[tennispro9911]

I don't have much experience specifically with gearboxes, but I do with acrylic vs polycarb. Acrylic cracks extremely easily. I wouldn't trust it with a gearbox, but it might work. I know inventor and other CAD programs probably have stress analysis tools, although I'm not sure how good those would be in this case. I would at least make it in CAD and put forces on it at least a few times what you think might possibly be enacted on it during competition.

The good thing with a gearbox is you can make all rounded edges. Make sure you do that, if you go with acrylic. As you probably know, sharp edges are stress points and produce cracks. I've done some laser cutting with 1/4 acrylic, and it isn't that great, and my team avoids acrylic as a rule. However, I don't have enough experience/knowledge to rule it out completely. With virtual testing, input from more experienced members, and real testing, it might or might not work.