Weird top layer and above supports...
I've been having an issue with my top layers and now above supports. It's an odd surface. Can anyone identify?
RE: Weird top layer and above supports...
RE: Weird top layer and above supports...
Is this under extrusion? Or over?
RE: Weird top layer and above supports...
Supports don't make for perfect surfaces, unless you use soluble supports in full contact (and even then it depends on the definition of perfect).
What you see is more or less expected. The layers touching the support cannot be printed 'squished' because they'd fuse to the support, so the printer has to lay them carefully and without pressure on the support. (This is tunable by the "Z separation distance" parameter.)
Which also means those layers will be made of round extruded filament that doesn't stick together well, rather than the normal fused mostly rectangular extrusion. This results in what you see.
The best option is to split the model into parts to avoid the need of supports and glue them together.
RE: Weird top layer and above supports...
But its doing the same texture on the top of the model? Are you saying there is no way to print a smooth rounded surface?
RE: Weird top layer and above supports...
But its doing the same texture on the top of the model? Are you saying there is no way to print a smooth rounded surface?
That is the "staircase" effect, an artifact of FDM layer heights. It improves significantly if you decrease the layer height for that particular region of the print.
RE: Weird top layer and above supports...
Yes, you can't have an entirely smooth rounded surface on the top and bottom of parts.
The best you can do is to use the lowest possible layer height (0.05mm) on the top of the part. That'll make it smoother, but not quite smooth.
See for example this Rigid.Ink Tutorial. They explain that a round bottom will not work and that it's best replaced by a 45° chamfer. That's also why most Prusa printer parts use 45° chamfers and not rounded edges.
There is a trick that'll get you closer (but not quite there) even on the bottom: Using 0.05mm Layer Height and changing the Outer Perimeter Width to a large value, like 0.8mm. You also need to increase printing temperature and have maximum cooling available, together with very low speed. Then you can print bottom curves up to 80°. But that's still not 90° and there will always be some ugly bits at the bottom of the bottom round surface.
RE: Weird top layer and above supports...
Thank you guys so much for the information. You have blown my mind a little. I'm going to work through the Rigid.Ink tutorial.
Thanks again!