And this is why we should veer away from using definitive statements when we are all honestly just curious and making observations.
Stifling research starts with the wrong attitude.
A friend asked and now I have to know, anyone with some of the filament have a Hall Sensor laying about and can confirm if it has a strong enough/any effect at all?
Could this just be static electricity?
The piece is light and the attraction is weak.
Wanted to confirm. Is this PA-CF or PAHT-CF? PA-CF seems to be discontinujed, or will be very soon
Wow, confirmed, PAHT-CF is slightly magnetic. Havenāt printed yet but have a reel. Havenāt noticed it in other nylons, and tested PETG-CF, PLA-CF, and PET-CF and no noticeable amounts of magnetism
Thank you for your findings, whatever the cause, it seems to be manufacturing based. be it doping, be it alignment of the subatomic structures, or otherwise.
This is what I used for the print in my original thread-starter aboveā¦ not PAHT, just PA.
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Honestly, Iām familiar with polymer chemistry and quite a bit of physics, so Iāll just go ahead and say that itās almost certainly due to the use of a ferrous mineral filler and not some of the more nutty reasons out there. Iām not familiar with a particularly good reason to use a ferrous filler in nylon, but maybe thereās a special balance of requirements for 3D-printed carbon-filled nylon.
Occasionally ferrous minerals are useful as pigments, but I donāt think theyāre exactly the cheapest or best for a lot of plastics. Sometimes mineral fillers are used to reduce shrinkage, but again, Iām not sure what advantage ferrous minerals would have over other minerals. Iāve seen some very high temperature silicones use iron oxide to help stabilize the material at extreme temperatures, so maybe thatās related to whatās going on. Some body fillers have a small bit, but I think thatās used as a convenient colorant for some of the red shades used.
Another very niche possibility is that certain grades of hematite help with injection molded part flow and improve part stiffness. Thatās my best guess, given that these are generally high performance filaments weāre looking at, so the stuff is getting added for a performance reason.
Iād be very interested if anyone could check what other PAs out there are magnetic, could give an idea of whoās making the stuff. Seems quite niche to add hematite to a nylon, guessing there may only be one filament vendor doing it.
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I could answer this question in a heartbeat if I still had access to SEM. Surely someone in the user group has access to this kind of equipment and can shoot a sample for us to see whatās in itā¦?
I do know some people at Thermo-Fisher. Iāll see if I can get a favor out of one of them.
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Hereās a simple approach:
Get some iron dust and place it under the filament.
Does the iron react to the filament? The particles would align with the polarity or not.
This would be a decent indication of what we are dealing with.
No need for a $70k machine or any chemical baths just yet. This is grade school science. Hall sensor, iron fragmented particles or some other ferro indicator will determine which realm of possibility in a heartbeat.
Is it possible that we are overlooking the simple possibility that the short strand CF that BambuLab is using in itās PA-CF and PAHT-CF is āFe-Co Fiberā because its either cheap or it offered the physical properties that they were seeking?
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Guys, itās ferromagnetic. The only question is why it is and exactly what ferromagnetic material it is. Iāve already tested it with several magnets, and you can pretty readily feel the 1/r^2 dropoff in force thatās characteristic of magnet sticking to a ferromagnetic material.
To be clear, ferromagnetic does NOT mean that it is a permanent magnet. It just means itās susceptible to magnetization, and it does not necessarily persist after removal of the field, so iron particles will not measure this accurately.
No idea why itād be added to cheapen anything - there are a wide variety of injection molding fillers frequently used to reduce cost, and the most common ones are things like talc (baby powder), calcium carbonate (chalk) and other really common minerals. None are ferrous compounds as far as I know
Which is why SEM would be able to answer the question. If thereās elemental Iron in the filament, SEM will identify it and weād know it was doped. If SEM sees no elemental Iron weād have to go with the alignment of long-chain polymer explanation.
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Cyclical conversations donāt get us anywhere. Bragging about equipment nobody here actually has public access to also does absolutely nothing.
Iāve presented ground level access testing to figure out if itās hematite or iron but it appears people would rather assert what it is than provide observation of proof.
Hematite will slightly realign the iron particles, iron will not. Until someone has physical proof of what they are saying, nothing is off the table.
Nobody but you are asserting that iron should be used for testing if plain iron is present.
Thanks for confirming what three others have corroborated as well.
There have been examples of how to test for iron listed above already, including aqueous washes causing oxide deposits, test strip from amazon in filament slurry etc. These should be sufficient proof to back your proclamations, oh wise leader.
This is super interestingā¦ so (sorry if I skimmed past and missed something) this is being seen in only Bambu brand PA-CF? but not in all examples?
Iād say this batch of filament has been contaminated during manufacture - more specifically the CF component. Wherever it was sourced from, it has been mixed with something ferrous at some point.
Orā¦ Bambu are trialing new materials with metal.
OneMoreDave had a different looking brand, and a few other reports about material makeup and the brand type.
It seems it is not consistent from batch to batch and it appears brand agnostic.
Most likely a base material change or manufacturing technique between batches.
Hope that helps clarify some as there is a lot of noise from experts who donāt seem to bring any real findings to the table.
Dude. Iām the thread starter. I think Iām entitled to say whatever I want as often as I want to. If thatās not agreeable to you, I encourage you to start your own thread on the subject. Donāt rain on my parade.
Iām not bragging about anything. I have a couple of decades experience with material analysis. If I can get access to a SEM, that would unequivocally solve the mystery.
Thereās nothing you can do in your kitchen to definitively determine why the filament has this property.
Except the things I say, apparently?
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You canāt own a discussion my friend and I was never specifically quoting you, there are a multitude of people in this thread. But if you believe the shoe fits, by all means go ahead.
How about we get back to the topic at hand.
Nobody stated anything was definitive except the people exerting what is and isnāt possible.
The things you have stated were not in question, except for the myriad of questions I had posed to you directly earlier, some of which you ignored outright.
If you have a problem with the conversation, then perhaps you are attaching too many emotions to a curious group of people.
We can draw many conclusions with 0.001% the budget of a SEM to the point where it may become trivial to even scan it. Will anyone be willing to perform any tests that could be done in the comfort of your own home?
Feels great: How to block or hide users?