Lasers

The topic says lasers, so I figured I'd post about this here

[www.repairfaq.org]

Hi Guys,
Just thought I'd jump in with a quick question.
Anyone exploring the idea of using a high power IR laser diode with fibre optic cable to sinter / melt a suitable material for prototyping?
They seem to be cheaply available on eBay. not sure why everyone always thinks of CO2 when considering lasers. Possible to get a tight burning beam with a fibre pigtail. Any thoughts?
Doug

CO2 lasers allow for a fairly cheap 50 watts of light power. I haven't seen laser diodes above a watt at reasonable prices. I haven't really looked either, so I could be wrong about it. With less then a watt, you won't get anything all that hot, so no burn or melting action. Do you have a reference source for laser diodes that are around 50 watts or higher?

... i built a sintering system with a pigtailed 8-Watt-diode-laser for 320Euros, which i drive with a self-made current-driver in 0,65Ampere-steps from 0,65 to 5,2Amps (e.g. 0,5Watts to <5Watts output-power for longer life)

The glass-fibre has a core of 0,1mm - i assembled a two-lenses-optic-head too and have a min-spot of nearly 0,06 to 0,08mm.

With this laser-head i sinter gold-paste on a 0,15x0,3mm big gold-pad to solid gold and when i'll drive with full power then i can melt the complete pad with the underlying ceramics or cut thin sheets of different materials too.

It's working as marking-laser for plastics too, but when you want to sinter or cut bigger areas or metalls and thicker sheets with usable moving speeds, then you should use much more power - a 20Watts-system is minimum, but most commercial systems use 60Watts or more ...

Viktor

Hi Viktor where did you get your laser and do you know of suppliers of the larger sizes and are you then into CO2 etc or do diodes go that big?

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Ian
[www.bitsfrombytes.com]

Hi Ian,

... next week (when on workplace again) i'll post the adress of the vendor and some more infos - it's a german company, but shouldn't be a problem with international shipping too ...

You can find diode-lasers from 1Watt to 60Watts with then drastically increasing prices - actually we are in developing of an assembly/justage-stage for a special ring-focus-diodelaser with 60 to 80 20Watt-diode-lasers formed into a single source!

Some years ago (between '94 and '96) i bought a 'naked' 3Watt-CW-CO2-laser-tube for 1500 DM (=Deutschmarks) as source in a self-build laserplotter for plastic-sheet-cutting. The two last systems in this group were built with 5Watt-RF-CO2-lasers and a price of 3000 DM from a lithuanian company named 'Eksma' - now a more high-tech-vendor: [www.ekspla.com]

My company starts selling NdYAG-puls-lasers in the range of 3KW/puls (with a quasi 20Watt-CW-laser) and a 10-micron-spot-pulslaser (with a quasi 3Watt-CW-laser) for 20.000 to 40.000 Euros, but this is a complete different area - i'm in developing custom systems for micro-laser-welding and such ...

Viktor

Hi Ian,

... here is the vendor: [www.lumics.com]

... and here the 8Watt-diodelaser: [www.lumics.com]

Viktor

Looks very good thanks I'll call them for pricing as soon as the office opens

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Ian
[www.bitsfrombytes.com]

please post here, as i'm interested in it too... i'd love to get one.

bulk buy? =)

... think of security! -- you handle here with invisible radiation, which even unfocused is strong enough to cause severe damage on the skin and especially in the eyes!!!

Even the 'weak' IR-LD's from salvaged DVD-RW-drives with up to 220 Milliwatts are strong enough to cut through plastic, so be extreme carefully, when testing or using LD's.

You can buy special goggles for every wavelength, but the prices are in the range of some hundred USD/Euros too.

I'll try next week shielding of the beam with the cyan-side of red-cyan-3D-goggles you can buy for some cents for viewing color-anaglyphs.

I have some dozens at home, so it should be no problem to stack some of the cyan eye-filters and fix them in normal safety-goggles (as used with grinding)

When this works, then we can have laser-goggles for a price of 10 to 20 Euros instead of the 200 to 500 Euros for professional ones ...

Viktor

Count me in on the bulk buy!

... back to cheap selfmade laser-goggles:

I tested the cyan-window of the red-cyan-anaglyph-spectacles -- THEY DIDN'T SHIELD THE DIODE_LASER !!!

I stacked until 8 of the cyan-windows, so it seems to be same colour and darker then my laser-goggles, but the diode-laser-beam went through - the comercial laser-goggles blocked the beam completelly, so it's not so easy to make a cheap look-through-laser-blocker ...

Viktor

First the disclaimer: In my opinion you should not build shielding goggles! They are too dangerous! If you burn your retina you might get in trouble. Buy professionally ones. They are safe.

Anyway, if you still want to try... I remember a recommendation at the last recent total solar eclipse visiting western Europe. Look thorugh a CD. You won't see very much, but you look through a thin layer of aluminium, silver or gold. You should find out their spectra in the literature before testing them.

Howie

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--
Airspace V - international hangar flying!
[www.airspace-v.com] for tools and toys

Hi Howie,

... i use (comercial, ~300Euros) laser-goggles for 'live' test-micro-welding gold-paste with a self-built diode-laser under a microscope - comercial lasers have shutters, so there it's not a point.

Some guys use home-brewed diode-laser (from salvaged DVD-RW-drives) cutting systems without any goggles, because of the high costs, so i looked around what's possible with cheaper stuff ...

My next try would be to to buy a sheet of a good plastic laser-protection-window and cut or mill two pieces for a cheap 'grinding-goggles' as inserts, this should be in the range of 20 to 30 Euros per goggles - so when this works, it could be maked as bulk ...

Viktor