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OpenBuilds OX CNC Machine

Discussion in 'CNC Mills/Routers' started by Mark Carew, Dec 15, 2013.

  1. Rhinofart

    Rhinofart New
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    Thanks Chris!

    I still have parts waiting to come in. Just limit switches. It took a couple of weeks in total. But for straight out time building it probably in the neighborhood of 18 hours of actual work time. I was only able to dedicate a couple hours a day to it with my Pneumonia, and hectic work schedule. The next one I build should be greatly reduced time with all that I learned for putting this one together.
     
  2. Paruk

    Paruk Journeyman
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    My Buffalo did this today!

     
    Thamli, Rhinofart, GrayUK and 5 others like this.
  3. Paruk

    Paruk Journeyman
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    Planet doesn't seem to have the same or a similar routine, Andrej is not a big supporter of the limit switches on the slave. I'm a bit puzzled, because this morning I had NO measurable difference between the 2 Y sides. After running "The Buffalo" text I got almost 1mm! Maybe because I have 2 steppers on 1 driver? Loosing steps?

    One solution I was thinking about is, switch off all power sources and move the non limit switch side into the exact position, making the X square. But with the power switched off, the stepper could easily be moved back into the previous position, hence X again approx. 1mm off. I have an option inside the software saying motor enable on exit. Does this mean that even with the power off, somehow the connection between A- and A+ is kept established, hence the stepper will move much less easy?

    Anybody any thoughts about this issue?
     
  4. David the swarfer

    David the swarfer OpenBuilds Team
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    the problem is microstepping and the stepper internals and driver enable/disable.
    as you can feel, the stepper has preferred step positions, known as whole steps.
    microstepping positions the rotor between the whole steps, but as soon as the power is removed (drivers disabled) the motors will step to the nearest hole step position.
    if one side is closer to the 'next' step and the other closer to the 'previous' step, the gantry will go in opposite directions.

    best is to have separate drivers
    and
    power on but do not move anything, the driver chips should power on at a 'whole step'. now shift one sides belt until the gantry is aligned.
    and
    go into the setup for the driver board and make sure 'keep drivers enabled' is always on. having them disable between cut files is a sure way to go out of alignment because you will bump the gantry during loading and tool changes.
     
  5. Paruk

    Paruk Journeyman
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    David, thanks for the reply and the excellent explanation. I had separate drivers, one died, for now it's 2 steppers on 1 driver until the new ones arrive. This is what I can do within the controller software for the steppers. Which option in your opinion would set the steppers in "keep enabled" mode?

    Screen Shot 2014-10-10 at 21.05.18.png

    The motor drivers are TB6600 from China and don't seem to have any way to set them on "keep enabled". Funny though, if dip switches M1-M2-M3 are on or off makes no difference, both give free, motor don't lock. Could that be a "lost in translation mistake" from the Chinese?

    I could shift the belt as an option, but being quite new belts I expect them to stretch a bit soon. Hence, the X will be again out of square. I'm really looking for a more robust and, if possible, permanent solution.
     
  6. David the swarfer

    David the swarfer OpenBuilds Team
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    confusing. maybe the best is to not use a pin out for this, but instead to just wire them to enabled so the software can never get in the way.
     
  7. Paruk

    Paruk Journeyman
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    Ay! And how should I do that wiring? Do you have any picture/example for that? Would be much obliged.
     
  8. Frederic Goddeeris

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    I see, interesting

    So, this means that one does not only has to have an additional driver but also a "channel" on the control HW/SW (say GRBL, TinyG or whatever) to drive the two motors separately. Right?

    If I understood this correctly, I do now wonder:
    I currently use GRBL, which can only drive 3 motor-drivers. In this case, it is beneficial to have 2 individual drivers for the 2 motors for Y while they would be bound to the same channel of GRBL?

    Thanks a lot,
    Frederic
     
  9. David the swarfer

    David the swarfer OpenBuilds Team
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    yes, 2 drivers driven by the same signal is good. both motors then get full power.
     
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  10. David the swarfer

    David the swarfer OpenBuilds Team
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    connect EN- to ground, and EN+ to 5V
    now the driver is enabled whenever the power is on.
     
    Robert Hummel likes this.
  11. David the swarfer

    David the swarfer OpenBuilds Team
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    from the user manual
    Standby mode

    The operation mode moves to the standby mode under the condition M1 = M2 = M3 = L or M1 = M2 = M3= H.
    The power consumption is minimized by turning off all the operations except protecting operation.
    In standby mode, output terminal MO is HZ.
    To release the standby mode, release the condition of M1 = M2 = M3 = L or M1 = M2 = M3 = H.
    Input signal is not accepted for about 200 μs after releasing the standby mode.

    http://www.hotmcu.com/tb6600-1-axis...ver-board-for-cnc-router-p-56.html?cPath=7_30

     
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  12. Paruk

    Paruk Journeyman
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    From the user manual? Man, I looked and looked for documentation for this board and didn't manage to find anything. Thanks so much for this!

    I was from the beginning looking for that driver, but couldn't find it for some strange reason. Always got other search results and finally settled for the ones directly from China. They take about a month to arrive. This one seems to have faster shipping times. I'll go and give them a try!
     
    #1572 Paruk, Oct 10, 2014
    Last edited: Oct 10, 2014
  13. Rhinofart

    Rhinofart New
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    Got my limit switches delivered to my desk at work today!!! Just in time for the Canadian Thanksgiving weekend. I know what I'm going to be doing while the Turkey is on the BBQ. ;0) How are you guys mounting limit / homing switches for the Z axis on this? I've got the X and Y switches placed, but am scratching a bit on the Z...
     
  14. Frederic Goddeeris

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    Have a look at page 40, there are pictures of 2 options there.
     
  15. Paruk

    Paruk Journeyman
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    I needed only 1 limit switch on the Z, the one for the upper position limit (since Z0 is the table, don't need a limit switch for that). I've got the micro switch set from Openbuilds, that comes with a little plate. Using a drop in t-nut and low profile 6mm screw I attached the plate with switch to the back of the 20x60 profile for the Z axis, just above the threaded rod plate. The cable is lead around the bearing to the other side and the cable goes into the v-slot on that side, up to the top and further into the cable drag chain. The v-slot is covered (to keep cable in) with one of these fancy slot covers http://openbuildspartstore.com/slot-cover-panel-holder/ . With some measuring you will get the limit switch in the right position. This switch is used for the homing procedure of the Z. I might put a picture in a bit later today (if I can have enough light on it to see it).
     
  16. Paruk

    Paruk Journeyman
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    Unlike some, I'm willing to listen to advice. I can see your point and it is very likely to happen one day (Murphy lives here at times). So I will mount the second one for peace of mind. BTW, how will that go if you wanna cut slightly into the table to have a clean cut on your work piece?

    Actually at second thought….. I might not do it. It's about jogging the Z below table level. Now, how would you do that? When I'm jogging the Z, generally I will be sitting with my nose right on top of the bit for getting it exactly in position above the workpiece. I'm also planning to use a movable tool sensor which will prevent the Z from "jogging" lower than the table.

    Of course there is a change that my finger will stay to long on the jog button and that with the speed of the Z coming down one is just to late to stop it, the deceleration will crash the bit into the table then. I can see if the software gives an option to regulate the speed which the Z jogs with to a lower one than the other axis.

    Anyway, thanks for bringing this up. One can forget all to easy (or just don't realize) what all can go wrong with human beings operating machines. ;)
     
    #1576 Paruk, Oct 11, 2014
    Last edited: Oct 11, 2014
  17. GrayUK

    GrayUK Openbuilds Team Elder
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    Set to your main table, then you can set to a sacrificial table, and quite happily cut low.

    Gray
     
  18. Rich C

    Rich C New
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    Ok, I got tired of waiting for all of the electronic components to come in for the TOAD4 controller board, so I bought me a TinyG v.8 board. Hooked it up and everything seems fine. (Kinda). Adjusted all my settings and loaded tgfx. Connected and was able to jog the steppers. (Now for the kinda part)... If I try to input a move in the command line, I get an alarm and the thing goes disabled. I am not running any switches YET. Just trying to test movement right now. All three homing switches are disabled in the settings. Attached are my settings (in case anyone wishes to try to figure out my problem).

    Rich
    PS...aren't I just having the dangdest time with controller boards???? jeeesh
     

    Attached Files:

  19. Rhinofart

    Rhinofart New
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    What do all those "nan" entries mean? None of my config files had any of that in it. I has having some weird issues with my TinyG until I did a factory reset "Entered $defa=1 from within CoolTerm" I then loaded up tgFX and configured everything the way I had it before, and everything worked great for me. My board is less than a week old, so it may have been something I inadvertently did during my initial configuration, or like the Synthios guys stated, some of the FW may have had some corruption coming out of the factory. I'd do the $defa=1, reprogram from tgFX, and see how it goes.
     
  20. Robert Hummel

    Robert Hummel Custom Builder
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    Little update on the Fiber OX
    The few parts I needed arrived from open builds and I got the Z assembly together :D
    image.jpg
    I will be cutting the belt clips tomorrow with the ones needed for kits and 4 plate sets :thumbsup:
     
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  21. Robert Hummel

    Robert Hummel Custom Builder
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    And I think it's time to call it a night :sleepy:

    image.jpg
    :D
     
  22. Paruk

    Paruk Journeyman
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    @ Rhinofart, picture of my limit switch on the Z.
    Buffalo Z limit switch.JPG
     
  23. GrayUK

    GrayUK Openbuilds Team Elder
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    Looks very professional Paul :)

    Gray
     
  24. Robert Hummel

    Robert Hummel Custom Builder
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    Just tying up odds and ends while the belt clips are milled :)
    image.jpg
    Squared everything up and now installing the pulleys
     
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  25. GrayUK

    GrayUK Openbuilds Team Elder
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    Just another excellent CNC Machine from the "Hummel Factory"!!
    Do the Local Council know you've got a factory going there?

    You have got to be running out of room?
    Or are you selling them, as fast, as you are making them?

    Gray
     
  26. Dave M

    Dave M New
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    Nice Work Robert!
    What are the dimensions of X and Y axis? looks pretty square.

    Dave
     
  27. Robert Hummel

    Robert Hummel Custom Builder
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    Hahaha
    I'm out of room after this one but that just means I need to make more room lol
    I can't keep up with the demand that's for sure.
    Ty for the kind words :)

    It's 980mm on the Y and 800 on the X ;)

    I have the final parts done now and then it's wiring time :confused:

    Not sure what I will make the Z motor spacers from but I'll figure something out :)
     
  28. Mike S

    Mike S New
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    What is the exact size difference when comparing the length of the rails to the cutting area? This question is for any build of CNC.

    I'm building an Ox, and I'm trying to figure out exactly how long to cut each rail to achieve a 28" x 18" cutting area.
     
  29. Paruk

    Paruk Journeyman
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    Thanks, Gray. I don't like the cable though. Probably going for a thinner one and try to figure out a nice 3d printed object to protect the cable and keep it perfectly in place.
     
  30. Paruk

    Paruk Journeyman
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    Got the electronics worked away in a box and still need to do some finishing on cables (hide/protect them). Tomorrow is the day for getting the tool offset sensors installed. By the way, my finger got stuck to the jog button and I DID crashed the bit into the table. Grrrrr…… Have to do the homing again now. Maybe after all a limit switch extra on the Z, Justin!
     

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