Are 3D printers a fire hazard ?
The only place I have to my printer is in my basement. A wood printer, with parts that heat to 230c (or much more if it malfunctions), sitting in a basement of a wood house. I have to say I’m concerted about leaving it unattended.
What are your thoughts ? Have you seen/heard of a printer catching fire ?
1st off no printer printing should be left alone . Too many things can happen. Plus a smoke alarm in the area would be good too.
So you never do over-night prints ? What about large items, that take 12-40 hours ?
I have not done over-nighter’s or prints longer than a couple of hrs.
Hopefully others will chime in who have.
Even if your printer is terribly assembled and completely miscalibrated the hot end shouldn’t be able to come in contact with the wooden pieces. And I’d be somewhat surprised if the hot end alone can ignite plywood.
But before you leave the printer unattended for an overnight print, you need to be confident it’s functioning properly and unlikely to fail in a dangerous way (or any way at all, assuming you aren’t interested in wasting your time and filament).
It’s not something that would worry me all that much, but I also wouldn’t leave a printer I didn’t trust to work properly printing a long unattended print.
IMO The biggest fire hazard is going to be the wiring. Make sure the wires being used for the print head and print bed are heavy enough.
I think too that the wiring is the most dangerous part. If its done correctly a 3d printer isnt more dangerous than any other electronic device at home. Probably cheap china electronic devices are more dangerous.
All of the above and make sure your everything and but especially your heaters are properly fused, in case of whatever failure they should be cut off before running to hot.
Automotive fuses are a great match for our printers - they’re cheap and come in all the right sizes. Also make sure the connectors are up for the job (use ones that are at least rated for twice the current you’re expecting), especially the 2.54mm crimp connectors and the green 5.08mm screw terminal plug connectors are prone to overheating due to bad contact.
That being said, i trust my wooden printer enough to have it printing totally unattended. The worst that could happen is the printer stopping, which would form a blob on the hotend’s end and turn the filament inside the hotend into black goo, but otherwise your firmware has safety measures baked in (which actually work, too) to prevent e.g. the hotend from overheating.
E3D print cave runs 3 machines, 24/hrs a day, 70% unattended running time.
I have seen pictures from my customers of molten aluminium dripping from E3D heater blocks, I bet that would have a pretty good chance of igniting plywood, blue tape, PVC insulated wire, acrylic build platforms etc. If you set up your firmware failsafes properly I don’t see this being a real hazard though.
Main concern is wiring, chiefly moving/bending wiring with stress concentrations/tight bend radii. One of my self-sourced mendel90s used 30A wire for the heated bed. Where it was clamped to the frame before making the jump to the moving heated bed there was a small concentration of bending. I thought I mitigated this by using spiral wrap to enforce a bend radius of sorts. And estimated 700 hours of printing later the wire had fatigued and snapped inside the insulation giving a poor connection. I only noticed this because my bed was not hitting high temps, and would actually work better with prints at the back of the platform than it would with prints at the front! (Wire more/less stretched depending on bed position)
Left unchecked that would almost certainly led to fire - ten amps in a fatigued wire is going to make a mess.
I now only use ribbon cable attached to a polyethylene strip, as @nop_head told me I should have done in the first place! The ribbon cable and strip enforce a very gentle looping bend that doesn’t wear out just one part of the wire.
not all ribbon cables are “flexible” rated tho jus fyi