Ender 3 Tool Holder with *Embedded* Magnet Bars by 6ROM7

Last crawled date: 3 years, 5 months ago

Remixed from this very useful magnetic tool holder for an Ender 3 (and other 20x20 extrusion printers), itself remixed from this original design.
This is not just my first remix, but my first ever 3D modeling effort! Any and all input very much appreciated. I hope I'm following proper protocols as I try to give back to this awesome community.
Here are the principal revisions:
In lieu of the surface-mounted magnetic discs, utilizes 4 neodymium magnetic bars (60mm x 10mm x 3mm) that are embedded into the print.

Adjusts the plate to be wider and longer (now 47mm x 128mm), increasing the surface area for storing tools and maximizing the dead space on the back/right side of the printer.

Makes the screw holes bigger and more recessed to better accommodate M4 pan head screws.MPORTANT NOTES – ESPECIALLY #1
The magnets are embedded/“sandwiched” between top and bottom (front and back) printed layers. This requires pausing the print (after layer 22 for me, at 0.2mm layer height), carefully placing the magnets into the cavities, and then resuming the print. This is akin to a color filament change at a certain layer height. (There’s a lot of documentation on how you can do this manually, through your slicer, or through Octoprint.)

The cavities are specifically sized for these magnets from Amazon. They friction fit, with just a bit of pressure. After several trial-and-error prints, I found that if the cavities are too tight, forcing the magnets in will cause bed/head movement that will interfere with the resumed print; if they’re too loose, the magnets tend to jump out of the cavity to stick to one another. Some people use adhesives (super glue or epoxy for these sorts of embedded magnets). I didn’t want to get started with potentially getting epoxy on my printer and wanted to limit the pause length. It is a delicate dance getting each magnet to stay in its cavity when inserting the adjacent ones. NB: Pay attention to the top/bottom of each magnet and install them all with the same pole down.

The screw holes are designed for M4 pan head bolts and M4 T-nuts. (Socket heads should work but may stick out above the surface slightly.)

I printed the object with the front face (with the countersunk holes) on the print bed. Yes, I realize this is counterintuitive, as it requires supports in the screw holes. Still, I chose this approach for two reasons: First, but I wanted the front face to be the smoothest surface (and I like the slight texturing effect from the glass on my E3v2). Second, I wanted the weaker side to be the back side, which is mechanically mounted against the rail. (Yes, you can print it without supports with the other face down.)

I debossed stylized text of my username in the bottom (assuming you print the front face down) of one of the cavities. That wasn’t an ego play — ok, maybe just ever so slightly — but was instead just an experiment for having slight grooves for adhesives if used.

PLEASE BE CAREFUL! Magnets are pretty amazing, but also hard to work with. They want to stick to each other and a lot of other things in your workspace. I had a scare when they pulled a sharp knife toward me unexpectedly. Also, two magnets can pull together with enough force to crack/break each other. (This happened to me twice.) Finally, magnets can mess with pacemakers and create other health issues. So, please proceed at your own risk, and be very careful.

MAKE SURE YOUR NOZZLE ISN’T MAGNETICALLY ATTRACTIVE. My brass nozzle is not attractive, but I suppose steel nozzles would be. To prevent damage your nozzle and hot-end, please do a careful test before printing and trying to embed magnets as described here.