Fires

by JAH on Mon Jul 07, 2008 9:52 pm

Looking into this business and have seen some mention of fires. Under what conditions can a fire occur?
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by AK Chris on Thu Jul 17, 2008 5:37 pm

According to my laser rep, fires are pretty rare but not unheard of.

The best thing to do is never leave your laser (esp. if you are unsure of how the material will behave and especially when vector cutting.)

I just engraved a bunch of moleskines and had the settings low enough and had so many that after watching the first couple, confidently walked away and worked on other things.

I have a CO2 extinguisher next to mine just in case. According to him, not speaking from experience, if a fire occurs just lift the lid, the laser will stop and put it out. Often just stopping the cutting will do it.

Anyone out there with more experience agree/disagree, want to share their experience?

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by winch on Sat Aug 02, 2008 1:28 pm

I've seen plenty of small flames and lots of smoke but never an actual fire. Perhaps lasering really thin materials or equipment malfunction could cause one.
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Fires - I had one... a biggie.

by LaserGregg on Wed Aug 13, 2008 12:34 pm

I thought it wouldn't happen , but it did.
yes I left my machine for a minute on a phone call once.
when I came back my 75 watt epliog was melting in front of me.
I went fetal for about four hours.
It was a raging fire that totally sucked. I had to rebuild most my machine's table parts like reader strips, belts, lenses, mirrors, and eventually the CO2 laser. I was lucky that the motors were not damaged. or the PC boards.
200 hours of service call time in four weeks. and I did not give up.
does that help. a laser can get up to 3000 degrees I think.
hows that for a testimonial?
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by adafruit on Wed Aug 13, 2008 6:02 pm

! wow. that is terrible.
what were you cutting/engraving? :(
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where other laser people do not go.

by LaserGregg on Wed Aug 13, 2008 6:27 pm

thin acrylics are for weak machines.
I dig deep. as often as I can.
this is where other laser people do not go.
I can cut 3/4" hardwoods all day long. even an inch thick.
I can cut 1/2" acrylics all day long.
its not terrible. says who. cutting is a big part of my gig.
fire is a part of my day. I deal with it.
what happens where you're at? surface etchings
thats ok too I guess. it takes all types.
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Re: where other laser people do not go.

by adafruit on Wed Aug 13, 2008 9:41 pm

LaserGregg wrote:thin acrylics are for weak machines.
I dig deep. as often as I can.
this is where other laser people do not go.
I can cut 3/4" hardwoods all day long. even an inch thick.
I can cut 1/2" acrylics all day long.
its not terrible. says who. cutting is a big part of my gig.
fire is a part of my day. I deal with it.
what happens where you're at? surface etchings
thats ok too I guess. it takes all types.


huh? i was asking what materials were being cut/etched. i didnt say anything about 'weak machines'. i was trying to be sympathetic to your loss. its useful to know what is a risky endeavour since its not discussed often.
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weak machines

by LaserGregg on Wed Aug 13, 2008 10:58 pm

To me a weak machine is under 60 watts.
everything becomes harder to do at 35 watts. no?
You are limited in capability, or slow. or small in area.
in any event.... i use the word weak.
I took a risk and lost . my CO2 tube was dying out. and it was off warantee. that was a $2700 dollar replacement part from epilog.
I had changed settings to make things work and suffered the consequence.
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Re: Fires

by jbrandt01 on Wed Jun 24, 2009 12:16 am

Yikes, quite frankly I'm astonished that fires in these devices aren't more common. I have a 1-watt argon laser that I've sliced through paper streamers from across the room many a times and thats even on TEM01 with some crappy mirrors.
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Re: Fires

by adafruit on Thu Jun 25, 2009 11:54 am

pretty much everyone i know who has a laser cutter has had a fire
its not uncommon, but owners dont like to talk about it because its always a "i just left it alone for a few minutes...." story
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Re: Fires

by westfw on Thu Jun 25, 2009 3:06 pm

So what do you do to avoid fires in particularly flammible materials? I've been wondering whether a laser cutter would be able to cut particularly THIN materials that would otherwise be a pain (tissue paper, for instance), and keep wondering "won't it just catch fire?)
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Re: Fires

by adafruit on Thu Jun 25, 2009 7:59 pm

always watch it while cutting
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Re: Fires

by jbrandt01 on Fri Jun 26, 2009 1:35 am

westfw wrote:So what do you do to avoid fires in particularly flammible materials? I've been wondering whether a laser cutter would be able to cut particularly THIN materials that would otherwise be a pain (tissue paper, for instance), and keep wondering "won't it just catch fire?)


Ferrari's could go 180mph, but that doesn't mean you always have to :wink: , and if you are doing so its generally advised that you pay attention. Me personally, I drive a car that can barely keep up with traffic and my laser is only powerful enough to amuse the hell out of people, not burn them.


As for how and why thin paper doesn't burn up (from somebody who can only cut such materials) the energy is being concentrated into a small area. It will burn through that area and then is more or less no longer impeded so the paper isn't being heated enough to burn further. Now I think the whole fire issue stems from the fact these thin papers are sitting on aluminum tables when being cut. The lasers aren't powerful enough to burn through them, but enough to heat them up quite a bit. Aluminum is also a good conductor of heat, so this is then spread out to a larger area. The rest I think you can think of on your own.
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Re: Fires

by westfw on Fri Jun 26, 2009 1:55 am

@ladyada: watching it keeps it from catching on fire? :-)

The heatsink story makes lots of sense.
So are there different support grates for different materials? I've seen the default sort of 10mm honeycomb used to support plexiglass/etc, but if I'm going to cut tissue paper, could I install a thicker Aluminum sheet with periodic 3mm holes (for suction and smoke removal) to be a BETTER heatsink? (Hmm. Sheet of copper clad PCB material with hole grid as an "intermediate" layer? I gather that the average laser cutter is really bad at burning away copper clad...)
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Re: Fires

by karlgg on Fri Jun 26, 2009 4:32 pm

All this talk about lasers is making it hard not to run out and buy one. Not having any money (in laser-acquiring quantities) makes it somewhat easier not to. :P
I think I am, therefore I am... I think.
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