Horizontal "bands" in print

[Verne64 0]

I have this weird issue with horizontal bands showing up in my print, and am hoping someone can shed a light on the reason for this. I'm using a bit of an unorthodox nozzle size and leyer thickness, but I don't think that is what's causing the issue. 

I am printing on an Ultimaker Original+ with a 1,8 mm nozzle. My layer thickness is anywhere between 0,4 mm and 1 mm. Print speed from 20 mm/s to 38 mm/s (I  make all speeds equal in Cura except for the initial layer, to prevent large pressure changes in the nozzle). I am printing in spiralize mode. The filament I am using is HiPs.

 

As you can see in the photo that I have attached, I get some pretty obvious horizontal lines over the printed surface. I tried messing around with different speeds, layer thicknesses and acceleration and jerk settings, to no avail. I took a real hard look at my layer preview in Cura and discovered that the horizontal lines are actually present in the preview and can bee seen in some angles (second image). I also noticed the location of the lines changes when I use different layer thicknesses. I think the lines show up every thirteenth layer, independent of layer thickness.

 

 

Can anybody tell me what could cause this issue? And maybe more importantly, how to fix it?

 

Edit: The problem doesn't occur without spiralize contour being turned on. However, I would like to spiralize, because of the z-scar...

 

 

Edited September 27, 2018 by Verne64

[sidnaique 2]

I am not sure how I landed here and its an old post, but I do know the solution for this. You have probably figured it out already but I thought I will share just in case. Just disable the "Smooth Spiralized Contours" option below the spiralize option. After that you shouldn't see these lines in the layer view and if that happens, then they won't show up in the print as well.