Our assignment this week was to produce a “Press-Fit” construction project using the laser cutter to pierce out parts which fit together without glue or fasteners, using tabs or dovetail-style joints.

A while back, I made a series of sculptures using the same processes I use for Zoa Chimerum Jewelry. They went into shadowboxes which I bought at Ikea and modified. Unfortunately they were water-damaged during an outdoor art fair when a sudden storm came through. I did my best to repair them, and they look OK, but I’ve been wanting to replace the boxes outright so this assignment seemed like as good an excuse as any to make my own display cases.

One of the sites in my RSS feed posted a link to Dutch design house Snijlab, which has discovered a way to make flexible plywood curves using a laser cutter. They’ve been using the technique to make snazzy notebook holders: http://www.snijlab.nl/?page_id=358

I decided that I would like to incorporate these curved corners into my shadow box design.

Fortunately for me, the Oomlaut Lab has already adapted these bendy corners to make an Arduino housing: http://oomlout.co.uk/?p=434, and they were kind enough to post their templates online: http://oomlout.com/ADBB/

I downloaded their template and removed most of the extraneous stuff like the bolt holes and what have you (remember the assignment calls for friction fit only).

I also had to modify the widths and heights of the various tabs to reflect the thickness of the material I was working with. (My plywood is .2" thick). This is important otherwise you won’t get a good fit when you assemble the parts. I did all of this using Adobe Illustrator and it was finicky and annoying. I had to manually click and drag a lot of individual points and I wasn’t able to find an easy way to make the kinds of changes I wanted in any kind of “batched” way. Probably other programs are better suited to this and I’d like to learn how to use some of these programs for projects like this in the future.

After the cut pattern was configured the way I wanted it to be, I sent it to the laser cutter and burned all the lines through the wood.

These were my settings:

speed: 8

Power: 100%

Frequency: 1325 hz

Unfortunately, we still have not replaced the bed in our laser cutter, and as such there is a focusing issue. The laser beam did not cut all the way through to the other side in a lot of places. For the back and front panels, this isn’t such a big deal because you can sometimes still force the pieces out of panel and then trim off any excess with a sharp knife. For the perforated curves, though, this is a HUGE problem, because if the cuts don’t penetrate all the way through, the hinge won’t bend, it will snap.

Which is exactly what happened with all but one of my corners.

Frustrating, but I wasn’t expecting to get it right the first time. With some tweaks to the settings, hopefully I would be able to get the cuts to go all the way through.