It's been two weeks since I have my hands on this DIY 3D printer based on Prusa i3 design and Melzi controller.

Right after I assembled the kit, I used it to 3D print right away and beared results that was, you guessed it, pretty bad: a lot of curled print surface and a nice loud musical sound like in sci-fi movies. The first thing I calibrated was the railing mechanics. I straightened everything and then all of the axes can slide far more smoothly. I then tried to lowering down the motor current and, indeed, the volume of the music turned down but still have no change at the print result.

Here is where the nightmare begins. I realized that my belt was not tight enough that the motor can groove a little without everything else moving. However, just after the belts are tightened up, my motors, both X- and Y-axis, vibrate violently when making a circle or arc movement and the musical sound is replaced by just a humming electrical noise. The problem do not show up on linear motion though, only in arcing motion.

I figure out that the vibration comes from the motor accelerating and stopping quickly and numerously as what you will get in a polygon-ed circular path.The tightened belt nicely propagates the vibration from the shaft to the whole frame. Loosening the belt only suppress the propagation but not the vibration source itself.

In fact, I don't know whether this violent vibration actually exist since the beginning or not, but the most noticable thing I know is the absence of the musical sound of the motor.

Any insight, suggestion, or even solution will be greatly appreciated. Thank you.

... does it loose steps?

Bad vibration is mostly connected to stalling (loosing steps) or coarse microstepping/halfstepping.

Set finer microstepping for smaller steps, so it won't vibrate so much ... and eventually rise the motor current, if it's stalling ...

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Viktor
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Quote
VDX
... does it loose steps?

Bad vibration is mostly connected to stalling (loosing steps) or coarse microstepping/halfstepping.

Set finer microstepping for smaller steps, so it won't vibrate so much ... and eventually rise the motor current, if it's stalling ...

How to know whether it lose steps or not?

I've experimented in commanding the motor to move at constant speed, both fast and slow and it didn't show any vibration at all.
It only vibrates when the motor is stopping/braking. I've tested it to move for 0.1mm several times in a set of G-codes, and it really is because of the motor stopping and running and stopping and running and so on.
Is this related to microstepping? How do I make it finer?
Thanks

Quote
Vashikovich

Quote
VDX
... does it loose steps?

Bad vibration is mostly connected to stalling (loosing steps) or coarse microstepping/halfstepping.

Set finer microstepping for smaller steps, so it won't vibrate so much ... and eventually rise the motor current, if it's stalling ...

How to know whether it lose steps or not?

I've experimented in commanding the motor to move at constant speed, both fast and slow and it didn't show any vibration at all.
It only vibrates when the motor is stopping/braking. I've tested it to move for 0.1mm several times in a set of G-codes, and it really is because of the motor stopping and running and stopping and running and so on.
Is this related to microstepping? How do I make it finer?
Thanks

Try checking your microstepping mode, make sure everything connected to achieve 1/16 microstep mode, if done, try increase the current flow at step stick pots, I had these problems now they are gone after I increased the current flow