Fire Safety Ideas

[delta22]

Looking for ways to build-in fire safety systems around a 3D printer.

Considering hanging this over my printer in case things get very ugly:

1) The Watch Dog Automatic Fire Extinguisher
http://htgs.pomodotech.com/product.php? ... =52&page=1

2) For fire containment, considering partial enclosure of cement board. This would help contain fire and concentrate effect of fire extinguisher.

Would like to shut off all power to the printer in case of fire or smoke:

3) Saw a very interesting suggestion on the web - take a smoke detector with a built in emergency/exit light and use the light circuit to operate a relay. Smoke detection = printer power cutoff.

4) Thermal cutoff - near the print head and near the heat lamp in my heated chamber. Over temp = printer power cutoff.
Would prefer to use a relay so thermal cutoff circuits are low voltage.
Many to choose from here: http://www.digikey.com/product-search/e ... tco/655696

More specifically to my modded Rostock MAX with heated chamber, I would like to find a way to automatically turn off my chamber heat lamp when the print job is done.
Heated chamber thread: http://forum.seemecnc.com/viewtopic.php?f=35&t=9706

5) Is there a circuit I can connect a relay to on the Rambo that is continuously powered during print jobs that shuts off at the end of a print job?
There are many heater and servo circuits that are intermittently powered, but I assume an additional logic board would be needed to switch off power at end of print job using these as inputs.
Considered using the PEEK fan circuit, but my heated chamber/lamp can keep the print head hot enough that the PEEK fan stays powered after the print job is over, so that would not work reliably.

Any suggestions and/or experience folks have would be greatly appreciated.

[Xenocrates]

1) Would certainly work. I might be worried about the sensitivity of it to say, the temperature of the chamber (although ~50C shouldn't trip it)

2) I would suggest you go for a metal cabinet, rather than cement board, or get a steel pan (They sell them to hold bedding for pets, among other things). I don't like the idea of trusting cement board to hold in those conditions, nor trusting whatever adhesive or mating system to work, and it would slowly crumble and make a bit of a mess, from my previous experience with cement board.

3) Worried about a false positive from PLA/ABS smoke and similar. Give it a try to see if it alarms before you hook it to your printer.

4) Thermal fuses, such as used in a copier are probably the easiest way to do it, as it could be tied into the wiring at the print head, as well as being connectable to the bed. Unfortunately, the cut-off temps on those you linked cut out at 240C, which is too low to print say, Nylon or PC well. (and both are 15$ parts with 100# minimum quantities.)

I'm currently working on making the Rambo control a chamber heater with a relay. Done right, and it will turn off at the end of the print just like the hotend or bed (As the printer will think it's a hotend)

5) I believe the PSU on pin, if it's enabled, would do it, and somewhere there's a suicide pin, which is always on while the printer is (if enabled), that I think is broken out somewhere (may also be the firmware side name for the PSU on pin). If you hooked the heater to your printer through one of the PWM EXT pins, you should be able to control the relay for it just like a heater. There being 4 thermistor ports on the board, and 2 extruder outputs, there's a spare one there for you to use to read the chamber temperature, even with dual extrusion and a heated bed. I will be testing how well it works over the weekend (if I have time), at which point I will attempt to document how to do it. You could also raise the temperature threshold on the PEEK fan a bit, so it's above the temp your printer can maintain.

[Windshadow]

These folks look to have one in the works but its not yet in their price list I just posted a bunch of stuff on their enclosures is this thread
http://forum.seemecnc.com/viewtopic.php ... =25#p84852
they are very expensive. for their boxes, and I would guess they are just painting black an OEM unit.
http://3dprintclean.com/enclosure-fire- ... on-kit.htm
[img]http://cdn.snappages.com/1tanat/assets/ ... 860677.png[/img]

[Eaglezsoar]

Cool looking extinguisher but I bet a very high price. I could not locate a price but you are probably correct, it is a stock unit that they painted black,
now we need the stock unit and it's price.

[Windshadow]

I would be happy with a high price for something like this if it was in Halon to preserve the bulk of the printer but the dry chem they mention makes a hell of a mess

[delta22]

Completed item #5 noted in the original post.
Upgraded to an E3D Cyclops print head, and followed installation advice to connect cooling block fan directly to system 12V power.

> This meant the PEEK fan circuit was now available for other uses.
> So I set PEEK fan circuit to shut off (when the print head is cooling down) to 100C and connected this to a relay.
> Relay is rated to be switched by 3 to 15VDC power and switch circuits up to 240V.
> This relay now reliably and automatically shuts off the enclosure heat lamp about 5 minutes after the print head heat is switched off.

The PEEK fan circuit comes on, and stays on continuously, as long as the print head heater is activated. Temperature setting for PEEK fan circuit only comes into play after print head is no longer powered and is cooling down. Had to increase this well above its original setting of 53C as the enclosure heat lamp would frequently keep the print head above this temperature. Setting it to 100C as noted above assures that the enclosure heat lamp will shut down.

[teoman]

You could have a look at arduino flame and smoke sensors.

[Windshadow]

[img]http://ecx.images-amazon.com/images/I/31ROyHufl-L.jpg[/img]the new smoke detectors are a lot smaller these days
http://www.amazon.com/First-Alert-Photo ... e+detector
about 2" in dia except for the base flange