SOLVED banding on one axis
@nick9one1 only using a single stepper for Z ?
@peter247 Z is dual MGN12 rails and dual steppers
@nick9one1 Should have said that better , only using 1 motor drivers for both motors and not a driver per stepper motor.
@peter247 ah I understand. the Z steppers are connected to the Z motor 1&2 ports on the duet2 board. I believe this controls them in series?
@nick9one1 The advantage of driving each z motor separate is X axis auto levelling.
alankilian last edited by alankilian
@nick9one1 WOW! That's a beautiful and huge printer.
I'm 0% COREXY experienced, so maybe this isn't helpful at all, but of course it's the internet, so I'll share all my ideas.
Initially, you saw that one axis printed well and the other axis had all these wiggles. When you rotated the object 45-degrees all walls had wiggles. I think that eliminates some strange issue with the slicer or GCODE (which no one suspected in the first place) and it's still consistent with one axis working well and the other axis having problems.
As I understand COREXY, both "axis" stepper motor turn when you move along X or Y, they just move different directions.
Since you see the problem going both "West" on X and "East" on X and it doesn't seem to wiggle around as you are traveling (It looks like it's still a straight line) it seems like when the printer finishes it's last Y move, that it is not in the exact correct location in Y and that's giving you the wiggles along the X-aligned wall.
The wiggles look big enough that you should be able to see them with your eye.
I would try this experiment:
- Set up some kind of square block on the print bed. Could be something like a can of Spam or something.
- Move the print head until some part of it (doesn't have to be the nozzle) JUST touches the block. Or maybe put a sheet of paper between them and move until it just grabs the paper.
- Command the head to move away from the block like 50mm in Y
- Command the head to move 50mm in X and then 50mm back
- Command the head to move 50mm back towards the block in Y
Then see if the head is in exactly the original location. Use the paper test to see where it is.
I think you are going to see that the extruder is not moving to the location it needs to be.
If so, you can experiment with moving just in Y and back to see if that works and moving diagonal etc.
It really seems like something is mechanically awry in your printer and that's causing this.
nick9one1 last edited by nick9one1
Thanks for the suggestion. I'll try that
I've done a little more reasearch and I think its also worth pointing out that on a core XY, moving just one motor moves the head at a 45 degree angle.
So unlike a non core XY, printing a cube square to the bed requires movement by both motors for each line printed.
This means that a problem like this cant be related to skipped steps, loose belts or anything to do with the motion system. If it was, the banding would show on both axes.
It can only really be movement or flex in the hotend assembly or bed.
@nick9one1 The problem with a BLV mgn Cube is there is so many ways to get it wrong ?
Assembling for example my Ender 5 plus it was put a bolt in a pre drilled hole so if they have drilled it correct you shouldn't be able to get it wrong. Is there a forum for the BLV mgn Cube and people who have built them ?.
it was alignment of the Y rails causing the problem. Unless they are perfectly aligned they can bind.
alankilian last edited by
I'm so glad you kept your experiments going and figured it out.
@nick9one1 Glad to know you fixed it, because I'm at the start of building a BLV mgn Cube, waiting for my frame to come so I can start to build it , but it is a winter project so still missing a lot of bits yet like the heated bed / extruder / and some nut and bolt for I'm not building a kit.
Most of my plastic part are printed at 7 hours a part printing at 90% on petg.