Alternative Support to Model Interface

I have a suggestion for a slightly different support to model connection point. The existing design places the most narrow point directly at the interface of the model surface. While this is a great option for models where you can orient an unseen side toward the model and makes removing support a piece fo cake, it can be a nuisance if you have to support something on a finished side. You can’t just break away the support without potentially leaving a smooth surface dotted by pock marks where the fracture left a concave artifact on the model. Would it be possible to add an alternate support that shifts the neck off the face of the model some tiny amount so that you are able to remove the bulk of the scaffold and then can just sand off the tiny nubs? This would allow for supported faces to be sanded clean without having to fill the dimples.

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I don’t get pock marks. I use, for grey resin, 0.4mm ‘structural’ supports and 0.3mm support on visible faces.

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Try removing the supports just after the IPA bath, if your parts allows it. Support points are much weaker at that stage and should break off without leaving a negative mark on the part.

That being said, I very rarely get negative marks on my parts, and I most often break the supports off after post-curing. Maybe it’s because I’m reducing the support size a bit (-0.1mm usually, most if I am more confident)

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I suppose I should clarify. I generally see these on the surfaces of engineering models where I have to use the default support contact point sizes in order to prevent warping or other deviations in the shape of the design.

I’m also solely printing mechanical/engineering parts for out internal needs. Density and orientation are much more important than point size from my experience, I have never had supports detach when applying the “-.1mm” rule and I have printed some pretty beefy parts.

Please enlighten me on the “-0.01mm rule.”

I was referring to my previous post just a bit higher in the thread, and I also typed 0.01 instead of 0.1 :wink:

What I meant to say was that I systematically dial the support point size down by 0.1mm for all resins even for reasonably big parts. I find that it makes a noticeable difference in what’s left on the part and I haven’t had issues with support detaching mid-print. For very small/shallow parts I tend to take 0.2 off. For Grey, Clear and Tough I find that reducing by more than 0.2 has to be offset by an increase in density which in my case is not advantageous.

Thanks. I’ll look for your previous post.

I’ve reduced the support point size down to 0.4mm successfully in more delicate areas; but I tend to stay with the default 0.6mm elsewhere. This is partially out of laziness on my part.

I’ve written and spoken several times with FormLabs support about the problem of media break points, but it seems they haven’t considered me…
I work in the jewelry industry and the supports created with Preform are too big, many times to remove them you break the piece.
For some time I have created a plugin for rhino3d that creates media. The shape of this support allows you to break without leaving holes on the surface of the object.
I attach the image of the support to make you understand what I mean.
I also submitted the explanation of everything to the form support, but as mentioned before they didn’t take into account my proposals.

That is exactly the same idea I was thinking. An alternate contact point style that puts the fracture line just off of the part so that it would never allow a concave break that removes material from the model. Sure, it adds a bump that needs to be sanded, but in some cases, id prefer that to the alternative.

I know some people haven’t had this issue and I can appreciate the difference in experiences but I still run into it, even after reducing the contact point size. Sure, it’s not as frequent, but still can be annoying.

For now, I end up filling these divots with resin from the tip of a toothpick, curing, then finish sanding. One thing to keep in mind when doing so is that it needs to be done before post curing in order to have any chance at the repair material cross-linking to the model material for a proper bond. Once you post-cure the model, adding resin only results in a mechanical bond. This is another reason why I would prefer the optional contact point, allowing completion of the wash and post cure While the model is still on the scaffold.