EDM / Reverse Feed rate

  • Hi
    I was wondering if there might be any plans in the future for EDM
    I think this question has been asked before on the forums

    Typically you have a spark jumping from an electrode to the work piece to erode it.
    The device that generates the spark is able to detect if the electrode is too close based on the current flow / voltage drop
    In some cases a reverse of the feed rate / speed is needed to back the electrode off if it's too close.

    There's been a video recently from Applied Science that goes into a bit more detail

    It turns out the only controllers at the moment that support reverse feedrate are the dynomotion boards
    Due to they're ability to be programmed to allow for live reverse feedrate / speed during operation via feedback, not just a slow / stop of the feedrate

    I think the feedback is provided to the motion control via an analogue voltage from 0 - 2V (in the case of the BX17)
    which is then amplified to 0 - 10V using 5x gain on the controller
    This leads to

    • Region 1: Voltage > 9.5V No Arc
    • Region 2: 2.0V < Voltage < 9.5V Arcing is taking place
    • Region 3: Voltage < 2.0V Short circuit

    I don't plan on using the BX17 myself but I am thinking of building my own EDM spark generator at some point.
    It'd be interesting to see if there could be a feature added in at some point to live adjust the feedrate based on perhaps I2C or an analogue input

  • Moderator

    Looks like we saw the same video. I just posted the same request.


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