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Thread: Senior Engineering Laser Galvo Engraver Project

  1. #1
    Join Date
    Jan 2018
    Posts
    4

    Laser Warning Senior Engineering Laser Galvo Engraver Project

    For my final year design in university myself and 2 other mechanical engineers have decided to take on the challenge of building a laser galvo marking/engraving system. This project will be then used as a research tool by the university once our project is concluded.

    As of right now we know that we will be using a 20 watt fiber laser but not much more to the project. Ive spent the past two weeks looking into galvo systems for the project, there is plenty of home projects designing laser light shows using galvos but little to no information on how to design an engraver. I recognize that is a much more complicated project given that you have changing focal lengths and must use a f-theta lens for it. It is also a rather expensive project compared to a cartesian system. As it will be used for by the school after we are done we are able to apply for lab fund, we are looking at a budget of maximum $4000 CAD.

    I was wondering where would the best place to start be, if anyone has information on a DIY galvo engraver project and what are some good sources for parts. Also any tips or advice.

    Thank you in advance

    Edit: A little more information on what I am trying to accomplish.

    In short I am really only designing the enclosure. My group is going to be purchasing the laser and galvo and we will really only be assembling it and tuning it to get it working and get it marking properly. This youtube video is basically how I envision the project going.

    Here is the 20 watt fiber laser we are looking at.
    Does anyone know if a fiber laser comes out as a columated beam?


    Then for the X&Y Galvos there seem to be a number of sources out there ranging from ebay costing 400$ to thor labs or edmund optics at 2500$. It would be nice to try and save money in this area if there isnt a substantial difference between them.

    Most of these galvos come in kits including:
    2 x Scanner Galvo with Mirror (X, Y)
    1x Scan Servo Driver (Amp)
    1x (X-Y) Scanner Mount
    1 x ±24 VDC Switched Power Supply with Cable
    2 x Cable for Scanner
    2 x Cable for Inputting Signals

    Would there be anything else i would need to purchase to run the system?

    Finally for the lens we are looking into possibly ordering a custom lens using Zemax software.

    Im really just wondering if anyone has done this as a DIY project and had some steps or even just a components list, right now i am just in the planning stage and trying to get funding through my school, but in order to do that i have to list all my parts for the project and sourcing. Im just haviung trouble finding any literature on the process of designing a galvo engraver.
    Last edited by ataylo35; 01-29-2018 at 21:33.

  2. #2
    Join Date
    Oct 2012
    Location
    Germany
    Posts
    1,478

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    ... I've did some "tinkering" with the cheapest available chinese XY-galvos for "show-laser"-application - got them for 100€, while the same type was available in Germany for 250€.

    The mirrors are quite small (6mm) - I've tested with a CW-fiberlaser with max. power of 50Watts and a beam diameter of 3mm -- damaged the mirrors with powers >5Watts.

    Then started to glue bigger mirrors on the galvos - got them working (but much slower too) with up to 14mm size (had to change the holders too) and beam-expander for 8mm beam diamter ... damaged them with maybe 15 Watts.

    Then switched to servo-motors instead of galvos and CNC-software to control the servos (a video testing it) - could apply 40x40mm mirrors, which were good enough for maybe 30Watts CW at a beam diameter of maybe 15mm ... stopped then the experiments - have enough comercial XY-galvos to play with.

    With my experience here in Germany, you can get comercial XY-galvo-heads with f-theta optics for maybe 1500€ and a 20Watt fiber-laser for maybe 4000€ as "reoptimized" chinese import ... for the software I'm using the controllers and software from HAlaser - http://halaser.de/

    Or, as a "pure chinese import", complete working galvoscanner marking unit, not housed, for around 8000€ ... or direct from China for maybe 5000€ ...

    Viktor

  3. #3
    Join Date
    Jan 2018
    Posts
    4

    Default

    Thanks for the reply Viktor,

    Thats interesting that the mirrors became damaged, i would not have thought of that. We were considering using servomotors but the galvo systems are all advertised to be more precise in positioning. This may be something i need to look more into as the servometers would save money and could allow use to choose out own mirror set.

    Right now I am almost thinking it would be cheaper to purchase a galvo head with a f-theta lens already and then take it apart and repackage the apparatus in the way I prefer. I just got a 2 week trial from zemax and im going to play around with the software and make a decision then.

    Thank you for the links and information i will definitely be looking into the halaser controllers and software.

  4. #4
    Join Date
    Oct 2012
    Location
    Germany
    Posts
    1,478

    Default

    ... for the damaged mirrors - I was testing with modulating or constant powering a CW-fiberlaser, so the Wattage was constant energy on the surface with the set energy.
    The damage was pure overheating, so the glass burst for thermal stress.

    With pulsed lasers this could be different, as the energy distribution over time is more like super-pulses with some Kilowatts of power in maybe 200 Nanoseconds and some Microseconds time between to cool down ... don't know exactly, if the averaged power (or thermal stress) will behave similar ...

    Viktor

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