At our house we do a lot of crazy puzzles at Christmas time, think escape room type stuff.
This year one of the puzzles uses a rokr laxer cut hand crank projector. The kids will complete tasks which leads them to the parts of the projector and eventually the film.
I want to make a custom film do the projector and have a template to generate strips of frames using transparency film but the sprocket holes are going to take forever.
The method that one guy used is to use a 4.5 or 5mm leather punch but I’m wondering if I could do it on the cnc either with a drag knife or even just drilling it using a sharpened nail or something smooth edged.
Sounds like a fun plan. You might have the best luck by pinching it between two pieces of sacrificial wood Or 3mm MDF and then drilling through everything with an endmill. Alignment might just be a bit tricky
My first thought is to laser cut the holes. If you are using Mylar as the plastic, and the edges are printed dark, then an inexpensive diode laser would cut the film easily…and you could cut more traditional rectangular holes as easily as round ones. You need to be careful with the kind of plastic that you laser cut. Some plastics, like PVC, put off toxic fumes that are harmful to both people and the laser.
Another burning solution would be to create a fixture as outlined by RobP, and use a soldering iron in your rig to cut the holes.
I wonder if you could mill the holes using the router. I experimented with milling “rubber” stamps out of EVA foam, and had pretty good luck using burr bits for the milling. The smaller diameter bits might have less tendency to rip up the plastic…even smaller diameter traditional end mills.
Another idea would be to experiment with Dremel bits. With a fixture, at least on the bottom, I could see these bits working well. I could also see making a fixture like RobP suggests using the CNC, but using the Dremel by hand to cut the holes.
Whatever you find that works, you might consider testing if the process can handle multiple sheets. Even if you ended up cutting the holes by hand using a fixture, being able to cut multiple sheet at the same time would be a huge time saver.
BTW: Very cool project. I love to see a image of the completed machine.
I think you could build a little jig with a pin setup and some sort of sacrificial layer to clamp and hold the film. From there you could drill by hand or have the CNC do 10-12 (100+) at a time, move the new last set of holes to the pins, and repeat for as long as you need.
If you need square holes, pins and a laser would do it, like Robert suggested.
Thanks all for your ideas. Waiting on the film from Amazon and I’ll start playing with a few.
Lasers would be ideal but they scare me as I’m constantly grabbing my eye protection just after I turn on the router and kids are prone to walking though the shop at any time.
I’ll post back on my progress as I figure it out.
Have you seen this article? He builds a punch for recreating sprocket holes to make his own film for a collectable camera that takes a format that is no longer available. He’s got a link to the design, so you may be able to modify it to your needs.