Changing beamsplitter size? SCAD changes?

I finally got a beamsplitter plate to try out some reflection microscopy, but I’ve been struggling with changing the SCAD files to adapt to the size of my current beamsplitter (I don’t have a way to cut the glass rn). It’s currently 20x20mm, which is a bit too large and ends up sticking out, while simultaneously not covering the full beampath.

I had to modify the lens holder at the top to have a wider base (because otherwise the gap for the 20x20 cube would leave the lens holder floating mid-air), and tried translating the beamsplitter plate so it would be better centered, but this also moves the beampath.

I’m currently considering just taking a soldering iron and cutting a deeper groove to fit the beamsplitter, but I figured maybe one of you good folks might know a better way to solve this.

This is the result of just changing the “dichroic” dimensions in lib_fl_cube.scad to be 20,20,1.1 - I thought this would be enough but it’s not quite working.

I have had a look at the beam splitter cube code. The parameterisation is not completely robust. The shape remains sensible for widths less than the nominal 12mm, but for wider optics it does not behave as expected. There also seems to be an issue dealing with optics longer or shorter than the nominal 16mm. However 20x20 is quite large and there would not be much of the part left to support itself, especially during printing. For 20mm width the beam splitter slot goes right through the sides of the cube as in your pictures, but is not deep enough. It seems that hacking is the quick solution, adjusting the code would take some time to understand how it is put together. I would suggest that making the slot deeper with a hacksaw might get better results than a soldering iron.

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I wonder if just cutting the glass isn’t the quicker solution. I wonder if it can be cut with a dremel and a diamond wheel. Might be a lot easier with a mini table saw attachment. Pretty sure one can be found to be 3D printed or laser cut. In the end all it needs is a clamp for the dremel and a piece of wood with a slot.

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You’re probably right, this is a “have a hammer, everything looks like a nail” situation. I have a 3D printer but no glass cutter so this seemed easier.