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bottom layer smoothness when printing with rafts

Posted: Sat Apr 30, 2016 5:21 pm
by gad31
Hello evryone,

I've been using S3D for a few months without requiring external help and I'm new to this forum :)
Recently I started to print with rafts.
When I'm printing with rafts, the bottom layer (of the part being printed, not the bottom layer corresponding to the raft itself) is not as smooth as it is when I'm printing without it. far from it actually...
With raft, it looks like if it was "under extruded" (but my top surface are perfect).
I have thought of increasing the first layer width but this setting applies to the very first layer, i.e. the one of the raft so it would be of no use.
I have tried decreasing the "separation distance" parameter between the raft and the bottom layer of the part but then the raft sticks too well to the print.

Did anyone manage to get a smooth bottom layer while using rafts ?

I'm with S3D, flashforge creator pro (+ a couple of reprap where I did not print with rafts yet) and I'm currently printing with PLA (although the goal of printing with raft is to print large geometries in ABS)

Thanks
Gad

Re: bottom layer smoothness when printing with rafts

Posted: Sun May 01, 2016 4:21 am
by CompoundCarl
Have you tried printing without a raft? I have that same machine and I find that a brim always works better than a raft. It's much quicker and does a better job of holding the part down. Plus the bottom of the part looks better and it's easier to remove.

Re: bottom layer smoothness when printing with rafts

Posted: Sun May 01, 2016 9:36 am
by gad31
Hi,
Thanks for the reply!
I do print with brim as well. However I sometimes experience difficulties to remove the brim properly : the first layer has a rough edge which I don't know how to smooth with PLA.
How distant is your brim from your part ? just 0.0 mm ?
How large is your brim for large parts (i.e. almost the whole size of the flashforge bed) in ABS ?
Any tricks to remove properly the brim :?:
Thanks !

Re: bottom layer smoothness when printing with rafts

Posted: Mon May 02, 2016 5:54 am
by andrewk72
Just adjust the offset until it separates easily. So if 0.0mm is too close, use 0.1mm or something like that.