Adding support manually in CAD Design?

Hi,
just making a model and was wondering if there is any trick to adding support manually...
reason being there are a couple of parts of the design that it's essential that no support is printed...

do i just leave a small gap between the support and the required print?

any help much appreciated!

From the prints I have done that needed supports, I would say there should be no gaps and the supports should be spaced so that you won't get any sagging of the prints between the supports.

I have occasionally done supports by adding 0.5mm thick "extra walls" (just thin rectangular blocks) that touch the object. On horizontal surfaces they snap off easily, on other surfaces you might need to trim it off with a file or knife.

Edit: To clarify, by "touch" I actually mean "intersect".

Edited 1 time(s). Last edit at 08/01/2014 02:38AM by jstck.

Hiya Zombies, my Big Blue design is all held up by supports. As jstck says above, try using 0.5mm walls. At the end of the day they don't really do much, except support the hot plastic till it sets. 0.5mm walls snap out nice and easy afterwards, and don't leave to much debre behind to clean up, so it's easy.

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The support method varies depending on what you're wanting to print - For example a flat countersunk screw hole is tricky because the slicers normally want to create the wall outline around the hole, but have nothing underneath to support it.
Automatic support can be difficult because you'd be removing it from within a hole.
A clever method of support that I've seen with the Prusa parts would be to close the hole, but with a very thin layer. This causes the slicer to bridge the gap as a solid layer and build the part over the bridged plastic, but when complete the layer over the hole can be removed with a craft knife or something like that.

An example here:
[www.thingiverse.com]

The hobbed bolt hole uses this technique:


Another support method is shown in the same part where there is a thin walled breakaway part. (bottom left of that image)

Edited 1 time(s). Last edit at 08/06/2014 07:54AM by VortyZA.

Yes, I use the thin layer method on several of my designs. Designing the layer to be 0.2mm works for any layer height you are likely to use on the Ormerod. Not only countersunk screws, but also nut traps and recesses for bolt heads - anything where a vertical cutout on a lower layer has a sharp step to a narrower cutout on a higher layer. In fact I find that countersunk screws don't need it, because the slope of the countersinking is gentle enough to print fine.

Dave
(#106)