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nozzle z-axis offset documentation
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Description

I noticed while adjusting nozzle z-axis offset on .61 FW that in order to move the 2nd nozzle up, the value must be decreased.
So a value of 0.9 makes the nozzle lower than a value of 0.1
Is this the intended direction?
I would think 0.9 would raise the 2nd nozzle not lower it

Event Timeline

logan created this task.Jan 2 2019, 10:20 AM
logan created this object with edit policy "LulzBot Hardware Products (Project)".
marcio added a comment.Jan 2 2019, 1:54 PM

Ummm, okay, I see what you mean. I pushed a fix in .63.

logan added a comment.Jan 3 2019, 11:47 AM

@marcio No change to behavior on m.63, a larger positive number still lowers the 2nd nozzle into the build plate

@logan: I believe this ticket can be closed? Perhaps check out .79 and make sure it's still good there?

karrad added a subscriber: karrad.Jan 29 2019, 2:48 PM

Testing on 2.0.0.79 SL nudge nozzle Z in the positive direction moves the nozzle up relative to the bed, negative values bring the nozzle closer to the bed.

marcio closed this task as Resolved.Feb 1 2019, 2:35 PM
logan reopened this task as Open.Feb 5 2019, 8:41 AM

Testing on 2.0.0.80
All adjustments made between prints to nozzle offset only.
Increasing the positive value of nozzle z offset pushed the 2nd nozzle closer and closer to the bed

marcio closed this task as Invalid.EditedFeb 5 2019, 2:35 PM

I already explained this to @logan, but for anyone else lurking, this behavior is correct. When you increase the Z nozzle offset, you are telling Marlin that the 2nd nozzle is higher relative to the 1st nozzle, which means that during a toolhead switch from nozzle 1 to nozzle 2, Marlin will move the Z axis down lower towards the bed. So yes, increasing the nozzle offset in Z will lower the 2nd nozzle closer to the bed.

This isn't generally very intuitive, which is why I added the "Nudge Nozzles" screen. It's a bit more user friendly in that regard.

karrad reopened this task as Open.Feb 7 2019, 3:43 PM
karrad added a project: Cura LulzBot Edition.

@marcio Thank you for the explanation. We will need to get this documented to avoid confusion in the field. Re-opening, kicking to documentation.

karrad renamed this task from nozzle z-axis offset direction to nozzle z-axis offset documentation.
karrad triaged this task as Normal priority.