Completey stumped on how to zero X & Y

Discussion in 'Calibration, Help, and Troubleshooting' started by Proto_BB, Jul 22, 2016.

  1. Proto_BB

    Proto_BB Well-Known Member

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    I'm at the point in the manual of Printer Commissioning. I'm following the "Zero X & Y" instructions but I keep arriving back to the same point.

    My X is out by about 20mm from the zero line on the edge of the bed. I run "Auto Home" then I Prepare -> Move Axis -> Move 1mm -> Move X, and move it to the 0 line on the bed. I then move the X away and tighten the X end stop screw a few turns. I run "Auto Home" it touches the X and Y stops but yet it goes back to exactly the same place before I touched the screw, and it still reads X: 175, when the zero is at -20. So X should really read X: 195.

    What am I doing wrong here? I can't see where the build manual tells me to do anything else... Am I meant to "set home offsets" or something else?
     
  2. Sarah Nicholson

    Sarah Nicholson Well-Known Member

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    The wording in the manual is perhaps a little unclear. When you home it won't stop at zero. So after adjusting the endstop, you home again, then use the LCD to move to zero, and check again if it's over the 0 mark on the bed. Rinse and repeat until it is, it may take a few attempts. The difference may not be obvious to the naked eye so when you home it might appear that the adjustment hasn't done anything but after a few rounds you should hopefully see it getting closer to the zero.

    Also if you're building a hybrid, make sure you used the correct screw for the X endstop as it needs a shorter one.
     
  3. Proto_BB

    Proto_BB Well-Known Member

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    Thanks Sarah. You have saved my day! I had the longer screw! Now it is perfectly aligned - with the left nozzle. Not that the manual states it should be the left one...

    I feel my very first 3D print might be imminent at last...

    Edit: Actually the manual says the right extruder (I assume looking from the front of the BB) should be aligned to 0,0. I wonder if this is possible. My end-stop screw is a fair way in now?
     
    #3 Proto_BB, Jul 22, 2016
    Last edited: Jul 22, 2016
  4. Sean

    Sean Member

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    If you've got a dual, make sure you're using a 10mm m3 screw for the X endstop - there's an easily missable line of text in the instructions that says this. The diagram is incorrect for duals.
     
  5. Sarah Nicholson

    Sarah Nicholson Well-Known Member

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    It's definitely possible to get the right nozzle over zero, but you will need to be careful with the printhead wiring as the wires can get between the carriage and the idler if they aren't positioned correctly. In particular the connector for the left hand PT100 tends to get in the way, so look very carefully at the picture in the build manual to see how the wires are routed and where the connector is positioned.

    For info my X endstop screw has about 7mm protruding from the idler, including the screw head.
     
  6. Proto_BB

    Proto_BB Well-Known Member

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    I'm not sure if I'm calling the left nozzle what you are calling the right nozzle? To me (possibly wrong) the left nozzle is on the left hand side when looking at the front of the BigBox. I measured my X end stop and it protrudes a total of ~6.5mm including the screw head. Yet my 0 is for the left nozzle lining up against the line. The right nozzle is on the line when the X hits the end stop - but that is -38mm. I'm not sure if that's correct?
     
  7. Sarah Nicholson

    Sarah Nicholson Well-Known Member

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    Sorry I may have got things muddled, it's been a while since I did this step and there's different ways of setting up the BB.

    If you have wired up as per the build guide, where the left extruder (viewed from the front) is connected to E1, then X=0 on the LCD should be with the left hand nozzle at the zero mark on the bed. You want to adjust your end stop so that when you use the LCD to move to X = -38 the right hand nozzle is over the zero mark on the bed, so it sounds like you've got it set up correctly.

    Sorry for the confusion. Alex has a post which explains this all very well here.
     
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  8. Proto_BB

    Proto_BB Well-Known Member

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    Thanks Sarah for the help. I will work through the reference material.
     
  9. Alex9779

    Alex9779 Moderator
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    It depends where you start numbering. Connectors on the Rimba are HE0 to HE2. Left hotend is HE0 in the build guide for dual. This renders then to T0 in gcode...
    Somewhere between there are one based numbers E1 and E2.
     
  10. Michael Patry

    Michael Patry New Member

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    I'm still stumped, i tried using the smaller screw to get things zeroed in, but now the end stop is not triggered. The closest i could get it was around 8mm away from 0, the wiring appears to be done correctly. If my print bed is 300 x 200 and it tries to center, should it not read X:150 and Y:100 after the auto home, not X:175 and Y:100?
     
  11. Kanedias

    Kanedias Well-Known Member

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    Is there a chance you have the x and y end stops the wrong way round?

    If the dual is the same as the single it finishes at y68, not 100
     
  12. Greg Holloway

    Greg Holloway Administrator
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    The IR sensor measures at 150x100, The sensor is obviously off the the left and so when it is done measuring the hotend will actaully be off to the right and not in the centre. If you have a look when you home you should be able to see this offset.

    To check you can move the head and see if T0 sits centered at 150 x 100
     

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