Drawers without supports: 45-degree slots.
Solid idea. It can be easy to design around support, yet very few people do so. Btw you're going to want an air gap in between if you haven't added it. The image looks like 0 clearance.
I think that the tolerance (0.75) is too large relative to the horizontal depth of the rail (2mm(?)).
Such tolerance overall sums 1.5mm offset between the two parts horizontally, which could make that little deviations of the drawer (which will happen as there is no geometry to prevent this). These deviations could (and likely will) lead to the case of the whole support of the drawer to be on only 0.5mm on one of the sides.
This will likely make the remaining contact tip (the 0.5mm on either side after it deviates) to wear out fast, making the whole drawer to dislocate rather easily just as the time passes. This is even further aggravated by the pointy end, which will concentrate the forces on the smallest point (the tip) making it deform very fast. I would recommend to increase the difference between the offset and the rail depth and add fillets, achieving eventually an “S” shape 👌
Total horizontal depth is actually 4mm. It's 2mm out, then back to center, then 2 mm in. That little snippet doesn't show the 2 mm inset but if you look at my original picture it has it. I probably could have gone smaller, but I wanted enough room for all the angles to allow a good fit.
Fillets wouldn't be ideal here as the point of this is to allow a very smooth, even print without using supports. Rounding fillets would pass the 45-degree angle and mean either a less than perfect, smooth print or needing supports (which could also lead to less than smooth prints).
I see. I still think that your depth is 2mm and not 4. If you draw an horizontal line where the rail “goes back to center”, the zigzag shape is symmetrical, hence the “positive and negative depths” cancel each other instead of accumulating.
I see your argument on support, and I agree. However, thinking on the printing and not only on the design itself, I will find that this container is VERY likely to be printed on its back, with the opening for the drawer looking up (otherwise you will need support for the “roof”). This will make the side rails to be printed vertical (not horizontal as you see them when you design them) , thus the filleting not only will not need support but also will indeed increase the print smoothness as there will be less sudden direction changes, hence less flow changes (better wall finish), and also less de/accelerations (less ringing and other mechanical-based artifacts).
Good luck and have fun 👌👍
I disagree, but I think it's because my illustrations aren't showing the design very well. Let's see if this illustrates it better.
Now this is a super narrow, short "drawer" but the "rails" and as well as the walls of both the drawer (Blue) and shell (Black) are dimensionally accurate. The drawer would have to clear 2.5 mm for the tip of the drawer to pass the tip of the shell (4mm - .75 -.75). It would require a lot of moving, tipping, and wearing out of the plastic before that happened. Is it possible? Sure... but highly unlikely given the relatively small size and relatively low weight of what's going in these drawers.
You are correct that the shell/box is printed laying on it's back, so fillets there wouldn't be a print quality/support issue, but the drawer are printed flat on their bottom, so fillets on there would be an issue.
In the end your point that I should have gone with less than 0.75mm gap is probably accurate. I was worried that with the crazy geometry that only 1mm total gap would be too narrow but I think I probably would have been okay with doing that now that I have some printed. But I think I'll be okay with the .75 gap per side.
I see. Some tests will probably show the way to go. Nice images and comments 👍