Ask Hackaday MRRF Edition: 3D Printers Can Catch Fire


[Jay] out of the River City Labs Hackerspace in Peoria, IL cleared out a jam in his printer. It’s an operation most of us who own a 3D printer have performed. He reassembled the nozzle, and in a moment forgot to tighten down the grub nut that holds the heater cartridge in place. He started a print, saw the first layer go down right, and left the house at 8:30 for work. When he came back from work at 10:30 he didn’t see the print he expected, but was instead greeted by acrid smoke and a burnt out printer.

The approximate start time of the fire can be guessed by the height of the print before failure.
The approximate start time of the fire can be guessed by the height of the print before failure.

As far as he can figure, some time at around the thirty minute mark the heater cartridge vibrated out of the block. The printer saw a drop in temperature and increased the power to the cartridge. Since the cartridge was now hanging in air and the thermistor that reads the temperature was still attached to the block, the printer kept sending power. Eventually the cartridge, without a place to dump the energy being fed to it, burst into flame. This resulted in the carnage pictured. Luckily the Zortrax is a solidly built full metal printer, so there wasn’t much fuel for the fire, but the damage is total and the fire could easily have spread.

Which brings us to the topics of discussion.

How much can we trust our own work? We all have our home-builds and once you’ve put a lot of work into a printer you want to see it print a lot of things. I regularly leave the house with a print running and have a few other home projects going 24/7. Am I being arrogant? Should I treat my home work with a lesser degree of trust than something built by a larger organization? Or is the chance about the same? That said, my trust is also placed in the greater open source community at large. I know Marlin has protection built in to compensate for this failure, which is more likely in home builds than in a tightly controlled assembly process such as Zortrax is likely to have. However, I’m expecting that code I’ve never finely reviewed done by a person unknown to me to protect my home from a similar failure. It’s hard to predict the location of a critical failure with distributed development, and I’d love to hear the communities thoughts on it.

The other side of the coin is corporate responsibility. By all reviews and regards the Zortrax M200 is a wonderful printer. It’s well made, their software is great, and it prints beautifully. Even after witnessing this failure, it’s still my go-to recommendation for a printer for small engineering offices (especially if you’re the one who will have to support the “dang stupid print machine”). It is, however, as closed source as they come. The warranty is voided if you feed off market filament into it. They insist that you send the printer in for repair, even for routine things like an extruder jam. Under this information, we can’t immediately fault them for not having the foresight to see this failure mode, though it is horribly obvious in retrospect. So, if you made a modification or dirt standard to a repair out of manufacturer insistence, and a critical failure occurred because a common-to-hackers-fail-safe was missing, who’s responsible? Is the manufacturer right because they wanted to do the work themselves and control the input to their machine to ensure proper operation? Or is the user right because it’s their machine and, by all regards [Jay] is competent enough to perform the repair to his machine?

A cautionary message from [Jay]
A cautionary closing message from [Jay]

It’s also a very good case for open sourcing safety critical code. Someone might have seen this lack and just fixed it. Just like with the debates around encryption, if we can’t look into the code that we’re trusting and make sure the things we expect are there, do we really own it? I have a little more trust over my printer not bursting into flame because the parts were all hand picked for quality, I’ve read the code, and I am a fanatic about electrical connections. However, if I had the cash I would have a Zortrax on my desk right now, (and a few of the ones at MRRF, they are very nice) and I know I would trust it too. It’s a subtle game.

In the end [Jay] is out a nice printer, but luckily the damage was contained. Do you leave your printer running when you’re out of the house? Have you had a real or avoided disaster with something you’ve made? Do you have an anecdote about a commercial appliance with a safety oversight? Or do you just have thoughts about personal and corporate responsibility? We’d love to hear it.



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