Laser questions

Suppose I wanted to blast away epoxy a bit at a time.

1) How do I know which wavelength works best? 2) Do I need to know a lot about optics or do I just aim and fire? 3) Safety tips beyond wearing glasses? Are there well known safety things like interlocks and such I should know about? How are these powerful lasers handled in everyday lab situations? I'd hate to make the news for frying my retinas because I didn't do something obvious.
Reply to
a7yvm109gf5d1
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Best advice is do it some other way!

The fashion at the moment is for UV lasers for smallest spot size and better coupling to transparent materials. Quadrupled NdYAG at 266nm, quintupled at 213nm or excimers at 193nm if you are made of money.

A fair amount. You are not going to do anything approximating laser ablation without good focussed spot illumination and pulse control.

You are definitely headed for a Darwin award based on your questions above. You only get one pair of eyes!

Powerful lab lasers are supposed to be fully enclosed in opaque guides. Though I have been in a couple of labs where the UV beam was contained in a plastic opaque to UV but not to green 532nm laser light which was somewhat alarming. The scattered light from the target can be harmful.

You absolutely need a pair of safety spectacles for the wavelength(s) you are using and some means of targeting that does not involve looking at it directly like a small CCTV. It should all be interlocked so that the laser cannot fire when the target chamber or beam path is open.

Lasers that can cut and burn are not toys.

Regards, Martin Brown

Reply to
Martin Brown

Last place I worked where we were quintupling Continuum NdYAGs all beam paths were completely open. Goggles were worn when ever running & we interlocked the lab door to the engine.

It was kind of fun focusing the beam down & ionising the air. Maybe our power was down a bit on what you are talking of.

Reply to
Dennis

Dunno about that.. they can provide a lot of amusement, even my little

40W fellow.

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
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Reply to
Spehro Pefhany

'Laser produced plasma' is the fancy name for that, but it's basically just dielectric breakdown of air caused by intense laser light.

One thing you have to remember about them is that once the plasma strikes, it moves backwards up the beam very rapidly. I used to have a

40x microscope objective with a neat hole drilled partway through it from a few dozen reps of that effect. (I was puzzled as to why the air stopped popping, until I looked at the lens.)

Cheers

Phil Hobbs

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Dr Philip C D Hobbs
Principal Consultant
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Reply to
Phil Hobbs

(Luckily) that didn't happen with our setup. From memory the beam was expanded up to around 6mm diameter. Maybe our plasma didn't travel along the beam path as we had a rather steep focus angle.

We also had a microscope in the setup but it was isolated from the beam via a splitter.

I miss working with lasers & the guys, lots of interesting fun!

Reply to
Dennis

Affix the following warning sign:

"Do not look into laser beam with remaining good eye."

--
Paul Hovnanian     mailto:Paul@Hovnanian.com
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Reply to
Paul Hovnanian P.E.

Some of those hand held lasers being sold eg 1W Blue, are instant eye poppers. They are seriously dangerous.

--
Dirk

http://www.neopax.com/technomage/ - Magick and Technology
Reply to
Dirk Bruere at NeoPax

I once turned down a job (I was unemployed at the time) because they had too cavalier an attitude to the lasers they used. I didn't know much about lasers myself, but seeing scorch marks in the walls was enough to convince me - neither did they.

You really don't want to jump into an area this dangerous without being trained in it. There will be all kinds of protocols and techniques you won't know about without being shown. For example, some optics researchers wear black lab coats instead of white to minimise stray light reflections.

You may be best with some other more easily controlled technique anyway. The ablated epoxy will condense somewhere, eventually gumming up your system. Perhaps a fine blade controlled by precision motors? Chinese reverse engineers are said to remove epoxy with nitric acid.

Reply to
Nemo

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