Trouble with Slic3r calibration

[Sebastian Finke]

Have a look at the image. On the left is a solid 20x20x10 calibration cube; on the right is a single shell calibration piece as per the Slic3r extruder calibration method. Both were sliced by Slic3r.



All relevant setting were filled in as required. All extrusion diameters were set to 0.4mm. I then printed the single shell item. Shell thickness cam out at exactly 0.4mm. Great. Looks very smooth and clean. Left extrusion multiplier on 1 as the shells were on size. Next I printed the solid cube as a test and well, you can see the result above.


I followed the calibration instructions very closely. I tried 3 brands of filament. All filaments were measured in multiple places (10 to 15 measurements over a two metre length per spool). The bed is levelled. My thinking is that if the extrusion multiplier is spot-on for a single shell print then it should work for any print. The height of both prints is right (10mm). But the sides are telling a different story i.e. very rough in the solid cube, smooth in the single shell.


Interestingly they are both over-size in X and Y. I always scale up my models by 0.7% to compensate for shrinkage. In Makerware the cube then comes out at 20x20, however in Slic3r the same model comes out at 20.15x20.15. This shouldn't happen either.


Some possibly helpful info:

• FFCX
• Makerware 2.4/Slicer 1.2.9 (both x64)
• Material: ABS (Esun, Flashforge, local brand)
• Feed: 50mm/s
• Extruder temp: 225
• Layer height: 0.1mm
  
  

I feel am missing some simple step but cannot see it. Thanks.

[curious aardvark]

judging by the lip round the squares you're way over calibrated, head is much too close to the bed. Or is that just abs glue ?
Also seems odd that the same file should have round corners on one and sharp ones on the other.

Ah esun - yeah hands down the worst pla filament I've ever used. Got two rolls with the klic-n-print. Just awful stuff.
No idea what they're abs is like, but I'll never buy anything of theirs, that's for sure.

[Sebastian Finke]

judging by the lip round the squares you're way over calibrated, head is much too close to the bed. Or is that just abs glue ? Also seems odd that the same file should have round corners on one and sharp ones on the other.

The 'lip' is just the brim I never bothered to remove along with some slurry. And the corners are correct. The trouble is a) the quality of the surface of the left print and b) the fact that both are oversize.

Ah esun - yeah hands down the worst pla filament I've ever used. Got two rolls with the klic-n-print. Just awful stuff. No idea what they're abs is like, but I'll never buy anything of theirs, that's for sure.

I like their ABS. Quality stuff. That said we also don't have the range available in Europe and US.

[3dkarma]

The left is over-extrusion without doubt. Are you printing inner perimeters first or outer? Each perimeter will overlap the others so that you get good adhesion horizontally, so you might expect some pushing out if you're over-extruding a little. I'd try dropping the extrusion multiplier by 0.2mm incrementally on successive prints until you get a good wall.

[Davo]

We use 1% oversizing to account for ABS shrinkage, and it comes out very well. Are you folks using 7%?

[Sebastian Finke]

The left is over-extrusion without doubt. Are you printing inner perimeters first or outer? Each perimeter will overlap the others so that you get good adhesion horizontally, so you might expect some pushing out if you're over-extruding a little.

In the solid cube ( the one on the left) there is only 1 perimeter.

I'd try dropping the extrusion multiplier by 0.2mm incrementally on successive prints until you get a good wall.

What do you mean by dropping it by 0.2mm? The extrusion multiplier is either a factor or a percentage, not a distance. Can you please clarify?

Thanks.

[Sebastian Finke]

We use 1% oversizing to account for ABS shrinkage, and it comes out very well. Are you folks using 7%?

I'm using 0.7% as the shrinkage factor.

[Davo]

I'm using 0.7% as the shrinkage factor.

Ah, thanks. I misread that. We actually calculated 1.15%, I think; but normally we just oversize the .stl by 1% in all axes. Perhaps because we usually print ABS at 235C.

[Sebastian Finke]

Yeah the shrinkage is lees of an issue right now. My main thing is that the sizes are way off and the print looks awful.

Makerware, on the other hand, gives perfect prints every time...

[Sebastian Finke]

Played around with this again over the weekend and the results are the same i.e. single shell (hollow) prints have perfect vertical walls. Solid infill prints look awful. Obviously this is a calibration issue but I haven't the foggiest idea how to rectify it...

I would love Slic3r to work properly as it has some many more - very useful - options than Makerware.