Wednesday, July 24, 2013

Emissions from a 3D printer - are they dangerous?

Like many educators working with kids and 3D printing, my ears perked up when I read this blog post title, Could 3D Printing be Dangerous?

Reading further, I learned that a group had measured total ultrafine particle (UFP) concentrations resulting from the operating of a common desktop 3D printers inside "a commercial office space in Chicago."  (Here's a third article, if you are interested.)

This image was, by far, the "scariest."  You can see that the PLA printers were barely a blip, but when those ABS printers were turned on, the number concentration of particles spiked.

As I glanced from my computer screen to my Makerbot, I had some questions:  What does this scale mean?  Are the UFPs actually harmful, or just present?  Are these particles equal to or worse than the particulate from a busy outdoor street?  Or cooking indoors? In fact, the second article writes, "These emission rates are on about the same order as several other devices and activities known to emit UFPs, such as cooking on a gas or electric stove, burning scented candles, operating laser printers, or even burning a cigarette!"

Many of these questions remain to be answered.

In the journal article itself, the authors state. "One important limitation to this study is that we have no information about the chemical constituents of the UFPs emitted from either type of 3D printer, although condensation of synthetic organic vapors from the thermoplastic feedstocks are likely a large contributor (Morawska et al., 2009). In addition to large differences in emission rates observed between PLA- and ABS-based 3D printers, there may also be differences in toxicity because of differences in chemical composition."

But, some salient points came out of this article:

1.  Ventilation.  "Therefore, results herein suggest that caution should be used when operating these 3D printing instruments inside unvented or unfiltered indoor environments due to their large emissions of UFPs."  How ventilated is ventilated?  Is a classroom big enough?  How about if we keep the doors and windows open?    Can schools afford a ventilation system?  Can schools not afford to have one?

2.  ABS vs. PLA (<< link added later) - both plastics have their pros and cons, but the article did make me think more carefully about my purchase of a third classroom 3D printer.  We ended up going with the Printrbot Jr v2 (link added), which is intended for PLA.

3.  It is important to stay within the recommendations of the manufacturer.  Our Makerbot, for example, is set to 220 degrees Celsius for ABS.  I've heard (see point #4) that ABS particulate is not toxic unless it is heated above a certain temperature, often quoted to me at 260 degrees C.

Many people also complain of getting headaches from ABS printing, but in the 2.5 years I've been working with kids, I have yet to hear of a student making such a complaint.  (And trust me, they can complain about smells: isopropanol, sulfur...)  I am in the room the most, and ABS "fumes" have never bothered me, but I am not particularly sensitive.  Conventional wisdom states that PLA is friendlier, and smells a little like waffles when it's being melted.  (My room often smells a lot like 7th graders, so it can be hard to smell the waffles...) :)

4.  I need to do more research.

I'll keep you posted.

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