Arc/Circles Bumpy/Bulge with Dev2 Firmware

kb1fch

I've recently updated my machine (an i3 clone) from a RAMPS board with V1 firmware to a RUMBA32 board with the dev2 firmware. Everything is working well for the most part, but when I print something with a circular or curved shape, it comes out bumpy on large radius or bulge on smaller radius. I'm using PrusaSlicer through Repetier-Host and the print preview shows smooth arcs. 

I wasn't able to find anyone else mentioning this issue so I'm assuming it's something specific to my configuration, but I've not been able to resolve it. Any thoughts on what might be causing this?

Bumpy: https://photos.app.goo.gl/aF2Fi9TjckvJnR6t8

Bulge: https://photos.app.goo.gl/CSL3mwR4nRT3K9r88

Thanks,
    ~Dave

Repetier

Looks like speed goes up and down constantly on any direction change. Normally you choose an allowed jerk to prevent this. So my first idea is that you have set jerk or Yank as it is called in V2 too low.

Is it using bowden or direct drive? With direct drive you can also improve this with linear advance.

kb1fch

Thanks, I'm currently using the default 10 mm/s for the X&Y jerk, I'll try increasing ti to see if it makes a difference.

It is a bowden setup.

Repetier

Bowden amplifies such problems. Here it is even more important to move with a more or less constant speed and have high accelerations/jerks to reduce the effects.