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Cutting gold leaf - can I use a 904 nm laser diode?

Posted by evalon 
Cutting gold leaf - can I use a 904 nm laser diode?
April 06, 2015 04:16AM
Hi all,

I will shortly be cutting some gold leaf with a laser and wonder if I can use a 904 nm diode to do this? It would be "feasible" if this was possible as I already have a laser diode and it looks as if it is a quite powerful diode (LH163-20; datasheet here: [www.datasheets360.com]; 25 watts although with a duty factor of 0.04% ~1/2500 if used at 25 watts) ... Additionally I need the focus of the laser beam - or the cut it makes - to preferably be no more than ~ 0.2 mm.

Also, I'm considering attaching the diode to a laser cutter/ 3D printer of some kind but I admittedly am without much knowledge of laser cutters eye rolling smiley - so my idea has been to maybe buy a small and not too costly kit that I may e.g. assemble myself and which is EASY, intuitive and reliable to program and work with. I know that I need to focus my time and efforts elsewhere but will be needing the laser cutting capability.

Might you have a suggestion for such a kit?

Any help appreciated smiling bouncing smiley

Jesper

Edited 1 time(s). Last edit at 04/06/2015 05:10AM by evalon.
VDX
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 07, 2015 10:39AM
... this are pulsing diodes with high peak powers but pretty low average powers.

While the peak power (=25Watt) sounds good, the averaged power (max. duty factor) is: 25W * 0.04% = 0.01 Watts or 10mW only! - I don't think, this is enough to affect the material eye rolling smiley


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 08, 2015 05:09AM
Hi Viktor,

& thanks for your reply.

Quote

While the peak power (=25Watt) sounds good, the averaged power (max. duty factor) is: 25W * 0.04% = 0.01 Watts or 10mW only! - I don't think, this is enough to affect the material eye rolling smiley

This has been kind of my own thoughts which unfortunately means that I have a - temporarily - very powerful diode confused smiley that I can't really use ... However, I've been reading up a bit on the internet and it looks as if a 445 nm diode is appropriate for this purpose of cutting gold leaf. Would you agree with this? Also, if I would like to also cut e.g. wood in up to 5 mm thickness will I then be able to do this with a powerful 445 nm diode (5 watts with focus lens?) and slow movements - or will I need something else?

Hope it's ok to ask you more questions - and thanks for any assistance you may give winking smiley

Jesper
VDX
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 08, 2015 06:54AM
... 445nm-diodes are actually only available with powers of 2Watts or 3.5Watts - 5Watts or more are modules with more of this diodes combined with complex optics and so much more expensive.

What's the material of the 'gold leafs'? - if it's gold, then you'll need high power pulse-lasers ... either NdYAG with 10W CW / 10kW pulsed, or fiber-lasers with similar pulsed peak powers ... expect costs of some (ten-) thousands USD!


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 08, 2015 07:15AM
...
Quote

What's the material of the 'gold leafs'? - if it's gold, then you'll need high power pulse-lasers ... either NdYAG with 10W CW / 10kW pulsed, or fiber-lasers with similar pulsed peak powers ... expect costs of some (ten-) thousands USD!
...

It is gold but it's very, very thin. Typically 0.1 micron (1*10-7 meters). So I would guess that even if there is a bit of heat transfer within the material it would be very little.

?? I'm wondering what the criteria is here? Is it the absorption/reflection of the actual wavelength emitted from the laser? If it is maximum absorption (not reflection) then a 445 nm laser looks as if it could be used according to this image - given it's got enough power:

[www.webexhibits.org]

Whereas the 904 nm diode that I now have (besides its low power) can't be used ...

Cheers winking smiley

Jesper
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 08, 2015 07:20AM
... then on the other hand an NdYAG laser has a 1070 nm wavelength ???

[www.rofin.com]

(bottom of pdf - in the specs tables) ...

It's (hopefully) not really an issue for me to build a simple pulsed electronics as long as I know which laser to use ...

confused smiley

Greetings,

Jesper

Edited 1 time(s). Last edit at 04/08/2015 07:20AM by evalon.
VDX
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 08, 2015 03:17PM
... it's related to the energy density needed to melt+evaporate the material - even with only 30% relectivity several Watts @445nm on a spot of 0.1mm could be insufficient to melt the gold or any other metal ... but testing will be cheap/easy enough to give it a try.

With the pulsed NdYAG- or fiber-lasers we're dealing with peak powers of some thousand Watts! - here even single percents of absorption are enough to evaporate the surface of solid metal pieces ...

Edited 1 time(s). Last edit at 04/08/2015 03:21PM by VDX.


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 10, 2015 04:05AM
Hi again Viktor,

& thanks once more for your reply smiling smiley I've decided to try it out and would like to make sure that I have a quite powerful (yet not very expensive) diode to start out with. 445 nm probably is the most realistic wave length to use. Searching on the internet I notice that there are many vendors and models - but maybe you know of a "trusted" vendor and reliable diode model that - likely? - combined with a suitable lens will ensure a very focused beam? I should be able to make the laser control and cooling myself.

Thanks for any advice winking smiley

Jesper
VDX
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 10, 2015 05:07AM
... I'm using the diodes from lasertack - [lasertack.com]


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Re: Cutting gold leaf - can I use a 904 nm laser diode?
April 12, 2015 03:05AM
Thanks Viktor winking smiley... BTW I didn't get an email that you had replied so have just seen your reply & link now. Will check it out ;-)

Cheers,

Jesper
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