@Paul_Arnold fluctuations in temp affect thermal expansion/warping which can make the bed bow differently during a print. As it cools essentially it should bow one way. Could mean the FET or more likely the PSU is no good.
Banding seems to appear in same distances on different objects.
The bed temp is constant throughout the entire printmissing/deleted image from Google+
@Griffin_Paquette makes sense.
I’m running a 230V bed which would eliminate a bad fet and psu
Additional Info: the driver (DRV8825) for the extruder is set at 0.7V (skipped steps at 0.5V)
They’re not perfectly regular. It could be variable bed bowing, but my money would be on filament tension. Tension builds up as the extruder pulls on the filamen, eventually lifting the extruder slightly, making an under-compressed layer. Then the tension builds enough that the spool moves. The extruder drops down to its normal position, and it prints normally until the tension starts to build again.
@Whosa_whatsis I also though about this. The spool is moving freely and without any tension. Though, i would expect the bands mit to be in this regular order.
Also the bed is a 6mm Alu plate, i dont think it’s the bed bowing
If you run the same gcode twice, do the artifacts show up in the same places?
@Whosa_whatsis I will check this tomorrow. Wifey is going to kill me if I switch on the printer after midnight 
From the last pic, the right part was sliced with s3d, the cube with slic3r
My money is on those springy couplers and the XZ stage binding. If you push down on your X gantry, you might notice it spring a little. Some people recommend reattaching those so that the ACME rod and the top of the motor shaft are touching within the coupler, with the coupler preloaded a little bit to provide some contact force.
I would think it’s the zrods. Might measure the distance in height change of 360 rotation of coupler. measure banding distance to see if it is related.
Actually for those couplers I’ve found the best way is to insert a ball bearing inside, it sits between the motor shaft and the screw. The screw would rest on the ball bearing, keeping the coupler from compression and allowing horizontal movement.
For it to be caused by the screw itself, it would be at the same pitch of the screw, so if it’s a 2mm pitch, the banding would be at every 2mm.
To rule out tugging on the spool, try printing a cone or pyramid, if the distance between bands increase as it goes up, then its based either on spool or the PID on the bed.
I say it’s the Z screws and those couplings. Do as others already suggested, get rid of the springiness in those couplings. I see you have an 8mm ACME screws, so it might be that. Also, from the high rez. photo of your printer, I see that the ACME rods are going through holes in your printer frame on the top. Make sure they are not touching the frame as they rotate. If you have contact there between the rods and the frame, than it could explain the z banding that you have there.
@Romeo_Pavel they dont touch the frame
After re-review, I see the banding in the Z height is less frequent over the course of the print (with exception of the large hole area). Given the print is somewhat pyramidal, I wonder if the issue is temporal. Perhaps low frequency temperature oscillations in the bed or extruder. Do as @Stephanie_A suggested and print a spherical pyramid maybe twice the size of your cube with the same infill settings. Even though not supported by the evidence with regard to periodicity, I would check for play in each axis to see if you have something like a lead screw loose. If all else fails, might also be worth increasing temp 5 degrees.
Did you check your z-coupler ? I replaced mine with this one, it improved quality
I’m leaning towards some cause that varies with heating and/or cooling. Notice how the banding seems to get more dense on sections that have more layer area, and wider on the smaller layers arond the midpoint of the circle. The 230 V bed may not react fast enough to keep it from warping up and down over the print? How are the temperature swings on the bed? Is the cooling more intense on some layers than others?
@Andreas_Wettergren the temp graph is a perfect horizontal like.
I also tried a print without part cooling, there was still banding without the part cooler running. That’s why I tend to something mechanical
Ok, so temp problems are probably pretty much ruled out then, that’s good. This seems like a tough one. For good measure I’d check, clean and lubricate the Z threads, rods and bearings. The rods and screws look pretty stout, so it seems unlikely they are bending much. I have the same style couplers with no issues, but my rods are hanging from them, with the rod ends resting on bearings at the bottom, so not really comparable…
Hmm, can’t think of anything else that hasn’t been mentioned really. Maybe check the X carriage for vertical play, and check that the hot end mounting is solid.
@Andreas_Wettergren I cleaned and re-greased the z leadscrews. Doing another test print as we speak. Yes, that’s indeed a tough one.
The hotend is mounted in a Titan extruder and there is no noticable vertical play in the x assembly