Jump to content
macio

Under extrusion when printing with PLA and PVA

Recommended Posts

Posted · Under extrusion when printing with PLA and PVA

Hi,

I have problems printing PLA together with PVA. Espesially I failed two times printing the following model:

https://www.thingiverse.com/thing:1979068

At a sertan hight it comes to under extrusion of PLA.

The first print already freed from PVA with water was printed with default settings in Cura 3.0.4 for a layer height of 0.2mm. For the second print I raised the temperature for PLA from 205°C to 220°C.

I still think it is a temperature problem because especially on the second print you can see unattached PLA at one side of the print. So I think that there is still a high pressure in the nozzle when it heads up again so the material comes out ... but too late. That material should have been on the last part of the previous layer.

I think it may have to do with the switching between both hot ends when the active one begins to cool down and the inactive one heads up.

Do I need to adjust the standby or final printing temperature for PLA? Does the printer cool down the nozzle for PLA too early?l

I also appended another picture with two ultimaker bots. The right one was printed with only PLA. The left one was printed with PLA and PVA with the robot lieing on its back. As you can see the walls of the left one have a bad quality. Maybe the reason is the same the more difficult print fails.

20171123_080127.thumb.jpg.f631b9cdf9b3021842e0c9e84bf51a33.jpg

20171123_080055.thumb.jpg.294f89a33c4d03e40822fc36f4833819.jpg

20171123_080102.thumb.jpg.3848da7c75b002341bcc734d06584803.jpg

20171123_080116.thumb.jpg.29cfc70350f10c30613fe0c35c0ecd03.jpg

20171123_080158.thumb.jpg.1d13a063a177a9a6676bf8564e2c8f56.jpg

20171123_080800.thumb.jpg.aee560b0e9ed1a790ac97d4d16a54082.jpg

Share this post


Link to post
Share on other sites
Posted · Under extrusion when printing with PLA and PVA

Have you done a series of cold and hot pulls to make sure the nozzle is not clogged. If the PVA gets too moist, and it does not take much for that to happen, it will clog the nozzle and prevent proper flow.

Share this post


Link to post
Share on other sites
Posted · Under extrusion when printing with PLA and PVA

What you mean by cold and hot pulls?

The problem occurs during the print at a certain height.

Share this post


Link to post
Share on other sites
Posted · Under extrusion when printing with PLA and PVA

What you mean by cold and hot pulls?

The problem occurs during the print at a certain height.

That could be because the humidity in the filament causes it to clog a bit during its heating cycles.

However, check this out to introduce yourself to the hot and cold pulls to clean out the PVA.

When dealing with PVA, moisture in the filament is just the first go to response in almost every situation. Cleaning out the nozzle will rule this out.

Share this post


Link to post
Share on other sites
Posted · Under extrusion when printing with PLA and PVA

The under extrusions happens to PLA, the PVA layers are all fine.

Doing a single extruder print with PLA directly after the fail print there is no problem with a clogged PLA nozzle.

Share this post


Link to post
Share on other sites
Posted · Under extrusion when printing with PLA and PVA

Hmmmm, I missed that......I was looking at the wrong thing.....my mistake.

So, to make sure the wee brain is working properly, the PLA is fine on its own and under-extrudes when using PVA?

Share this post


Link to post
Share on other sites
Posted · Under extrusion when printing with PLA and PVA

So, to make sure the wee brain is working properly, the PLA is fine on its own and under-extrudes when using PVA?

Exactly!

Share this post


Link to post
Share on other sites
Posted · Under extrusion when printing with PLA and PVA

That is weird. I do not believe I have ever heard of that. I know I have never seen it on my printer.

Wanna try something out of the ordinary? Try switching the cores to the opposite slots and feed the materials through again to match the cores. Then, reslice so that the printer can identify which core is where properly, and see if it does it again.

I know it sounds weird, but maybe give it a try.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Our picks

    • Ultimaker Cura 4.0 | Stable available!
      Ultimaker Cura 4.0 is mainly focused on the improved user interface and cloud integration.
      As always, we want to collect your user feedback for this release. If there are any improvements you can think of, feel free to mention it here and help us to shape the next release.
      • 98 replies
×
×
  • Create New...

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!