Ah. OK.
Um, no. I don't think you can control a chop saw carefully enough to do it.
Traditional method would be to drill holes, and then use a jigsaw or scroll saw to cut out the openings.
Less common method would be to use a wood router, hand-held, with a 1/4" or larger aluminum-cutting bit, using a plywood or MDF template, and a bearing or collar, to cut out the 'triangles' after drilling access holes. Note that this is more dangerous than average, gotta be super careful and slow (about 1" per second). And hearing/eye/skin protection is mandatory. (We did this with 3/16" aluminum some years ago, nobody died...)
Of course, you can also do it with a coping saw. Assign it to a freshman.
