QUESTION Dual-extrusion oozes, requiring a prime & wipe tower

MobyDisk · January 17, 2022

I have a brand new S3 and I can only print dual extrusion if I "Enable prime tower" and "wipe inactive nozzle on prime tower." Is this normal? If I don't use the tower, the ooze from the inactive head drags across the previous layer. The "ooze shield" option does not help. This causes:

several effects:

1) The inactive nozzle oozes until it touches the print, at which point the ooze string tears off the head and sticks onto the print. This repeats until it switches nozzles.

2) The inactive nozzle oozes but does not drop the string onto the print yet. When the printer switches to the new nozzle, the string is put down when it starts printing.

3) Worst-case: The ooze sticks to the print and tears the material off the print bed, ruining the print entirely. This happens on small prints with thin columns.

The wipe tower resolves these problems. I want to just know how normal this is. I am going to take some pictures of prints with and without the tower, showing the difference. The S3 replaced my ancient Replicator Dual which oozed so much that I declared dual-extrusion printing useless. I am disappointed to find that 10-years later, the oozing situation does not seem to have been resolved, and I don't see anyone really pointing that out. When I look up dual-color prints or prints with PVA I get nothing but glowing reviews. Is my experience unusual? If it is not unusual, then why is "Wipe Tower" not on by default when using dual-extrusion? I just don't see how anyone can successfully print without it. The Stratasys printers I've seen have a dedicated wipe area, and they wipe every layer (maybe even more often than that), which leads me to believe this is normal, just unstated.

I'm experiencing this both with Ultimaker PLA and Ultimaker PVA, both fresh out of the box.