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Thread: Galvo details for beginners?

  1. #21
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    Quote Originally Posted by mixedgas View Post
    Unless you are talking about some very exotic, beasts that use digital encoders or rotary interferometers, most galvos are analog. They do exist, but the cost is enormous.
    "Enormous cost" sounds like laser marking industry. May be such galvos are widely used there meanwhile?

  2. #22
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    mixedgas is offline Creaky Old Award Winning Bastard Technologist
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    Quote Originally Posted by Elmi View Post
    "Enormous cost" sounds like laser marking industry. May be such galvos are widely used there meanwhile?
    Yes for marking and semiconductor manufacturing use. Finding complete used digital systems in known working order is difficult, and I've never found a schematic of a typical driver.
    I have seen over the years, request after request for help with those go unanswered. No problem understanding what the processor must do, but not very hobbyist friendly.
    Analog is good enough for most one off, homemade things, unless your building a wafer stepper in the basement..

    I was told by the president one of the galvo manufacturers years ago, that there were far better things they made for in house use, and for remarkably large clients. Then there are the lessor performing semi-commodity items they sell to the tier two and tier three clients. In house use means they sell whole manufacturing systems as a separate product line, administrated by their parent company. This after five minutes of looking at a projector moving very large mirrors at the limit of the physics, scanning an image that one would not expect a large galvo to scan without flashing in the image from slow retrace. Trade shows are often wonderful places for seeing high performance unobtainium, after paying dearly for travel costs.

    So unless you buy directly from the factory, you may be on your own for documentation and support.

    Adding an external optical tracking or sensing system to a scan system for digital enhancement has never been much of a problem either.

    Steve
    Last edited by mixedgas; 07-18-2020 at 14:55.
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  3. #23
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    William benners book as suggested is VERY good..
    but there is also this old one..
    The galvo part is still relevant but the color control and "modulation" isnt so relevant anymore.
    http://elm-chan.org/works/vlp/report_e.html

  4. #24
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    Just an other question: what voltage are these galvos driven with typically?Background: I got a used set of driver and galvo. The driver has two voltage regulators on it for +-12V, but amazingly at the OpAmps output I could not see that voltage, there I measured a signal which was more some kind of white noise with a very low amplitude while driving the galvo from one extreme position to the other. So I'm not sure if I'm measuring crap or at the wrong position or...or...

  5. #25
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    Just remember galvos are finicky. Dudevos are much more logical and stable.

  6. #26
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    Quote Originally Posted by kecked View Post
    Just remember galvos are finicky. Dudevos are much more logical and stable.
    Dudevos cost MUCH less in the long run, too. If you part with dudevos, they also don't take 50% of your equipment!
    If you're the smartest person in the room, then you're in the wrong room.

  7. #27
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    Quote Originally Posted by absolom7691 View Post
    Dudevos cost MUCH less in the long run, too. If you part with dudevos, they also don't take 50% of your equipment!
    heheheh. It took me a minute to get this joke. I guess I'm just slow.
    "Help, help, I'm being repressed!"

  8. #28
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    For engraving purposes with f-theta lens which galvos are better ?

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