K8400 problem printing circle

I have problem, when I print circle - circle is not regular (is like as oval).What can I do to make it better.Calibration is made, and the problem still occurs.Is it a hardware issue.Please help me.

Please check the manuals website.
manuals.velleman.eu/article.php? … ESAREOVALS

Best Regards,
VEL337

Voltage parameters have been checked, have been removed and re-mounted engines, but it did not help me. Photo print my last.

What will happen if you turn it 90° in Repetier and print it again ?
If you still get it like the pictures I would suggest you have a mechanical problem.

Could you ad a link to the file so I can try to print it and see what happens ?

ok I’ll try today.

my test print object in normal orietation and rotate 90:

and my file STL

http://www.alexnet.pl/pliki/tuleja.stl
unfortunately, my problem is still.

Any ideas what’s going on with the printer?

It’s always shifting in the same direction so my guess is a loose motor pulley or an axis not running smoothly.

I printed it just now and it came out very round and nice.
I’m with raby and suggest there is a mechanical problem somewhere.
If you detach the belts, does the print head move equally easy in both X and Y directions ?
Looking closely at the latest picture it looks as if the layers are shifted, not on top of each other. Is it so ? If it is this is a good indicator that something is not running smoothely enough.

Have you tried printing something larger ? What happens then ?

I print larger circle and effect is the same

It seems to me that the circle is not so much oval as it is uneven thickness which suggests shifting layers, is it so ?

Did you try my other suggestions ?

So I tried, dismantle belts and rollers, one of the shafts had a length of 299mm (298mm should be according to the manual) which could be a problem, when assembled everything back is better but still not perfect.

Is there any good way to assemble this?

Proper functioning needs the assembly to be perfect. With the belts removed, the carriage should be very easy to move from side to side (means it moves easily when you tilt the printer). If the movement is difficult near the ends, you’ll have to widen the space between the clamps (check the Wiki).

Next thing to do is to adjust the belts and pulleys to have all axis and belts // to each other. The belts must run straight on the pulleys and not from one side to the other. Careful with the pulleys hosting 2 belts : avoid any overlap (usually you’ll have to tilt the motor a bit to get the belt staying at the right place (i.e. against the outer flange of the pulley).

Irregular circles is almost always the small belts from the motors to the upper pulleys that are to lose. Please check these.

viewtopic.php?f=62&t=14822

I agree with the Velleman mod. My first testprints after assembling round was not round. After that i tighten the motors more in other words you need extra hands. 1 to push the motors down and you to tighten the screws. The printer is not faulty just needs some tinkering and adjustment