Issue with printing PVA/Printcore BB

[SunnyB 0]

Hi everyone,

First time 3D printer user here, we bought an UM3Ex for our lab, and I'm playing around with it, trying to see what is possible. I'm really loving it so far, thank you for this great poduct.

However, I am repeatedly running into problems with PVA. It would not print very well, as sometimes it felt like the extrusion control was not great, so there would be PVA in places there shouldn't be.

I have tried to clean the BB printcore as specified and when cold-pulling, my PLA filament looks like follows:

There is an elongated section in the filament, as well as a part close to the tip that looks partly "shaved off". Is this supposed to look like that, or am I making a mistake during the maintenance?

Additionally, the BB printhead looks burnt (shown in the picture below), and this is after only one print. I'm not sure if this is related to my issues with the PVA, but it does not look normal. Is there anything I can do to prevent this from happening?

Thank you very much for all your help,

SunnyB

EDIT: One more thing. When unloading both print materials after print (silver PLA and tranparent PVA), the end of each filament looked quite different. PLA looked as I expected, but PVA had a very elongated, uneven tip.

Once again, I'm not sure if this is something caused by erroneous handling on my part, normal, or a sign of a problem with the printer. Any help and information is greatly appreciated.

Edited December 7, 2016 by Guest

[neotko 1,417]

PVA leaves that look on the nozzles. To clean it you can heat the core to 120-140 and with a peace of pla try to scratch the burn out, but most of the time the only solution is to use a metal brush. BUT this doesn't affect the print, I only clean on the pla core, pva since is just pva can look like that and perform the same as brand new shiny (also a metal brush erodes the brass so isn't the best solution for a core).

About the atomci pull/cleaning of pva. It looks like still has some residues, try to push more PLA while doing the method to ourge the pva inside. It takes quite some time to leave it as brand new but is doable.

About how the pva prints to give you a hand it depends highly on the object. For example, PVA sticks quite bad over PLA, that's why the PVA support structures are usually really big with much Horizontal Expansion (supports option hidden by default).

If possible try to post images so we can try to debug the issue. Also check if the feeder tension is too high or if the lever is in the middle. To change it unscrewing the screw hole on the top of the feeder will tight (lever indicator moves down pressing harder). Screwing it will move the tension indicator up releasing the pressure.

But first, some photos.

[neotko 1,417]

About the tip. The Core AA has a different design then BB. BB core is designed to keep the filament from burning inside (a characteristic of PVA). So the tip difference is normal.

[ultiarjan 1,223]

Picture may explain.

[xt275232127 0]

Hi, new maker here. After several trails printing with PVA, I have the same problems as what you had. Especially, the small oozing out PVA, which causes tiny bundles or bird nest like support structures. I would think it could be PVA is kind of burnt in the nozzle, not sure, or as I printed it at fairly slow speed, 30mm/s, I should lower the temperature.  I look at the printing process, I can always see a tiny drip on BB extruder while AA is printing. Sometimes, as so many stringings sticking on the support structure, nozzle bumps on it and knocks off the entire support.

Does anyone know what is happening here and any suggestions on what I can make change on settings?

Thanks in advance.

[tomnagel 126]

SunnyB, you mention that you run into problems with PVA printing.

Can you describe the problems that you see? Pictures help a lot!

Some tips in advance:

1) Use Cura, and no other slicer, to print PVA. At least until you know what you are doing.

2) Use the default quality profiles that come with Cura. Don't mess around with settings that are under "advanced" until you have made good prints with the defaults.

3) Use Ultimaker materials. The quality printing profiles in Cura have been adjusted to Ultimaker filaments.

4) Watch ambient temperature and humidity. PVA prints unreliable at higher temperatures and humidities. Stay below 28 degC and 55% RH.

If you want any extra help, please post what slicer, settings and material you are using.

Good luck!

Oh, about the cold pulls: the elongated one might be caused by pulling at a too high temperature. At what temperature did you pull?

[HultiH 0]

Unless the tips which are summarized in the previous reaction I have the same problems with the printing of the Ultimaker PVA with my Ultimaker 3. Enclosed I have some pictures of my settings, which are the default settings from the Ultimaker cura software.

I have tried to print it several times without a satisfied result. The pictures are taken from my 3th attempt.

It looks like that after a short period of printing the PVA layer doesn't stick to the layer before.

Help!

[gr5 2,266]

If the cold pull result is in the shape of the tip then that's good. The "long neck" is not an issue.

Burnt filament on the OUTSIDE of the nozzle is fine. My nozzles look like that after a while also.

The little leaking is normal and is a problem that should be fixed by using the "wipe tower" feature. Or do what I do and design your own custom wipe towers.

[tomnagel 126]

The pictures are taken from my 3th attempt.

 

I think you forgot to include the pictures.

[fabreax 15]

I have good results with PLA+PVA and PETG+PVA but I have changed the Cura default settings.

[ultiarjan 1,223]

I have good results with PLA+PVA and PETG+PVA but I have changed the Cura default settings.

 

so what did you change?

[fabreax 15]

- 215°C temperature for Ultimaker PVA (default) or 210°C for Formfutura Atlas support

- I'm still using a prime tower because without, I have little holes on the walls, due to PVA residues.

- 35° support overhang because the walls are not clean at 45°

- 25% support density (15% can be ok)

- 0 support Z distance

- 0 support X/Y distance (if not, the part is not well supported at high angles)

- 0 minimum support X/Y distance (same reason)

- 2mm support horizontal expansion (or more, depending on the part, PVA does not stick on the PLA, this setting can help)

- enable support interface

- 1mm support interface thickness (default 0.8mm should be ok)

- 100% support interface density

- 0.1mm support interface resolution

And the most important thing is to be sure to have no humidity in the PVA (you can put your entire spool at 70°C in the oven for 5 hours).

[ultiarjan 1,223]

I use this to fight humidity;

https://www.youmagine.com/designs/drybox-for-pva-ultimaker3

[fabreax 15]

I use this to fight humidity;

https://www.youmagine.com/designs/drybox-for-pva-ultimaker3

 

Thanks !

[MetaCAD2010 0]

use one of these

To clean PVA core use one of these. just lightly push n twist , then push through PLA then repeat and all the soot and crystalised PVA will come through.

[xuyao 0]

On 12/7/2016 at 3:52 PM, ultiarjan said:

Picture may explain.

hello, a question. Where do you got this picture?

In order to ask you, I signed up for an account.

Thank you!