Dual extruder BlTouch setup in RRF
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Hi, I noticed that I have problems with my mesh bed compensation on my modified FFCP.
I have two guesses why my model doesn't stick with bed mesh active on one corner.
One is that this corner is out of probe's scanning area.
Second is that my probe x offset is configured based on x coordinate of the left extruder.
And that led me to a question.Is there a way to set another offset for the second tool, so that the firmware understands that it should compensate for the active tool?
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I guess in 2019 the only way was to set a single point. Maybe something has changed or is going to change?
Here is the answer from the 2019 that I found : https://forum.duet3d.com/topic/12513/dual-extruder-setting-up-offsets-print-area-homing/14
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@Inlinebrother yes that is the best way to do it. Set your probe offset relative to one nozzle (say the left one), then set a tool offset for the other (right nozzle). That's how I do it on my chimera. (Edit: you may then have to set the nozzle offset to zero in the slicer depending on how you set that up, else it will double account)
Also note that any tilting in your carriage as it moves around will be magnified by the offset, so minimising the offset is important when designing your print head. Difficult task with two nozzles though!
Also worth checking if the weight of your wiring causes the print head to tilt in one area. Again, with two nozzles you've got twice as much stuff in that bundle, and it will throw off the mesh compensation.
If you're still struggling, it may be worth trying manual probing (probe type P0) and comparing that against your bltouch mesh? It takes time to do, but could be a useful debug to see any differences that point to something in your setup.
Finally, I'm assuming that you've already checked you've got the probe offsets correct?
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@engikeneer Thank you for your answer, I think there is some kind of tilt, but offsets seem to be correct. For now I'll try to increase the maximum probing attempts from 1 to 3 and see how it goes. Also disabling mesh bed compensation works better for now)
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@Inlinebrother you can try it, but if you're getting tilting of the head which varies around the bed, then that effectively means your probe z offset changes with position, so no amount of re-probing will help... really you'd need to focus on the mechanical issue or move the probe closer.
Having said that, multiple probe attempts is always a good thing as it should make the results more repeatable, and helps avoid any odd spurious false probes getting through.
I guess if you're able to print fine without mesh compensation enabled, then that's also a good thing! It's only really there to compensate for bent beds or saggy gantries after all
