Annoying z banding issue prusa i3, possible fix?

hello peeps,
so to give you all an update, my tests over the weekend didnt help at all. I tried the anti Z wobble isolators and removed the nuts in the x ends when i decoupled it from the z axis, i made sure the bottoms of the threaded rods were flat, i tried flexible couplers and solid printed couplers, no difference, i had the threaded rod sat directly onto the motor shaft and also tried it with a slight gap, no difference, i tried without having the fan on the hotend and had the heatbed switch off after the first layer by chance it was thermal related, no difference.

I also tried lowering the extrusion multiplier down from 1 to 0.70 to ensure that it wasnt over extruding, no difference, the banding is still present and still matches the pitch of the threaded rod

How tight are your belts? I've seen similar issues on my i2 when it's not tightened up well (I've seen cases where this can also match the pitch of threaded rod).

I'd also make a pass & make sure your frame is reasonably tight.

BTW -- how fast are you printing?

I've said this before you don't have Z wobble you have Z banding it is two totally different things. Lookup reprap calculator3 and depending on what you have for pitch of the screws for the Z and the stepper motors need per revolution 200 standard or whatever you have and then layer height that you are trying to get close to will say 3 mm and it will tell you with an number in decimal will say something like 2.897 that will come out to an even number of steps for Z punch punch the number it gives you in to your slicer for layer thickness so you don't end up with corrections. Start with that first and in the firmware make sure you keep the power on the Z motor they should be kept electrically locked and adjust the Z driver so that they are not overheating and dropping out

Edited 3 time(s). Last edit at 03/04/2014 01:01PM by cnc dick.

Hi tymm,
The belts are tight enough to be plucked but not too tight, the frame itself is a tight as i can get it. I am printing perimeters at 40mm/s (although i have tried 30mm/s with no difference) and infill at 50mm/s

Hi Cnc,
thanks for you're reply, i realize that i have Z banding however i thought i would cover all bases and include solutions for z wobble to try and work out all issues. I have use the reprap calculator and since im using M5 threaded rods and layer height of 0.2mm is okay, the Z motors are always enabled and the Z driver current is set correctly. Even tho all of this is correct im still getting the Z banding, i tried using M8 threaded rods instead of M5 however that made it worse so i went back to M5

Ive also dialed back the extrusion multiplier and although the z banding effect is slightly reduced it doesnt fix it even when i reduce it to the point of layers having holes in them

All in all im really frustrated and im at a loss at what to try next, i believe the issue is with the Z couplers / threaded rods but im not sure

Your machine just might not be strong enough but other people have printed with same machine with better results. Strength means a lot this is a picture of a bottle opener I made on a extremely strong hand made machine I built. Do your printed parts print at the correct height or are they shorter or taller

Edited 3 time(s). Last edit at 03/10/2014 03:43PM by cnc dick.

Have you solved your banding i have same issue?

Are you running the heated bed? I had a very similar issue of z banding (not z wobble) caused by the heated bed flexing up and down as it maintained temperature, changing the distance from the extruder. Worth a shot, to try a print without the bed.

sorry if you already tried it but if you havent try this [prusaprinters.org] helped me a ton with z wobble it basically sets the layer to were it helps to remove the inconsistensies in the rotations.

Did you solve your problem? One way to determine whether it's z wobble or not is to connect your printer to Pronterface and give it a +Z10 command two or three times. It'll make the head go up a few inches, look closely at the carriages and you'll be able to see if there's a slight wobble or not. I'm having the same problem myself, I think my stepper motors don't turn perfectly in their axis and the flex couplings are not helping the issue.

Hi all,

I have a Prusa I3 C (Acrylic frame with printed X carriage parts).

I got rid of my z wobble, I had a connector made by a fried that has a 5mm hole on one side and an M8 threaded hole on the other. Sraight as can be.

However, I still hae banding issues, and the bands' distances occur in multipes of 1.25mm, which is the thread pitch.

I calculate my steps for the 1.8° NEMA17 motor and the A4988 at 1/16 and 1.25mm pitch to 2560steps/mm, which should be right.

Any ideas?

I Recently switched From Cura to MatterControl. I like it much better. And it's FREE.
I can adjust the steps in the Startup G-Code right in the software. Made a Big Difference, BTW my firmware is pre programmed at 2560 steps / mm. Ya, like that would ever work.

And I was having a similar error in both X and Y, Parts coming out with massive rings layer to layer. Tightened the X belt and Viola Only banding in Y.
BUT, Y is as tight as the adjuster goes so it's time to actually shorten the belt a bit. Argh...
Took me too long to get this thing level and this is likely to ruin that as I must turn the printer on it's side to do the adjustment.

Oh Well, guess this is what ya get with a less than $200 US kit. Oh Ya, it's pressboard or some such cheap material. I should have sprung the extra cash for the Acrylic.

Edited 1 time(s). Last edit at 10/31/2016 09:39PM by ScRamjet.