Making very small slide top boxes



I am wanting to make some small acrylic boxes with a dog-tag as the slide top. I’ll be using the layer cake method. The dog-tags will be somewhere around .040" thick.

So, should I try to source one of my layers as .045" or should I etch .045" off a thicker layer?



I imagine the engraving .045" off will take a lot longer for each cut vs layers. How much is laser time + laser operating cost vs your time (gluing) + (probably) more expense in materials worth?


Using this formula, it will be well worth at least trying to source a .045±" sheet. We are talking only one layer of several and being horseshoe shaped they could be nested quite well.



A quick search suggests that 0.045 might be hard to find. There’s 0.4, 0.6, 0.63…

If I were doing it I would overthink and run a 0.22 etch off two pieces. A lot will also depend on your work flow and how many of these boxes you’re making. You’d need a few dozen to use up one sheet of the thin stock.


@markevans36301 Is the laser the only tool you can bring to bear?
I would probably tackle this with a mill, surface sander, or even a router.

Glue up the all the layer from bottom to top stopping at the one you want as .045. Then machine off the extra and glue on the next layer.


Plus the layer you cut could be turned into new wooden dog tags!


The whole thing could be routed but I was looking for efecency in the work flow thus was hoping for parts ready to glue then finish.
What you suggested could work well if I make a jig and have a dozen to do at a time.


Not sure if your construction allows this, but could go with two easily-sourced pieces, one 7/64 and one 1/16 (leaving a difference of 3/64, or ~0.045"). Something like this:

I’m assuming “available on McMaster” is a good proxy for “easily-sourced”, so YMMV.


For that matter you could use a taller piece that is cut “narrower” as @lawbecke suggests but only on the sides. Then laser cut two pieces to glue inside as rails. Use the manufactured thickness as the horizontal dimension and the laser cut one as the vertical. The end part would not be supported, but that should not be a big deal if I understand what you are trying to do.


Now I’m feeling a bit dull having not thought of this. Combined with @jkopel input I should have no problem with this.


It is possible to etch off a groove to run a lid down, the rest of the box though depends on your construction technique to make it exactly the right width every time. In practice I found it easier to use a layered wood technique, but there is a file here if you want to try it for yourself


I think any of these techniques would work; I’ve both engraved the slot and cut layers, then rotated them to make a groove.


I’ve been playing with this in F360, as much as I love F360 I suck at it. I don’t know if I should be happy that this is an opportunity to be most improved or really really sad and mad at myself. I’m the guy who when playing a maze game goes down every dead-end before finding the way. The good news is I am tenacious AF.
At this rate, I’ll have something to share in a day or so.


i think this is about as far as I can get before I start iterating with real material.


better render