Problems with PVA (ultimaker 3)

[Gmajor 1]

Having problems with extrusion with PVA. The first layer (on the print bed) is consistently flawless.

However as the quality deteriorates as the printing goes on, as the photos below show.

 

I have tried:

• manually leveling the bed
• cleaning the printcore
• changing the printcore
• changing the PVA roll to a new one

 

Nothing seems to help. Does anyone know what the problem is?

[MariMakes 192]

Hey @Gmajor,

 

Have you tried printing this printjob without supports?
I don't believe it needs it. 🤔

 

Something seems to go wrong with priming the PVA.
Are you printing a primetower? 
Are you slicing with the latest verison of Cura? 
Have you considered increasing the horizontal expansion to print more PVA so the material is properly primed?

 

Do you have a project file for us? It contains the printer and settings we need for troubleshooting. 
To save a project file go to File -> Save project.

[Gmajor 1]

Thanks for the quick reply.

There is a handle on the pot that I'm pretty sure requires some support. Even so, can the fact that support isn't needed make the support fail when it's there anyway?

 

No primetower. It hasn't been necessary before. I'll try however.

 

The version of Cura I' m using is 4.11.0. Is that the latest?

 

16 minutes ago, MariMakes said:

Have you considered increasing the horizontal expansion to print more PVA so the material is properly primed?

 

 I'm not familiar with this setting (bit of a newbie, me). What does it do?

 

It's someone elses project. I'll try to get a hold of it. Does it need to be saved after slicing?

 

Thanks again!

[MariMakes 192]

Hey @Gmajor,

 

You can get the latest version of Cura here.
Cura 4.11 is from Sep 7, 2021 you are missing out on a year of development including improvements to PVA supports.

You can follow instructions here to get more support if you feel too little is generated. 
If you are a bit of a newbie I highly recommend downloading the Settings Guide Plugin if you want to get more familiar with the settings. 


For troubleshooting purposes we just need a project file with your settings and your printer. That can be saved before printing, to save a project file go to File -> Save project.

[Gmajor 1]

Thanks. I will get the project file and post it as soon as possible.

[Gmajor 1]

Hello again. Here is the project file you requested. 

I downloaded the plugin you mentioned and will continue to experiment.

UM3_Teapot v5.gcode

[MariMakes 192]

Hey @Gmajor,

 

Thanks for sharing the file.
It is not the project file I was looking for, but I can already see something that might have caused your issue. 

The model has very thin single line details. Your printer needs to deposit a very small bead of filament on a bed of support, this can go well if the part quickly gains more body, but is more likely to fail if the conditions are not perfect. 


I also see that Cura is struggling with merging two meshes. This makes me think that the model is not correctly exported.


My main question would be:

Did you make the model yourself and can it be edited?
Personally I would resize the printjob all together and print it at 200 or 300%.
If the size is important I would try to increase the wall thickness, and drop the handle a little down so the model can be printed upside down.

Are you planning for the model to hold any liquid? Because that will also require a number of setting changes and is never guarenteed. 

 

[wdwt40 1]

The 4 easiest fixes Ive found to fix support are;

- Support pattern style (grid or triangles usually form and hold best for me)

- Support walls also help keep the support column steady

- Support flow rate(I have increased the flow to 110%, it helps with some rolls of PVA when they are almost gone)

- Speed is also important to adhesion (slower is better)

 

Hope that helps

 

[Gmajor 1]

Thank you for your help. The model is not of my making, but that of a student of mine. I'll pass on your comments when the holidays are over.