Blobs first when doing circles

Hi, does anyone know how to eliminate this problem.
When the printer is doing a circle, it puts a blob down first which is higher than it should be and then when the print head comes back around it hits this blob and judders.
Any help would be appreciated, thanks, James

Can you post a picture of the problem?

Hi. sorry not sure I can as it all happens very quickly and is very small. You can just see the blob and then the head jumping when it goes over it. Not sure its causing any major problems.
Thanks anyway

Do you have the impression that the printer is printing a bit to “fat”?

seems to print fine apart from this small issue. Main headache is getting z axis sorted to smooth out the print edges so not too worried about this at moment

Do you print a skirt first? This is a good way to get the startup blobs and strings taken care of before you actually start your print. Doing 2 loops of skirt about 10mm outside of the print should get rid of all the startup mess.

yes i do this first. The print is mainly good. Its only the circles that have this so mainly ok.
I have a few more issues you may be able to help with.

Heater plate was warped in the centre. I noticed people are using mirrors/glass. Put some glass on so its now flat but had a print that curled up at the edges and one a few that dont stick very well. Setting is 50 degrees ans 190 degrees. I have tried to sand this a little to add grip. Any ideas?

Also I believe this problem ( pic ) is due to the z axis not being perfect. Wavey edges. How smooth should these be with perfect setting.
Was going to print a new bracket that someone had released for use.
The wavey edges are uniform on all upright sides ( internal and external)


I’m getting this too. I think it’s due to the z access rod being bent, or it wobbling where it is attached to the servo.

I’ve seen some mods which require replacing the rod and other parts with a more precise rod and follower, and recompiling firmware, but I’m hoping there is a way to improve this out of the box.

I tightened up the locknut on the top of the z access rod, so now it protrudes about 1mm above the top locknut, and the waviness is less, but still visible.

Hi, i have the same probleme… about z-axis (z-ribbing). i found this and if i had understood… you can reduce this with “layer height” setting.
Anyway if someone from Velleman can solve this problem that would be very fine because i use the factory setting.

The layer height is already chosen with that article in mind. When you have excessive Z banding the problem lies with the Z rod screw, it is probably bent. You can take it out and check it on a level surface. if you detect a bend you can gently bend it the opposite way to remedy the problem.