problem with my prusa

I recently set up a prusa and am having problem with my z axis. The motors just sit there and chatter at me bu when I run them seperately they are prefectly fine. I have messed with my current settings on my potentiometer on the polulu driver and they don't change their functionality. I don't even have them hooked up to my z axis anymore and they still chatter. I do not know what is the matter.

With the motors unmounted, but both still hooked up (wired) and sitting on the bench, when you move the Z what happens?

All of my driver pot's are all pointed the exact same way for all axis's, and I'm running 13.5v power supply.

Are all of your Lead screws and linear rails (drill rod) straight, smooth, and square?

Do both motors run the same direction? Stepper motors are regenerative so with the power disconnected if you turn them the same way they will turn freely but if you turn them opposite directions they resist moving - that is if they are connected correctly.

Failing that check that the z-axis lead screws turn freely and the nuts are correctly sitting in the x-axis ends. I have had a similar problem once with one of mine and it turned out to be a lead screw nut not sitting in the x-end correctly was causing the motors to run with different loads which resulted in chattering like you describe.

---

_________________________________________________________________________________________

Richmond, New Zealand
Thingiverse ~ YouTube

alright thanks for the info. new problem. My axis on that moves left and right on the z axis part has prblem when reverseing. It doesn't look like it is a belt problem it just doesn't move when reversing. I don't know whats happening with it.

alright, I did more trouble shooting. It may be the motor. The motor stalls and the stepper driver does not. I need to pull the motor out and do tests. Maybe swap x and y and see how they fare. If it is the motor do you think I can swap a z?

Stripped my x and y axis down and rebuilt them. Ran some tests before rebuilding though, both motors are turning fine. After rebuilding I played with tension and current on the stepper drivers, fixed my stuttering of the axises. I have not printed again as I was too tired. I will set up this weekend and do more tuning, I lost my firmware settings I had but I can probably get close to them fairly quickly with calibration objects.

Think I am going to print out a set of mendel pieces first and seed them to a friend, I have a goal of each of my printers reproducing at least once. I have done it twice with my cupcake and the mendel I have now should be part of my personal botfarm that will hopefully become a small replication business. We'll see.

back to the buzzing stepper motors on the z. I think this is an alignment problem. Walked away from it before I broke something. Will come back into it tuesday.

the problem isn't drivers it works if I give the commands manually but if I run a print I get a problem. I think I need to mess with some preferences. should be good tonight.

I had a similar problem with my z-axis and it seemed to go away and come again with the version of firmware that I loaded. I ended up trying Sprinter, Makerbot Sprinter, Marlin, and in the end settled on the Sprinter because that firmware seemed to work with minor tweaking. Like everyone keeps stating, the pots on the drivers should likely never be set to more than half their full turn around, at least none of mine are right now. It's too bad that the config is such a pain to get everything working, but to some I guess that's part of the challenge.

Travis

baslisks Wrote:
-------------------------------------------------------
> the problem isn't drivers it works if I give the
> commands manually but if I run a print I get a
> problem. I think I need to mess with some
> preferences. should be good tonight.


What speed are you using when you enter manual commands. I've had my x carriage run fine with manual high speed commands, but start to stall if the speed was at "normal" print speeds. If you're using pronterface it lets you adjust the speed of manual movement. Try a slow speed and see what you get.

It was firmware settings I had set way too high. Looks like had put a 0 on my z axis, as in, instead of moving a 5mm/s it was moving at 50mm/s causing it to freak out. My printer is working now. I am a couple points of mm off from near perfection. just tuning now. Nice straight walls with very little extra plastic.