Dual Extrusion Brim Problem

[lewisa3 0]

Hi there,

 

I am experiencing some dual extrusion issues. For some reason, my printer won't print my second material on the brim.

 

In Cura, it shows under the preview tab that it will print the second material on the brim, but the actual print shows up without the second material on the brim.

 

I attached a couple pictures. I just wanted to test the dual extrusion capabilities on my UMS5. The red PLA was my first material and the black PLA is my second material.

 

As you can see from the pictures, the black PLA doesn't print out in the brim.

 

Also, I'm not sure why the red side with the black circle came out clean whereas the black side with the red circle came out stringy.

 

If anyone knows why these things are happening please let me know.

 

Thank you!

[Dim3nsioneer 556]

Looks to me like the filament in extruder 2 is not at the right position (due to whatever reason) and it prints thin air first.

Enabling the prime blob for extruder 2 might give enough feed to fix the issue. If it is a hickup in the firmware, a Cura Connect reset might help.

[NBull 14]

I sometimes have kinda the same problem. only with PVA though (BB core) and only on slot 2 (right side)

 

At the first 2-3 layers it only prints air. well I am actually not sure it prints air, but suspects it's only moving the print head around. when putting a finger on the fillement next to the feder you can normally feel that it's pulling the filament (even if the head is clogged, it still have a small pull) when I have this problem I can't feel any movement on the filament.

 

Enabling prime blob results in the head moving to the corner as normal but then right away it moves away again. no extrusion.

 

I can start the same print 2-3 times with the same behavior. 

So when I get this problem I "change" the fillemet. unload and load the same filament again, and the problem is gone. I know its not a fix. But it gets the print started. 

[Cymon 4]

1 hour ago, NBull said:

I sometimes have kinda the same problem. only with PVA though (BB core) and only on slot 2 (right side)

I experience the same problem from time to time. What helps me is at the first print of the day / after turning on the printer, I pull the lever of the second feeder and push the PVA a little bit forwards. I do this right before the PVA nozzle wants to start printing. 

There is no real resistance when pushing and it can be pushed quite a distance before something comes out the nozzle.

After that, it works fine as long as the printer is powered on.

 

I feel like the printer is retracting the PVA too much somewhere before the prints or after the prints.

 

@lewisa3:

I place my bet also on printer printing without material / printing air in the first 3 layers. Try my workaround and tell us what happens.

 

Edited September 11, 2019 by Cymon

[Cymon 4]

@NBull Funny enough, it just happened again, but with Breakaway...

I did the XY calibration right before the print and it worked very well. Started the print right after that and look, no material printing on nozzle 2 in the first 3 layers.

Didn't not think about touching the filament before cancelling to see if it gets transported sadly. 😞