Seam placement

[Pridanc 2]

Folks, 

Today as I finished up one of my typical prints, I took greater notice of some artifacts seen only on one corner of this box. In hindsight I'll admit that this rhythmic set of artifacts has always been there with other "like" prints, but as I had just added some extra flow to this part to help with what appeared to be light under extrusion on the long walls of the part, I'm convinced the artifacts are more pronounced because of the added flow.

 

At first I couldn't for the life of me figure out what the heck was causing this but after looking at the sliced view, I could see the clumps of white seam "zits"  on this left front corner. But ONLY that corner.  

 

I've included some pictures as well as the .3mf file for y'all to ponder.  One picture is a close up of the artifacts.  The other is a picture of the same corner from the slicer where the white dot clumps are obvious.

 

Whilst looking I'd like to know the following, or best guess, and how you feel I should approach ditching the flaw.  Please realize, even flawed the part is usable so I'm not terribly worried but I am always trying to make things better. This is one of those times.

 

Help me understand why these seams (zits) show up

a) on this corner only

b) rhythmically.   IE, the clumping is not top to bottom on this corner as one might think. OK, as I would think!

 

Then your suggestion on how to:

1)  "hide" these clumps.  I'll imagine another choice of seam alignment could alleviate the clumps or should I even tell the slicer to build the walls in another manor?   I'm ignorant so just humor the ramblings of this old man.

2) no matter what, is it best to use some greater retraction so the zits are better controlled (not eliminated so much as not so big) or just reduce flow (120% now) or combo of both? Or a combo of more things?

3) enable coasting?  (can you tell I'm grasping at straws?)   

 

Old ender 3 v2 with some of the OE parts moved around to have a DD extruder.  Forget what you might see in the 3mf file, I'm using PP filament (no PP base settings in CURA that I've found so made my own starting with TPU settings.  Seems to work reasonably well. 

 

OK, that's it for now and many thanks for all the help!

CURA 5.6 Triumph Steve PP V1.3mf

[Slashee_the_Cow 272]

It looks like it's overextruding at the Z seams. There's a bunch of ideas in here so read the whole thing before you try anything - and remember, small scale testing is your friend. In this case you really only need to print up to the height where there's a problem, because this is the sort of thing which could potentially disappear if you shrunk the whole thing.

(Don't worry, I'm sure you read all of my wisdom and most of my ramblings before doing anything 🙂)

 

 

1 hour ago, Pridanc said:

Help me understand why these seams (zits) show up

a) on this corner only

Not sure I can give you a good answer on this one. My best guess is the route it takes to travel that corner might pick something up or is so short it can't retract properly.

1 hour ago, Pridanc said:

b) rhythmically.   IE, the clumping is not top to bottom on this corner as one might think. OK, as I would think!

This one I can definitely give you a good answer for: those white dots in the layer preview? That's where it starts a layer (or starts after having had to travel from somewhere else on the layer which there isn't a continuous route to from its previous position). Your settings have them sort of spread around the whole thing. I cover this topic (and it's definitely worth trying!) in a little bit.

 

If you want to try and address the overextrusion directly, you can try two opposite options:

• Walls > Outer Wall Wipe Distance will make the nozzle continue slightly past a Z seam without extruding. The idea is if there's a small gap where it started whatever material is left in the nozzle gets to wipe it closed.
• Experimental > Enable Coasting will make it stop extruding slightly before a seam in case there's too much pressure in the nozzle and there'd still be some left by the time you get to the seam.

1 hour ago, Pridanc said:

is it best to use some greater retraction

In this case, I'd say "probably not". Although I've never used PP or a direct drive extruder bolted on after the fact, your retraction settings almost look like they're for a Bowden extruder - on my E3V3SE (comes with direct drive extruder as stock) the highest retraction I ever need to set it to is 3mm (for TPU, because its elasticity makes it so stringy) and I run it at 45mm/s - increasing the speed might help if your extruder can handle it.

 

1 hour ago, Pridanc said:

just reduce flow (120% now)

Always a good idea to test that if you have overextrusion.

 

1 hour ago, Pridanc said:

"hide" these clumps.  I'll imagine another choice of seam alignment could alleviate the clumps or should I even tell the slicer to build the walls in another manor?   I'm ignorant so just humor the ramblings of this old man.

Maybe a good starting place -> Your settings have Z seams show up in all corners but only one corner is a problem? Set Walls > Z Seam Position to User Specified and then Walls > Z Seam Position to a corner which isn't the one you're having problems with. The problem might have something to do with travels so it might just move the problem to this corner but since all your seams will be on the same corner it'd be easier to fix (as in, by hand) when it's finished if it bothers you.

 

1 hour ago, Pridanc said:

Forget what you might see in the 3mf file, I'm using PP filament (no PP base settings in CURA that I've found so made my own starting with TPU settings.

You can change relevant things like extrusion distance/speed, printing temperature, speed, etc., independently of the material you have selected. You can also create your own custom material which has all of these already set! Go to Preferences > Configure Cura... > Materials (in the left sidebar) > Create New (button in the top right). If you want to be able to change more settings for your material than it allows be default, then download the Material Settings plugin by the I-don't-know-how-he-does-it @ahoeben by clicking "Marketplace" at the top right and searching for material settings.

[Pridanc 2]

Thanks Slash.  Not sure HOW the heck retraction got to that as I typically run .8 but then what the heck. I'll change that and as you say, print a portion of the model to see what I can find. Many thanks.

[Pridanc 2]

Slash, never having created my own set of parameters for any filament, I've set out to create one for the PP filament I went into materials to create my own PP filament. 

 

Problem is, once I choose it as the filament of my choice, CURA stops and says "Not supported" and at the same time wont' let me do much of anything. I really think it is because I don't know how to answer what CURA is asking.

This is 5.6

 

Clearly I can still work with my old settings and can modify those but I'd love to get unstuck here. 

Stay well, PDC

[Slashee_the_Cow 272]

TBH I still don't know how to get materials like that set up - try setting it to be a type of PLA or something.

[Pridanc 2]

Slash, I do have my PP setup under a PP file I took and modified. I "saved" it as a PP file but now that I've created a PP Material file, what the heck is next?   I guess in the end it does not matter but it is a bit silly that one can't create your own and move on.  

 

I think that somehow I need to assign a printer etc. to the choice, but whenever I do that in order, then choose my made up PP material file the system gets all silly and refuses!   :-)

 

Oh well, I'll close this for now as I've no doubt your answers will help me fix the Seam / blob issues.  So many thanks, stay well, PDC

[Pridanc 2]

Slash, 

Update.  First off, I'm about to do a test print with new settings however, with nothing else changed, I noticed that the blobs only happened where there was not one of the tiny "break away" attachments on the two triangle ears mid way down the length of the longest walls. "Rhythmic" solved :-)

 

Clearly the breakaway ear to body wall attachments won the "I will place the seam here" award by CURA at that point! I will still try to force other choices to kind of hide the seams, but I just wanted to mention it so that the next schlep who comes along can be forewarned by you, the brains of the operation.  If you'd seen that before forgive me.  I was excited.  

 

Stay well, PDC