Motion Sickness - Commissioning woes - BB Pro

Discussion in 'Build Help' started by James Woods, Apr 14, 2016.

  1. James Woods

    James Woods Member

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    I have two issues I'm hoping you can help me with...

    1) Homing - Printer moves forward (along Y axis but only ~1 cm from any position) It does not attempt to go all the way to the endstop.

    Then correctly hits the X endstop and sort of centres (along X but never Y)

    2) Set Z offset to -5.00 then move manually in 0.01mm increments (after moving the IR sensor etc) I can only get to about 1cm from the nozzle to the glass bed. With no room left on the screws.

    Clearly I've messed up somewhere. I've gone back and retraced my steps and can't seem to find the error of my ways ;)
     
  2. PsyVision

    PsyVision Moderator
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    Is your Z and Y end stop wiring the correct way around ?
     
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  3. James Woods

    James Woods Member

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    Good call thanks! One of the pins on the board for Y was bent inwards and not seating properly. Straightened it out and am now homing correctly.

    Anyone have any thoughts on my Z axis issue?
     
    JohnEsc likes this.
  4. Anthony Ballard

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    I had a a similar issue to you, although not quite as much as 1cm. I fixed the issue by raising the stand-offs of the heated bed. Mine are about 3mm from the base. That and the thickness of the glass made the difference.

    However if that is not enough you can also check that the heater block is not screwed in too far along the heat break. That should also be a couple mm between the block and the heat sink.
     
    #4 Anthony Ballard, Apr 15, 2016
    Last edited: Apr 15, 2016
  5. Dr Jeep

    Dr Jeep Well-Known Member

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    yes the standoffs aren't supposed to be screwed all the way down as they are there to provide the ability to level the bed though 1cm is about as much height as you can cover unless you get longer ones.

    The other thing is did you level out the bearings on the corners of the build platform. The tops of the bearings should be level with the tops of the bolt heads in each corner (i.e the bearings shouldn't be centred in the holders)

    Not sure the heatbreak/heater block thing would cause this...if you screw the heatbreak into the heater block too far then the nozzle won't screw in so far..so the effective length would be the same as the two butt up together inside the heater block
     
  6. Anthony Ballard

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    Yeah, my bad, don't think its the heater block. Good call on the bearings though, forgot about those.

    Here is a pick from the manual, what it should look like:
    [​IMG]
     
  7. Dr Jeep

    Dr Jeep Well-Known Member

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    Oh finally I don't like the ordering of the that whole homing section. they have you setting the Z height way too early I think, I'd recommend doing it once at the start and then rechecking it once again after you have done all the other bits as some of them can cause the Z height to change.

    Oh and something I might actually get wiki access to fix as it caused me a nasty Z axis head crash. When you get to the bit for centring the Z axis lead screws (where you slacken off the Z motor screws and run the bed to the bottom and tighten them again) do not try and raise the bed back to 0.00 before running autohome again. As if you did up the bolts tighter then you compress the cork and it lifts the home position and you get a head crash.
     
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  8. James Woods

    James Woods Member

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    I'm still having issues with the Z-offset. I did a quick video to show how after setting the z offset to -05.00 I cannot get the nozzle to get to the glass. I've tried manually getting it there then continuing to follow the process but I get bed/head crashes.

    I've made sure the standoffs are not screwed in all the way.

    I've taken out and reinstalled my Z-rods.

    Not sure where I'm messing up. Thoughts?

    Here's the video https://youtu.be/qmTVCvTXmKw
     
  9. Kick2box

    Kick2box Well-Known Member

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    Just put the sensor a little bit higher at the start.
     
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  10. JohnEsc

    JohnEsc Well-Known Member

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    My personal would be start with the bed a little higher, adjust it manually to raise and definitely move your IR sensor as @Kick2box mentioned. Set the IR sensor so it's just below the nozzle tip before you set the -5.00 and Auto Home. Use a ruler when manually raising to get both sides as close to level as possible.
     
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  11. James Woods

    James Woods Member

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    Thanks guys that got me through it. Ignoring the whole "put the sensor as far down as it will go" and using your guidance did the trick.

    Yay documentation on a precision instrument ;-)
     

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