I am having several issues that have come up. But, let me start by saying everything was working fine for several weeks with the Dual Extruder before this started.
First Issue:
This started without warning and without changing anything. I have tried many things and still have not resolved the problem. I have a mountain of wasted prints from my attempts to resolve this as I need to print quite a few layers before it is easy recognize the X axis shifting.
I have updated firmware
I have uninstalled and reinstalled Luban (V4.7.3)
I have run calibration several times
My current configuration is:
Firmware V1.15.23_20230404
Touchscreen V1.15.14
Controller V4.5.34
Luban V4.7.3
Second Issue :
This began with the Luban V4.7.3 upgrade. I get a warning concerning Nozzle Diameter Synchronization when I attempt to start printing. I have not been able to find the cause of this warning to prevent it.
You didnt descirbe what problem one is, but i guess you are having layer shifts. Share some photos, print settings, connection type of printing host (touchscreen or serial connection or wlan?).
Just ignore the sync error, its a known bug, try searching in the forum.
Layer shift is putting it mild. It appears to initially print without shifting, but once it starts to shift, it continues to shift. These photos are all taking from the open end of the print surface and show my last attempt.
If this is the case, what speeds and accelerations are you printing?
Is your buildplate moving and causing the shift?- I clamp the sheet on the heated bed.
I guess your x-axis linear module is overheating, what printer vesion do you have?
Maybe try to cool the stepper by letting the door open and additionally mount a fan for a experiment?
OK - It is not a hardware issue. It is apparently something wrong with Luban 4.7.3
I used the same .stl file with a new installation of Cura. I kept all stock Cura settings except I changed the temperature up from 200Āŗ to 210Āŗ and first printed a single piece that came out perfect. Then I used the exact same Cura settings and printed 10 pieces at once and they came out perfect.
My next step will be to compare Cura print settings to Luban to see if I can find what is causing the shift.
I was going to suggest trying Cura and you beat me to it. There simply isnāt that much room for the build plate to move along the X axis, so that would narrow it down to the X-axis linear module or Luban. And odd as it may be, Luban was the only component that changed.
But surely this is not in the g-code generated from the STL, right? Do you have Luban controlling the connection to the SM? Is it over serial? And if so, does it happen when you run the print from the touchscreen with Luban not running, or when run from Octoprint?
Itās still shifting. Some how I got lucky and managed one round of decent printing. But the very next job was right back with the Y offset issue. I guess its safe to say it is not Luban. At this point Iām thinking it has to be something in the firmware setup. Iām going to roll back a couple versions to V1.15.20 and see what happens.
Iām not sure what you mean by ācurling issueā . Iāve been printing multiple of small items for over a year without issue, including the few months I had the dual extruder. If I reduce the speed or lower the temperature Iāll have to glue the filament pieces together to make anything.
I really doubt the build plate has anything to do with it. If you look at those orange prints, there simply isnāt that much room for the build plate to shift, even if it started out all the way to the right and got nudged all the way to the left. There isnāt any sort of circular pattern to the shifting layers, they move in a single direction, and the build plate wouold start to rotate once it hit the Z axis module.
Both are happening with the dual extruder. I would suspect that the firmware is determining the position of the toolhead using the wrong nozzle offset (as an example of how this would happen: after a pass, the toolhead returns to an offset from 0 based on the the edge of the print, and it uses the current position of nozzle to determine how far to travel to return to that offset, but it starts printing off nozzle B, and the error is compounded after each layer), OR the X axis has a problem. It could be that the firmware is not accounting for the difference between the nozzles correctly, and when it returns t origin it overshoots, grinding the carriage against the end stop and causing excessive wear on the module - mean the core problem is the firmware, but the module is what needs to be replaced. That might explain why it is seen only n a few machines (heavily used printers with the old linear modules?) and not on every single one.
If this were happening to my machine (and it might; I have a dual extruder but have been afraid to start using it as I only just got the A350 to produce reliable prints), I would measure the distance that a shift happens per layer (use the thickest layer height you can and just print some squares) and compare that to the distance between the nozzles. I would also pause the print at the start of a layer and make a sharpie mark on the X-axis module, then pause a few layers later and see if the sharpie mark aligns with the module. This wouold be tricky to do though; might require adding actual pauses to the gcode.
I agree with others about the linear module being the cause. The difference in weight between the single and dual extruder is significant. The linear module is not maintenance free and the added weight will only accelerate the need to open them up, wipe down and add new grease. The stepper motors already get fairly warm during normal printing. Any added stress due to weight or debris is going to heat them up significantly.
I personal have been thru something similar with my a350 shifting layers but in the y axis. I tried everything I could think of to fix the issue. Read something about matching the linear modules to the manufacturing date which can be found inside the end of the linear module, so i swapped around every module I could and the issue persisted in the y axis. This lead me to believe that it was not a linear module, so then I tried swapping the main display and the main controller that everything plugs into. Still that did not work. So at this point I felt it wasnāt a hardware issue although yes there are splitters and cables I didnāt go thru testing. So I tried to go at it from the software end and yet still I was not able to resolve the issue. This was all with the original print head, however what I finally narrowed it down to was that I could not print more than 3 of the same object at once or it would layer shift. Other than that it still works fine to this day. I now am even using the dual extrusion module. At the time I was trying to production run a product I was wanting to sell and I found that ultimately I could print two of the objects at once and it would be fine but anymore at once and I would have a layer shift. Someone also mentioned heat in the linear modules, i tried putting heat syncs with fans on the end of every module and lubricated everything inside the linear modules. That didnāt help in my case either. I thought maybe the increased number of prints was causing heat but adjusting the speed of the print and cooling the modules still was to no avail. Try printing just one part and see if it works.
