Is Scaling causing thin-wall problems with my MK3S printer?  

Please save your project as a .3mf file

Files > Save Project as

Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.

Also a picture of the outside of the part, the same area looking inward, might help us.

Cheeriio,

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Thanks for responding!  Attached is an external view of the plastic hoop that has errors; it's four inches tall, by 8 inches in diameter.

Also attached is the 3mf code in a zip bile.   Hope it posts ok. Thanks for any input.

JonSleeveZIP

Did you save that .3mf from Prusa Slicer?  None of your settings were in the file.  Reload and slice then save again and we'll be able to see your parameters for diagnosis.

The model you provided is at, I presume, full size, the original that you scaled down.  If the design size matters I checked, it's possible to fit it on the build sheet by slicing it in two with the intention of joining the halves after printing.

Cheerio,

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Save the 3mf from Prusaslicer exactly as it was when you printed the model. That is, scaled down to whatever size you want it. As diem explained, saving it as a 3mf from say Fusion doesn't help us, it won't have your slicer settings. Scaling down is usually a game of luck. The walls may become too thin to print properly, or you may end up with weird gap infill that can cause artifact. Sometimes there's ways around it by using height modifiers with modified extrusion width etc but usually you're better off designing it as the right size in your CAD software. One simple thing you can try is to tick the option "Detect thin walls". It may or may not help, and it can create artifacts elsewhere but it may just work for something simple like this. 

RE: Is Scaling causing thin-wall problems with my MK3S printer?

@maskedmarvyl

I sized the provided model to the specifications you provided in your first post 8"D X 4" H. I can confirm that Scaling is not causing your trouble. Upon looking at the photo's you provided I am seeing under extrusion. I can't diagnosis the reason for it with the information I have. From here I would research causes of Under extrusion, and see what applies to your situation.

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Sorry, I didn't realize you wanted me to send the file from Prusa Slicer.  Attached is the 3mf file from Prusa Slicer I scaled down to 90%.  I hope this is what you are referring to.  Thanks, Jon 

SleeveShortenedBothSidesMESH v2PRUSA

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Thanks, I appreciate the input!  My friends in the Fab Lab suspect under extrusion as well, and also that the nozzle tip may be over or underheating.  They might try tweaking the flow rate, to see if that helps as well.  

My friends in the Fab Lab suspect under extrusion as well, and also that the nozzle tip may be over or underheating. They might try tweaking the flow rate,

DON'T change anything, they're almost certain to be wrong.

Reslice and post the .3mf, we'll take a look at what's actually happening.

Cheerio,

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Diem,  I posted the scaled 3mf file from the Prusa Slicer program in the discussion thread above, but in case it isn't visible, here it is again.  

Thanks,  Jon

SleeveShortenedBothSidesMESH v2PRUSA

RE: Is Scaling causing thin-wall problems with my MK3S printer?

I was skeptical, like diem, but I for one don't see anything obviously wrong with the settings, certainly nothing that should cause holes in the walls. Walls seem thick enough. But then again, I can't really see anything in the pictures, so I'm just going with "holes" from your description.

As far as the model is concerned, I don't see any point printing it at 0.2 mm layer height. 0.3 will cut many hours and will be just fine. Also, I don't quite understand the purpose of the mouse ears, unless for some reason they're integral to the model but I can't spot them in the photos so I assume they get removed after the print. The way they're attached actually makes the model hover in the air, so the 2nd layer is all overhang/bridge. If you need them (and I don't see why—on a clean sheet with good live Z this should print just fine), they should be flush with the first layer of the model. And last, why not flip the model around 180 degrees, again assuming the mouse ears are not integral? No supports needed that way.

RE: Is Scaling causing thin-wall problems with my MK3S printer?

it looks like an underextrusion problem. did you try printing at the original 100% size to see if the problem manifests again? 

you could try to slice the model in a different slicer to see there's any difference if for some reason it always prints fine at 100% but gives problem at 90%, particularly Cura with its experimental Arc Welder mode, which generates different gcode for printing arcs

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Like Fuchsr said, flip it around, remove the mouse ears. No supports needed. This will print fine, 0.3mm layer height sounds like a reasonable thing to do.

As mentioned by Diem: Do not mess with the extrusion settings! They are not your problem (you know that, because they worked before - see original post). On your picture there are signs of unterextrusion but this is most likely nothing you can fix with your slicer settings (because if your settings were off, you would expect consistent under extrusion, not in some spots and not in others), it looks more like a hardware issue. Possible causes:

1) partially clogged nozzle -> clean it ( https://help.prusa3d.com/article/clogged-nozzle-hotend-mk3s-mk2-5s_2008 )

2) filament feeding issue -> check the filaments is fed to the extruder with no mechanical problems (drag in PTFE tubes, resistance of spool holder, entanglement)

3) worn or damaged nozzle (the strangest  things can happen if your nozzle is damaged or worn out) -> check/replace nozzle

4) wet or crappy filament -> dry/get better filament

RE: Is Scaling causing thin-wall problems with my MK3S printer?

I still think under extrusion. If it was me, I'd start with a few cold pulls. Now knowing it's prusament PLA I'd turn the temp up 220C and decrease the infill to 15%, and try printing again.

It could be caused by a partially clogged nozzle from the high infill, that's why I suggest the cold pulls.

Those discs at the base were not in your original file ... ?  As set, below the first layer, they will cause adhesion and quality issues.

I agree with @fuchsr, inverting the part will remove the need for support and simplify the print.  As this is quite a large part I would add more perimeters for strength and this would improve the walls as a side effect but perhaps it's ok to be flimsy.

I too suspect you have a partial clog, an over-temperature flush and a cold pull would be my route:

https://help.prusa3d.com/article/cold-pull-mk3s-mk2-5s_2075

If you would prefer to print this at original size - too big for the print bed - get back to us and we'll go through cutting the part for joining post printing.

Cheerio,

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Thanks for your response.  I will try printing in 0.3 rather than 0.2mm height.  The "mouse ears" are little pads I attached to the bottom of the round sleeve, because otherwise the part kept detaching from the bed as it was printing.  I do remove them afterwards.  I didn't know they weren't properly attached to the base, I'll try to fix that.  The problem with the part is that when you hold it up to the light, you can actually see the light through the wall in some areas.  It did it again today with a new part, despite inspecting it in Prusa Slicer.  The part is usable, it's just a mystery why it keeps happening.

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Robin,  Thanks for your response!  I am informed these are new Prusa machines purchased for my school, and the filament is from Prusa, and is new as well.  I will try the suggestions of doing a cold pull to see if that helps in case there is a partial clog.  Thanks.  

RE: Is Scaling causing thin-wall problems with my MK3S printer?

Even very new machines can have partially clogged nozzles or damaged nozzles, all it takes is one change from high temperature filament to low temperature filament without enough purging to clog the nozzle or one attempt to remove some cold filament from the nozzle with a pair of cutting pliers to damage the nozzle…