Fire, how easy it is to start one!

smreish · #1 Wed 08 April 2009, 14:48

MM fans.
A cnc company last week had a dreadful week. The 5' x 10' machine (similar to the Shopbot PRT) was busy cutting 3D relief panels. These require about 20hrs of constant machining for completion. The operator went home for dinner and left the machine busy removing 1/16" of material per pass. Well, the tool bit hit a holddown screw, sparked, and burnt down the entire shop, machine and finished goods. HUGE financial loss.

MDF dust is very flammable. Be careful out there.

Sean

jhiggins7 · #2 Wed 08 April 2009, 17:31

Sean,

Thanks for sharing. Reminds us all how easily (even innocently) a FIRE can be started or something else can go wrong.

I would say a CNC machine CANNOT be operated UNATTENDED even though it might be a mind-numbing, boring job just to watch it do EXACTLY what it is programmed to do.

Regards,
John

domino11 · #3 Wed 08 April 2009, 20:10

This happened to a guy on the shopbot forum last year as well.
His dust vacuum caught fire.

http://www.talkshopbot.com/forum/mes...312/29351.html

Scary stuff. Be careful guys always.

Gerald D · #4 Wed 08 April 2009, 23:53

I would say that the system can be left unattended, to the same extent that lots of industrial machinery gets left "unattended". However, those industrial plants are tended by fire detection and fire suppression systems.

If you do want to leave your MM unattended, tell your insurer about it and see what book he is going to throw at you . . . . . .

Marc Shlaes · #5 Thu 09 April 2009, 13:01

Here is some personal experience. JR and I had a 1/4" downcut spiral mounted just to compare cuts with the "standard" upcut bit. On some straight plunge cuts - basically drilling 1/4" holes, the downcut started a fire!. No kidding. Had we not seen it immediately, there could have been a big problem in the dust collector.

WTI · #6 Sat 11 April 2009, 19:10

If your shop has running water, you can just plumb in some sprinkler heads. One over the MM and one over the dust collector.

Many people I know have plumbed one in themselves over their furnace and hot water heater.

Heads cost $10 USD each. A small price to pay.

WTI · #7 Sat 11 April 2009, 19:14

In the rough and tumble world of a workshop, get the cage guards that fit over the heads. You don't want to break a head off accidentally.

Each head activates only when it reaches a certain temp. They do not all activate at once because one was triggered. That is just in the movies!

inventall · #8 Sun 12 April 2009, 07:48

I like this Idea
26863_FAM.jpg

G30ff0 · #9 Sun 10 October 2010, 20:22

Brings back memories,

I actually witnessed/put out a fire on a multicam (the first router i operated in 95), was cutting 6 or 8 mm alloy when the end mill broke, the shaft hit the collet & sparked. At the time was using (as instructed) kerosene & oil as a cutting lubricant & had a 400 mm flexible air vent duct just off the table, The ducting went up quicker than i would have thought possible spreading the fire into the next room as well.

Luckily there were a couple of extinguishers around & the damage was little apart from charred paint, destroyed ducting & polystyrene foam. Those fire drills in navel cadets came in handy…

The stupid thing about it was that when I suggested vegetable oil & getting 3/16th shank bits instead of 1/8th to reduce the fire risk I got told to "do as i say boy"
I found another job a few weeks later