Clogged BB Core

[kmanstudios 1,120]

@fbrc8-erin has an excellent tutorial that lists not only temps but also the temps for low melting filament like PLA and the temps for high melting filament like Nylon. It also has the pumping actions that I described as a way to 'plunger' out the hardened materials. I am hoping that she will see this tagging and respond. Her tutorials are top notch.

[tinkergnome 927]

15 minutes ago, pfordmedia said:

I would like everyone to notice that no where in the cold pull article are temperatures mentioned

 

True, i thought that the "print core cleaning" wizard takes care of the temperatures and you only have to follow the advices on the screen?

But i have not double-checked.

The second article about the Atomic Method (for other Ultimaker printers) mentions 90°C for PLA and 110°C for ABS.

[gr5 2,172]

8 minutes ago, tinkergnome said:

True, i thought that the "print core cleaning" wizard takes care of the temperatures

There's a print core cleaning wizard?   I've been using my UM3 multiple times per week for over a year and I didn't notice?  Was that there when it was still in beta?  I thought I went through all the menus when I first got the machine.  Maybe I just forgot about it.

[Brulti 177]

The UM3E has a menu for doing cold and hot pulls, and, for cold pulls, the screen tells you when to push, when to stop, and when to pull once temperatures are ideal.

 

How to find it is indicated on the user manuel, it's on the System->Maintenance menu, if I'm not mistaken.

Edited February 9, 2018 by Brulti
Adding precisions.

[tomnagel 126]

temperatures used to be in those help articles. Maybe they took those out because the printer takes care of that when you follow the built in procedure (UM3 only)

(printer also moves the print head into one of the corners, so you can't forget that as well)

 

(edit: I didn't see the responses above)

Edited February 9, 2018 by tomnagel

[Choclit99 0]

I finally cleared out my BB 0.4 print core which was completely clogged after a problem with PVA.  Hot and cold pulls would not remove the blockage at all.  What finally worked was raising the temperature to 275C and forcing PLA through with a lot of pressure.  Even after it started oozing, it took a while to get clean flow.  This is picture of what came out!  The PLA I used was purple.  Everything else is burnt on PVA!

 

[AustinMaker 2]

After 2 PVA clogged BB cores, I learned my lesson about printing with wet PVA. Was using Ultimaker Natural PVA and even after several trips through the filament dryer, I could still hear some popping when it printed. Sure enough the BB Core clogged.  No amount of hot pulls and heating the core helped.

 

Wanting a solution other than buying another BB Core, I decided to take one of my clogged cores apart.  It was simple with a 7mm socket and a vise.  The nozzle was blocked solid with burned PVA. I dropped the nozzle in a cup of water and over the course of 5 days finally got it clear.  Took the nozzle out each day and dug at the hardened PVA with a dental pick. Bit by bit I was able to clear it.  

 

Carefully reassembled and back in the printer. Worked like a champ.  So, I decided to do the same thing with the second nozzle and this time took pictures to share.  The PVA wasn't burned in this one like the original, but it still took 3 days of soaking and picking to get it clean. You can see here the nozzle in the vise, the clogged nozzle, and in the last photo all the crud that came out of it.

 

I've read here that you can't take the nozzle out of the BB Core, so wanted to share that although maybe it isn't the optimal approach, you can do it and reassemble successfully.  With the cost of these cores, good to know that its at least worth a try when all else fails.

[Dadkitess 19]

Damn, this Ultimaker PVA is really far from perfect, users are not really satisfied about it, you'll want to switch to another PVA such as the PolyDissolve which is way faster to remove when dry, as well as way faster to dissolve.

 

And BBCores are so picky, they clogged instant if there is some miss-extrusion caused by some defect on the prints that occlude the output of the material.