yawstick

Curious if you came up with anything on this?

I originally envisioned your extruder pump as a screw in a barrel type pump. I had to google yours to see what you meant. I would think that type of pump would naturally have a bit of a pulse to the output when running at a continuous speed. Do you have a link to it? How many steps required for a full revolution?

Is it possible to remap the motor outputs so that you could swap A & Z to different driver chips.

Have you tried just making just one vase form to see if it still happens in the same place in Z?

I would go along with that suggestion… in the extreme make your pump speed constant and vary only the x,y, speed… to produce the irregular effect… otherwise you have about exceeded my ability to contribute other than to observe… it is an interesting project. I am curious about the pump stroke… does the stepper for A axis come to a stop in the cycle or just slow down. If so it seems the jerk could be a factor unless you’ve overridden it somehow. If not it would seem worth experimenting with… as if it works as described would help create the fat in center deposit without having to create it in the program.
You could also experiment with making A, a fucntion of distance traveled in X,Y. and introduce some jitter into that to avoid or reduce the condition of the droplets stacked exactly on top of one another.
I realize that’s not addressing whats causing your issue… but any fix is a good fix 😉

It seems like you may be on to something with the a axis getting too big… unlike the other axis that go back to home or at least near to it… sounds like your a axis just keeps getting bigger and bigger. I’m not a power user or anything but would it be possible to reset the a axis after each stroke so your number doesn’t get so large.

That’s a pretty cool project… would be nice to see part of it in normal speed. Curious how often you have to replenish your ceramic paste supply… could it be as simple as a difference in the mix.