. I'll double check my settings tonight. I haven't tried the Cura settings lately, I can do that too. I'm not totally giving up on the Bowden setup, now it's kind of becoming a personal vendetta against this thing! Hehe... But perhaps a direct drive adapter kit could be something you could consider making as an optional kit?

[bpopilek]

So I just don't get it! Hehe... I changed it back to 0.2 layer height and retraction to 5mm at 60mm speed. Shut everything else related to retraction off and got the following result.





The overhang torture test passed with almost perfect results and no stringing! I think this printer just likes to mess with me! Still using the same PETG and temp settings as my other failures...

[3DprintedLife]

So weird haha but wow that print looks really good!!