Gaps in PVA support.

[TwoDrunkOwls 0]

Hello,

 

I am the new owner of an Ultimaker 3.   (I love saying that, even though I've had little luck with the blasted thing so far)  Anyhow, I'm trying to print my favorite practice model of an Egyptian cat.  Unfortunately the support material stops extruding at regular intervals, causing the print to fail as seen below.  The grey one in the back was one I had left over from my Prusa I3 MK2/S.  The silver one in front is an earlier UM3 attempt that failed the same way, the support gets knocked off at the week point and I have to abort.

 

 

This print also failed twice for the same reason.  You can see the gaps in the support.

 

 

At first I thought it was moisture in the PVA.  I had snapping and bubbles in the PVA that came with the printer but the Egyptian Cat PVA was brand new and printed clear and silently.  I originally posted this in another forum and Community member Smithy suggested this:

 

In my opinion you could have to different problems:

1.) PVA stops extruding (moisture?, clogged nozzle in the BB core - do you use the BB core for PVA?)

2.) support structure not stable enough - there are some Cura options, but I am not the support structure expert.

 

Community member Shadowman asked me what version of Cura I was using.  3.5.1 was my answer.  He then suggested this:

 

I asked because I have read where others were having support issues with Ultimaker Cura 3.5 and 3.5.1 and reverted back to using 3.4.1.

 

I use 3.4.1 and until today when I am trying the Ultimaker Breakaway material; all of my prints have required PVA support.

 

The only issue  that I have had with PVA has been the Prime Tower.

 

Unless someone has a better or more viable suggestion I would encourage you to try Ultimaker Cura 3.4.1.

 

I am using the BB core.  My filament was wet but still failed after being dried out, as did the new package of PVA.  I had a 2 day print of the 'gyro' going at the time and that was going OK until the end (see my other post in this forum).  I saw no sign of cooked PVA and the extrusion had no bubbles that I could see.  In my experience a clogged nozzle stays clogged.  Is that correct?

 

As for the Cura version I will try version 3.4.1 tomorrow.  I have the PVA drying on the print bed.  I hope to have time to draw up a simple test model for this problem.

 

Have any of you seen this before?  I found one post that had a similar issue with the AA .4 mm print core but they never received any replies.  I can't help but think that the apparent regularity of the intervals of poor extrusion is a clue.  What do you think?

 

Regards,

TwoDrunkOwls

 

Edited November 4, 2018 by TwoDrunkOwls
Added a link

[Smithy 1,141]

Please do not crosspost the same issue on different places, one is enough - and you will not get more, better or faster help if posting duplicates, it is more confusing and often you get the opposite that nobody replies.

 

Thanks!