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My 1st C-Beam CNC

Discussion in 'CNC Mills/Routers' started by mikework, Oct 9, 2017.

  1. mikework

    mikework Well-Known
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  2. mikework

    mikework Well-Known
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    I am really looking forward to any feedback during this.

    Right now I am thinking of cutting the 4th c-beam into 2 375mm legs for the gantry and 250mm for the z-axis c-beam.

    I guess if that is too short for a 1.5kw spindle on the Z axis I can always replace just that piece.

    Any thoughts folks?
     
  3. mikework

    mikework Well-Known
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    Got some more work done over holidays. Its not bolted down yet as I want to get some electronics installed and test the motion before locking it to a surface. As is, its very rigid.

    All aluminum plates cut and drilled by hand. I can not wait to be able to machine these instead by hand as tolerances HAS to be waaaay better.

    Also discovered I had to improve my tablesaw 90 degree cuts of the c beam ends as I was getting some serious motor shaft to leadscrew misalignment.

    Thanks to William Ng's '5 cut method' for tablesaw crosscut sled alignment the c-beam ends are now within .9991% tolerance of 90 degrees.

    Z plate was sized for 2.2kw spindle which will be one of the last upgrades. I have a beater router I can test with for now.

    4 Thread 8mm leadscrews are used for y and x, but I will stay with the 2 thread 8mm to help the 275oz stepper motor haul that 5 kg 2.2kw spindle up and down. Other axis are using 425oz steppers.

    Finding a source for lock collars locally was ridiculous so I drilled out some standard nuts and added 2 60 degree offset setscrews.

    Stepper motor spacers came from electronics spacers stash. Wide variety of lengths employed.

    'Y' / Gantry support plates cut wider for extra stability. I may add more wheels to all plates based on performance.

    V Slot calculation spreadsheet indicates a total .06 mm deflection (total weight 11.5kg with spindle) in side c-beams so I may go to a 2 sided support Y plate 'sandwich' instead of supporting the beam in the middle.

    Waiting now for a Arduino Uno to install GRBL on to. This will run the 4 DM542 drivers for each stepper.

    Sorry for lower picture resolution, main camera has hidden charger over holidays.

    PHOTO_20180112_093222.jpg PHOTO_20180112_093320.jpg PHOTO_20180112_093514.jpg PHOTO_20180112_093533.jpg
     
    #3 mikework, Jan 12, 2018 at 9:19 AM
    Last edited: Jan 12, 2018 at 9:41 AM
    jamesdjadams likes this.
  4. GrayUK

    GrayUK Master
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    Just a thought. :rolleyes: Seeing as how you have a little room left at the top of your towers, why not strap a piece across the top of them, with a plate and some wheels attached to the Z axis, to act as a brace for the Z axis and remove the chance of a pivot point, or router/spindle nodding. :thumbsup:
    Gray
     
  5. mikework

    mikework Well-Known
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    Very good point.

    Might as well, the 'towers' were left tall to allow me to change the Z depth depending on stock or project needs.

    IF there was a need. I am very much still in 'Discovery' mode.

    It will have to wait till I get more aluminum extrusion. A 20x80 piece oriented facing down should do the trick nicely.

    Thank you for the great observation!
     
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