Ridges in Cylinder

[runninfarmer 0]

I'm trying to narrow down what's causing this phenomena. When I try to print cylinders 6 mm in diameter there are terrible edges (not the bottom one or messup at the top) and I'm not sure what's causing them. The edges run the whole length of the cylinder. Has anyone seen this before? My xyz acceleration is 500 mm/s^2 (all belt driven axes) and I have my extruder acceleration set at 500 mm/s^2. Is this in Cura or an acceleration issue or some other type of issue? Jerk is set at 10 for all axes. I'm using 14.03 Test 2, thanks for the help. Here's a pic:

 

[gr5 2,005]

It's almost certainly a Z issue in your hardware. What happens is you command a move of say .2mm layer for each layer but at some point (the bad area) it only moves .15mm and so you get .2/1.5 or 33% overextrusion which looks like a bulge. It looks like you get this for two consecutive layers and then things are fine again for a bit.

Try playing with your Z axis using pronterface (it's free):

http://koti.kapsi.fi/~kliment/printrun/

 

Consider maybe putting a ruler along side your Z platform (if that is what moves) and commanding different heights. Or maybe cut power and turn by hand. Any part of the bed could be sticky or wobbly - not necessarily the screw or Z nut.

If you tape a ruler near the bed and place a pencil or something flat on the bad that lightly touches the ruler then you can command pronterface to go to various heights and look to see if it is correct. However your error is pretty small - I don't know your layer height but it looks like no more than 50% of layer height so if those are .2mm layers than the error is probably somewhere around .1mm or less - and only in that region. If those layers are .1mm layers then the error is even smaller - and that much harder to measure!