UM2 Print Random Banding Problem

[vintagefuturist 0]

Hi all, I've been using my UM2 with generally great results once material settings are dialed in, but even though my print quality has been rather nice I've sometimes had the problem of a single layer being indented slightly causing a slight ring around the print at any random layer. Some prints it's 5mm up from the bed and others it's 2/3rds up the print nearing it's completion. It's always just a single layer or two, never multiple rings or bands.

Here are some examples of prints showing this error:

These are old prints with a white PLA that I've stopped using, I don't have any recent prints on hand with the white ABS that I now use as I've given them to clients.

It's not every print but it's often enough to finally make me decide to write a post about it.

Does anyone know what could cause this?

[Nicolinux 288]

Hm, this is hard to pinpoint. I don't think it is a slicing problem but rather hardware. I think your best bet would be to find an objects that prints quickly and then print a few to see where the error happens. Also try to move the object on the heated be - don't always print in the center.

I am sure you checked this, but your filament is not tangled or obstructed in any way?

[tinkergnome 927]

Hm, this is hard to pinpoint.

 

To exclude an overheated stepper driver as the reason: you could try to reduce the motor current for the z-axis a bit (approx. 10% lower) - you can adjust it via "Motion settings" on the printer.

But i also see those lines from time to time if i use cheap filament (with unequally diameter)

[vintagefuturist 0]

I'll give your suggestions a try, thanks guys.