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MOPA Fiber Laser Engraver

Discussion in 'Laser Cutters' started by Stephen Uhlhorn, May 18, 2021.

  1. Stephen Uhlhorn

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    Hello--

    New here to OB, and would like some advice on a CNC laser build. I have a 20W IPG YLP fiber laser that I would like to set up in a Workbee with the Blackbox controller. I know the toolhead output of the controller is not designed to control a MOPA/Q-switched laser, but I'm trying to get creative about how I can make it work.

    The way I see it, there are 2 approaches:

    1) Gat a second controller to serve as in interface between the Blackbox and the IPG laser:
    JCZ Control Economic Card V4 Ezcard for 1064nm IPG Raycus MAX Laser Marking Machine

    Here, I would need to find a way to use the toolhead output of the Blackbox to send a relevant signal to the laser controller... not sure how this would work.

    2) Use the TTL/PWM outputs of Blackbox controller as inputs to another microcontroller (Arduino?) that would generate the signals for the laser... again, not sure how this would work.

    Just wondering if anyone out there has any experience with this.

    Thanks!
    -stephen
     
  2. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

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    See if you can find the datasheets for the laser PSU to see what input signals it needs
     
  3. Stephen Uhlhorn

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    I have the specs and datasheet. It takes an 8-bit word to set the power level (0-255), and a LATCH pin to store the word in the laser controller. The laser output is controlled by a TTL trigger (20-80 kHz) to set the rep rate, and a gate signal to enable output. I know I'll have to use some form of microcontroller to set the power level, and likely the generate the gate, but I'm wondering if the TTL signal from Blackbox toolhead output can be used to generate my laser trigger.

    After some more thought, I think the right way to do this is to use motors with encoders on the X and Y axes. I can use the encoder output to determine the real velocity (feed), and use that to calculate the correct rep rate (speed). I may have answered my own question, but I would be interested to see if you think that makes sense.

    Thanks--
    -stephen
     
    Peter Van Der Walt likes this.
  4. Stephen Uhlhorn

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    OK, after some more homework, I think I have a plan. It looks like I'll be building a laser controller to interface to the Blackbox controller. I figure what I need is a signal "translator" from the toolhead signals to the laser control signals. I'm going to try to use the PIO in a Raspberry Pi Pico to do the translating for me. I need 3 laser signals; power, rep rate, and gate.

    My question for the forum is: can the toolhead connector output these 3 signals? Can I somehow use the servo output (or is it an input)?

    Thanks-
    -stephen
     
    Peter Van Der Walt likes this.
  5. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    It outputs what Grbl gives you. Basically PWM. Sample the PWM, and use that as your input signal. No pulse train = laser off. PWM pulse train with duty between 1 and 100% = your power scaling.
     
    Giarc likes this.
  6. Stephen Uhlhorn

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    Thanks!
     

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