I figure by the time the flames have got there the machine has problem already got problems of its own!
I have a smoke alarm in my printer enclosure, but will definitely use one of these in he cnc enclosure (well that may be a long way off, but I"ll definitely use one! ) 
(Link chosen at random as an example - not an endorsement of this vendor.)
Halide systems are expensive and I’m pretty sure they depend on displacing the oxygen in a relatively sealed space. My enclosure would not be anywhere close to air tight.
If I wanted to go fancy I would probably do a liquid co2 system. I feel it’s better suited to these kinds of fires. It would be cheaper (co2 is available everywhere here) and it would still be relatively safe for the mpcnc components. Pluss then I could rely more on removing the heat to put out the fire rather than just displacing the oxygen.
Got me curious as I knew race cars had used halon systems for years and they’re not much of a sealed space. Seems other compounds are replacing halon as it’s a known depleter of the Ozone layer. Gasses that don’t leave a residue seem like a good option.
https://www.pegasusautoracing.com/advcat.asp?CategoryID=FIRESYSTEMS
This was definitely a good reminder for all. I will sheepishly admit I haven’t used my mpcnc for a while. I never leave the shop when it is on, but I am in the room.
This system appears to be fairly air tight. I am guessing the operator didn’t smell anything and only noticed a flicker out of the corner of his eye. When I am cutting or sanding, I wear PPE, 3M half face mask p100 filters. I don’t smell smoke through them.
I having been in small lab fires, I think they did a decent job. I wouldn’t want to be exposed to the smoke.
I wonder what was needed to bring the unit back to life.
$$$$$$$$$$$$$$$$
Nice thinking, but I hope my mpcnc doesn’t catch fire often enough to have an effect on the 100year carbon footprint (and I don’t believe co2 has an effect on the ozone layer)… or at least less of one then all the trees they had to cut down to make the wood I’m turning into chips XD.
Still think co2 would be my go too. I can buy 10lb bottle of co2 for $45 (at my local grocery store no less)… beats the hell out of the $400 they are asking for some of those alternatives. And it should not require any clean up either.
Problem there is they always make smoke it would be hard to sense what is good and when its gone bad
@timonjkl Yeah you would need a good sensor that can measure actual parts per million of a substance. Or one that detects heat intensity.
I know we used co sensors in our direct fired hvac equipment, but I’m not sure how much co a wood fire produces.
string on a weight strung over the top of the machine.
string catches fire. string breaks. weight falls and lands on button triggering fire suppression system.
New application for conductive filament… just run strings across the top of the enclosure. The fire will melt the filament and break the circuit tripping the alarm&starting the fire suppression.
It’s in a solid enclosure, just turn it off. That’ll kill the ventilation and It’ll burn itself out. Same rule for an oven fire. Do NOT open the oven…
Now, not only do they have a ruined machine, they also have smoke damage to a bunch of other things in the room.
But it is soo Hard to not peak 
Yea
Oven fires can be real bad.
My late grandmother had Alzheimer’s. She put a box of donuts into the oven and turned it on. Thankfully I was there. I screamed not to open the oven as I ran for the fire extinguisher. And when I got there with it, and the door opened I was able to blast the fire with it. And yea the air hitting an oven fire makes a nice burst of fire. And not in a good way.
Thankfully in our case no damage except for having to clean up the powder from the fire extinguisher.
True. A buddy had an oven fire. He couldn’t resist. He got lucky. It only took a few months for his eyebrows to grow back…
Another addition to why we watch our machines…
Last night, cutting small job had vacuum disconnected (shop vac was in the basement and I didn’t feel like going to get)
Mistake #1
Had loose end of vacuum nose dangling over edge of / near MPCNC (
Mistake #2
I was two feet away from the above photo, reading an email on my phone and thinking only two more passes around and this cut is done! And then I detected a change in tone from the router, it didn’t hit me at first but the stepper clicking sure did.
MPCNC had deviated from cutting path and was cutting a a fresh route at .405" depth.
On one hand I was proud of the little sucker plowing thru and valiantly trying to complete the task at hand.
On the other, what the heck is going on here?
Loose grub screw? Nope
Broken belt? Nope
Controller / Wiring glitch? Nope
That loose dangling hose had gotten trapped, compressed and wedged between the perimeter tubing and the x-axis, hindering any change in direction along that axis. But the y-axis was unhindered so the MPCNC, like a good soldier, carried on to the best of it’s ability.
Now since I was right there, I was able to abort and put the dewalt out of it’s screaming misery and access the damages. (It’s funny to me that at times I think the MPCNC cuts slow, but it sure cut an inch long path pretty quick here!)
Ok some deviation on the cut, but good news it veered outside the path of the cut, not inside, so as long I could re-zero I might be able to salvage the piece (I could, and I did - not perfect but close enough that a little sanding took care of it).
One bit who’s tip was blackened, but surprisingly completed the cut in the 1/2" baltic birch stock. (Have not tried any new cuts with the bit to see if it truly is still usable).
One big slap on the forehead for not moving the hose completely out of the way or not hooking up the vacuum before beginning (I attribute that to being excited about getting started cutting early on a Friday night while the wife was out of the house)
One very big sigh of relief on how LUCKY I was that:
A) I was right near the machine where I should be
B) I was cutting baltic birch and not MDF
C) There was NO burning of the plywood at all (Due to one of Ryan’s fantastic bits? maybe…)
D) I was able to shut down quickly and avoid any serious damages to project, machine or house.
What could have happened had I NOT been right there? (Those thoughts took over after I re-zeroed and completed the cut. As a result, I shut the MPCNC down after the cut, counted my lucky stars and called it a night).
Now is there any long term damage to the MPCNC?
Dunno, streched belt? maybe…
$5 bit burned to toast? maybe…
Shortened life on gears, steppers etc due to trying to cut damn near 1/2" deep in one pass? I’ll know sometime or I won’t.
Bottom line to this little tale of not so much woe?
Stay near your machine when cutting because you NEVER know what could happen.
I think it will be fine. We have all done some crazy cuts.
Super glad you were nearby, if it did start heating up it gets ugly fast.
You can cut pretty dang deep in BB sheets. The reason most of us do not push the limits in other materials is knots. MDF is very homogenous, and therefore you can push the limits further because you know there are no surprise knots in there to mess things up. (too bad MDF is one of the hardest “woods” to cuts). BB is very reliably surprise free, any knots are sliced to a thickness that does not matter. The worst thing about is apparently is the glue between layers. On regular Ply you can get gobs of it in small voids but BB does not have those.
People do cut 1/2" aluminum in one pass, they just typically use trichoidial milling. I do not have the eggs to try that.
That makes me think about all those benchy speed tests. We need something similar. 12mm MDF Logo runs?
Didn’t we work out an MPCNC “Benchy” project a while ago? Something like cutting both sides of a V1 logo inlay with the top rotated so the grain didn’t match up…
I remember trying a few things in CAD but never got too far with it.
Well, sheesh. Time to open that file back up. 
(Or source it from someone here…)
