Not your regular Z-axis band/banding issue

[bltouchdude 0]

Hello guys and girls,

 

The following issue has been keeping me awake for days now.

 

A regular recurring Z-band, I am not the only one experiencing it. It has gone unsolved before so let's try to straighten it out once and for all.

 

I have a CR10MAX and a new CR20PRO, I use Simplify3D and Cura, I have printed many kilos of filament and fixed many problems myself before.

I have sliced this chromatic vase with Cura and the CR10MAX does a perfect job, just amazing, absolute perfection.

 

Now I tried printing it with the CR20PRO, same model, same settings, same everything and these bands show up at the same spot again and again so it should be a hardware issue with my new machine? OR software related difference between these machines.

 

I have tried everything and I believe the following variables can be eliminated.

 

1. Temperature, I have printed many kilos PLA using 185-190.
2. Speed, I print slow, 900-1200mm/min
3. Hotbed cooling down causing shrinking causing bands, I tried printing with hotbed on and off
4. Z-axis bolts and nuts are checked, fully greased rod, filament is not pulling on it.
5. Bed leveling is perfect, I use a glass plate and BLTouch.
6. PLA shrinking causing bands, no because the other printer does a perfect job on same settings, I use 100% fan cooling.
7. Bad quality filament, no I use top quality only.
8. I use Microswiss nickle plated wear-resistant nozzle.
9. Checked all other bolts and nuts.
10. Tweaked all settings I could find on the machine and no difference.

 

I DO use relative extrusion with a 0.8mm nozzle and 0.32 layer height and spiralized contour aka vasemode.

 

As you can see these bands are very subtle, but clearly visible, it is recurring at 3 and 4 cm so no regular interval either it seems.

The first band has their layers a bit close to each other, you can feel a bump, the second and third band are only visual, you can't even feel a difference in layer.

 

[Tomahawk_101 1]

Hi there,

Is that the model with a single Z-screw and 3 wheels on each vertical extrusion?

You should check the wheels, at different positions on the Z-axis try to roll each wheel without moving the gantry up or down. If any are too loose the gantry will be sort of "swaying" as it goes up, leading to predictable banding.

Something like this might help with that: https://www.youtube.com/watch?v=TwVxkukxJlw

[bltouchdude 0]

Got to be kidding me, yes the model with a single Z-screw and 3 wheels on each vertical extrusion.

 

Your suggestion was the very last thing I thought of before going to sleep.

I figured there's a loose wheel on the X-gantry, the one on the most up-right side, tightening it for another test run.

[bltouchdude 0]

It did make a change but the end result is still disstatisfying.

It's the result of the single Z-screw making it less reliable lowering the overall quality.

 

My advice to anyone is to buy a printer with a double Z-screw because the overall quality will be so much better on high quality prints, definately worth the extra money since the CR20PRO is now completely useless to me.

 

Double Z-screw is king so I guess my only option to make it work is to add another Z-screw on the other side, already found some promising mods on the internet, thanks a lot everyone, special thanks to Tomahawk_101.

Edited July 30, 2020 by bltouchdude

[Smithy 1,144]

I am quite happy with the quality of my Ultimaker single Z-screw printers. When the Z stage is stable enough then I see no problem.

[Tomahawk_101 1]

Hi sorry it's been quite a minute, IIRC, tightening the outer wheels to compensate could permanently set your gantry at an angle. You'll want to adjust the inner eccentric nut. If I remember correctly.....