Live Z adjustment vs Slicer Z adjustment - printing using Octoprint
 
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Live Z adjustment vs Slicer Z adjustment - printing using Octoprint  

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mathieu.n
(@mathieu-n)
Active Member
Live Z adjustment vs Slicer Z adjustment - printing using Octoprint

Hey guys,

First things first, for the record I had a bit of a storm with my mk2 this weekend - the thing was printing hairy balls of PLA and screwing up models really badly.

I must have dismantled it many times, cleaning the nozzle using the fires of heaven (well, a butane torch) and for the life of me never thought to look inside the heatsink section, in which some PLA seemed to have accumulated in melted form. So I suspect the first time it clogged was due to the nozzle which had caused back flow up the nozzle, and then when I didn't clean the parts under the heatsink it jammed right after.

So all in all, learning process.
I also got hit with the PINDA probe no longer triggering with the same sensibility for some reason. Another poster's suggestion of shaving off some plastic from the probe ended up working for me, and I now do get the right level of sensibility. Unfortunately, not before digging a scratch in my bed's PEI layer, and then proceeding to even scratch a think layer in the actual bed itself. Things still work and fortunately its right on the X axis 100mm part, where the 1/4 calibration initial point is.

Anyway, everything now works back to normal and I've learned a lot in the process!

Now for the actual question of this post:

One can adjust Z through live Z adjustment. One can also do so from the slic3r profile.
When you print through the SD card, I would presume the device printing is the actual LCD controller itself.
However when you print through Octoprint (essentially USB), would it be accurate to say that live Z adjustment is no longer relevant at this point and that you have to take the value input on live Z adjustment and use that as the Z offset in slic3r in order to get the same result?

Thanks!
Mat

Publié : 12/09/2016 1:58 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Live Z adjustment vs Slicer Z adjustment - printing using Octoprint

Hi Mat

I would presume the device printing is the actual LCD controller itself.

The SD card is just once possible source of GCode which the RAMBo uses to print from; it reads the SD card which happens to be located for convenience with the LCD screen

However when you print through Octoprint (essentially USB), would it be accurate to say that live Z adjustment is no longer relevant

No. The Live Z Adjust is applied to all GCode sources when the printer positions (in this case) the Z axis, the adjustment is applied after reading the GCode from the source.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Publié : 12/09/2016 2:19 pm
mathieu.n
(@mathieu-n)
Active Member
Topic starter answered:
Re: Live Z adjustment vs Slicer Z adjustment - printing using Octoprint

So when I print something through OctoPrint and have a live Z adjust of -0.500, and also put -0.500 in my Slic3r printer profile, I am effectively configuring -1mm of Z offset, correct?

Publié : 12/09/2016 3:14 pm
David T.
(@david-t)
Noble Member
Re: Live Z adjustment vs Slicer Z adjustment - printing using Octoprint

No, printer will not print under minimal Z height.

Publié : 12/09/2016 3:54 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: Live Z adjustment vs Slicer Z adjustment - printing using Octoprint

Mathieu

Sort of. You use a Live Adjust of -0.5 because your probe is 0.5mm too low to get the nozzle gap correct. Then you include a Z offset in the slicer of -0.5mm which lowers all layers by that value.

However, any layers that have a Z value of less than 0.15mm will be printed at 0.15mm, as that is the lowest the firmware will allow the nozzle to go - irrespective of the actual nozzle gap.

It's the Live Adjust that is important as it is that which is used to determine the actual nozzle gap and is there to adjust for probe installation variations.

Ideally, you should be able to raise the probe by 0.5mm and set the live adjust value to 0, but in practice each probe has slightly different sensitivity so your setup is almost at the best distance.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Publié : 12/09/2016 4:22 pm
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