Hi, after a 1000 hours of succesful printing Pla / ASA I am exploring new trics.
During printing with pause on H2D the polarity of the small magnets reverse, so not physically but due to the temp and strong work bed magnetism combo they flip polarity, anyone else that has this experience? Am I to close to the bed?
Thanks!
No, no one else has reported that experience.
Scientifically, I would say this is not possible
I would say the magnetic field and the heatbed temperature might have some effect on the strength of the magnets, but totally reversing the magnetic field doesnât sound very plausible.
Maybe you made a mistake with the polarity.
If the magnets are not secured, they can physically come loose and physically rotate, or you might have inserted one incorrectly.
Exactly what Gerrit says, it may have a very slight effect on the strength of the magnet but wonât reverse the poles.
What nozzle are you using? The hardened steel ones will attract a magnet and can then pull them out, use the normal one.
Magnets can and have been known to have their polarity flip. My guess is something with the heating coils in the bed would be the culprit.
Maybe highly improbable is the better way to put it.
Neodymium magnets can reverse their polarity, but that is one â â â â of a process that includes it needing to be exposed to other very powerful magnets.
I have noticed that the only picture you are using is on the print bed. My guess is that the magnetic field of the print bed and the inserted magnets are combining and tricking you to think that the polarity is reversed. Though this will not be permanent, all you have to do is take them off the print bed.
Have you tested them after taking them off?
More importantly, how are you determining that the polarity if flipped?
Neither heatbed nor nozzle are getting them to their curie temperature
Perhaps it is installed upside down 
I use reference jigs when doing this work - print a small square or whatever, cut holes in the same magnet pattern, glue a set of magnets in it for your own use. Now, when you have a need to insert magnets into the print, put 4 fresh magnets on your jig, they will self align to the pattern and polarity, hamfist it on the print, slide it off, done, theyâre all in there in one action and a known orientation
Just adding to the list of voices saying this is scientifically impossible. Sorry.
Pretty annoying the tone of the comments above, I am clearly stating what is actually happening!
Seems to me a lot of âscientificâ knowhow but clearly none experience on this matter whatsoever.
comments should be more like:
Maybe the build is to close to the bed, try printing the part on a support structure!
Is it possible to mount a part on a support structure?
Fine. Share your model and weâll try to replicate your results.
I would be willing to do the calculations if you share the magnets (part number preferably), the model, and machine parameters.
My experience tells me it is not possible. But you are not telling us the whole picture.
But then again you did say âso not physically but due to the temp and strong work bed magnetism combo they flip polarityâ and people are responding to that statement when they say it is not possible with the temperatures and magnetic forces involved. People have suggested other possible reasons which you have dismissed as being the cause but that doesnât at this stage mean that your original conjecture is therefore correct. As has been said this needs to be tested on other machines and also rule out other possibilities.
Ok, well, if you think itâs happening to you, you need to share your methodology for inserting magnets in a known polarity orientation into a print. So far youve shared the result but not how the result came to be.
If youâre not using a jig or something that asserts the polarity on placement, your flipped magnet is likely that youâve simply made an error and may need to accept that lol
Crazy, people have been doing this way since printers had heated beds. Think of the magnetic sticker or other beds that use real magnets, and then heat up to 120c over and over.
Would be funny if the printer shot the build plate into the air after heating.
This is what it would take to hit the Curie temp.
I have watched a magnet flip, as the nozzle went over it, during a travel
It is important to point out that the Curie temp refers to the temp in which a magnets looses magnetism, not reverse polarity.
Also, Tc is the point in which magnetism is lost completely. The loss starts at lower temp, ie, 80c for NdFeB.
Thanks for adding that.
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