Supports question
Hopefully this is the correct location to post. I have question about how different people are handling supports, with a specific problem.
I have the need to make a cylinder with a flange. The part is fairly simple, a 25 mm cylinder with a 5 mm hole in the middle. The issue is that each end of the cylinder has a 1mm high, 2mm wide flange (for a bolt). As a result the end of the 25mm wide cylinder needs to have support, which causes problems for me.
If I print it with a z contact of 0 then I get a great print. The edge of the cylinder bottom is square and straight...but it is impossible to remove the support! Not impossible, but difficult and time consuming. Changing the value to .15 (suggested Prusa default) or .2 (detachable) results in the bottom outer edge of the cylinder to be curved since the first layers of the cylinder are not contacting the support. I use Sli3cr, and the top of the support ends at .40 (layer height) where as the first layer of the cylinder ends up at 1.0 (using .2 detachable). That .6 gap (which I can't seem to get smaller than .6) ends up with no contact.
It appears to me that the z distance is .4 (nozzle size) + z height as long as the z height is > 0. If it is 0 then the distance is 0. So I can't pick (say) .3 or .2 distance, which would probably result in a better situation for the support, harder to remove but not impossible...yet much more support for that first layer of the larger cylinder to contact.
Any thoughts on how to increase this without resorting to 0 contact distance and having to grind away the support?
(btw, tried to include my stl but no luck)
Re: Supports question
I have played around extensively with supports.
I've found that the bigger the layer height the better.
Using PE Slic3r the lowest contact distance you can go before it starts to do strange things is 0.07mm. If you try any settings from 0.01 to 0.06mm the support structure will not generate properly. I find 0.07mm works well with 0.2mm and 0.35mm layer heights.
Re: Supports question
You are right, that's the way the actual support generation in Slic3r is working. There is some logic behind it, but it doesn't work well nevertheless.
But there is a work around, it's a little bit advanced, but if you want read here: https://github.com/prusa3d/Slic3r/issues/102
Re: Supports question
The problem you discuss of the slicer not recognising the contact distance has been partly fixed with the newer versions. It is only values from 0.01 to 0.06 that it behaves strangely with the new versions.
Give 0.07mm a try. I also alter the interface layer angle so it is not running in the same direction as the first layer that gets put onto it.