Z touch plate set up

This topic contains 9 replies, has 6 voices, and was last updated by Profile photo of alexpewpew alexpewpew 2 months, 3 weeks ago.

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  • #11280
    Profile photo of alexpewpew
    alexpewpew
    Participant

    I’m using the MPCNC as a router and I am trying to set up a touch plate for my z axis. Its basically a penny glued to a 3d printed holder. The z home works perfect, but I want to set the actual home to be lower than my touchplate. I’ve enabled eprom editing, but i haven’t had any luck with setting an offset.

    http://imgur.com/ACbEZZg The touch plate in all its glory

    What I want to do:
    Hit home z and have bit touch the touchplate that is on my work surface.
    ramps knows that my z axis endstop is 12mm too high
    remove the touchplate
    Run the gcode which starts cutting 12 mm lower than the touchplate

    I can get around this by manually lowering the z axis then restarting ramps, or adding a move command to all my gcode to lower the z axis but I feel like there is a right way to do this.

    Alex

    #16071
    Profile photo of Forrest
    Forrest
    Participant

    Hey I’m super curious if you ever got anywhere with this? I feel like adding a z height adjustment for the endstop in the ramps firmware is probably very doable.

    I also think that embedding the penny into your table also wouldnt be that hard, since it is a CNC and all. You could just cut a hole the perfect size for a penny and then glue it in there. Wires to the side or bottom.

    And on another node, I’m curious if the bit of the dewalt 660 is grounded to the AC power supply ground or something like that. How cool would it be to check for conductivity against ground and not have to attach some connector to your bit every measurement.

    #16248
    Profile photo of Barry
    Barry
    Participant

    I’m just using a thin piece of sheet metal. Aluminum foil would work, it’s just not very durable.

    #16253
    Profile photo of Jason
    Jason
    Participant

    This must be far more accurate then a conventional mechanical lever end stop. Might have to change mine out.

    #16256
    Profile photo of Barry
    Barry
    Participant

    Touch plates are good for stuff that moves, like the top surface of stuff we’re cutting. For the x and y, a switch works just fine.

    #16648
    Profile photo of Joakim
    Joakim
    Participant

    Did you find a solution to set the z startpoint 12mm lower then the touch plate? If so, how did you solved it?

    Is it possible to do what the creator of estlecam has done, but in ramps (https://www.youtube.com/watch?v=bhZdbgM6S70&feature=youtu.be). I would like to find the z, x and y start point on the workpiece

    #16649
    Profile photo of Barry
    Barry
    Participant

    No, I just use a really thin touch plate. For what I use it for, the .25mm isn’t that big of a deal.

    #16673
    Profile photo of Joakim
    Joakim
    Participant

    Many this would do it for the Z – check the part about Multi-Pass Cuts:
    http://www.akeric.com/blog/?p=3603

    #24378
    Profile photo of P3DCNC
    P3DCNC
    Participant

    If you haven’t resolved this, you can home Z like you’ve said then send this command: “G92 Z12”. Change the 12(mm) to whatever your touch plate thickness is. 0 will now be the surface of your material.

    #24431
    Profile photo of alexpewpew
    alexpewpew
    Participant

    Brilliant! Thank you, this was just what I needed.

    Alex

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