Weird Z seam phenomenon

[RCAddiction 0]

Trying to print the PlanePrint thinwall wing test part in anticipation of building their Notos. https://www.planeprint.com/notos

Printer - Prusa Mk3S, diamondback 0.4mm nozzle, 0.25mm layer height, with Polymaker LW-PLA (pre-foamed).

 

I have no problem printing this material normally, but have run into an odd issue.  This part (and most of the plane) is designed as a surface, so it can only be sliced using experimental Surface mode in 4.12.1.  I have mostly move to PrusaSlicer, but the single wall surface design cannot be sliced in PS. 

 

I was struggling to get the underside of the angled flat wall solid.  It was underextruding, I believe, leaving tons of holes in the small triangular flat surface. Despite the appearance of the part, prior to cleaning it up, I am having zero issues with stringing. Internal parts are clean.

 

Per Rene at PlanePrint, I've increased the retraction prime amount to as high as 1.5 to get the angled wall to fill completely.   At the Z seam I can watch the print head actually print this weird wall perpendicular to the Z seam, despite it not being visible in the slicing preview movements. As I increased retraction prime amount  from 0 to 0.3 to 0.5 to 1.0 to 1.5 I've seen this weird wall extend further and further out from the actual wing part.  The weird wall is actually a full wall thickness thick.  Temp makes no difference. I've run it from 200C (where it normally likes to print this material) all the way up to 235C.

 

In the cleaned-up part, you can see the underside of the triangular wall. The slot in the back vertical wall is for a hinge to be inesrted

 

I have not seen similar defects in image searches I've done.  Any idea what causes it and what to do about it?

[GregValiant 1,252]

Use the "File | Save Project" command and post the 3mf project file and someone will take a look.

Off the top of my head (which I don't like to do) it appears you might have "Wipe nozzle between layers" enabled (???).

[RCAddiction 0]

Cura 4.12.1 PI3MK3M_WINGTEST_P3 LW_Planeprint.3mf

 

You were correct, Greg. "Wipe nozzle between layers" was enabled. I've just disabled it. The sliced project file is attached, with that correction made. I am starting a new print right now to see if it fixes it.

 

I'll know when I come home for dinner whether that fixed it!

 

 

[RCAddiction 0]

It's perfect now!!!  Many thanks!

[GregValiant 1,252]

Even a blind squirrel finds a nut every now and then.

 

I used to fly RC planes (and U-control)  Of course they were balsa then with big ole 2 strokes Enyas, Foxes, etal.  I loved the smell of nitro-methane in the morning.  I didn't care so much for that fact that often, both planes would fit in one 5 gallon bucket on the way home.

 

 

[RCAddiction 0]

I'm very appreciative that you found this particular nut!  This must by why you are an Expert!

 

I don't fly electric stuff very often, but am venturing into my 2nd 3DP plane. I've been flying RC for >25 years, and at this point it's mostly giant scale gas powered aerobatic planes. 3DP planes is another dimension in the hobby to explore.  Naturally, I had to pick one of the more challenging models to print.  This plane (Notos) requires printing in Cura 4.12.1 for certain parts that need surface mode like this one, and Cura 5.0 or greater for other parts, because the earlier versions make it come out a bit heavier.  But the newer versions add other issue on the ones that require 4.12.1 Love it.

 

Well, I'm now off to order some carbon fiber rods from WindcatcherRC for the build!

 

warmth from sunny Sarasota

 

 

Edited January 13 by RCAddiction

[GregValiant 1,252]

Sunny Sarasota?

 

It's been raining here in Venice for the past 3 weeks but the sun is trying to break through now.  It looks like it will be cool and drizzly for at least the next few days.  I guess it could be "El Nino".

[RCAddiction 0]

LOL.  Had no idea you were nearby.

 

I fly at Venice RC!  The field is at the back of the Sarasota County landfill, at the end of Knight's Trail Rd, off Laurel Rd near the highway.

 

I don't know about Venice, but north Sarasota was sunny early this morning when I walked the dog.  But it has gotten more gray and cold as the day moved on.