alackofcolor wrote:Well here's a pictures of the the same part (printed in two pieces) that I found, printed with a different printer. The underside of theirs is smooth after the support was removed.
The pic you showed as an example is not perfectly smooth either....it only looks that way until you zoom in. (We generally analyze objects to see which printing direction is least objectionable from a "gravity" standpoint, and sometimes that means cutting the part into pieces and gluing them together after printing. On the other hand, if a face is hidden underneath a part, we might not bother with it. But the underlying problem, gravity, is not something that we have figured out how to circumvent yet with this kind of printer.)
The second print you posted is
a lot smoother than your first result, which means the guy had his settings dialed in correctly for that filament.
(If that level is acceptable for your needs....read on.)
I would experiment with the following, one at a time, until I liked the result:
1. Make sure the Outline Direction for that print runs from Inside to Outside.
. Printing in that direction for overhang areas gives the filament something to hold on to, otherwise you're trying to print over empty space. (Needless to say - use multiple outlines.)
2. If you're printing PLA:
a. Remove the fan guard on the bed fan. This increases the cooling power to the print. PLA both warps up and slumps while it is hot
, it stops when it cools completely.
b. Purchase a small desk fan and point it directly at the overhang areas that the bed fan does not reach.
c. Print at the lower-middle end of the print range - 220° is too hot for PLA with overhangs. (I print Hatchbox at 205°, with no fan guard, and don't need to use the desk fan very often.)
(i suspect that most of that slump problem in your print is from it printing too hot.)
a. Horizontal Offset from part - 0.2 mm.
b. Use 2 dense support layers - 60%.
c. Extra inflation distance of 1.5 mm
d. Increase the support density to about 30%
e. Support angles of 45° and -45°
It's going to be a lot more tedious to remove the support, but it will give you a smoother bottom finish. (That's the trade-off.)
4. Outline Underspeed - 80%
Try those settings as a starting point and see if it works any better. If not, adjust one setting at a time
and keep reprinting until you determine what works best for your shape.
(BIG Note: NOT
the same when printing any other kind of filament. This is just for PLA. Other filaments have their own quirks, and can be read about in the Filaments section of the forum.)