So, found out the hard way that you can’t apply heat to neodymium magnets. Had 16 magnets to press into a print (tool holder). Thought since the soldering pen I use for inserting threaded nuts into prints works so well, I would use it for this too. And it did work well, but now all the magnets are not magnets any more. Yup, heat will demagnetize them. Part is useless, so had to trash it. Found out something new, but wish I had heard about this beforehand.
Lesson learned, I guess 🙂 here’s some more:
At what temperature a material loses its permanent magnetic properties is called the Curie temperature. For Neodymium magnets this temperature is around 310–400°C (ca. 590–752°F). So if the heat is below that, you’re mostly safe.
Maybe look into how to design/modify a part and how you can pause your print a at a specific layer height so you can just drop in the magnets (use a drop of super glue to they won’t attach to the hot-end or make a test print with various diameters to find out the perfect width for press-fitting the magnets in) and then continue the print.
This also results in nicer looking prints because the magnets are invisible. Depending on thickness above the magnets and strength of the magnets the result might be less strong, so ideally there are only very few layers of material covering the magnets.
This is a very straightforward and in-depth video on how to do this in a good way:
https://www.youtube.com/watch?v=wJgoH2Or03s
They lose their coercivity far sooner. The higher the magnetization, the more sensitive it is. So N52 is more temperature sensitive than N45 (but both start to suffer around 80 °C). You also get alloys that are more tolerant and get specifications like 44H that can be used up to 120 °C or 35SH up to 150 °C.
Commenter above you said 60*C.
Not saying you’re wrong but one of you is and I don’t think OP heated their magnets to 310*C+
A soldering iron could be easily 310°C
Yes but it doesn’t need to be, and the soldering iron being 310 doesn’t mean the magnet is 310.
Fun fact - some soldering irons regulate their temperature using the curie point. There’s a disk of ferromagnetic material with a particular curie point in the tip. A magnet in the barrel of the soldering iron is attracted to the tip, and when it sticks to the tip, it switches the heating element on. When the disk hits its curie temperature it’s no longer magnetic, and the magnetic switch opens and shuts off the heating element (it’s on a weak spring). When the tip cools down enough it becomes magnetic again, and the magnet is pulled to it and turns on the heater. You can have different tips with different curie temperatures, so one soldering iron can do multiple temperatures with very cheap internal electronics (basically, just a switch).
ooh, that is a fun fact!
I am pretty sure @Eheran is. I just paraphrased the linked Wikipedia article section for convenience. The video on how to print in magnets still worth watching, though.