K8400 starts to print OK about 12 layers but then suddenly all will be mess. ref picture:
What might be the main cause for this?
Check if all axis are running smoothly and check also if the belts aren’t too thight.
Cheers,
Dylan
Hi,
I have checked all the axis and I think they move fluently (a bit difficult to say). I added some oil also to the rods.
When I manually move the x and y with the software control it seems that the printer head moves normally just where it is told to move. I just wonder why this happens after printing a while? A temperature related issue?
I haven’t checked the motor pulleys yet could they slip when the motor warms up? My x y motors run at about 45 celsius.
Dylan, if you move the printer head with hand in x or y direction what kind of force is needed to move the head? Could you be able to measure the needed force with some method just to get reference?
Undo the belt clamps and free the belts. Now move the head in all directions. Make sure there is no resistance whatsoever. If there is, then your rods are not parallel. Fix this first.
Once the head moves freely without the belts, put the belts back on but keep them as loose as you can while making sure they won’t come free of their clamps. Check for increasing resistance (obviously the motors add resistance, but it should be smooth, not variable).
Most of the missed steps seem to be down to over tightening the belts.
I can move the printhead with the belts attached with my finger 
Cheers,
Dylan
How to not over tightening the belts? No need to fully thight the clamps?
[quote=“Jurij”]How to not over tightening the belts? No need to fully thight the clamps?[/quote]Yes, just leave a little wiggle room. Make sure you don’t leave them so loose that they can work loose from a clamp during a long print.
I have the same issue with shiffting layers (last 100 layers of 200). This was my third print. The first two prints was okay. So you think it will be enough just to lose a little my belts? They are realy tight…and I can confirm that this is also the reason why it is hard to manualy move possition of printed had.
SOLUTION FOR THE PROBLEM! (At least in my case):
I removed the x y motors and checked the motor pulleys. One of the motor pulleys was slipping.
It was slipping so little that it only affected when the motor and motor shaft warmed up.
I moved the pulley also 0,5mm off from the motor frame so that if the belt tension even a little bit bends the motor shaft the pulley edge will not touch the motor frame (This could also cause friction, just wanted to make sure).
I used a little bit Permatex Blue threadlocker to ensure the attachment of the pulley to the motor shaft.
Now it is working like a charm 
Great to hear you’ve got some prints, but your Vertex is capable of much better. What’s going on with the side walls of that print?
I have not been testing a lot with parameters yet due to the initial motor pulley problem that is now solved. Could you describe the problem with the side walls a bit more specific. I remember in this print the layer height was 0,2mm. Is the filament running too hot. Any suggestions to improve the print.
Yes, it looks like you would get better results by lowering the temp. Is this at the default 210C? If so, I’d try 190 and reduce the flow rate to 75-80%. Black does seem to be a bit runnier than other filaments, but you can get very good results with it.
Yes it is the default 210C. Do you adjust the flo rate and temp on the printer LCD HMI or from the repetier?
You can change the printsettings in Repetier. The preheat settings can be set in the LCD menu.
Cheers,
Dylan
Hi, I tested to reduce the temp to 190°C and also reduced the FR to 85%. I changed the parameters from the printer LCD HMI. The results are now much much better Thanks for the advice. Has anyone tested 0,05 layer height? I wonder what parameters should be used when printing 0,05mm z steps?