Few questions..

New Home Forum LowRider Advice – LowRider Few questions..

This topic contains 76 replies, has 4 voices, and was last updated by  Jeffeb3 3 months, 3 weeks ago.

Viewing 17 posts - 61 through 77 (of 77 total)
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  • #36649

    Ryan
    Keymaster

    #36654

    Christopher
    Participant

    I updated the firmware and still nothing so I decided to wire the z motors in series.. It moves now. Slow, but it moves.

    Any disadvantages to running in series? I think I’m probably going to do it to my X axis as well..

    #36655

    Ryan
    Keymaster

    Series has disadvantages in the higher rpm range, but we come nowhere near it.

    #36657

    Jeffeb3
    Participant

    I can’t remember where I saw it, but I remember seeing someone piggyback two 8825s in one port. They basically soldered those male/female headers like Arduino shields have on all the pins but the motor output, then put another driver on top, but with those motor pins going to the second motor. I have been meaning to try it and then share, but you know, time.

    #36679

    Christopher
    Participant

    Is there a way to wire 2 motors in series while reversing a coil so that one goes the opposite direction?

    #36681

    Ryan
    Keymaster

    Yup I have it in my little hand drawing, labeled as the rev. You can also follow the hard wired modified harness shown a few pics below.

    1 user thanked author for this post.
    #36682

    Christopher
    Participant
    Yup I have it in my little hand drawing, labeled as the rev. You can also follow the hard wired modified harness shown a few pics below.

    So if I’m reading this correctly all I have to do is wire everything like you would to have the motors going the same direction but take a pair from one of the motors and flip flop them. So red/blue are a pair, I would just switch them.

    #36683

    Ryan
    Keymaster

    yes

    1 user thanked author for this post.
    #36703

    Christopher
    Participant

    As an electrician, I’m ashamed that I cannot figure this out.

    I’m wired exactly like the diagram. I’ve included a photo. Yet one motor doesn’t move.

    #36707

    Ryan
    Keymaster

    Your sketch is correct, you didn’t wire it that way.

    1 user thanked author for this post.
    #36708

    Ryan
    Keymaster

    Sorry you did wire it like your sketch. So the only thing now is maybe your stepper plugs are not set in pairs. Meaning black and green might not be a pair, they are not set in pairs on extruder motors, so these probably are not either.

    To test this unplug it all and short the black and green and see if it gets hard to turn.

    1 user thanked author for this post.
    #36755

    Christopher
    Participant

    I figured it out.. 2hen I originally wired in parallel I flipped a pair on the far motor and never accounted for that all the times I was wiring in series. I’m an idiot.

    Now I tried to cut for the first time.

    It works!

    BUT the z axis always ends up uneven. When I shut the machine off, one side never falls either. Also, my z motors make a squeak/growl When I suspend the axis in the air.

    #36758

    Jeffeb3
    Participant

    Alright!

    Onto your new problem. What do you mean “ends up uneven”? Like it’s skipping steps, or just that when it starts, it’s not parallel to the work?

    You have to start them at the same height. Not having it come down is annoying, at least. I know that if mine aren’t at the same height, then one can bind up a bit. I always turn my Z axes a little bit before I start, just to make sure there isn’t any buildup in the Z coupler, because I’m so anal about those being at the same height. I was thinking of printing the MPCNC pineapple to attach to the bottom to make this easier.

    I think any work spent on making that move smoother is going to be time well spent. If you can look for places where it’s binding, or add grease to the leadscrew or something that will help.

    A workaround for now would be to always drive back to Z=0 before disabling the motors, or turning off the machine. I think Ryan suggested in the guide to append to the end of your gcode a command where it will drive to a safe X/Y and then lower itself down gently. You might have to drill a hole for the bit and collet to clear.

    You’ll also want to make sure the two sides of the cart are square before you start. Specifically, you X perpendicular to Y. I know my torsion box is square, so I make sure the two carriages are even with the front of the box before I turn on the motors. I think I have a pic somewhere of it…

    #36765

    Ryan
    Keymaster

    Hefe nailed it.

    My ending gcode drives -15 X&Y and then down to Z0, before the power off. After doing this a few times I realize I think I need to update the firmware to not kill the steppers when the job is finished, at least not the Z so you can manually lower it. Or maybe (I’m gunna get crap for this), add a Z endstop, used only for parking it, not as an actual z endstop.

    When it powers down, if the router is all the way to one side it does tend to lower crooked.

    I have been spending more time with the lowrider, so I have a few minor changes in mind. This is also the first machine where I think a gamepad would actually be useful.

    #36766

    Jeffeb3
    Participant
    Or maybe (I’m gunna get crap for this), add a Z endstop, used only for parking it, not as an actual z endstop.

    Is there support in Marlin for one on each side? I guess you’d need a separate motor driver for each one.

    This is also the first machine where I think a gamepad would actually be useful.

    Yeah, I square it up, like that pic, and then I keep all of them on. I think it’s just too hard to get back to square otherwise, so I move it completely with the software. I should look into a joystick.

    #36770

    Ryan
    Keymaster

    Yeah, I start mine all the way back, up against the belt holders and drive it to my starting point to keep it square, then all my gcodes start with a zero all axis command.

    #36838

    Jeffeb3
    Participant

    Wait, your machine is 2x heavier than mine/Ryan’s, your Z should definitely drop on both sides.

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