Is this a good config?

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  • November 7, 2012 at 12:13 pm #3585
    lhd
    Member

    A while back I invested in a 4’x8’x4″ gantry CNC called a Digirout DR1000. I wanted a turnkey device and the Digirout rep said it would take about a month of lead time to have a unit put together for me which I could come pick up. After a year of promises I was told it was ready for pickup and arrived to find a gantry mostly assembled but none of the controls setup, wired, installed etc. I ended up taking the unit as is for the cost of my deposit. So now I have a a fully assembled gantry with no documentation on any of the controls.

    I’d like to use a GRBL shield on an Arduino Uno connected to a booksize computer running LinuxCNC to run this machine. The gantry is gear/screw driven. I can’t for the life of me remember what kind of stepper motors I have but I can surely find out tonight when I get home. Is there any reason this setup will not work?

    I also have a CNC mill but it’s from CNCMasters which requires their proprietary software to run. I’m not new to CNC but this will be my first controller build.

    • This topic was modified 11 years, 10 months ago by lhd.
    November 8, 2012 at 6:43 am #3587
    alden
    Member

    The main question is whether or not the drivers on the grblShield are adequately sized to drive the motors and the mechanical system. The drivers will put out up to 2.5 amps (we recommend cooling about 2 amps).

    If the machine is not well constructed there may be issues with friction in the drives which would load the motors heavily. You might try turning the gantries by hand to find out.

    Also, are there dual motor gantries? In a machine that big I’d suspect so. GrblShield is designed to drive a single motor per axis. Although it’s possible to slave 2 motors to a single axis, the total current of both motors should not exceed the driver limit.

    Alden

    November 19, 2012 at 9:35 am #3595
    lhd
    Member

    Each axis is controlled by a single stepper. The largest of the motors is a <a href=http://www.kelinginc.net/KL34H295-43-8B.pdf>KL34H295-43-8B</a> which looks like it draws between 3 and 6 amps depending on the config. Is there a way to control more than 2.5 amps via a GRBL shield? Can I use a transistor network for the power and return the signal directly to the GRBL shield?

    • This reply was modified 11 years, 10 months ago by lhd.
    November 21, 2012 at 10:48 am #3599
    Riley
    Keymaster

    While this is possible, its not something we support.  This introduces a bunch of headaches for mis-wring and frying stuff!  Obviously 3-6a per motor is wayyyy too much for the grblShield.  Your application does not sound like grblShield is a good match.  However, this is your hardware!  Do what you would like just understand we cannot support the modifications you are describing.

     

    Riley

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