PVA BB04 printcore; Does not extrude throughout print

[nmsr1196 0]

I have a new UM3 and I used PVA in the #2 BB Printcore with the default settings. I did a print that was supposed to last 3 1/2 hours. The BB printcore extruded about 2-3 mm of height, PVA and then stopped extruding the material. I tried the print again, this time increased the default temperature up 10 degrees Celsius. This time it extruded about a height of 2 mm and stopped extruding. Again, both printcores are new.  Both filaments used are Ultimaker NFC. It's the Natural PVA. I did the print with the PLA only, using PLA as the support....no issues.

Any ideas?

Edited September 2, 2017 by Guest

[kmanstudios 1,120]

Just to be thorough, have you tried to do a set of hot pulls and atomic pulls? I am thinking something may have gotten stuck or burned inside.

When I first got my UM3E, it did not want to extrude until I did a cleaning. And, the BB core requires a bit more love and care than the AA core because of the nature of the PVA.

[nmsr1196 0]

I will try that tomorrow with the .4 BB.

I swap it for a BB .8 but Cura does not switch it to BB .8 even though the UM3 recognizes it. But, I will try the .4 BB again tomorrow.

thanks.

[nmsr1196 0]

I tried the atomic pull. But, it did not appear to have additional filament in the printcore. I tried a few pulls.

[tomnagel 126]

How's the environment?

PVA gets soft from higher temperatures and higher humidities. Use it below 28degC, and below 55%.

If ambient humidity is higher, store the PVA in a dry place, with desiccant. When using it for long prints (>24h), craft some drybox to print from.

[nmsr1196 0]

I'm within those numbers for temperature and humidity. But, I used this as soon as I unwrapped it and that's how I got these results. So, the PVA was not laying around. After, the bed leveling and setup, I unwrapped it at that point. So, there was no time for it to develop any issue like that with such short time frame.

[nmsr1196 0]

Like I mentioned before, I would have tried my BB/AA .8 but, Cura doesn't let me select the BB/AA .8 when switched out from a .4. (That's another case I have open).

[rebekah_harper 60]

hiya,

this might be your problem.

I had this problem and it was the hot pull that worked for me.

https://ultimaker.com/en/community/51107-ultimaker-3-bb-core-problem-solved-here-is-how

when you check the filament length all the way to the feeder, do you see a massive gouge where the gear has eaten into the filament?

[rebekah_harper 60]

this is my working solution

https://www.youmagine.com/designs/pva-reel-casing