Tips for surface finish on top of support?

[somepunk22]

My parts usually require quite a bit of dis-solvable support. Right now surfaces printed on top of support are always messy and droopy. To help fight this I use 45 and 135 degree supports to make a checkered pattern and 0 separation. Parts still do not come out nearly as well as my Zortrax printer. The Zortrax prints a very loose support, but then prints a raft on top of the support. This seems to work very well as the material physically can not droop and doesn't waste a ton of material on a dense support pattern.

Any tips quality surface finish on supported surfaces? FYI I'm using ABS and HIPS. Thanks!

[jimc]

if your using dissolvable support then use zero separation distance like you mentioned but you need to up the density. you cant get any better of a surface than printing support an 100% and zero sep.

[somepunk22]

100% Support? What a waste of material and time. Even if I did the same material, how are people getting anything usable for a surface finish? I can't imagine it would change much using ABS for everything?

[dennisjm]

I've had pretty good results using 60-70% fill. There is a part I'm printing as I type that I'm using 100% support fill on. It's for a smooth curve on the bottom of the part.

Point is though, it's true, What I wish is that there was a setting for solid layers or something that has to do with support material, not the main material. LIke you could do 20% support material with 3 100% filled layers on top, then print your real part on that so you could not waste as much support material.

I suppose you could do this with two processes IF (and only if) your support material all ended at the same layer. But you really need a setting to control this. A little box that says "solid top support layers" or something.

[somepunk22]

Or I guess I could make my own support model? That way I can choose the infill, and it will have a nice outside layer to print on. Little bit of extra work up front, but could be faster print, use less filament, quicker to dissolve, and hopefully easier to breakaway.

[jimc]

yes for sure. i have done that in the past if i need something thats real nice. one of these days maybe we will see low density support with solid interface or raft layers on top in s3d. right now though all you can do is just increase the density for the whole thing and your right it is a waste and time consuming. on the automatic supports though thats all we got.

[laird]

+1 this.

While you _could_ achieve this with a very thick support structure, that's really inefficient (wasting time and filament) and is so dense that it is hard to remove. (Yeah, I tried, it worked, but took forever to print and wasted a ton of filament).

One thing to keep in mind is that the supported object might be an irregular shape, so I think that a simple raft wouldn't work.

What you really want is a thin support structure (e.g. 10%) until you get near the top, then a dense support (e.g. 50%) structure for a few layers (each rotated 90 degrees from the previous layers), then a gap, then the bottom of the object. That way the loose support holds up a denser mesh, which then holds up the object. And it would fit irregularly shaped objects.

[3Dprintergear]

You don't have to make it so complicated. Both the Zortrax and UP/Afinia printers use a raft on top of support before the object and both of these printers are class leaders in this department. Zortrax having copied the UP. Works fine on all sorts of irregular shaped prints.
Leave support the way it is and simply add a raft on top. The interface layer (raft) should follow the contour of the object.

[somepunk22]

You don't have to make it so complicated. Both the Zortrax and UP/Afinia printers use a raft on top of support before the object and both of these printers are class leaders in this department. Zortrax having copied the UP. Works fine on all sorts of irregular shaped prints.
Leave support the way it is and simply add a raft on top. The interface layer (raft) should follow the contour of the object.

And how do you add a raft to the top of support in S3D? Trying out a designed support now. Does the auto part alignment feature ever work? Figure something that was imported with the same coordinate system would be easy to align...

[somepunk22]

Trying out a designed support now.

Surface finish is 10x better with a designed support vs S3D. I was able to print my support part at 5% infill, 2 bottom layers, 2 perimeters, and 4 top layers. Takes a little extra time in design. If the auto align feature worked in S3d, that would help a ton. Guess this will be my new normal plan for complicated parts.