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Now for the questions
4

Now for the questions

Now for the questions

(OP)
I will start with the background. I work for a company that has two Trumpf TruLaser 2030 cutting tables. Both machines are about five years old with cut tables that are enclosed on the sides but not the top. There are no overhead operations so there is no employee exposure at heights beyond the top of the walls.The most exotic materials cut on these machines are stainless steel and aluminum, however most of the time carbon steel is all that is being cut.

When the machines were purchased anyone having anything to do with the operations of the machines attended the training provided by Trumpf. My employer has had a maintenance agreement with Trumpf where the they do the required maintenance on the machines, so our people never go into the resonator or the other sensitive laser parts of the machine. The machine has multiple interlock points and of course the key at the opertors console. As far as I have been able to determine the short list that follows is all our people routinely do with the machines.

1) Change cutting heads
2) Empty the fines that collect in the waste container
3) Fill Kluberlube
4) Change gas cylinders
5) Clean mirrors and I think sometimes change them as well.
6) I think they are also able to make some adjustments to the beam, but not turn the machine/beam on until the interlocked operators access door has been closed with them outside the walls. (not 100% sure of this)

So, here is where my questions begin. The machine is a Class 4 laser inside the walls during normal operation and Class 1 outside the walls during normal operation. With as far as I can tell all of the maintenance work being done by Trumpf can I develop a Laser Safety Program based on the machines being Class 1 instead of Class 4? Or must I implement a Class 4 program even though our employees do not perform the routine maintenance on the machine? Can I get away without any written program or a LSO? Or do I develop a Laser Safety Program that does not address all of the maintenance activities our employees do not perform?

Any guidance or light other members can shed on this subject would be greatly appreciated. Don't worry, I will be contacting Trumpf and continuing to ask questions of others until I get to the bottom of the issue, further, I will implement whatever level of safety program and ongoing monitoring I must to make sure we are in full compliance before this is all said and done.

Help a greenhorn if you can, Thanks.

RE: Now for the questions

Do you even have an LSO? Shouldn't that already have been done before your time?

As to your maintenance items, ANY work that requires penetration into the work area of the laser must be treated as working on a Class 4 laser. The simplest example is if someone intentionally or unintentionally starts up the laser while the maintainer is cleaning the mirrors, BAD things could happen. That said, your shrouds should interlock that scenario out. But, there are people that will bypass such interlocks as a matter of course. Sounds like you need to verify that each of your interlocks still work.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

RE: Now for the questions

(OP)
You are correct, there should have been a LSO designated when the machines were first purchased and the Trumpf manual stated as much. As to the interlocks as far as I have been able to determine all of them are functional as they came with the machine. The operator showed me how they work, each stopped function of the machine and threw error messages at the machine when tested. For example, with the doors opened at the control panel nothing would work when changing out the cutting head, as soon as the doors were opened all function ceased. I have no reason to believe any interlocks have been bypassed either.

I was only hired a couple of months ago and I have made this one of my priorities to make sure the company is in compliance with ANSI Z136.1. I am eager to make whatever corrections we must to make this situation correct, but with little background in lasers I do not want to take well intentioned steps that possibly were/are overkill and in no way apply to the situation.

Is what I described what is known as an "embedded" type of laser? No mention is made of that in the machine manuals, but in what reading I have done it sounds like this is what we have which has created more confusion for me. On the other hand I think this must not be so or the machine manuals would have made mention of this.

RE: Now for the questions

Embedded should be interpreted loosely. When the system is normally in use, with all shrouds in place, then it's Class 1, with an embedded Class 4. However, when you are maintaining it, and there is the possibility of being exposed to the beam or reflections, it's definitely a Class 4. The laser safety markings should be consistent with that, i.e., if you are inside of the shrouds, all the laser markings should indicate Class 4, and only on the outside of the shroud should there be an Class 1 markings. There are very few lasers that are Class 1 at every possible position within the laser.

So, for each of your 6 items listed above, you need to determine by physical inspection or inspection of drawings whether the person can be exposed to the internal lase:

1) Change cutting heads
I'm guessing this requires getting inside

2) Empty the fines that collect in the waste container
I'm guessing this is a runoff collector, so probably OK

3) Fill Kluberlube
Ditto

4) Change gas cylinders
Probably OK

5) Clean mirrors and I think sometimes change them as well.
This requires access to the innards of the machine

6) I think they are also able to make some adjustments to the beam, but not turn the machine/beam on until the interlocked operators access door has been closed with them outside the walls. (not 100% sure of this)
Sure, but that's a tedious process, and there may be some motivation to cheat the process by defeating the interlocks.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

RE: Now for the questions

Oh, btw, there is someone with Krugtech as his handle who I think is pretty knowledgeable in laser repair and maintenance, and you should probably wait to see what he weighs in with.

TTFN
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RE: Now for the questions

(OP)
I appreciate your rapid response. The Class 4 status during maintenance I understand.

1) The changing of the cutting heads is done from outside the machine. The operator travels the bridge to his end of the machine, I watched him turn the machine off, however he also showed me that if he did not turn the machine off then as soon as he opened the doors to change the cutting head a big error message came up on his screen proving the interlock worked. The operator did not have to enter the machine, he simply reached in and with the aid of a simple tool removed the cutting head that was mounted and replaced it with another; All done standing outside the machine and next to the control panel.

2) The fines sat behind a door on the outside of the machine that you opened and removed the waste then replaced and closed the door. This too was on the ouside of the machine.

3)Same as waste/fine removal, yes.

4)Removed from the machine and secured to the wall of the building behind the machine.

5)Correct, I confirmed this as true. I assume this will be a determining factor even if all interlocks are functioning and our folks are applying electrical lock-out.

6) I understand questioning the proper operation of the interlocks, but just for the sake of discussion assuming all of the interlocks are functioning as they originally came with the machine where does this leave me if to make the adjustment I also have them apply lock-out to do the beam adjustment as well?

Again, thank you for the help.

RE: Now for the questions

(OP)
So by your response I take it that under normal operation (excluding maintenance) what I described is what many are calling "embedded" correct? At least that was what I took from your response.

RE: Now for the questions

(OP)
Actually, I do not recall seeing any Class 1 markings anywhere on the machine. In fact, the only place mention is made of Class 1 ouside the walls was in the operators manual sent with the machine. The manual also said under "normal" operation no laser glasses needed as it was a Class 1 environment. The manual also called for Class D fire extinguishers which I have had the company order for each machine. Of course the manual went into full details of guarding against Class 4 for maintenance work.

RE: Now for the questions

OK, slight misunderstanding, the fact that the operator does not "enter" the machine is irrelevant; the opening of the protective shroud is what changes the situation.

Item 6 is clearly an Class 4 situation during the actual mechanical adjustment, assuming the shrouds are opened for that.

TTFN
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RE: Now for the questions

The interlocks should be the key. If the beam can't be generated when someone would be endangered by it, you have a fairly safe situation.
Bear in mind that a runaway axis can kill you easier than a laser beam can.
Interlocks, and for some things, how about Lockout/Tagout?

cheers
Jay

Jay Maechtlen
http://www.laserpubs.com/techcomm

RE: Now for the questions

(OP)
IRstuff: So any beam adjustment regardless lockout, or interlock function makes this Class 4 activity then correct.

JayMaechtlen: I plan to require lockout for anything beyond normal operation so yes certainly lockout is part of my game plan.

RE: Now for the questions

I'm having trouble understanding where you're hung up. If that laser could be operated and the beam could be accessible to a human being, then you have a Class 4 safety concern. Given that concern, you institute interlocks, googles, warning lights, etc. Once you have interlocks, you then need to be concerned about bypassing, since there's a certain level of complacency that comes with, "It's interlocked." This then enters the realm of procedural controls.

TTFN
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RE: Now for the questions

I can't comment here. The safety people have corrupted my mind. Right now I'm suffering from beeper indifference syndrome, warning light indifference syndrome and sticker indifference syndrome. There's so many beepers and stickers and warning lights now that they just saturate my mind. Just another thing the greedy lawyers left for us to deal with.

The way i stay safe is to break down the dangers and understand them. As mentioned before, axis runaway is what hurts people, followed by touching the HV section while it's on. I saw some people stick their fingers near the nozzle and get burned by the CO2 beam but it was either a safety interlock was bypassed or the shutter malfunctioned. On that note, the fiber lasers are a totally different ballgame, that light is VERY DANGEROUS! (cumulative and permanent eye damage)

When I work in a shop w a lot of rules, I request a variance. I walk around the machine w the LSO and explain what I'll be doing, what exposed dangers will be present and then we decide on the safety measures, usually taping off the area and no lone zone (I get a babysitter). After we agree on the variance, we both sigh it and follow it.

There's so many holes in all the safety rules I've seen. Personal responsibility and understanding the equipment will keep people safer than rules.

Chris Krug http://krugtech.com/
Maximum Up-time, Minimum BS

RE: Now for the questions

I am surprised that no one had mentioned the Zinc selenide used in the lens.
-HR

RE: Now for the questions

About the ZnSe, per lens manufacturer, toxicity studies have shown that this material is not toxic. HOWEVER, long term effects of ZnSe dust inhalation are unknown. Therefore, it should be handled with caution. It's when the lens cracks that dust could fly around and get inhaled. I recommend waiting for the dust to fall down before going in for cleaning. Wear a mask to avoid breathing the dust. Wear gloves and avoid touching your face. Wash your hands once done to avoid transfer of ZnSe into the mouth. When cleaning, use soapy water to avoid airborne dust.
As already mentioned here, the manufacturer should mention if the machine is a class 1 or class 4. In any case, as soon as a cover or safety is removed (during repair, maintenance,…) allowing the laser beam to potentially reach someone, it becomes a class 4 laser.

RE: Now for the questions

We use ZnSe optics for all of our infrared sensors, without a problem. Unless you plan on zapping the optic every day, and breathing in the vapors every day, there really isn't a problem. Getting clobbered by a high-voltage supply is a more likely hazard.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

RE: Now for the questions

(OP)
The situation has been resolved for me. When I started the thread I was initially hearing that our people did virtually nothing in the way of maintenance and I was not really sure they were involved at any level with beam alignment. Everyone involved with the laser had been trined through Trumpf and discussion indicated they were all well aware of concern areas.

Where I was having problems was Trumpf's operator manual said under normal operation the machine is a Class 1 laser. They clearly indicated that service and maintenance was all Class 4 activity. However, I kept hearing that our people were not involved with any maintenance activities, and quite limited activity that could be called service.

As discussion has continued finally it has come out that in fact our people are doing maintenance on the machine because they will get on the phone with Trumph technicians who will direct them over the phone what they need to do and what to adjust, change etc. There is no more gray area here for me it is class 4 and will be treated accordingly, end of questions.

I do apologize to anyone I might have frustrated with my ongoing questions in this thread, but as I said in the beginning; lasers are an area I have had very limited experience with and as such I have really been feeling my way along with what I am sure for some have been stupid questions but as we all know stupid questions are part of the learning experience. I have now sorted this all out. Thanks to everyone that has helped me along with this as I fumbled my way around.

RE: Now for the questions

Another OSHA question. Did anybody hear about OSHA requiring tinted (or darker) glasses for laser operators? Or are regular clear glasses OK?
Thank you.

RE: Now for the questions

Foostrap,

Please refrain from hijacking this thread, even though the subject is related.

Regular clear glasses are NOT OK, if there is an eye protection requirement, but there is necessarily one in place:
http://www.osha.gov/pls/oshaweb/owadisp.show_docum...)

It depends COMPLETELY on the laser classification and ancillary safety constraints. If this were a non-Class 1, then laser eye-protection is mandatory, and it needs to be adequate for the assessed laser hazard classification of the laser. And laser-safety glasses are NOT run-off-the-mill "colored" or "tinted." This level of certainty and disinformation is extremely HAZARDOUS to the operator

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

RE: Now for the questions

the laser light is part of the danger, simply burning steel w O2 requires tint. How about when high power N2 cutting and it blows out the top? That'll have you seeing stars....

Chris Krug http://krugtech.com/
Maximum Up-time, Minimum BS

RE: Now for the questions

Thanks. I did think it was related. But sorry for hijacking; won't do it again tongue

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