Laser cutting a dark box for an AZ100 microscope

Recently, we received a Nikon AZ100 on loan from a lab at UCSF that was no longer using it. We wanted to make it available for researchers to use, but we didn’t have a darkened space to put it in. Sitting on a lab bench, there was far too much stray light to be able to acquire fluorescence images. Since our sister lab, the Center for Advanced Technology, recently acquired a laser cutter, we set out to laser cut a dark enclosure for the microscope.


The final enclosure

Enclosure, close up

Close up

The enclosure is a five-sided box made of 1/8″ black acrylic. For simplicity, it hangs around the objective turret, with black plastic attached to the bottom edge of the enclosure with Velcro. The plastic hangs down to the table and enables easy access to the sample stage, and also accommodates the fact that the objective turret moves up and down for coarse focusing.

The box is assembled with finger joints, which is a pretty standard way to laser cut boxes (for background, see here). There are a number of web sites that will generate box patterns for you, but since I needed a bottomless box and I needed a cutout to clear the focusing knob, I just drew plans up in Adobe Illustrator. At least on our laser cutter, when cutting acrylic, you can neglect the kerf of the cut and just design the joints so that the fingers and slots are the same size. The resulting finger joints fit together loosely, but tight enough that they’re easily glued up and make sturdy joints after gluing.

The box is composed of two halves for easy installation and removal; the two halves are held together by plastic pieces that screw into press-fit threaded inserts installed into the box tops. These, and the Velcro, are available from McMaster-Carr. The plans for the box are available on the NIC Wiki; if you’d like to cut your own but don’t have a laser cutter, custom laser cutting is available from places like Pololu and Ponoko, though I’ve never used either.