I (as a newbie) have recently made my own 3D printer that I'm adjusting right now. I've come to a point where I only get blobs in my print. I have searched a lot on the internet and came to the conclusion that it has something to do with the retraction settings. After some experimenting with the retraction speed and distance, the problem was not solved. The blobs are reproducible and see again in the same places every time I start the print.
I use Cura 15.04.6 as Slicer and print by SD card. I hope someone in this forum could help me with the blobs. Below I have an example of the blobs and a picture of my printer. Besides that, I have added the Cura settings in the Attachments.
After some tests I was unable to solve the problem using the retraction speed and the Cura version. The blobs kept coming back to the same place. After a new search on google I came on the 3d print part of Reddit. Someone else had the exact same problem and had also tried the exact same. He found the solution by halving the jerk.
After reading this have I done the same and this has solved the problem for me. See below the result, left the old situation and right the new one: