Tubing keeps coming loose when printing PVA on printer head 2

[3DDane 0]

I need help diagnosing why my printer head 2 keeps causing the Feeder tube to become dislodged during printing.  I am printing PVA and have gone through 6 failed prints where printer head 2 fails to print while printer head 1 keeps printing.  The feeder tube in the back of the machine keeps popping out so the material is fed into space and not pushed into the printer head.  

[gr5 2,224]

You may have 2 unrelated issues.  Let's first talk about nonextrusion.

 

PVA is very easily clogged in the right nozzle.  If you keep the nozzle hot and don't extrude for many minutes the PVA starts to caramelize into a gummy gunk that is hard to push out the nozzle.  It turns brown or black as well when it caramelizes (just like everything else that caramelizes - like toast - or caramel).

 

On the front of your S5 go to the second menu down tab on the left then click in the top right corner on the material in the right core and then choose MOVE.  When it gets up to temp (don't let it sit there at temp for a long time), try getting the PVA to come out through the nozzle.  If that works keep going until it's no longer brown or black.

 

If you can't get it to come out it's okay to help the feeder by lifting up hard on the filament.  This might keep the bowden from coming out.

 

If you can't get material to come out you should try some cold pulls.  Go into the maintenance menu to do cold pulls.  You may need to do 5 or 10 or even 20 cold pulls so be patient.  It's worth it.

 

ISSUE 2 - Bowden popping out.  If you fix issue #1 you probably won't have issue #2 anymore.  However it should never pop out.  The PVA should grind to dust before the bowden comes out so you can decide if you want to fix this or not.

 

First be aware that there are 4 tiny metal blades in the white collet.  by now these blades have scraped the bowden so it is smaller.  Simply cut a few mm off the end of the bowden so the tiny metal blades have fresh virgin bowden to dig into.  Also maybe inspect the blades.  If one or more is missing then buy a new collet.  They cost less than $1 or 1 euro each.

 

When removing a bowden ALWAYS push firmly down on the collet ring while pulling out the bowden.    If you don't do this you will damage either the bowden (scrape it thinner) or you will damage those tiny blades.  Usually the bowden is what gets damaged.