I have a custom Delta and I’ve run into this issue when printing a benchy and was just looking for general feedback as I’m working through trouble shooting it. I run a smoothie on a belt driven delta. The linear rails move smooth but I think there has to be something slightly off. Multiple prints exhibit similar displacement at similar intervals along the Z. other than that I’m super happy :P. I’m suspecting my magnetic balls are rocking a bit as it is moving around.
I also printed a 10x10x50 cube to see if there was anything I could directly examine.
Is this on the polygon? I’d check that belts are tight, and aligned from top/bottom (distance offset between motor driving and the idler at the bottom). I’d make sure carriages aren’t rocking back and forth. Additionally, look at some more ‘regular’ prints (like a 20x20x140) tall print and see if you can find any patterns. Usually if a pattern repeats, you can measure the distance it repeats at and see if it’s some value that matches an idler, a pulley, etc.
Additionally, you can do a “6 tower test” (it’s what we do @ DM) and put a tower at each delta rail, and then in between. If you see the problem mostly directly under a vertical rail, look at the vertical rail. If you see the problem in between a set of towers, look at the tower opposite.
Thanks @ThantiK those are some good ideas. It is a smaller version of the polygon that predates the revision for the KS. I’ll see if I can get it figured out. Deltas are truly different beasts.
