Got my K8400 up and running. Great fun building it
But as of now I got a problem when I’m levelling the build platform.
I follow the instructions of levelling by the three levelling screws. And when I’ve dialed it in perfect (with a folded sheet of paper) it stills just about scrape the the buildplate a the middle point (100,100) .
Could this be caused by the glass not being perfectly flat?
I’ve checked for airbubbles between the build glass and buildtak sheet, there are none.
Can you check if the aluminium plate where the glass plate rests on is perfectly flat?
Sincerely[/quote]Thank you for the reply.
I’ve just tested by placing the glass plate on the aluminium without using the bed clips and I can tip the glass plate to both sides and front and back, not much but there is a bit of play.
It’s as if the aluminium plate is a bit… I think it’s called convex.
Sorry to read you experience troubles.
You could try to straighten the alu plate by slightly applying pressure on the edges.
If you do not succeed, then we suggest to return the plate for inspection/exchange.
[quote=“VEL417”]Sorry to read you experience troubles.
You could try to straighten the alu plate by slightly applying pressure on the edges.
If you do not succeed, then we suggest to return the plate for inspection/exchange.[/quote]
Thank you for the reply.
I tried carefully straighten the alu plate a bit and it seems to have helped. I’ve tried printing some smaller (40 x 40 x 10 mm) pieces and it went fine.
It seems to be making some kind of “ripples” on the surface of the printed pieces though, as if some of the layers are just a little bit wider than the others. I will try and get some pictures of it and start a new thread as I’m guessing this has nothing to do with the beds flatness. Maybe the noozle just need to settle in?
That is called Z wobble and the printer should not have it. Can you check if the threaded rod rests on the motor shaft inside the Z coupler and if so can you loosen the two setscrews of the threaded rod lift it about 1mm and tighten them again and print another object and see if the Z wobble is still there.
I did that when i assembled the printer. I’ve just doubled checked, the threaded rod do not rest on the Z coupler.
I’ve printed some more tests and the Z wobble is still there.
Try to put a little ball (maybe from a bearing or some) between the rod and the motor axis.
This will the rod allow to move free horizontally while being held by the motor axis (and the ball) vertically.
[quote=“ichbinsnur”]Try to put a little ball (maybe from a bearing or some) between the rod and the motor axis.
This will the rod allow to move free horizontally while being held by the motor axis (and the ball) vertically.[/quote]
But still use the Z coupler, correct? I tried it with a small ball from a bearing and the Z coupler, but it didn’t help… Thanks for the advice anyway
What is causing the Z wobble? I’ve disassembled/assembled the Z stage twice now, but it hasn’t done much. The Ø10mm rods has a bit of tension when placed into the Z rod mounts (K8400-MQP-ZRM1), could that be the cause for the wobble?
The threaded rod seems to be straight when rolled over a table. But when it’s assembled the rod do wobble a bit at the top.
[quote=“DaKrunz”]What is causing the Z wobble? I’ve disassembled/assembled the Z stage twice now, but it hasn’t done much. The Ø10mm rods has a bit of tension when placed into the Z rod mounts (K8400-MQP-ZRM1), could that be the cause for the wobble?
The threaded rod seems to be straight when rolled over a table. But when it’s assembled the rod do wobble a bit at the top.[/quote]
Wobble in z axis is mostly caused by a non smooth running linear guide.
A wobbly theaded rod/leadscrew may cause it too.
As you said you have tension on the gouding rods, that may cause the bed move in stic/slip motion, resulting in uneven layers.
Reassemble the z axis guide again and make sure it moves very smooth along the whole range with no tension.
