Help with strange blobs/calibration

So I got my corexy assembled a couple months ago but was traveling and only now I can take care of some issues.

I am unsure if that's a lack of alignment, or wrong belt tension or something else, but I can't get to get rid of those 'ghosts' that happen:





It was suggested it could be speed/velocity/jek, but I loweed them and seems to have incrased the problem.

Any idea for me to test, thanks in advance!

The ringing got worse when printing with slower parameters can only mean, there is too much backlash in the belts.

Quote
o_lampe
The ringing got worse when printing with slower parameters can only mean, there is too much backlash in the belts.

Hello! So I found some backlash on a badly screwed pulley, and also tensioned my belts as much as I could. It got better, but still super weird:



I changed settings on the firmware and tried speed differences and motor currents and etc. Still at a loss.

If anyone wants to take a look at my duet config: [gist.github.com]

PS:

Printed the same cube with a 50% reduction on speed (via the duet interface) and the rings happen at the same place, but less pronounced.

Edited 1 time(s). Last edit at 01/26/2018 12:43AM by coredump.

I see no more ringing, but maybe you can finetune your extruder retraction? The horizontal lines seems like underextrusion to me.

Edited 1 time(s). Last edit at 01/26/2018 03:21AM by o_lampe.