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Thread: CNC Laser Engraving 8bit Shades of Grey 445nm

  1. #61
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    ... when CNC-engraving with a 445nm-diode and around 40mm focal distance I'll get around 0.05mm spot size ... when XY-scanning with 200mm distance, the 'spot' gets a line with roughly 0.4x0.1mm.

    With the fiberlaser it's much better -- when engraving with 60mm distance, the spot is around 0.02mm wide ... when XY-scanning with maybe 300mm distance, it stays round and gets maybe 3x bigger. But when using a beam-expander, this could be halved in size - so around 0.01mm engraving, 0.03mm XY-scanning ...

    Viktor

  2. #62
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    Have you tried varying the power instead of pulsing? All I see is black & white dithered image engravings which is the standard method.
    Last edited by JJWMACHINECO; 03-15-2014 at 13:36.
    Extensively Re-worked/Re-designed/Modified Servo K2CNC KG-3925, Mini Diode Laser Engraver and now a Shapeoko 2 Laser Diode Engraver.

    https://www.picengrave.com

  3. #63
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    Quote Originally Posted by JJWMACHINECO View Post
    Have you tried varying the power instead of pulsing? All I see is black & white dithered image engravings which is the standard method.
    ... I can import grayscale images and engrave with varying energy too, but actually I'm testing the different materials and the limitations of the cheap scanners.

    Have to decide if changing the scanner mounting-block for allowing bigger mirrors and a beam-expander, or switch for stepper- or servo-motors instead of the galvos ...

    Viktor

  4. #64
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    ... the decision goes the servomotor-direction ... especially because of bigger (heavier) possible mirrors and so higher energy densities without wrecking the mirrors.

    Attached are some samples I've made with the fiber-laser on different materials -- 10Watts for the ceramic tiles and the plastic housing, up to 50Watts for the metals.

    Last week I've got a 120Watt-fiberlaser with modulation capability of up to 1MHz, so the mirrors in the scanner should be much more reliable (=bigger) than the actual 20x20mm-ones!

    In contrary to the commonly used fast scanning galvos with Q-switched pulsing lasers I'm using modulated/switched CW-lasers, so instead of scanning the same dot in high-speed (up to 40kpps scanning rates) several times to get it marked, I'm heating them some microseconds with a 'steady beam' before moving to the next position.

    I've calculated possible 'scanning speeds' of 1m/s with 200kHz stepping rates for the motors and 5 microns resolution -- but could be faster too ... have servo-drivers with up to 300kHz stepping rates and stepper-drivers that can be driven with up to 10MHz in 1/256 microstepping!

    As I don't have big masses to move - only a wire, wound on a small roll, pulling the rotating axe of the mirror - the 200kHz/10MHz 'limits' of the drivers could eventually be reached by the mechanics ;-)

    Viktor
    Attached Thumbnails Attached Thumbnails Faserlaser2.jpg  

    Metall1b.jpg  


  5. #65
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    OMG! That is awesome! I sometimes wake at night and see symbology like this around all my walls and ceilings - Aztec like stuff. (I'm on some interesting medication - I'm not just mental)

  6. #66
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    ... hmmm, didn't want to cause night-mares ... made the aztec-codex only for it's "coolness" and to show the possible complexities ...

    Viktor

  7. #67
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    Quote Originally Posted by VDX View Post
    ... hmmm, didn't want to cause night-mares ... made the aztec-codex only for it's "coolness" and to show the possible complexities ...

    Viktor
    Oh no, no nightmares - I really enjoy seeing them and am always urging them to last a little longer. The complexity is awe-inspiring.

  8. #68
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    Victor,
    Great work. I'm starting to turn very envious.
    John Champlain

  9. #69
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    swamidog is online now Jr. Woodchuckington Janitor III, Esq.
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    i am having pretty good success with my machine. the biggest problem i'm having is finding the sweet spot between marking the wood and burning holes through the wood.

    Click image for larger version. 

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    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

  10. #70
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    does anyone here have a nice .nc file for me to test my homebuilt dvd drive engraver on?
    my specs are 36x36mm and 0.072mm per step

    i tried converting some bmp files, but i keep messing it up...
    apparently my method handles greyscale terribly
    i would like a gcodefile with some nice detail in it so i can callibrate speed and laser output power

    thanks ^^
    Last edited by mrfloppy; 04-01-2014 at 07:55.

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