Electromagnetic Capper

Tools
1

Hi all,

We are trying to replicate the electromagnet capper developed by [2601.07043] PANDA-film: an automated system for electrodeposition of polymer thin films and their wetting analysis (On Opentrons instead). We faced an issue with metal discs (for vial caps). We decided to use smaller discs (5/8 in.) for smaller vials, but we saw that the iron disks do not attach at the center of the electromagnet but instead slide toward the edges. It seems that the regions with the highest magnetic field gradient are at the edges.

Has anyone had a similar experience with this? Has anyone tried using smaller electromagnets?

Sina

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2

Any videos or pictures you could share?

3

We’ve only tried that magnet/disc. Conceptually, using smaller discs and a smaller electromagnet makes a lot of sense. There is a small concern that the force wouldn’t be strong enough, but you’d have to try it out.

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4

@mseifrid sounds like you’ve done some work related to this too. Any comments?

5

My comment is that @SinaDT‘s my student :wink: I think we ended up going with a smaller electromagnet

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6

:man_facepalming::sweat_smile:

That’s great. @SinaDT if you end up with pictures or findings on how this goes, would be great if you could add here.

7

this looks cool, we were thinking of doing something similar for moving vials and caps using a vacuum gripper.

here’s a short list of parts:

  • 12V vacuum pump: for using with one of those cncs, it connects directly to the spindle which outputs a 12V PWM signal. the same connector that is normally for the CNC spindle connects straight into the terminals on the vacuum pump.
  • 1/4" ID tubing. we’ve stepped it down to smaller tubing but this can be done a million ways.
  • 1/4" barb
  • suction cup there are many options for different size cups on mcmaster. it just needs to be 10-32 thread to connect to the barb above
  • optional mufler for the vacuum pump