Quick comparison:

  • Supported FDM (Stratasys) - can print overhangs to any angle, although keeping it under 45 degrees saves time because it doesn't bother with support material. Can print an object inside another (hollow) object, provided that the outside object has a tiny hole for the support material to dissolve through.
  • Unsupported FDM (every cheap printer) - can print overhangs to around 45 degrees nicely, getting much further tends to require lots of tweaking and produces lower quality. Can print bigger overhangs with support structures that hold the weight of the new part.
  • SLS (Peachy) - can print overhangs approaching 90 degres nicely. Might be able to do 90 degrees too. Can print bigger overhangs with support structures, and support structures can be thin because they are only for positioning. The weight of the overhang is supported by the water bath.



On the other hand, the Stratasys printer at my university was about $15K, filament for it costs a fortune and it can only print one model material (ABS) in one colour (white).

Here's an object that the Stratasys printer can (ideally) do but the Peachy can't do nicely.

sixballs.jpg

It's a buckyball (red) inside a buckyball (yellow) inside a buckyball (green) inside a buckyball (cyan) inside a buckyball (purple) inside a buckyball (blue). Colours are just to make it easier to see; it all prints in one colour. I did a three-layer one on the Stratasys printer and that worked beautifully, although it took days to run and a vast amount of support material. This one can't actually be printed because the STL file is massive (over 50MB even with Coarse export settings) and it causes the Catalyst EX print software to crash during slicing. Hopefully the Peachy software can handle it...

You could do it on a Peachy, but it'd have support struts going all over the place and getting them out without damaging the (thin) inner shells would be very difficult. Not as difficult as getting the support structure out if it was done with an unsupported FDM printer, however.