I have had terrible luck with tear-out when milling plywood on the Shopbot. Here is an example of the kind of issues we're experiencing:
Notice how the top ply or two is getting ripped up during the milling process. And this is when using down-cut endmills and proper speeds & feeds.
The tear-out has been very frustrating. It's hard enough to make wood pieces that feel light and thin, an aesthetic I really want for the lamps. (This desire for lightness is why I want to use metal for the lamps, but I've been finding it very hard to do accurate metalworking at the scale of a lamp)
A month or so ago I decided to see if I could use the laser cutter to create wood pieces that approximate the look of what I wanted from a CNC router/mill. The first sketch was promising:
I was able to take a design in Fusion 360, slice it up intelligently, and create a set of DXFs for the laser cutter, cut out 1/8" plywood and reassemble the design.
So I took this basic idea and created a new design, with channels for the aluminum spine in the back and the diffuser in the front. These channels would be cut out separately and registered to the side pieces via holes filled with glue and wood dowels.
Assembly was pretty easy and anti-climactic. Just assemble the pieces with 1/8" dowels and wood glue. Then sand to remove the laser cutter burn marks.
The end result was pretty good, if a bit messy because I didn't use much care in applying the glue.
For future attempts, I would like to eliminate the need for the registration dowels and find a way to register the layers externally (e.g. via clamps or temporary jigs), because I think the end result would look cleaner.