Flexible PCBs are super-useful things, but they can have a limited fatigue life. [Carl Bugeja] has been using them to create flexible actuators, though, and he’s getting an amazing 100,000,000 cycles out of them after some rigorous development.
[Carl] explores all manner of optimizations to his flippy actuators in the video. He tried making them oscillate faster by putting a hole in the middle to reduce drag. Other tricks include getting the arm thickness just right, and experimenting with rigidity through adding or removing sections of soldermask.
Fundamentally, though, he learned the key to longevity laid in the copper traces on the flex PCBs themselves. After enough flexural cycles, the traces would fail, killing the actuator. He experimented with a variety of solutions, eventually devleoping a ruggedized two-arm version of his actuator. Twenty samples were put to the test, oscillating at 25 Hz for two weeks straight. All samples survived the test, in which they were put through around 107,820,000 cycles.
[Carl] has put in plenty of hard work on this project, and his actuators have come a long way since we saw them last. He hopes to use the better actuators to improve his FlexLED display. Video after the break.