Poor finish above support material

[bryankerr]

After finishing a few prints that required support material, the finish of the prints is quite poor in places where support material was printed. Are there any tips to improve how the support material is printed so that the object looks better? I can post some pix tomorrow. We're using Simplify3D.

Thanks.

[jimc]

vertical seperation should be set to 1 layer. other than that you can increase the % of infill. normally i will use maybe 30% which works but the surface finish isnt great. i recently did another print where i did 90% support and it came out fantastic.

[Zeeflyboy]

I think the problem is that the better the surface finish, the lower the layer separation and huger the density, which means it's harder to clean up afterwards.

The only way as far as I can see to get the really nice smooth finish would be to use dissolvable support material with no layer separation.

Which is why I am eagerly awaiting the dual head from makergear

[Artenen]

vertical separation should be set to 1 layer. other than that you can increase the % of infill. normally i will use maybe 30% which works but the surface finish isnt great. i recently did another print where i did 90% support and it came out fantastic.

I will try this. I also am having trouble with this because I'm only a few prints in.

[jsc]

There are two issues at play: marring of the surface from little bits of support left over after detaching, and loose threads when printing overhangs that is what necessitates support in the first place.

On the first issue, I haven't really had those with Simplify3D. The support detaches cleanly and doesn't leave bits behind. It's the second issue which is most apparent. You can see it on the chin of the statue I have attached below.

The brown spots, I believe, are caused when the overhanging perimeter started to curl up during printing and wiped off some of the gunk on the outside of the nozzle.

I was about to say that there's no way to improve the loose threads, but I reread jim's comment. I thought he was talking about infill percentage at first, and thought that's interesting, why would that make any difference. But now I understand he's talking about support infill percentage, and yes, that should help.

Another option, if you can take it, is to reorient the print to not use supports at all by not having steep overhangs, even going so far as to segment the object into different parts and printing them in different orientations. It can be hard to join them afterwards with an invisible seam, though.

(Full photo of print here: http://www.thingiverse.com/make:75288 ; note the artfully hidden chin.)

[jimc]

ahhh yes i meant the support. went back to reread what i posted and it was confusing.

[bryankerr]

There are two issues at play: marring of the surface from little bits of support left over after detaching, and loose threads when printing overhangs that is what necessitates support in the first place.

Yes, it's the latter, the loose threads. In particular, there were many loose threads on the underside of this beetle print: http://www.thingiverse.com/thing:315586. I could try to reorient, but since the overhangs are quite low to the ground, more infill on the support shouldn't be too big a deal.

Does anyone make a slicer intelligent enough to increase the density of the support infill immediately below the layers being supported? That would help save print time and plastic.

[jsc]

Slic3r has "interface layers" which are kind of like that, I think. Sadly, slic3r generated support is awful in other ways so I haven't played around with it.

Meshmixer has support generation that looks interesting and low waste, but I'm not sure it is suitable for high quality surface finishes.