Welcome to Our Community

Some features disabled for guests. Register Today.

ACRO Laser.

Discussion in 'Laser Cutters' started by Richard Gallatin, Aug 3, 2021.

  1. Richard Gallatin

    Builder

    Joined:
    May 17, 2021
    Messages:
    16
    Likes Received:
    1
    I have the ACRO system with the BlackBox. I am using the NEMA 17 steppers 1.9 with 14 tooth pulleys. I would like to upgrade and was wondering if I can us a .9 stepper with a 16 tooth pulleys and belts.
     
  2. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

    Joined:
    Mar 1, 2017
    Messages:
    14,026
    Likes Received:
    4,117
    Yes, just remember to set new steps per mm values in Grbl Settings and make sure its 3v/1.3A or higher motors. BlackBox is 1.2-1.3A minimum
     
  3. Richard Gallatin

    Builder

    Joined:
    May 17, 2021
    Messages:
    16
    Likes Received:
    1
  4. Richard Gallatin

    Builder

    Joined:
    May 17, 2021
    Messages:
    16
    Likes Received:
    1
    Little more help maybe needed. I installed my .9 Steppers. These motors seems to be running warmer than the 1.9's My temps are 118 degrees to 125 degrees. Just wondering if this is to hot. I am using the blackbox. I have turned the voltage down. Is there anything else I should be looking at.
     
  5. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

    Joined:
    Mar 1, 2017
    Messages:
    14,026
    Likes Received:
    4,117
    Did you spec them correctly? If they are low current motors, BlackBox has a 1.2-1.3A minimum (ideal for 1.7A motors, as you don't want to run motors at their max rating. You want to run it below) and up from there. Check your motor datasheets - if they are too low current they would not be a good match for a BlackBox

    C or F?
    Motors do run warm, but shouldnt be hot enough to burn your hand, melt insulation, warp the Acro plates, etc
     
    #5 Peter Van Der Walt, Aug 18, 2021
    Last edited: Aug 18, 2021
  6. Richard Gallatin

    Builder

    Joined:
    May 17, 2021
    Messages:
    16
    Likes Received:
    1
    Do you have any recommendations on where to get stepper motors i found a place on Amazon but not sure on amps. It says a 2a but not positive.
     
  7. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
    Staff Member Moderator Builder Resident Builder

    Joined:
    Mar 1, 2017
    Messages:
    14,026
    Likes Received:
    4,117
    We have ours only in 1.8 deg.

    Amazon specs are hard to find for sure. The theoretical resolution doubling of 0.9deg motors are very impractical though - half the speed, and the frame is the bigger contributor to accuracy error anyway.

    Our standard Acro+BlackBox config has 1/8deg motors, with GT2 16T pulleys and 1/8th microstepping: Lets calculate the resolution

    200 steps per rotation * 8 microsteps = 1600 microsteps per rotation
    16T * 2mm pitch GT2 = 32mm per rotation
    32mm / 1600 microsteps = 0.02mm already - you cannot measure that distance in the results of any laser engraving

    With 0.9deg motors, that doubles to 0.01mm (but half the maximum feedrate) The difference is 100% yes, but.... the difference between 0.01mm and 0.02mm is ONLY 0.01mm - is it worth the cost, effort, and loss of speed?

    Improving the mechanicals on the other hand: How to calculate V-Slot® deflection comes into play, and the acrylic plates which can flex quite a bit, lack of Eccentric spacers to perfectly adjust the wheels, etc makes the Acro a budget machine, and can benefit from upgrading on the mechanical front much more than in the drive system
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice