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Openbuilds 4x8 cnc

Discussion in 'CNC Mills/Routers' started by Sam Keller, Aug 14, 2020.

Openbuilds 4x8 cnc

Openbuilds 4x8 cnc

Discussion in 'CNC Mills/Routers' started by Sam Keller, Aug 14, 2020.

I built this cnc using 2 z axis actuators thinking it would minimize deflection and it seems to be very sturdy. I used 2 1500mm c channels for my x axis, 1 1500mm c channel for my y axis, nema 23 stepper motors, dm556 drivers, 2 24v power supplies, smc5-5-n-n controller, 9mm wide belts, and the Hitachi m12vc router. So far it's working very well with a few hiccups. Programming the controller was a learning experience but I'm very happy with it.

4x8 cnc
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  1. Sam Keller

    Sam Keller Well-Known
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    Not a problem Chuck, i should have taken more pictures when I was putting it together.
    1. The aluminum angle on the bottom of the gantry is to hold each end of the belt. The angle is screwed to the bottom of the gantry with 2 screws into 2 existing tapped holes. Then I tapped one hole in the angle side pointing down to screw in the belt clamp.
    2. On the aluminum plate between the c beam and the motor mount, the 4 outside holes are thru holes and i used the v slot nuts for those 4 screws. The 2 inner holes are drilled and tapped in the aluminium plate for those 2 screws.
    3. Yes i think the c beam can hang over the table 3-4 inches.
     
    #61 Sam Keller, Sep 23, 2020
  2. chuck english

    chuck english New
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    Sam,
    I see one end of belt attached to z axis but not sure how the other is and how to tighten it. How much tension is on these? Really tight?
     
    #62 chuck english, Sep 24, 2020
  3. Sam Keller

    Sam Keller Well-Known
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    Hey Chuck, the belt on my gantry is held at each ends with this contraption. It has worked great so far, i was able to get it plenty tight by hand.
    20200820_100749.jpg

    Both ends of the belt on my long rails are clamped to the aluminum angle under the gantry cart and then loop around the motor pulley in one end and loop around the belt frontier in the other end. Does that make sense?
    20200820_100655_HDR.jpg 20200813_104400.jpg
     
    #63 Sam Keller, Sep 27, 2020
  4. chuck english

    chuck english New
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    Hey Sam,
    thanks for the answer.. Im really confused over all the pulleys I have. I can only figure where 5 of them go and 2 idler pulleys. 1 at each end of the 2 rails;(4) and 1 on z axis with 2 idler pulleys. I think I have like 15 pulleys of all sizes and 4 idlers, Some that are 20 teeth; I dont think fit the belt. Are all of the pulleys on the motors and end of rails supposed to be the same? How about how tight for the long rails?
     
    #64 chuck english, Sep 27, 2020
  5. KramE

    KramE New
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    In theory you can have different belts on each axis, but you'll have to calculate the steps for each different type of belt, pulley and type of motor.

    You need to match the toothed pulley with the correct width and type of belt.
     
    #65 KramE, Sep 27, 2020
  6. Sam Keller

    Sam Keller Well-Known
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    I'm sorry Chuck, the 3GT pulleys at the top of the list are the wrong size, I meant to edit those out. You should return those if you can. The belt is a 2GT. If you bought the same motors, they have 8mm shafts so they would use the same pully, 2GT 20 tooth with 8mm bore. The 2 belt tensioners use the 2GT 20 tooth idler pulleys with the 5mm bore. And the 2 smooth idler pulleys go on the top gantry cart.

    The long rail belt is not real tight. I tightened too much once and popped the belt out of the clamp. It looks flimsy but is pretty taught
     
    #66 Sam Keller, Sep 27, 2020
  7. Joe Tworivers

    Joe Tworivers New
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    Hey Sam, your list calls for 5 pcs of 5' c beam but you said the x axis was comprised of 2 c beams,(with 4 pcs for the y axis) would you not need 6 pcs? Thanks.
     
    #67 Joe Tworivers, Sep 27, 2020
  8. Sam Keller

    Sam Keller Well-Known
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    My x axis is my long axis, it has 2 1500mm c beams on each side . My y axis is the gantry and has 1 1500mm c beam between the z axis actuators. I didn't specify my x axis having 2 on each side in my original description.
     
    #68 Sam Keller, Sep 27, 2020
  9. JustinTime

    JustinTime Veteran
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    That's an interesting choice you did here. I had done it with the belt teeth meshing together. Bonus effect is you don't even have to clamp them together supper tight. :D
     
    #69 JustinTime, Sep 28, 2020
  10. chuck english

    chuck english New
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    Sam
    where did you find the Hitachi router mount that fits the Metabo router. I think it measures 84mm. I cant find a mount that fits that.
     
    #70 chuck english, Sep 28, 2020
  11. Sam Keller

    Sam Keller Well-Known
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    #71 Sam Keller, Sep 28, 2020
  12. KramE

    KramE New
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    My turn for another question!

    How did you build your table? What did you use for the top?
     
    #72 KramE, Sep 29, 2020
  13. Sam Keller

    Sam Keller Well-Known
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    I built the frame upside down on the floor then flipped it over, squared it up and used cabinet grade plywood on top, it seamed flatter and nicer than regular plywood. I used 2x10s and 4x4s witch is way overkill but it's what i had laying around. The frame is really heavy. I would have made it with 2x8s or 6s if i had to buy the wood.
     
    #73 Sam Keller, Sep 29, 2020
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  14. chuck english

    chuck english New
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    Ok Sam: waiting on parts, so now for the BIG ONE.
    Wiring--- as I have no clue where to start; do you have a wiring diagram or a list of what goes where or first. I did get the blackbox, hoping thats going to make it easier. Guessing I need to wire stepper motors(5), limit switches (8) , emer. stop button, blackbox, power supplies (2), to computer
    Anyone that might help explain this to a moron, please feel free to help. You can't hurt my feelings.
    Thanks all
    Chuck
     
    #74 chuck english, Sep 29, 2020
  15. chuck english

    chuck english New
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    Oh yeah, just to mention; the stepper motors I got from openbuilds have a 1/4 inch shaft. None of the pulleys I ordered would fit the 1/4 shaft and the 9mm belt.? Some were 1/4" for shaft 20 tooth but didnt fit belt. Some fit belt but not shaft, Not sure which one is not right. The belt or the pulleys
     
    #75 chuck english, Sep 29, 2020
  16. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    #76 Peter Van Der Walt, Sep 29, 2020
  17. chuck english

    chuck english New
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    Thanks Peter
    if I click the link you sent it shows me a description of the blackbox. I need a wiring diagram of some sort.
     
    #77 chuck english, Sep 29, 2020
  18. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    click the Menu on the left for the relevant sections:

    upload_2020-9-29_22-48-38.png
     
    #78 Peter Van Der Walt, Sep 29, 2020
  19. chuck english

    chuck english New
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    So if I have 2 motors on y axis, I wire them together before I wire them into the blackbox?
     
    #79 chuck english, Sep 29, 2020
  20. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    #80 Peter Van Der Walt, Sep 29, 2020
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  21. chuck english

    chuck english New
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    thanks peter
    I kinda understand that but I have 5 motors and looks like only 4 places on blackbox, or am I not seeing that right
     
    #81 chuck english, Sep 29, 2020
  22. Sam Keller

    Sam Keller Well-Known
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    I'm trying to find out about this Chuck, the black box has internal drivers where mine does not so I have my signal for the 2 motor axis split from one output to separate drivers. I'm not sure if you can drive the 2 z motors off the one internal driver. Did you buy the external drivers?
    Should probably ask the open build guys.
     
    #82 Sam Keller, Sep 29, 2020
  23. Giarc

    Giarc OpenBuilds Team
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    You may have to wire your Z in parallel (two wired to the Z). The Y carries the most weight so I would use two separate drivers for that as per the Blackbox labeling for the inputs.
     
    #83 Giarc, Sep 29, 2020
  24. chuck english

    chuck english New
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    Sam
    Yes I did get the dm556 drivers. Think maybe I could use one of those for extra driver?

    Giarc, thats what I was thinking but apparently that wont work according to Peter. I certainly dont know.
    thanks for the input
     
    #84 chuck english, Sep 29, 2020
  25. Giarc

    Giarc OpenBuilds Team
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    #85 Giarc, Sep 29, 2020
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  26. chuck english

    chuck english New
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    The z motors are nema 23
    4.2A
     
    #86 chuck english, Sep 30, 2020
  27. JustinTime

    JustinTime Veteran
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    I made mine from 2x4s only and man is it solid. I have a sheet of 3/4" plywood on top of the frame and on top of that I have a sheet of 3/4" MDF. The MDF is the sacrifice board.
     
    #87 JustinTime, Sep 30, 2020
    Sam Keller and KramE like this.
  28. chuck english

    chuck english New
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    so Peter did you understand I had 5 motors
     
    #88 chuck english, Sep 30, 2020
  29. Giarc

    Giarc OpenBuilds Team
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    That may be to much for one of the onboard drivers on the Blackbox.
     
    #89 Giarc, Sep 30, 2020
  30. chuck english

    chuck english New
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    Maybe I can get someone from Openbuilds to respond.
     
    #90 chuck english, Oct 1, 2020
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