I´ve been following this discussion for the past few days, and I want to acknowledge @RocketSled for sharing this info. I started with doubts regarding the integrity of this info(sorry), as my Polymaker´s PA6-GF and PA12-CF filaments do not show any magnetic properties.
To clarify my mind, I just decided to open the BL PAHT-CF bag, and I confirmed the filament is ferromagnetic; despite not being strong, it is well noticeable by the human eye, i.e. a tiny magnet sticks to the filament and slides with gravity, and small but neodymium magnet stays fixed.
Manufacturing composites can be challenging, so imagining that a contained filament will prevail is hard. This rather-than-expected filament composition is intended and required to achieve high-temperature resistance.
Nevertheless, good practice standards would include such information in the technical and safety datasheets. This magnetic behaviour may cause problems if the print is used in sensitive components(e.g. electronics).
Has anyone tried to contact BL? I found no info on the TDS and MDS, but I was not looking for it then. Has anyone checked the datasheets?
Many thanks @RocketSled
I have noticed from working in a fiber manufacturing plant that uses tons of nylon pellets among other materials pa6 and pa12 both create alot of static when being conveyed in a vacuum system so id say that might be what you are seeing
Just found this, this is really interesting. Regarding the static electricity, it is very possible that handling nylon creates a ton of static electricity, this can even become dangerous. One of the best ways to get rid of static electricity is to make the stuff conductive.
Maybe, just maybe the additive we’re talking about was added to prevent static electricity from building up. Something conductive, probably ferrous.
So to join the club I need to order BL, PA6-CF, right? While I’m in the store, do you know of any conducting filaments from bambu?
Carbon Fiber is conductive. If dissipating electrostatic charges was necessary, the CF by itself is enough. Though it’s not really conductive enough to carry currents to do useful things like light up a LED.
Conductivity is “relative”. The wires carrying electricity around inside your house are very low resistance, milli-Ohm range. To be effective at dissipating static electricity, resistances in the mega-Ohm range are generally enough. Many orders of magnitude less conductive. Like CF impregnated thermoplastics.
That being said, I’ve got to disagree with “dangerous”. You would never be able to build up enough of a static charge on a 3D print to do you any harm. Even in a very low humidity environment, the charge is going to leak off almost as fast as it can build up. If you were making a print for use in an explosive-gas environment, there’d be some indirect risk of a spark setting off an explosion. But that’s about all I can think of.
The reason for ESD (Electro Static Discharge) safe plastics is because electronic components can be very susceptible to damage from static discharges. If you’re printing something that you’re going to be putting electronic components in to and then taking them out again, repeatedly, ESD plastic is a must. Or something with circuitry inside that will get handled.
I made a thing that uses a 4x 1" square LED panels arranged side by side, for a 32x8 “marquee” scrolling display. Works great in the summer when it’s humid. Two winters in a row now, just touching it inadvertently, I’ve blown up some of the LEDs with a static shock. I need ESD-safe plastic for my print to fix this problem. The charge has to be able to dissipate through the plastic instead of finding a better path through my LEDs. Alas, I have not as yet found a white ESD-safe filament that comes in 1.75mm…
Did you ever get the results back? I found this whole discussion fascinating and would be interested to know if there actually was iron in the filament.
Never bothered to find out. It’s magnetic, so it’s got to have some ferrous material mixed in. Maybe related to the tint or something (since I don’t think it’d help the polymer chains any). Ultimately just a curiosity…
I thought iron or other magnetically-active metal in filament was strange but remembered all the cinnamon contaminated with lead recently. It was added to make the cinnamon weigh more for increased profits even though it sickened a bunch of children.
I’d bet iron is cheaper than the plastic used to make filaments. Since it’s sold by weight and not length, it could just be a profit-boosting adulterant. Maybe there is a valid reason it’s in there. It will make the plastic and things made from it heavier. For some things that’s desirable.
One was indeed for color - that was the applesauce adulteration last year where lead chromate was added. But there was also a ground cinnamon recall this year where lead and chromium were found at high levels.
I had seen a report saying it was to increase weight and maybe some was, but this Consumer Reports article says it is just the trees absorbing lead from their contaminated environments.
I’d still bet the iron in filament is to increase weight though.
We discovered the magnetic properties of the material in the experiment and tested it using an atomic magnetometer. Approximately 2cm of the raw material contains about 50pT of residual magnetism…
I had intended to SEM/EDX a sample to see what its constituent elements were, but I lost interest. I don’t see how it can be anything else but Iron. The mystery isn’t so much what causes it to be magnetic as why the Iron is being mixed in. As some have suggested, maybe it’s just to increase weight. If Iron is cheaper than Nylon, that lets them ship less Nylon for the same overall spool weight. Though I’d like to believe there’s a more scientific reason.
