WTF!? with my prints warpping EVERYWHERE

[Balshaj 1]

1 hour ago, SandervG said:

 

Scarring is usually used to refer to the little remains you see on the surface of your print where you removed support (with pliers). PVA doesn't require the removal of support since it dissolves in water, so there should usually be no scarring indeed. The smoothness of your surface can be influenced with the X, Y and Z distance between support and your model, and your support structure + density, but the default profile settings should give you pretty good results from the start.

and they have but all of a sudden im noticing that the support isnt printing well because the pva feeder keeps slipping...if it goes at a slower feeed rate it seems to be consistant,...is there a way to set the speed feed rate in cura for filament feed?

[gr5 2,224]

If the PVA feeder is slipping you almost surely have a partial block.  The PVA caramelizes (turns brown, harder, stickier) and can coat the inside of the 0.4mm passage inside the nozzle.

 

This is best fixed with a lot of cold pulls.  See the Maintenance menu on your printer.  It walks you through hot and cold pulls.  You may need 10 to 30 cold pulls to get most of the gunk out.  Really.  3 cold pulls won't be enough.

 

Also you can google about "cold pulls" as there are tons of great videos and it's interesting to see how people do it on other printers - actually quite informative.

 

Another option is to just "throw money at it" and buy another BB 0.4 core.

 

Another thing I like to do is after I heat the nozzle, I use a hypodermic needle (23 gauge which is 0.35mm diameter) to scrape the inside of the nozzle back and forth for a few minutes.  Get all that brown gunk off.

[Balshaj 1]

19 hours ago, gr5 said:

If the PVA feeder is slipping you almost surely have a partial block.  The PVA caramelizes (turns brown, harder, stickier) and can coat the inside of the 0.4mm passage inside the nozzle.

 

This is best fixed with a lot of cold pulls.  See the Maintenance menu on your printer.  It walks you through hot and cold pulls.  You may need 10 to 30 cold pulls to get most of the gunk out.  Really.  3 cold pulls won't be enough.

 

Also you can google about "cold pulls" as there are tons of great videos and it's interesting to see how people do it on other printers - actually quite informative.

 

Another option is to just "throw money at it" and buy another BB 0.4 core.

 

Another thing I like to do is after I heat the nozzle, I use a hypodermic needle (23 gauge which is 0.35mm diameter) to scrape the inside of the nozzle back and forth for a few minutes.  Get all that brown gunk off.

there is no clogging in the BB core, when i go to materials and manually move the filament it flows perfectly, is there a way to slow down the feed rate , i guess i can slow down the travel speed?

[gr5 2,224]

If the filament is slipping then yes you can fix this by slowing everything down.  You can either make the layer height smaller or you can lower the printing speed.  Note that there are about 8 printing speeds for each extruder.  Make sure you are on the extruder 2 tab and make sure you adjust the support speed.  Usually you want to go 2X slower as an initial test.  You can then speed things up in the TUNE menu while you are printing live.

 

However unless you increased the speed or layer height from the defaults, it should be able to print without slipping even at double the default speeds the feeder shouldn't slip.  This indicates possibly the feeder isn't set to the middle tension setting (the indicator should be about in the center) or there is a partial clog.

 

Yes you say it feeds PVA just fine but it may be slower than normal - it may be that the pva has lowered the inner diameter from 0.4mm to 0.3mm.  Unless you time how fast you can extrude it's hard to notice (other than the feeder starts skipping).

[Balshaj 1]

sorry its been a while since i replied, the issue is simple the feeder starts off great that after 30 min is grinding through the pva filament, only happens with PVA!  i hate the God Damn inconsistency since the material has always been ultimaker pva!

in help other than adjusting the screw on the feeder!?

[gr5 2,224]

In cura enter "speed" in the settings search and click on core 2 tab.  What is your support speed?

 

Definitely don't slow down the travel speed.  You want the travel speed at least 150mm/sec.  Maybe 250mm/sec.

 

Did you check the print head fan?  What you describe is common if the print head fan is broken.  The middle fan - not the side fan.

[Balshaj 1]

travel speed is 250mm/sec

 

i had the support fan off reset it to 50% per default

 

the middle fan is working fine!  its the feeder just cant stop slipping!  ive lowered the tension screw but slips even more!  gonna tighten it to see if that helps!

 

ill post a pic of the chewed up PVA.

[Balshaj 1]

[gr5 2,224]

So the dots - the impressions in between grinding look perfect.  This tells me the feeder is working quite well.  The problem is somewhere else.  Most likely the core. 

 

How many cold pulls did you do to clean the head?  I know you said it feeds fine but compared to what?  Did you time how long it takes to feed a spot of filament down to the bed?

 

Again - another quick fix is to just slow down the speed on the support.  You've brought up travel speed twice now but travel speed has nothing to do with the printing speed of the PVA.  You have to select the second extruder.

 

Here are a very limited set of ideas of what the problem might be:

 

1) water.  80% of PVA issues are because the PVA absorbed moisture from the air.  Just putting the filament on the back of the printer for 1 day is enough to greatly degrade the performance.  One week at 50% humidity and it's time to dry the filament.  When it has a *lot* of water you will notice steam coming out of the nozzle along with pva and you will hear hissing.  When pva is dry, the bottom layer is transparent (versus snowy).  The first tiny bit of extrusion is always clear because the filament has been drying for 30 seconds inside the nozzle but once you get printing it gets more snowy.  the entire bottom layer needs to be 100% clear.

 

2) Clogging or partial clogging.  At normal printing temperatures, PVA caramelizes into brown or black gunk in just a few minutes (like 15 minutes).  That is one reason the inactive head must cool down while waiting.  This can make the nozzle thinner (say 0.3mm) and when you print a lot in a row without letting the pva escape it will build up pressure until it slips in the feeder.  Occasionally it slips enough to grind a bite and complete fail.

 

Partial clogs can also be when a chunk of brown pva farther up in the nozzle ends up in the narrow channel but it sounds like this is not your issue.

 

3) Feeder - it could possibly be the feeder.  I doubt it but the test is very easy - with the filament far above the head use the MOVE feature on the printer to move the pva up and down and then fight it with your hand on the back of the machine.  The feeder should be stronger than you.  It can push pva with about 10 to 15 pounds (5-10kg) of force.

 

4) Core - there are many things inside the core that can go wrong.  These are rare but it's worth trying a different core sometimes.

 

5) Bowden tube - after printing a few kilometers (not sure how many spools that is - 10?  30?) the friction in the bowden can be a problem.  3dsolex has extra slippery bowdens although the ones from ultimaker are cheap and work just fine.