Radiation with a Class 4

[Jiten Patel]

Hey all,

I have been using our class 4 galvo for almost 2 years now. In that time, I have never worn safety glasses and there is no enclosure for the laser beam. I have been doing some reading about Radiation and class 4 lasers and thought I would see if anyone could shed any more light on this subject.

I know that on the regular laser-engravers you have your safety plexi lid which shields all/most of the radiation but on our open laser, does this pose a threat. If it does, how worried should I be?

The reason I ask, if I believe I am allergic to the dust caused by our work. I have cracked and dry hands due to it, but it got me thinking that maybe the deflected radiation may have something to do with this. Just want to know I am not slowly killing myself!!!

Thanks

Jit

[john banks]

Presumably the manufacturer advise on this with warning labels, guards, interlocks, shields etc?

I would have thought it should be enclosed if it is a CO2 laser, class 4, even low power deflection could blind you. Do you have your hands near it whilst operating?

What dust are you producing and does it give you a reaction anywhere else other than your hands?

I'm a general practitioner BTW, but I have never treated a case of laser injury.

[Jiten Patel]

Hi John,

Warning labels yes - interlocks yes, but these are optional and are not installed. No shields.

Sometimes hands go near the beam as it finishes it's cycle, so swap the piece out for the next.

The dust being produced is from cutting paper/card. Docs seems to think it's an allergy and got me on steroidal cream which is working, but not something I want to use forever. I wear cotton gloves now, but they are not great.

More worried about my eyes - not getting hit by a direct beam, but scattered radiation and long term effects.

[john banks]

Can you show a picture of the machine with a typical workpiece on it and your hands where they would go when you change the piece? Are you certain your hands are only going near when the laser is off, or is it finishing up the job when you reach towards it?

I think this setup should be arranged so that it is not possible for your to be exposed to scattered (never mind direct) radiation. It would be interesting to see if your hands improved once this is done as scattered laser over your hands could produce a similar appearance to an allergic/contact dermatitis.

Alternatively, wearing goggles and laser opaque gloves might help, but surely that is a second rate option to a proper interlocked enclosure, even though this might slow your work rate slightly you must prioritise safety.

I also wondered what training you had when you started on the machine or when it was installed and if your procedure is compliant with the manufacturer's safety instructions? I bet the supplier/manufacturer would want it guarded and interlocked to Scotland and back. Has an interlock been defeated to allow the present operation method? The scatter off white card could be substantial?

[Jiten Patel]

I will get a picture up later on tonight when I am near my machine. My hands do go near the machine while it is still firing, and coming to the end of its cycle. So that could be an issue. The doc said it was allergic dermatitis but it only affects my thumb and fore fingers. If it were due to radiation, surely it would be a more evenly spread affliction?

Adding an enclosure would drop my production rate down to a 1/3 so I don't think this is an option. I know safety comes first, so maybe gloves and goggles are the way to go and see if that improves things.

[john banks]

1/3 is quite a dramatic drop and agree on the distribution as you would expect it to be in the areas where you get scattered radiation, but it depends how you handle it and where the scattering is.

Do you have any option to feed your material automatically?

Would also look at the safety of others around the machine, if I was lasering with the lid of my machine open (I wouldn't except for alignment) I would insist that anyone nearby also had laser goggles on.

I'm used to lead aprons for x-rays and people standing back for DC shocks to patients, so apply the same principles to other dangerous sources. Double important if you have employees or visitors from the liability point of view.

[Jiten Patel]

No one goes into the laser-area apart from me and a few temps we have who are all trained on the machines (they wear goggles for liability reasons).

Feeing automatically would be a god-send but an very expensive bolt on! Cheaper to employ staff than to get the system in place.

[Dan Hintz]

I'll try not to admonish you, Jit, for doing something you know is a very bad thing long-term ;)

In short, though, the laser is not the cause of your skin issue, so listen to your doctor on that one. I would be heavily concerned for your sight and lungs, however. You do mostly paper, if memory serves, so being near it without a good collection system is equivalent to standing in a room with someone burning paper all day (same process). From an eyeball standpoint, reflection from paper isn't a big deal, but who's to say you're only getting reflections from the paper... what about the table? It may be minor reflections overall, but the effects can be cumulative, so it's like hanging around smokers but not smoking yourself (not to tie it back to lungs or anything, just an appropriate analogy).

I would consider changing your work habits, if nothing else just wearing a pair of glasses (of any type), as it's such a simple change.

[Scott Shepherd]

Adding an enclosure would drop my production rate down to a 1/3 so I don't think this is an option. I know safety comes first, so maybe gloves and goggles are the way to go and see if that improves things.

Maybe not. Without seeing it, I can't say, but the few galvos I have seen are very easily tooled up to do high production stuff. Have you seen the machine that does the laser tiles? The one with the rotary table on it? Think that way. Put a "lazy susan" style table in place, put guards around it, run the laser, pull a pin or push a tab or something, and rotate it to the next piece. It might take 2 cycles to get it to the point where you can load it outside the guard, but you could be loading pieces no where near the actual laser itself and be fully protected.

If you don't understand what I'm talking about or haven't seen that machine, it looks like this....

I'd make some modifications to it so it had more protection, but you get the concept.


http://www.youtube.com/watch?v=usOEApAJdYg

[Jiten Patel]

Dan, consider myself firmly admonished.

We do have an extraction system which doubles as a vacuum bed so smoke is pretty much non-existent. But i failed to mention, I do wear a mask to protect my already damaged smokers lungs!!!

Completely get what you mean with regards to damage over time with minor reflections, so goggles it is.

Scott - funny enough we were offered that exact machine at the time we purchased our 30w galvo. Trotec acquired a company who has a 100w lying around and offered it to me for the same price, but as it had been sitting around and without the chance to test it, I politely declined.

A shuttle system like that would be fantastic but due to the varying sizes we cut, I can't see how each section would line up perfectly for the cut? I have seen simpler shuttles with just two pieces, one cutting while the other gets swapped. Might have a go at making one when I get my flat bed - easier to manufacturer rather than messing around with tools. Give me a computer and a design package and I will design you the world, give me a piece of wood and a hammer, expect nothing but broken thumbs!!!

Thanks for the advice folks, much appreciated.

[Rich Harman]

What kind of radiation is being emitted that can have a cumulative effect?

[John Bion]

No one goes into the laser-area apart from me and a few temps we have who are all trained on the machines (they wear goggles for liability reasons).

Feeing automatically would be a god-send but an very expensive bolt on! Cheaper to employ staff than to get the system in place.

Hi Jiten,
would you be able to send me some pictures of your machines worktop. What type of surface do you have? My imagination is tickled as to how to try automation. Not saying I can help but I would love to have a look at it.
kind regards, John

[Matt Turner (physics)]

The "radiation" from the laser is just the laser light itself. Exposure to the CO2 laser wavelength can cause burns, but I'm guessing that you'd feel the heat before any real damage happened. I'm pretty sure there's no cancer risk. I'm a physicist, not a doctor, though :)

The cracked and dry hands reminds me of a seasonal symptom I had, where every spring the skin on a few of my fingers would get dry and start cracking. At first I thought it was a side effect from my allergy medicine, which I start taking about the same time. After changing medications, though, I discovered the real cause of the symptom—spring also corresponds with when I start grilling every week, and when I grill I check the temperature by briefly holding my hand over the grill. My wife got a good laugh at my expense when I figured out that the symptom was from me cooking my fingers. Anyway, maybe the scattered laser light it having the same effect?

[matthew knott]

Jit, you bad bad boy !!!! But seriously running a class 4 with no saftey glasses is a no-no both legally (in the UK) and just being sensible. The risk of getting a beam in the eye is probably remote, I honestly think it would be no more dangerous than being in a machine shop with bits of metal flying about in the air, but it is there. At least the co2 wavelength would 'only' damage the cornea (not exactly ideal). I regularly saw operators (China-Thailand) using way more dangerous lasers, day in day out with absolutely no eye protections and I was told that no one had ever had a problem, but I wonder if they just sacked the blinded workers!

https://mail.google.com/mail/?ui=2&ik=1d3327e6e0&view=att&th=137d1f703ad2d136&attid=0.1&disp=thd&zw
I think you could enclose this with some acrylic panels, you could leave a small 5mm gap and slide the paper under. I hope the vendor told you not to use this bit of kit with out following all the safety rules, they should have made you sign something (i would)!! Oh and wear some surgical gloves, they will still protect you.
Cheers
Matt

[Dan Hintz]

What kind of radiation is being emitted that can have a cumulative effect?

We're not talking Gamma radiation or the like, so don't confuse yourself with the term "radiation" here. The cumulative effect is damage to the cornea and lens over time. One-time or short-term damage (like surgery) will heal, but repeated damage (such as low-level hits with a laser) can cause the body to take more reactive measures... kind of like your foot's heel hardening over time with use. Cataracts, for example, are a very real possibility if you're hit often enough with a strong enough beam.

[Rich Harman]

We're not talking Gamma radiation or the like, so don't confuse yourself with the term "radiation" here. The cumulative effect is damage to the cornea and lens over time. One-time or short-term damage (like surgery) will heal, but repeated damage (such as low-level hits with a laser) can cause the body to take more reactive measures... kind of like your foot's heel hardening over time with use. Cataracts, for example, are a very real possibility if you're hit often enough with a strong enough beam.

It does not make sense to me that exposure to IR radiation (heat), which does not cross the threshold into causing damage, can accumulate. The amount of scattered radiation that you are exposed to is going to be roughly the same as what you would get from a light bulb of similar wattage.

It is the one in a million reflection off just the right shape of surface that warrants wearing safety glasses in my opinion.

[Dan Hintz]

It is the one in a million reflection off just the right shape of surface that warrants wearing safety glasses in my opinion.

This is what I'm talking about... minor reflections that do a little bit of damage here and there (like off of the cutting table), but go mostly unnoticed, and they're not one in a million. It adds up. Scattered reflection from the stuff you're cutting is, for all intents and purposes, irrelevant.

[Bill Cunningham]

Along the same note, I'm not sure if this happens in the U.S. or just the nanny state of Canada. I had a visit last month from a government inspector checking lasers for radiation/laser type, and safety equipment in use near it.. She was polite, but like many government inspectors, she really didn't know a heck of a lot about CO2 lasers of our type.. She left by giving me a piece of paper that said our system was safe and inspected by the Ontario Government. I feel Sooo relieved...

[John Bion]

Older thread now, but I thought that this You Tube clip was of particular interest, though would probably require a bag of gold: http://m.youtube.com/watch?v=0_3o1OiLcO4&feature=related#/watch?v=0_3o1OiLcO4&feature=related, this is sent from an ipad, so hope link will work ok.
regards, John