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Speaking mainly to the folks who are running their laser(s) out of their homes. As I prepare to receive my laser I want to ensure that I am creating a safe environment in which to operate. Obviously the number one cardinal rule seems to be not to run the laser unattended. Aside from that what are you doing as far as fire protection or prevention as this seems to be the second biggest concern? Read a blog post yesterday of a guy that lost his garage and laser in a fire. That sparked my thinking.
I've got my CO2 and my fiber in my basement.
As far as safety, you mentioned most. First, Never, ever leave anything running that can catch fire. I might go to the bathroom that is 10 feet away if I'm running a cermark SS cup. Just say'n the laser itself might have meltdown, but not really much to burn inside the box. If I'm running anything else, Acrylics, Rowmarks, Wood, plywood, paper, foam, ANYTHING else, I'm usually at the machine or checking on it every few seconds at computer that is 3 feet way.
Second, have a good extinguisher near the machine. And know how to use it, and anyone that runs machine needs to know how to use it. Not intuitive for some folks, so instructions may be necessary. (you think I'm kidding, search for Tom Gresham, his wife allowed his house to burn with a minor fire and extinguisher right on hand.)
Third, make sure you keep your exhaust working decently. Mine will stop up or hose collapse and smoke will quickly be generated that fills up the laser and really can stink up the room. Keep it going outside.
As another point, I have been engraving mainly with air assist off. Seems to be std with Epilogs, but not necessarily with Chinese lasers. Rowmark and some woods. If power is high, you CAN have flareups. Some Rowmark type acrylics will flare badly, some not at all. Be careful and watch.
one way to use air all the time is to put in manual valve, something I should probably do.
DO use Air assist whenever you are vector cutting! Watch cutting things like corrugated and cheap ply, air pockets can create fires.
If you have kids that are not near adult level, insure that the laser is unusable by them. i.e. separate room locked, unplugged, computer disconnected, whatever you think is best. They might just want to show their friends your new machine and it's a toy to them. Train to help, but keep safe. Keep lid closed while operating as much as possible. I fail to do this on some items, if smoke or odor is an issue, lid is for sure closed.
In general, it is good tool, just be safe and think about safety as you use it. Hope this helps
Have a spray bottle filled with water right next to your machine for a quick grab to snuff out a small fire. Invest in a Halotron or similar fire extinguisher of at least 2.5 lb because when used it will not coat everything in the laser as well as the room with a thick layer of white powder. You can get decent prices for these if you do a bit of internet searching. Place it a few feet away but along your normal direct entry/exit path into the room that contains your laser. You don't want it right next to your laser because if you come into the room after forgetting the laser is running and the laser is ablaze you don't want to have to lean down next the blazing laser to reach the extinguisher. I have a second ABC-type white powder type extinguisher sitting on the other side of the door just in case the first one didn't quite finish the job.
Clean your cutting table occasionally to get rid of flammable buildup. Resin from woods, tar from acrylics, etc., will build up in the honeycomb cells if you have that kind of cutting table.
Buy a high quality 3M or North vapor mask with the most comprehensive vapor filter cartridge they offer (there are different types of filter cartridges so do your research). Every house should have one even if it is just used when doing deep cleaning. In regard to the laser, vaporizing the acrylic, the masking paper and the adhesive for the masking paper releases fumes. The level will vary by manufacturer. One I use barely puts out any noticeable fumes. Another I used put out incredibly strong fumes from the paper and its adhesive. If you are doing a run that takes hours you are going to get a buildup of these fumes even when you have an exhaust fan running. My guess is that your laser will be in a fairly small space and you can't leave it unattended. There will be times when it is smart to wear the mask.
Learn when you need to use your air assist and how much. While it isn't common, these cheap Chinese air assist pumps can and have gone out on people in the middle of a job. Flame-o-rama if you are cutting thick acrylic or wood slowly.
A good LED headlamp is a must have for repairing and maintaining these machines. A set of good optically clear safety glasses are a good idea to keep from bumping into things when your head is down in the machine fixing things that could poke your eye, although I admit I don't' use mine much. For most Chinese glass tube CO2 lasers, you don't need special laser protection glasses. Common safety glasses provide all the protection you need from the laser beam itself. You can research the archives for in-depth discussions about how much laser danger there is or isn't with these machines.
First and foremost, never operate the laser unattended, especially when processing flammable substrates such as wood or acrylic.
As Doug said, a spray bottle of water at the laser is good; it's cheap, simple, and quite effective for flare-ups. I've had the edge of a piece of wood I was cutting catch fire and keep burning even after the laser beam left that area, as well as two pieces of acrylic that caught fire (one while cutting near the edge and one in the middle of the piece while cutting out several small details that were closely spaced). The wood fire was obvious and was extinguished by blowing it out. The two acrylic fires were almost invisible and I detected one by noticing the bare surface of the acrylic was bubbling, the other by seeing the protective cover on acrylic start to crinkle and smoke. Both of the acrylic fires were extinguished with a couple of spritzes from the water bottle.
If you don't see the fire quickly enough, the spray bottle will be too little, too late. Have a good fire extinguisher with "reasonable" capacity (not one of those little spray can things) on hand; I have a 10BC CO2 unit because it will work on anything burning in the laser without leaving powdery mess behind, and I'm not concerned about anything inside the cabinet being damaged by cold shock. My laser is about 8 feet from the door to the room and the fire extinguisher is between the laser and door. In case the fire extinguisher doesn't function or complete the job, I also have a fire blanket suspended there; pull the bottom tabs and the blanket drops down to be flung over the fire, hopefully smothering it or at least delaying its spread to wall and/or ceiling. Directly above the laser is a dual sensor smoke/fire alarm that is designed to detect both slow (smoldering) and fast (blazing) fires. I suspect the fire would have to be pretty far along (as in burning through the cabinet lid) before the alarm would sound so, since you will "never" be operating the laser unattended, you really should notice the blaze before it gets to that point!
I will not leave it unattended, always staying in the shop, but when cutting will stay right next to it. I have a large extinguisher mounted right next to it, and a pump spray bottle of water. If I cut something that tends to flare I mist it with water before cutting.
Acrylic catches fire easiest when cutting near an edge. Always cut your parts from a panel that is a good 3/4" larger overall. Fine to cut much closer, but just pay attention. I also keep an air hose nearby, often in hand while cutting acrylics and other stuff to spray air right under or near an edge that is nearly catching fire.
Another tip - if you cut wiith the lid safety's over-ridden, so you cut with the lid open (Officially saying, don't do this, but if you do . . .) realize that if you get a flame or want to inspect a cut closely, your involuntary reaction is to lean down to blow or look closely. This is bad, as I burnt my nose from getting my face right in the beam path. You think you would never do this, but I did it twice. I fabricated a shield that mounts on the head so nothing gets in the path. Shield has to be short for when the head travels all the way to the left, but still works.
Glen brought a good point to mind. Some materials, particularly wood, can smolder after a cut. I believe that is what started Russ Sadler's fire (of YouTube fame). He cut something, pulled out the par but left the rest of the wood sitting in the machine, then walked away to work on the part. The leftover wood flamed up into a fire.
I never put my fire detector over the laser because I figured it would get triggered. Interesting to hear that has not been the case for at least one person.
by all means DO put a smoke or fire detector as near as possible to the laser! Under most circumstances the laser box is in a vacuum condition because of the blower. If your blower is inside, like mine in my garage, the blower will push small amounts of smoke into the room thru leaks in the blower housing and plumbing, and if a fire starts, hopefully (no experience yet!) enough burn residue will find its way to the smoke detector. But, if your blower is outside and very good at evacuating smoke, you could have a bonfire inside with no smoke for the smoke detector to detect! --until the plex melts, and at that point you want the detector to go off as fast as possible!
Me, I rarely cut anything, and being mostly a one man show with a five man workload, I don't have the luxury of babysitting machines. I've had a couple of fires in the LS900, usually due to me learning things the hard way (leaving combustible stuff in the laser that will be eventually be in the laser's path), fortunately I've caught them, and before the smoke alarms went off, both of which were 10' or more from the laser, which is why I suggest moving them closer! (I still need to move a couple of mine!)
FWIW I've never had a 'false positive'...
I have been operating in my basement for 20 years. Never leave the machine unattended--yes, if I have something that won't burn I may make a bathroom trip. I keep two fire extinguishers handy. One is probably enough but I just bought a new larger capacity one and kept the old one just in case.
Some people also have a fire blanket. Sounds like a good idea but I don't have one.
Nobody runs the machine but me.
Thanks for all of the input! It sounds like the Laser is as safe as the operator makes it. Since I have never owned one and nearing the time to order, spending a large sum of money and thinking of the risks involved, my engineering side of the brain took over and began to over analyze the idea to the point of talking myself out of it. (this happens to me all of the time)
Your exhaust extractor should be pulling any smoke out the back of the cabinet and pumping it either outside or through a good filter and returning it elsewhere in the room, so there really shouldn't be much chance of setting off a smoke alarm positioned over the laser unless you have a fire that is far enough along that it has burned through the (typically) acrylic cabinet lid. If your exhaust fan is marginal, you have been cutting something that is pouring out copious amounts of smoke, and you yank the lid open the instant the laser finishes cutting, you _might_ let out enough smoke to set off a detector?Quote:
Originally Posted by Doug Fisher
Keep your catch bin clean. That's the only place I have seen any unwanted fire.