I'm building a machine that will pick-and-place plastic cards, but they keep sticking together when lifted. How do I avoid this? My attempted workarounds - shaking back and forth and scraping against some foam - aren't reliable enough. See picks 3 & 4 in video...

i think the issue is that you're trying to lift the cards vertically instead of shearing it off the deck. casinos use this device called a shooter to do just that, maybe you can use it as inspiration.

Ah, super interesting! I think that relies on the cards bending a bit? But this is giving me some new ideas to try... I think you're right that shearing is key

How thick are they? You could maybe do something similar to coin dispensers - a spring loaded stack of cards where only one can slide sideways

~.76mm thick Yeah, going to try this approach, but I may try to skip the spring - I have a Z probe to check stack depth while picking, so I can pick up from any height and then lift to the fixed slot height before sliding.

If you had an air pump forcing a jet of air exactly where the gap between two cards would be when it first lifts, it may force instant separation and hopefully the second card drops back in place to be picked up on the next cycle.

Xerox, to a degree, went out of business due to this very difficult problem. There are inherent speed limitations in picking up single sheets of paper reliably and they fell behind the continuous-roll production printer systems.

Need an ionizer to reduce static

At a factory I worked in they used a small amount of air blown in the side of the dispenser at the point of lifting to break the tiny vacuum that is created. May need a small finger there as well. Hope this helps.

small compressed air blast in the lifter to separate the cards ?

Are you able to use a vacuum lift instead of suction cup (I'm guessing)? You're probably building up too much static between the layers when pressing down. Hovering just off the surface and vacuuming the top layer up might solve it.