Crowning FAILS on Thin Wall Parts

[Ken Huebner]

Kisslicer Pro works great -- except for thin walls.

 

 

I continue to see large 2-3mm gaps and blobs of plastic whenever my BFB 3000+ printer attempts a thin wall of .90 mm thickness or less.  It always occurs when Kisslicer generates a single crowning path. 

 

 

This means that the crowning flow rate is not quite correct for my printer or filament when using Kisslicer.

 

 

I wish there was a Crowning Extrusion Width parameter or a Crowning Flow Tweak parameter in Kisslicer.

 

 

This way I could boost material flow rate for crowning to get more reliable thin wall construction.  And even if the thin wall is slightly thicker than designed, at least I may not get a useless part with holes and blobs.  I would have an acceptable prototype part.

 

Attached is my thin wall test part STL and BFB files.  I print it upside down with large flat region on bed.

 

If anyone has ideas to improve thin wall creation -- please let me know.

 

Ken

[Ken Huebner]

Here's a photo of my TESTCONE part comprised of 3 cones, each having 0.70mm thick walls.   In two cones, there are gaps and blobs where the crowning paths exists for thin walls of two cones. 

 

The fully formed "good" cone with thin walls does not have any crowning paths.

 

 

Ken

 

 

 

 

 

[funBart]

Hi, I think to have understand that Cubeltmod / cubex has it's own settings to tweak and maybe causing this, but in general:

How do the paths's look like after slicing on the "path" view? Gaps as well? 
When slicing with 0.05mm oversample and 1mm crowning I seem to get descent results with your stl.

Other Blob and Missing extrusions causes:

• for large blobs or missing segments: Destring settings on the Material tab not tweaked well
• for small blobs: Seam hiding not tweaked well

A Cubeltmod user can help you probably better..

Bart

[Colen Casey]

i've done several prints similair to yours with no problems
if you truely are printing it like it loads into kisslicer (base on top ) rotate it 180degrees and put the base on the bottom this might do wonders for you

[Timmay]

I'm not sure if it's possible to calibrate a BFB printer - I'm not familiar with it at all - but if you can I'd highly suggest going through a number of calibration cycles to get your printer dialed in.  I just printed the STL you linked and it appears to have printed out just fine:

That said, you're also asking KISSlicer to slice (and your printer to print) a surface that is 0.107mm wide with a nozzle (I'm assuming) that's at least 0.35mm wide:

Short of under-extruding with extremely unpredictable results, there's no way a printer with a 350um orifice can print something that's 107um wide.  Also, the hole in the base layer is under 0.2mm wide at points:

The smallest width of plastic a printer with a 0.35mm orifice can realistically put down is 0.35mm*.  In order to make that part connect, the slicer would have to guess whether you wanted the intended hole a bit smaller to account for the width of the path, or make the part's outside a bit bigger to accommodate the path. The slicer can't possibly know what's more important to you: making the hole the exact size it is in the STL, or making the outside wider than the STL actually has it.  The solution is to either dial in the settings of the slicer as close as you can and accept the results, or redesign the part keeping in mind the physical dynamics of slicing and printing.

*It's actually larger if you want it to stick to the preceding layer, but for argument's sake this will suffice.