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Wakezor

Discussion in 'CNC Mills/Routers' started by Wakez, Dec 27, 2015.

  1. Wakez

    Wakez Well-Known
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    I'm starting my first own build cnc machine which is inspired by routy and the ox.
    Were my goal was not to use the ox plates but use the standard plates available in the parts store for the design.
    At this point my only experience with mechanics is a solidwork course!

    My goals:

    • Build my own CNC machine, learn a lot! ;)
    • Let it mill various types of materials (Woods - Metal) with the ultimate goal PCB's.
    • Not to use OX plates initially (print them afterwards probably)
    • Use nema23 (The more power the better!)
    Read more about this build...
     
    #1 Wakez, Dec 27, 2015
    Last edited: Dec 27, 2015
  2. Wakez

    Wakez Well-Known
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    Any suggestions or opinions? I like to hear them!
     
  3. Wakez

    Wakez Well-Known
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    After sorting all my parts and starting assembly i quickly discovered i had some missing parts (screws... i hope the local shop got low profile screws...) and other design issues which I did not see during the ordering and designing..
    • Nema23 plates do not fit the 20-80 gantry plates on the small side.
    • Using three wheels on the 20-80 gantry plates on the small side makes mounting a 20-40 beam more difficult
     
  4. Tracy Ranson

    Tracy Ranson Journeyman
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    I am not sure if the A4988 drivers will run Nema 23's I am currently using a ramps v4 that has 4988 driver's to drive another machine that is uses nema 17's. The Nema 23's usually run best at 24-48 V 1 Amp minimum...I know that the A4988 drivers or stepsticks are maxed out on power at 12-38V 2amps. I have burned up a few stick sticks at .79 amps trying to run Nema 23's
     
  5. Wakez

    Wakez Well-Known
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    Hmm thanks for pointing that out, are the DRV8825 stepsticks sufficient ?
     
  6. Giarc

    Giarc Master
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    The DRV8825 are what are used on the CNC xPro board I believe. They are what I am using in my build.
     
  7. Tracy Ranson

    Tracy Ranson Journeyman
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    If you have the CNC xPro board which incorporate the drv8825 then you are on the right track. The ramps board, which is the board that I have, uses either the A4988 or the DRV8825 drivers. The A4988 drivers are similar to the DRV8825 but the DRV8825 operate at 8.2 V to 45 V which is a bit higher than the A4988. Basically the DRV8825 is a higher performance IC than the A4988.
     
    #7 Tracy Ranson, Dec 29, 2015
    Last edited: Dec 29, 2015
  8. snokid

    snokid Veteran
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    I have used both the 8825's and the 4988's don't really see any difference but I only run 24V.
    Bob
     
  9. Tracy Ranson

    Tracy Ranson Journeyman
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    Most users won't notice a difference in the two IC's but there are specific differences between the two. The information can be found here
    https://www.pololu.com/file/download/drv8825.pdf?file_id=0J590
     
  10. Wakez

    Wakez Well-Known
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    I have almost fully assembled my machine and are looking into calibrating and tuning the grbl settings (going to update the build page soon!).
    The power supply is still being shipped over so i use another 24v power supply i had around but this one cant supply the current needed.

    At the moment I have a hard time calibrating all the grbl 0.9j settings.. due to the fact I still do not fully understand how to find all the values for each setting.
    I have the following settings:
    $0=10 (step pulse, usec)
    $1=25 (step idle delay, msec)
    $2=0 (step port invert mask:00000000)
    $3=2 (dir port invert mask:00000010)
    $4=0 (step enable invert, bool)
    $5=0 (limit pins invert, bool)
    $6=0 (probe pin invert, bool)
    $10=3 (status report mask:00000011)
    $11=0.020 (junction deviation, mm)
    $12=0.002 (arc tolerance, mm)
    $13=0 (report inches, bool)
    $20=0 (soft limits, bool)
    $21=0 (hard limits, bool)
    $22=0 (homing cycle, bool)
    $23=0 (homing dir invert mask:00000000)
    $24=25.000 (homing feed, mm/min)
    $25=500.000 (homing seek, mm/min)
    $26=250 (homing debounce, msec)
    $27=1.000 (homing pull-off, mm)
    $100=26.670 (x, step/mm)
    $101=26.670 (y, step/mm)
    $102=100.000 (z, step/mm) Currently i didnt had anymore jumpers so the Z axis spindle is at full step settings and not 1/8th like the other axis.
    $110=1500.000 (x max rate, mm/min)
    $111=1500.000 (y max rate, mm/min)
    $112=500.000 (z max rate, mm/min)
    $120=50.000 (x accel, mm/sec^2)
    $121=50.000 (y accel, mm/sec^2)
    $122=50.000 (z accel, mm/sec^2)
    $130=300.000 (x max travel, mm)
    $131=400.000 (y max travel, mm)
    $132=15.000 (z max travel, mm)

    But determining all the settings for homing and the settings for max rate, accel, step pulse and step idle delay i cant figure out yet.
    I read homing is an extra feature so I left it to defaults.

    For the pololu a4988 stepper driver do I need to calibrate the current? if so I have the steppers already mounted to the so whats the best way to proceed
     
  11. Wakez

    Wakez Well-Known
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    Further I tried above settings with chillipeppr logo test gcode in chillipeppr and gbrl controller but when I run this it's done in like 10 seconds with alot of errors like the following:
    error: Invalid gcode ID;33 [for N15 G2 F800.0 x39.0719 Y-3.7614 I-2.0806 J1.2144]

    When I run the gcode with UGS it worked fine.. Anyone has a clue?

    What gcode senders do you guys use for your machines and which version of grbl?

    Btw is it better to open a new topic about these questions?
     
    #11 Wakez, Jan 3, 2016
    Last edited: Jan 3, 2016

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