Geeetech

Hi,

I am currently facing severe quality issues with my new A30. The prints dont look good compared to the my "old" Mecreator2. Edges of printed objects are not sharp and i have blobs and zits on every print. Maybe the vibration of the z axis are the reason for this? One of the z-rods is making constantly noises and hits the frame. Hard to explain, but ive found this video on yt from a guy having exactly the same issue. If this happens, i can see the top frame move forward and backwards like 1-2mm.

https://www.youtube.com/watch?v=xJoOoaSstLw

How can I fix this? Please help.

Regards,

Gamera

Hi


It does not look good.

For the test, you can try filling in the gap to make the fit tighter.
I would wrap the end of the trapezoidal screw in paper or foil. Alternatively, use adhesive tape.

If there is an improvement, something more serious must be invented.

I have the same problem.
Someone have fixed th Z wobble introduced by z axis?
Thanks

Sadly, there seems to be no solution for this. I am currently limited to printing "flat" objects. But even then, you can definitly see how the vibration influences the quality of the print.

Some clarification about the mechanics in a cartesian printer:

- The Z-axis is guided in the A30 and all the CR10, Tevos and other printers out of Al-profile, via the profiles on the sides and the roll bearings on the sides.
- This mechanic part is responsible for the guidens of the Z-axis. They should be linear in the Z-direction and the wheels must be (in best case) perfectly round.
- The threads and the nuts are only responsible for the lifting of the z-axis.
- The problem is that the threads in this price region are never perfectly straight.
- The threads are fixed at the bottom with be coupler in and the motors, because they are never be straigt you need some play to compensate this. So the nuts should never be to tight with the screws on the Y-z connector and the threads must be lose on the top.
- If you make the nuts ad the Y-Z connector tight (you should be more loose than tight) all the movements of the thread that will happen in Y and X direction (because the threads are not straight) will go into the connector and will move the whole carrier slightly in this direction, that is called Z-wobble. Caused by unstraight thread for Z that are to much tightened.
- If you placed the top end of the threads fix and they are not straight you will get the same problem.

So the nuts and the threads on the top should be loose like this to a certain extend, to prevent Z-wobble.
You can print this coupler https://www.thingiverse.com/thing:602481to prevent the wobble more.
This is the best solution for wobbles if you use this cheap threads.

That shaking bar should be loose, that allows compensation for the bar not being perfectly straight which no bar will ever be! You should disregard the comment about putting tape in the machine, it is purposefully designed to have play!

Given that during the video you are printing a single layer, the z-axis should not be moving at all. I will assume that your bed is not even close to level if the z axis is moving so much on a single print layer.

As mentioned above the brass bits on the z axis should also not be tightened down. they need a bit of play (4 bolts per side).

You want to make sure your gantry is parallel to the bed, if only one side is moving its probably not.

Finally zits and related are caused by the extruder, nothing to do with z axis. Either you need more retraction or less heat. Maybe your material is fractionally thicker than your slicer thinks.

Thanks a lot for the very in detail explanations of this issue. Interesstingly, this issue went away after printing a lot. Looks like the z-axis rods got bent during some prints, so the clicking/shaking doesnt happen anymore. Nevertheless, I printed two of those things https://www.thingiverse.com/thing:3111251 to avoid collisions between the z-axis rod and the frame. These things dont fixiate the z-rods, there is still plenty of play/space. I will update my issues thread accordingly.

Thanks!

gamura wrote: ↑

Sat Jul 21, 2018 4:31 am

Hi,

I am currently facing severe quality issues with my new A30. The prints dont look good compared to the my "old" Mecreator2. Edges of printed objects are not sharp and i have blobs and zits on every print. Maybe the vibration of the z axis are the reason for this? One of the z-rods is making constantly noises and hits the frame. Hard to explain, but ive found this video on yt from a guy having exactly the same issue. If this happens, i can see the top frame move forward and backwards like 1-2mm.

https://www.youtube.com/watch?v=xJoOoaSstLw

How can I fix this? Please help.

Regards,

Gamera

Exactly the same problem! Bought the A30 last year. I tried to explain it in this topic https://www.geeetech.com/forum/viewtopi ... 95#p101295. I've got no printed part since I bought the printer! Only problems!

I am using this anti tremble "things" and everything is now silent.

https://www.thingiverse.com/thing:3111251