YAG Laser: Safety

General
1

This thread is for discussion and updates around the YAG Laser Safety Situation.

The main task here at the moment is the design, plan, budget and implementation of screens to go around the machine for laser safety.

2

Recent discord discussion:

[ 4:43 PM ] Brendan (nog3) :

Need to see the standard en25980:2015, pretty sure welding curtain won’t be protective against a 1064nm ndYag

[ 4:43 PM ] Josh [President] :

i think people are getting things confused

[ 4:44 PM ] Josh [President] :

the beam is 1064mm. but there is also flash from the cutting process.

[ 4:44 PM ] Josh [President] :

that flash will not be 1064nm

[ 4:45 PM ] wixted⚒ :

but the laser can and does reflect off the metal.

[ 4:45 PM ] wixted⚒ :

which is what you are shielding for

[ 4:45 PM ] Brendan (nog3) :

Yeah, this is what I’m concerned about.

[ 4:46 PM ] Josh [President] :

i’m saying you should be concerned about both.

[ 4:47 PM ] Brendan (nog3) :

Absolutely, which is why these tend to be run in big metal boxes.

[ 4:48 PM ] Brendan (nog3) :

Curtains is a wild goose chase.

[ 4:48 PM ] wixted⚒ :

safety glass for 1064nm will shield against both, weld curtain will only shield UV

[ 4:48 PM ] Josh [President] :

i have not seen / cannot find any actual reliable source documentation or material about the real risk of reflected laser light. not saying its not a thing, its thats lots of people are having opinions at the moment with no facts.

[ 4:52 PM ] wixted⚒ :

Attachment file type: acrobat

FULLTEXT01.pdf

4.76 MB

[ 4:53 PM ] wixted⚒ :

research paper on the absoption of laser light on rough metal surfaces

[ 4:54 PM ] wixted⚒ :

jump to page 103 for results, starting with mild steel

[ 4:54 PM ] Josh [President] :

its 9 pages long?

[ 4:55 PM ] wixted⚒ :

…226 pages long?

[ 4:55 PM ] wixted⚒ :

might not have fully uploaded or something

[ 4:55 PM ] Josh [President] :

oh whoops i’m looking at the wrong thing

[ 4:57 PM ] wixted⚒ :

and dangers of 1064nm to the human eye http://www.dermatology.org/laser/eyesafety.html

[ 4:58 PM ] wixted⚒ :

“Exposure to the Q-switched Nd:YAG laser beam (1064 nm) is especially hazardous and may initially go undetected because the beam is invisible and the retina lacks pain sensory nerves. Photoacoustic retinal damage may be associated with an audible “pop” at the time of exposure. Visual disorientation due to retinal damage may not be apparent to the operator until considerable thermal damage has occurred.”

[ 5:00 PM ] Josh [President] :

Attachment file type: acrobat

rockwell1983.pdf

743.58 KB

[ 5:02 PM ] Josh [President] :

[ 5:05 PM ] Brendan (nog3) :

This is the hell we had to endure with laser safety on the smaller lasers, everything is standards based, but all the standards cost $$$.

[ 5:05 PM ] wixted⚒ :

the rockwell one is for power levels under 300w, so not applicable.

[ 5:05 PM ] Josh [President] :

i wouldnt say not applicable, just… more info to consume.

[ 5:06 PM ] Josh [President] :

but doesnt directly translate.

[ 5:07 PM ] wixted⚒ :

it’s also specifically only plume radiation, which is the radiation generated by the melt/cutting pool, not the reflected laser beam

[ 5:09 PM ] Josh [President] :

so whats the solution at this stage. ‘laser safety curtain’ is very expensive and not really straightforward fit for purpose, more for scientific use. we can just straight up put up walls, if so what should the walls be made out of. and or would it be enough to get say, heavy duty tarps and hang that as a curtain.

[ 5:17 PM ] wixted⚒ :

I would just put up walls. Thin sheet metal on a frame should be sufficent, with overlap on doors/openings.

[ 5:19 PM ] wixted⚒ :

we don’t need a roof, just walls higher than head height, maybe to 2m or so. (can’t pull a paper on this, but the reflection angle is limited, head height provides sufficent protection.)

[ 5:19 PM ] wixted⚒ :

cheap solution for monitoring it during use is a camera and screen.

[ 5:22 PM ] Josh [President] :

if you make panels that just take standard sheets of say, composite panel, you can just put them ‘on end’ and get a 2.4m high wall.

[ 5:23 PM ] wixted⚒ :

yep, most sane.

[ 5:23 PM ] Brendan (nog3) :

Composite panel seems reasonable, since it’s a sandwich of alu and usually non translucent acrylic

[ 5:27 PM ] Josh [President] :

1830 high panel is $82/sheet

[ 5:27 PM ] Josh [President] :

Plastic Warehouse

ACM Board | Aluminium Composite Panel | Plastic Warehouse

ACM Board or Aluminium Composite Panel is lightweight and durable. ACM is a low density polyethylene core between two aluminium sheets.

[ 5:28 PM ] Josh [President] :

https://www.sassignage.com.au/undercoat-undercoat-bc-03.html < $40 ea

[ 5:29 PM ] wixted⚒ :

if the bottom of the wall is just below the edge of the machine, we could maybe turn them sideways?

[ 5:31 PM ] Josh [President] :

yeah that might be sufficient

[ 5:31 PM ] Josh [President] :

basically someone needs to take this on. make a plan, design, budget.

3

Oh, one other thing i forgot, is building the safety barriers. Nd:YAG operates ~500-1200nm wavelength. So the easiest thing is fully opaque walls, but we might also want to look into thick pvc strip curtains or similar.

4

YAG Laser’s output infrared light. Arc Welding puts out UV. These are opposite ends of the visible light spectrum. Welding curtain doesn’t protect against Infrared, which is specifically highly damaging to eyes.

The simplest solution is moveable solid walls, preferably with interlocks. Improved visibility of jobs can be achieved by the installation of a simple camera/monitor circuit, or for a failproof method laser protective glass panel into the walls (can be rather expensive, but can also be retrofitted).

5

Xenon-YAG is in the UV range. the xenon peak is 595.6nm but the YAG crystal doubles the frequency to ~300nm which is definitely ultraviolet. The system doesn’t have a beam collminator so reflected laser beams can’t happen. It’s basically like staring at a TIG arc, so curtain should be fine. How long does it have to be? Know any good shops to buy it from?

6

it’s not xenon YAG , it’s nd:YAG, 1064nm.

1 Like
7

Manual from manufacturer says: wavelength 1064nm

The seller said it puts off uv in the flash of cutting, but i dont have documents to back that up at this stage.

8

Does anyone know where to get a copy of the standard mentioned in the specs for this curtain? Sydney Tools

9

@jabelone I’ll need dimensional info so I know how many curtains we need. We’ll have to install at least 3 poles and string cable between them. Does anyone have Craig’s contact details?

10

This is a 1064nm ndYag, welding curtain will not be even 1/3 sufficient to prevent eye damage to users and onlookers.

1 Like
11

This stuff works for those wavelengths.

https://www.rli.com/Products/Laz-R-Barriers.aspx
12

The ACM also has 3m x 2m size that suggests a vertical motion curtain aka stage curtain. About $275 a sheet.

13

I am looking at part of the safety screen problem. After a look at some manufacturer videos I have penned the following short story. See Open Type Fiber Laser Cutting Machine GF Series |

It seems agreed that the safety screen should be very close to the machine. Meaning that no one can be between the screen and the machine when the screen is closed.

A solid material should be used that will block all radiation both from heating the material and the laser light. Also. Contain any ejected material.

The top of the screen should be about 2100mm off the floor. The bottom of the screen about 100mm below the cutting surface of the laser bed.

From the above posts I suggest:

Fixed walls on two sides (near wall and next to welding gear) and movable screens on the other two sides .

Materials are ZnAl (0.42mm x 762 mm x 1800mm) sheet, ali U section 20x20 (plus others as needed), treated pine

Construction will be:

  1. the fixed screens/walls built using basic building timber house framing techniques with the ability to remove them without too much hassle
  2. movable screens are flat panel(s) or concertina and made from Zincalume roof/wall sheet and ali sections
  3. the movable screens are built out of multiples of ZnAl framed in ali section
  4. the size of the movable panels depend on how the panels are moved. (concertina - one sheet (762mm), flat panels up to 2 or 3 sheets)

Key decisions are needed about the movable panels options:

  1. sliding flat panels from an overhead track Vs
  2. using wheels on the floor Vs
  3. wheels running on gate track Vs
  4. legs and feet.

The idea of building panels is to allow later reworking, (for example legs to track), and for automatic operation and other ideas.

I look forward to your comments. Did the ending turn out like you expected?

14

After more looking I can offer some rough costings for modular safety screens.
To give you a better idea about modular screens I include the Stratco good neighbour fence system. See Fence panels. The idea is to add legs/castors.
A home made version made of corrugated iron/custom orb and ali channel has been costed. As has a screen made with building paper (sarking) in place of the metal sheet .Wall paper
Costings for 10m of panels:
Good neighbour panels - about $550
Ali plus custom orb - about $350
Ali plus wall paper - about $200
Plz note. Costs are based on RRP not trade prices. Some extra is added to buy steel flat to make legs. No fittings or handles for moving are costed.
Enjoy.
Hopefully this is enough to get thru a members meeting.
I’m done on this for now.