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Thread: Some gears and testing for laser-ablating and -marking ...

  1. #151
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    Being able to switch out lasers sounds pretty cool! I don't know much about this topic, so can you tell me why you'd want to do so? Are some better at cutting and others at fine marking material?

    -David
    "Help, help, I'm being repressed!"

  2. #152
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    Hi David,

    ... I'm building/developing different types of laser or laserdiode-modules - have 405nm-UV-modules with powers of up to 1W ... blue 445nm-modules up to 6W (or multi/combined) ... red 652nm with up to 20W ... NIR (808nm to 975nm) with up to 200W (or too 6x combined with up to 1.2kW on a 0,4mm-spot) ...

    Or different fiber-lasers (CW or pulsed) ... or CO2 ... or TAE-N2 ... or ... -- this can vary widely with the target-application

    The attached image shows my actual "test-rig" - it's a servo-driven XYZ-CNC-mill with 257x210x210mm and sometimes a bit too small ... so the new one will allow a working area of 500x500mm for a direct laser or 610x610mm in combination with the galvo-scanner (+ 110x110mm)

    Viktor
    Attached Thumbnails Attached Thumbnails Faserlaserhalterung-montiert.jpg  

    Last edited by VDX; 01-07-2020 at 17:08.
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  3. #153
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    ... got another (abandoned) XYZ-machine, which was designed for laser-marking of insoles with a blue 6W-laserdiode through a galvo-head -- now some time to find

    Viktor
    Attached Thumbnails Attached Thumbnails XYZ-Aufbau201.jpg  

    XYZ-Aufbau201-Schublade.jpg  

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  4. #154
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    ... ordered 2 ruby rods for "tinkering" with old NdYAG-lasers, where I'll try to replace the NdYAG-rods with the rubys and pump them with high power 405nm-LED's (have some with 9W@405nm out of a 5x5mm array and four with 100Watts out of a 20x20mm array).

    Viktor
    Attached Thumbnails Attached Thumbnails 2x Rubin-Stäbe.jpg  

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  5. #155
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  6. #156
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    Quote Originally Posted by VDX View Post
    ... ordered 2 ruby rods for "tinkering" with old NdYAG-lasers, where I'll try to replace the NdYAG-rods with the rubys and pump them with high power 405nm-LED's (have some with 9W@405nm out of a 5x5mm array and four with 100Watts out of a 20x20mm array).

    The chromium atoms in the ruby rod are what actually participate in the lasing action, and they have big absorption peaks at 410 nm and 560 nm. So the 405 nm LEDs are a pretty good choice for pump energy, at least in terms of the wavelength.

    But even with 400 watts of pump, I'm not sure it will be enough to get the rod up to the lasing threshold because it's going to be a continuous pump, which is not ideal.

    The flashlamp PSU on even a small ruby laser dumps a few thousand joules through the lamp in something like 5 milliseconds or so. Even after accounting for the efficiency loss in the lamp (converting electrical energy to light output), that's still a peak pulse pumping power on the order of 10 ^ 5 watts. Your LED pump source will be 3 orders of magnitude lower than this, and CW as well.

    You can't really pulse an LED like a flashlamp to cram more energy into a shorter time period. You can flash the LEDs off and on, but that will only reduce your pump energy. And since ruby lasers are 3-state devices it's nearly impossible to get them to operate CW.

    I suspect what you'll end up with is an expensive fluorescent light, not a laser. But so long as the rods didn't cost a ton of money, it still sounds like a fun experiment. (And you can always install a flashlamp in the cavity and get them to lase that way.)

    Adam

  7. #157
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    ... it's meant for testing and tinkering, not for "real life work", so -- let's find some time and have some fun

    And maybe I'll find some "tweaks" or shortcuts into other pumping strategies and setups -- have a Nitromite with 200ps-400kW pulses at 337nm and can add 405nm LED's and laser diodes for more energy and maybe fiber-coupling the LED-grids to higher energy densities for end-pumping too ...

    Viktor
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  8. #158
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    Where did you manage to source the rods?

  9. #159
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    ... they were from a Russion vendor and manufactured 1984 (certificate date) - both togethert with shipping around 80€

    Here the link - https://www.ebay.de/itm/143442900770

    Viktor


    *** EDIT *** -- some 405nm-light
    Attached Thumbnails Attached Thumbnails Rubinstab1.jpg  

    Rubinstab2.jpg  

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  10. #160
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    You can see it fluorescing nicely with the 405 nm pump.

    Adam

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