Quote Originally Posted by curious aardvark View Post
..It does this reinforced edge infill thing that prevents the ovehang from curling and the finished print was smoother than the sanded ones.
True, this is something that S3D does - I'm not completely sure, but I believe that it's doing that because it recognizes that part as 'bottom' surface (as it should) and thus it gives it a solid infill depending on your 'bottom layers' setting.

Now this can be good, like your example, where it reinforces the edge.

But it can be a bad thing too and result in even more curling.. which is my experience - I'll try to explain this (but I should actually make an image to really explain it)
- imagine a pointy overhang
- it prints the shells, all good (these pointy parts normally curl upwards a bit, but with the amount of cooling I have this is not an issue)
- then it prints the 'bottom' layers (reinforcing) - in result it moves the head towards that pointy part which puts heat into that pointy area again! Thus curling up the corner more than it should!

Hope that makes sense. Still, this is only my theory based on my examinations. But I'm 99% certain that the additional heat being transfered in the workpiece does more bad than that additional blob of plastic (reinforcement) does good.

I think the right way to print this piece is by using 3 processes:
1 process for the base, normal settings
1 process for the slope-part, no infill, no bottom layers, no top layers - also lower down the speed (travel speed too!) a bit just for the double helix
1 process for the top, normal settings again

Like many other things, I will do exactly this as soon as I have time~! (Man I wish I could just 3D print all day long!)
Currently busy with getting rid of the vertical ridges/vibrations.. making some good progess, but still need to do a few tests. Also will give you guys an update of the advantages/disadvantages of upgrading my firmware as soon as I've done all the tests