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Dual Extruding Print leaving blobs after switching extruders

Posted: Wed May 12, 2021 7:30 pm
by britain006
I am using a N2 Plus with dual extruders. There is PLA in the left extruder and PVA in the right extruder. Whenever I start a print the first layer of the print goes well and switches between the left and right extruders with no problem. Then it goes to print the second layer with the PLA in the left extruder and it shoots out a blob of filament when starting the wipe tower. I am only having this problem with the left extruder after switching from the right. Eventually the blob builds up large enough that the nozzles get caught on it and the print breaks loose from the print bed. I have tried adjusting the retraction settings under "Extruder Switch Ooze Control."
Currently my settings are: Retraction Speed: 50mm/s, Retraction Amount: 3.5 mm, Restart Speed 20 mm/s, and Extra Restart Amount: 0.
I have tried changing the restart amount to -1, and -2 but I have not seen a change. Any idea what could be causing this to happen?
Attached is a picture of the blob on the bottom right of the red wipe tower.

Re: Dual Extruding Print leaving blobs after switching extruders

Posted: Thu May 13, 2021 11:51 pm
by Steven@Raise3D
britain006 wrote:I am using a N2 Plus with dual extruders. There is PLA in the left extruder and PVA in the right extruder. Whenever I start a print the first layer of the print goes well and switches between the left and right extruders with no problem. Then it goes to print the second layer with the PLA in the left extruder and it shoots out a blob of filament when starting the wipe tower. I am only having this problem with the left extruder after switching from the right. Eventually the blob builds up large enough that the nozzles get caught on it and the print breaks loose from the print bed. I have tried adjusting the retraction settings under "Extruder Switch Ooze Control."
Currently my settings are: Retraction Speed: 50mm/s, Retraction Amount: 3.5 mm, Restart Speed 20 mm/s, and Extra Restart Amount: 0.
I have tried changing the restart amount to -1, and -2 but I have not seen a change. Any idea what could be causing this to happen?
Attached is a picture of the blob on the bottom right of the red wipe tower.


Have you ever calibrated the XY & Z offsets for both nozzles to ensure dual printing will work properly? Also, would you be able to attach a few images of your hotend assemblies?