I've recently installed an E3D V6 hotend on my prusa i3 and I'm experiencing problems with blobbing. What I mean is clearly illustrated in the attached picture. As you can see there are blobs that are formed at each entrance point to the stacks. These blobs come out of the hotend as it leaves one stack and moves across to the other one. When it reaches the other stack, the blob that was formed on its way over, comes off by sticking to the blob below it or to the actual stack. I'm using Slic3r with the retraction length set to 1mm and retraction speed set to 30mm/s. Although I've tried 3mm and 30mm/s as well as 1mm and 60mm/s. They have the same problem.
Re: retraction and blobbing Did you change something else? For example, the filament. I can see grey silver on the picture, which is one of the most oozing filament (no matter, PLA or ABS, grey filament I used was oozing more than almost any others).
Re: retraction and blobbing It could be the filament I suppose. I have some natural ABS that I can try, but is there no way to prevent oozing with grey ABS and an E3D V6 hotend?
Re: retraction and blobbing Apart from what you already tried, you can prevent oozing and its effects by reducing hotend temperature and increasing travel speed and/or X/Y acceleration. Some cooling may also help (even with ABS). Try also to increase E acceleration. It sounds strange that your E3D V6 is oozing so much. I found it doing the contrary
Re: retraction and blobbing Did you tighten the noozle while your Hotend is at 285°C? Looking at the Bridge, i would say you printed it a bit too hot. Try lower the Temperature by 3-5°C per Step to get to the point when the filament stops bonding to the last layer or wont go through the noozle because its not melted enough, then go 3-5°C up again.
Re: retraction and blobbing Sorry for the delayed response! I've been trying to get rid of oozing and blobbing for the last month. I've tried natural ABS, but that didn't seem to change the behavior in the slightest. I've tried varying the temperature of the hotend and going as low as 200C. That made it ooze a tiny bit less, but it is still significant. I've also tried varying the retraction length all the way up to 3.5 mm. That made minimal difference. Next up I will try some cooling. Also, I did initially tighten the nozzle when it was hot. If it helps, I'm using the 3mm direct V6 on a prusa i3 with a greg-wade accesible extruder.
Re: retraction and blobbing As a comparison, could others try printing this simple bridge test and post the pictures along with the settings that were used? http://www.thingiverse.com/thing:12925
Re: retraction and blobbing Wow! I just figured out the problem. I have been mixing up units this whole time! I ended up recompiling Marlin to enable the firmware retraction options. That allowed me to play with the retraction settings on the fly, which was very helpful. I then started fine tuning and realized that the extruder motor was slipping because it was trying to move way too fast. So I lowered the speed substantially and it stopped slipping. The reason all of my prints looked the same before no matter the retraction distances I tried, was because the motor was slipping for all of them so it didn't actually apply the distance I specified. My settings are now: 0.6mm retraction, 10mm/s. Thanks for all the advice! In the end, it was a silly mistake on my end.
Re: retraction and blobbing Congratulations on finding the problem! No mistake is silly if something is learned from it. Cheers!
