It’s rare to encounter a problem with an iris, but if there’s going to be a failure anywhere, it’s usually a pin breaking or jumping out of its slot. The latter causing the leaf to scrunch up, taking a neighbour or two with it.
All products have an expected lifespan, and irises are no different. So how many aperture cycles could an iris endure during it’s entire life? This is an answer I’m curious to find out…
How best to test an iris diaphragm?
Initially I setup two very crude rigs to explore how best to test a multitude of irises. The first uses a Raspberry Pi to control a servo, which then operates the iris. And the second is simply a drill setup to use a back-and-forth locomotion.
The drill seemed to provide the extreme amount of abuse I’m looking for, so I rigged up a quick method of mounting the iris and drill together. Unfortunately DeWalt drills seem to have a cut-off timer when in constant use. So despite a zip-tie around the trigger, to hold it on at a constant speed, the drill stopped after 5 minutes…
After over an hour of repeatedly restarting the drill, the iris was disassembled to inspect any damage that may of occurred. But despite this particular iris being made from 3D printed PLA, there was no discernible wear. And when the iris was reassembled, it operated perfectly as before.
For the future, a better test rig needs to be constructed. Ideally one that counts the number of cycles…
If you’d like to have a go at making your own iris design, please do sign up to our design software. You’ll be able to customise the size and many other design parameters. And once you’re done, you can export and print the templates as a guide.
