Magnet Card

This weekend, I made a special magnetic tool for my 3D printer. Sadly, I forgot about the “opposites attract” rule for magnets (it's a natural fact!) and put all four magnets in the same way. This was a failure. But a learning failure!

I had been using my iPad case - which is magnetic and polarized - to insert the magnets. This is great if you want all the magnets the same way. Funfortunately (that should totally be a word?) sometimes you need magnets to be facing opposite, known directions in a piece.

Enter the Magnet Card!

First off, I don't think the Magnet Card should be used with teeny magnets. I think a larger (12mm or larger, 4-5mm thick?) magnet should be used, but I'm not going to tell you your business.

If you think what you really want is a smaller magnet, or a larger magnet, as your reference magnet, just let me know in the comments below. The two things I need: the exact measurements of your magnet, diameter in mm, and thickness in mm. You probably want it to be tight and flush, so use your “X-Y hole compensation” feature of your slicer to make sure the hole grips the magnet tightly.

I'm going to be using this card on a crafting mat, so I'll be pushing down on the mat, not empty air. At first, I made the card exactly as thick as the magnet (in this case, the first one was 1.6mm, so I made the card 1.6mm thick) but that's too thin, and the magnet didn't have a lot of grip on the hole. So I made the card slightly thicker 2.0mm. Then I realized that I needed a slightly larger, thicker magnet, so I switched to the 12mm diameter, 3mm thick magnet, which fit nicer.

If you need this magnet to stay in no matter what, even if there's nothing below the card or whatever, I've included a version with a 0.2mm bottom that only has one side of the magnet facing up, and the other side of the magnet touches plastic.

Next, you might be asking yourself “how did you figure out the polarity of the magnet so the N faces up and the S faces down?” Elementary my dear Datsun! Grab the Pole Detector App for your smart phone:

https://www.supermagnete.de/eng/poledetector-app

Or you can use a compass, which already has a reference “N” on it.

Just remember, opposites attract!

The text on the top and bottom is 0.2mm debossed, so for my 0.2mm layer height, it's almost perfect, just barely visible, not requiring supports at all. My Bambu Lab X1CC bridges those just like the bottom of a 3DBenchy. (You did know the bottom of a 3DBenchy has slightly debossed text on it, didn't you?) If you'd like a version with 0.1mm (toight!) or 0.3mm (maybe a little more common?) just leave comments below, and I'll upload a special card just for you.

I'm not going to tell you how to print your stuff, but I suspect you'll want the “S” down, and the rest of the text ("Magnet Card" and “N”) facing UP, so that the “S” is a subtle reminder of down, and the front of the card is well-debossed. If your slicer has a “put this face down on the bed” click on the “S” face and you're golden.

As always, please leave comments, questions and suggestions below, and I love to see your makes!