Y-shift after mid-print material change

[LumcoMFG 0]

I am currently having a similar issue with the material station.  When the material station runs out of one spool and has to change to another, I am getting almost 1/8" shift in the print.  The first time it was only a few layers from the bottom, so I was able to do some trimming and make the part function, but the second time it was halfway through a 10hr print, so I don't really have that option.  Any idea what could be causing this?

[CarloK 208]

  

On 10/27/2021 at 11:04 AM, CarloK said:

@LumcoMFG It seems like you have a different problem from the original topic start. The original topic mentioned a problem with XY shift, but when I understand your problem correctly, then you have a Z-shift?

What is the software version running on your printer?

 

[CarloK 208]

  

On 10/27/2021 at 1:46 PM, LumcoMFG said:

@CarloK It is a 1.7mm shift in the +Y direction, I believe (away from the front of the printer).  Printer is running Firmware 6.5.2 and part was programmed in Cura 4.11.0.

I am currently running another print and am going to try manually loading material into the material station in the same bay to see if it has something to do with changing bays, but that somewhat defeats the purpose of the material station.

 

I apologize that it is not quite the same issue, I probably should have created a new thread.

 

[CarloK 208]

Sorry for the ugly quotes above. I seldom use the moderator functions of this forum and in splitting an existing thread into a new topic I made a mess out of it.

[LumcoMFG 0]

Just to update any lurkers here, I have been back and forth with Ultimaker support directly on this issue and have been able to rule out play in the X axles.  I have also been able to isolate the issue to Extruder 1 with any material or core inserted.  For now I am just running extruder 2 for the main material and 1 for support or secondary material, but I will still need to watch to make sure it doesn't end up needing to change that filament mid-print at this point.

[robinmdh 108]

Pure speculation:
The printcore's  bottom of the cold zone locates into a cup in the printhead, could this combination be somehow giving you problems? I've never seen this go wrong mind you but when changing material, it is pulled up/out of the printcore and this could unseat the core from that cup. if the spring tension is then not big enough to push it back into the right place...

Could there be anything getting in-between these mating surfaces making locating the same position repeatedly harder?