This is a photo under blacklight of an opaque white PLA printed part. Some layers glow under blacklight, some do not. It’s hard to photograph but the streaks of fluorescent material are really obvious in person.
UV-fluorescent pigments are pretty common for “neon” colors and super-high-brightness whites, but the concern here is that the UV-sensitivity of the pigment is very inconsistent within a single spool. What I suspect is that some recycled white plastic was added into the pellet feed. It may or may not have been PLA. It may or may not contain toxic chemicals. Without paying to send it to a lab, there’s really no way to know.
I don’t recall the brand used here – I printed these over a year ago and only noticed the fluorescent streaks recently. I don’t buy really cheap stuff though, I’m sure it was a ~$30/kg spool.
Even if your filament vendor is reputable and perfectly trustworthy, their sub-suppliers may not be. It’s quite hard to keep junk out of the entire supply chain without rigorous lab testing or very cautious US/EU-only sourcing.
I’m a chemical engineer with professional background in materials safety and chemical exposure hazards. I also have a 7 month old son who likes to chew on plastic. And I’ve decided that Taulman nylon and a few other natural/clear materials from US/EU manufacturers are about the only filaments I’m comfortable with for making toys or food contact items for my family. I’m NOT worried about nanoparticle emissions – but I am worried about lead and cadmium and strontium in the stuff I give to my kid.
This is an area where we need more community outrage.
Most 3D printing doesn’t make sense for food contact, extrusion type has layering and extrusion lines with voids and crevices that trap particles, and few standard plastics used for FFF can withstand the temps for proper sterilization. The real outrage is misleading marketing that gets people thinking that food safe on the label means you’re making food safe parts - you’re not, by a long shot.
@Nathan_Walkner True, but not a lot of people would buy children’s toys or food service items direct from China off aliexpress. But people will buy cheap filament and then print cookie cutters or action figures.
@Nathan_Walkner yes, and everyone gets up in arms about that. It’s regulated, the media reports on it, and there are often large product recalls when contaminated toys are found. We’re not there with filament yet.
This place blows up with concern and commentary every time somebody mentions fumes or nanoparticles… And yet every thread about filament vendors has many people recommending the cheapest AliExpress stuff they can find. It just needs to be part of the dialog.
If I might go out on a limb, I’d say chipped filament with 3rd party safety certs would be a good option for the market. Then all the closed vendors could justify why their stuff costs 2-4x more.
Most folks won’t have the means to determine whether what they have is dangerous or hazardous or not. I know I don’t. I can trust the labels and make my decision based on those sources of information.
I doubt older plastics are safer since they were flagged safe before the long term exposure risks of certain chemicals were known/understood.
To be honest, i would not use filament printed plastic parts for things coming into contact with food or if they will be in someone’s mouth for a period of time.
For clay cutters, adapters, and other non-food usage? Sure. For something I’ll handle on an extended basis…? I would make sure I sourced the best possible plastic. But even then, the seller may have gotten a bad batch or perhaps they got swindled with some cheap heavy metal laden batch. At that point, I’m kind of SOL.
Chip’d and certified plastic sounds like a great solution save for the added end product cost and the issue of trusting a certifying body. Others will complain about choice/etc.
I think that ultimately, the best solution is cheap/affordable/available hand held scanners capable of telling you how much of what kind of heavy metals/substances are present. Then the consumer can truly make their own informed choices.
Hmm, there’s an idea, open-source material identification guns. We use them in my line of work sometimes but they’re very expensive. Not sure how well they work on trace contaminants though. You need a proper lab setup for trace element analysis.
The big issue here isn’t “some small fraction of plastic is contaminated” like we see with housewares and toys. It anecdotally appears to be a LARGE fraction of Asian-made filament.
Yes, some meaningful portion of the market will pay extra for verifiable/traceable materials free of contamination. Taulman makes medical-grade nylon for that exact purpose. The fraction of people willing to pay extra for safer material will rise as awareness spreads of how legitimately bad the cheap stuff might be.
I WILL pay significantly more for higher-quality material when it comes to stuff for my family. And I’m no chemophobe.
If you’re buying toys at Dollar Tree, yeah, a lot of it is going to be contaminated. Their violation rate is insane.
A ton of stuff is tested these days though, by both the government and consumer advocacy groups. Even if the tested stuff is a small portion of the total, there’s so much plastic imported that if you randomly test even 0.1% of the total, then that will still give you a statistically valid measure of the total contaminated fraction. Kind of like how a voter poll only needs to ask a few thousand random people to get reasonable accuracy. We don’t know the exact percentages, but we should have a good idea of what the likelihood is.
What I can’t figure out is what fraction is actually dangerous. For example, if you ask “what fraction of Chinese plastic toys contain any measurable amount of lead” then the answer is huge, apparently MOST of them do. As do many American/EU products because trace lead is a common additive in many types of materials. But if you ask “what fraction of Chinese plastic toys violate actual regulatory limits for mobile lead” then the answer is going to be much lower. Some trace lead is allowed, particularly in applications where it’s not likely to shed dust or leach into liquids. Exposure routes matter just as much as the detectable ppm concentration levels.
