slic3r v1.2.9 not generating supports properly

Hi folks,
finally got the metal filament to work so I've done a biggish print that has been sitting around.
However after inspecting the print I discovered the underside was droopy.
Repeating the print I watch the support being generated and saw it was close to 0.5-1mm from the
surfaces needing support. My Contact-Z distance is set to the default 0.2mm.

Any suggestions? Support that isn't actually touching a surface seems kind of pointless.


Many thanks,
Andrew

Hi Andrew,
Yes you can change the contact distance, although it is not obvious from the interface.

You can just type the contact distance you want into the Contact Z distance dropdown.

I use:
Contact Z distance: .06mm
Pattern spacing: 7 mm
Interface layers: 2
Interface pattern spacing: 2mm

Note that my extrusion width is .8mm and larger (custom hot end).

You will need to do some tests to see what kind of results you get, lowering the spacing until the bridging extrusion sticks just enough to it that the extrusion is under control.

In my opinion the bridging extrusion used over the support should stick enough to the support that it does not move out of place when doing curved support, but not so much that it is very hard to remove. I don't mind a small bit of difficulty removing it if the results are better.

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My printer: Raptosaur - Large Format Delta - [www.paulwanamaker.wordpress.com]
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Thanks Paul,

I've been frustrated with this as well.

Note that when you choose 0 as the contact distance, it's actually zero, but as soon as you make it non-zero it adds quite a bit to the distance. There's no way that I could find to actually get 0.1mm distance, for example. From memory it adds 0.2mm to the contact distance whenever you make it non-zero.

I eventually settled on zero as a contact distance, but make the contact surface very sparse. This means you have to clean off a layer of zigzags on the final piece but at least it doesn't droop.