Zero-width faces left over from difference (openscad)

I found openscad a couple of weeks ago. It's pretty cool and everything I've done so far has seemed logical, but now this is stumping me.
This code is a bit hard to read, but my problem is the thin wall to the right of the main object. I have a way around this, but I was just curious what might be causing this. All the objects I use to subtract with are exactly the size they need to be, and this causes fuzzy half-existing faces in the preview render, but nothing every stays in the full render.
The photo is attached with the model file..

Edited 1 time(s). Last edit at 11/23/2015 08:51PM by Montiey.

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Master Tinkerer

My OpenSCAD 2015.03 on Linux Mint 17.2 does that also. As long as it looks right in a full render F6 it seems to slice and print OK.

that's what happens in slic3r for me to.. "nope! too thin.. ignoring.."

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Master Tinkerer

That's a well-known artifact in openscad when subtracting two objects that have the same dimension. As you say, it goes away in the rendering. The typical way around it is to make the dimension of the object being subtracted slightly larger. I typically add 0.01mm and it works fine.

It you're worried about the effect of doing this on the final rendering, instead of using a literal value, use a variable, set it to 0.01 when designing, and then set it to 0 for the final rendering.