Build Platform Funnel

Hello Fellow Formers,

I read a post recently, about the need to drain the resin out of the build platform when switching to another color, especially from black to white. It seems that with long prints the resin soaks into the build platform, which leaks out of it during the course of the print. A solution would be to purchase a separate build platform per color, but since I don’t have the room to keep them and I don’t like to spend more money than needed, I came up with another solution; a build platform funnel!

I started sketching in Rhino, which I love by the way, and after a few hours of tweaking and tinkering I came up with this design:

It consist of two parts, the upper funnel part and the foot with a drain hole and some support. Here is a picture of the funnel:

I used half spherical shapes to lift the sides of the build platform of of the sides of the funnel, in order to let the resin leak out of the build platform.

The foot is actually just a round disc with a hole in it to accommodate the funnel at one side and to be used as a lid on the plastic cups I often use:

The lower side of the foot is strengthened with four small supports:

For the funnel part I used the following orientation and support in PreForm:

… and for the foot, this orientation and support:

Just as a previous project of mine (the [resin tank comb][1]), I would like to share this one as well. So here is the list of files that are open for download, sharing and building;

First, here is the STL file of the funnel part of the build platform funnel:

Second, here is the FORM file of the funnel part of the build platform funnel, for quick and easy printing:

Third, here is the STL file of the foot of the build platform funnel:

Fourth and finally, here is the FORM file of the foot of the build platform funnel, for quick and easy printing:

I haven’t had the opportunity to print both items, since I have some problems with my Form 1+. I guess the mirrors need cleaning, so I opened a support ticket to resolve it. As soon as I finished my own Build Platform Funnel, I’ll post some pictures here.

In the meanwhile you all could give it a try, don’t wait for my build. I hope you enjoy this project and I would love to see some builds here… :wink:

Kind regards,

[1]: Comb designed for cleaning the resin tank


I’m baffled: your resin is soaking into your platform? I’ve never seen this before (i routinely switch between Grey/Clear).

@Matthew_Bohrer the build platform is a hollow box, and if the plastic sides warp even slightly (both of my platforms warped over enough time) then resin gets in. There is a rubber seal between the plastic walls and the aluminium plate - but warping breaks the seal.

My solution was to drill a hole in the top and pour in plaster of paris - it’s been working perfectly now for more than a 100 prints.

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Yes @Matthew_Bohrer, this happens. If not right away, then over time.

That’s a complete other approach @KevinHolmes, but OK if you don’t mind drilling in your build platform. I’m not that fond on altering existing stuff. I like to think of a solution everyone can use, without the need of changing something.

@Jolmer well - infilling the build platform has a wealth of advantages over a draining system.

  1. Filling the platform with plaster is a 100% solution; a draining system like yours without any modifications to the build may not drain all the resin. Build platform warping happens primarily in the middle of the plastic wall sides, the seal at the corners is often intact - so depending on the particular warping in a given platform - then draining as per above could easily leave a pool collected in the downward facing corner that can’t drain until the platform is level again.

  2. it’s easier to use - once implemented you don’t have to do anything, it just works.

  3. it’s cheaper, faster (assuming you already have some plaster or casting resin), and easier to implement.

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I don’t have any plaster or casting resin, I just use the normal print resin. I still wouldn’t choose to drill in the platform and fill it. I’m not familiar with all casting materials, so I could end up using something that will affect the print resin. I’m not comfortable about it.

You’re right, it could be that the orientation of the build platform should be tilted for a better drainage, I’ll test this later on.

@KevinHolmes, @Jolmer I think both are good ideas. Another thought is to drill holes all the way around into the sides, say 1cm diameter hole every 3-4cm on center, with the hole tangent to the top surface of the aluminium plate. This would allow overfilling the tank, but it’d get messy probably… Or better, just design the build platform to not displace so much resin in the first place. :smile:

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Well, that would be great; just a flat surface as a build platform. But I’m still not comfortable in drilling holes in existing stuff. Perhaps this will be fixed with the Form 2? :wink:

The problem is, that it is almost impossible to really clean the top-surface of the build platform (or only by using a lot of IPA, loosing quite a bit of resin in the way.
So you probably need a build platform for every resin type…

So as much as I like to have a Build platform displacing less resin, I guess it has a reason why it is built that way!

I haven’t really noticed this problem, however, the funnel is a nice design.

Here is a suggestion, would it cause any problems to just seal around the edge of the build platform with silicone caulk?