Overhang issue

Hi there Slic3r specialists!

Slic3r is continuously doing a great job in my Mendel 2 (from RepRapPro) setup. Although a simple printer, it performs beautifully. However, when it comes to overhangs, I have not really managed to figure out good settings. It usually ranges from bad to worse. This time, I have set as much as possible to default (zero) in the support settings. In the picture below, there is a mushroom shaped part to the right (as seen from below) with the removed support to the left. It looks like the perimeter does not quite stick to the support material and makes "shortcuts", distorting the shape of the part.



The following support settings were used, but I tried with quite a few variations with just about identical results:
contact z 0
pattern honeycomb
pattern spacing 2,5 mm
pattern angle 0 deg
interface layers 5
interface pattern spacing 2
do not support bridges checked

Suggestions?

Thanks,
/Chris

Edited 1 time(s). Last edit at 03/20/2016 10:25AM by cahlfors.

Quote
Chris's settings
contact z 0
pattern honeycomb
pattern spacing 2,5 mm
pattern angle 0 deg
interface layers 5
interface pattern spacing 2

I think the interface pattern spacing is too wide.

I sometimes use:
Contact Distance .07mm
Pattern: Rectilinear or Rectilinear Grid
Pattern Spacing: 4.5mm (the support material lines are this much apart)
Interface Layers: 2
Interface pattern spacing: .65 (a meander pattern is used that is this distance apart)

What this does is make an interface that is not very thick (2 layers of the tight meander pattern) and that has a fairly closed surface (.57 is my nozzle diameter). For me it is close enough that it sticks slightly to the print (so the lines stay put), but can be removed. I am printing ABS.

Note that these settings are as individual as Bridging, and I think those first round outside diameters are output with the bridge/flow settings (you could try varying the ratio). The gcode would tell.

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
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You can also set more perimeters and set to print internal perimeters first. This results in the inside perimeters having a solid base, and the external perimeter is held in position by the internal perimeter(s)

Dave

Thanks for reaching out to help!

@Dave: I was thinking along those lines too, so I left "print external perimeters first" unchecked from the beginning.

@Paul: With your parameters, it got significantly better. The support was still easy to remove. Thanks!

It appears that this is a difficult part to print. It is at its widest right on top of the support structure and the perimeters are still taking shortcuts (too small diameter circle). I made an additional test with contact z=0, to see if it would bond better to the support. It is still in the printer, but does not seem to make any significant difference.

Thanks,
/Chris