Different Z-Offsets for Different Layer Heights?
Apologies if this has been asked/answered before, but it is normal to need different z-offsets for different layer heights? And if so, is this something I should measure and then adjust in the slicer as opposed to manually changing the z-offset while the first layer is printing?
To be clear, for example, my first layer is great with a 0.2mm layer height, but when I switch to 0.3 or 0.4, it usually needs adjustment (up usually), and then back again when I print in 0.2. It's very tedious to do this at the printer every time I print with a different layer height. I know there's a setting in the slicer but I want to make sure that this is normal behavior.
Thanks in advance!
RE: Different Z-Offsets for Different Layer Heights?
Are you changing the 1st layer height when adjusting layer heights? I use a 0.2mm 1st layer height regardless of other print adjustments, including raising successive layer heights. This works well for me using everything from 0.1 layer heights with a 0.25mm nozzle to 0.64mm layer heights with a 0.8mm nozzle. Live-Z won't have much of an effect on layers after the 1st if it's within reason.
RE: Different Z-Offsets for Different Layer Heights?
In the slicer the first layer thickness is a separate setting and usually doesn’t vary no matter what layer height you have selected (at least on default profiles). So no, it’s not normal to change. For different filament types yes, for different sheets then most certainly but changing from a a0.1 or 0.3 layer height with say pla then nope.
RE: Different Z-Offsets for Different Layer Heights?
Interesting. So I'm using the Revo Six, which behaves almost identically to the stock hotend in terms of z-height. I was printing with the 0.4mm nozzle and everything is great and I switched to the 0.6mm nozzle (correctly tightened and everything which is easy with Revo) and when printing the first layer, it was obvious that it was too close so I raised the z-height by a bit and everything was peachy. Any idea why this would be the case? You're right that the 1st layer height is the same regardless...
RE:
You didn’t say anything about a revo, you mentioned changing layer height, not nozzles. Changing nozzles does require you to adjust z height. Even with a revo. While the machining is good it’s not accurate enough to have zero change, at least that’s what everyone who has them is reporting.
For future reference layer height and nozzle diameter are 2 different things.
RE: Different Z-Offsets for Different Layer Heights?
Oh sorry! I do know that. I also had the same problem switching from a 0.2mm layer height to a 0.3mm layer height with the same nozzle. I thought the problems were related.
RE: Different Z-Offsets for Different Layer Heights?
Also then, for the nozzle change, should I put a setting in the slicer to change the z-offset? Or should I do it at the printer?
(So two different things)
RE: Different Z-Offsets for Different Layer Heights?
Yeah, not mentioning nozzle changes wasn't particularly helpful. Even the Revo still requires live z adjustments. If that wasn't necessary I might even be bothered to install the copy I bought even though the host of issues reported indicates to me that E3D still has some work to do.
RE: Different Z-Offsets for Different Layer Heights?
Changing the nozzle is very difficult to keep the same distance between the Minda and the nozzle tip.
MBL is checking the bed level. The z-offset sets the nozzle heigth to have optimal distance between itself and the bed surface for the moment the Minda stops the nozzle above the bed. This also defines the distance between the nozzle tip and Minda bottom. Changing the nozzle, this distance can change. So the z-offset change necessity is not a dependent on nozzle hole diameter change but on the nozzle tip and minda bottom distance change.
Long story short - you have to re-adjust the printer's z-offset by updating the first layer calibration.
even an old man can learn new things 🙂
Standard I3 mk3s, MMU2S, Prusa Enclosure, Fusion 360, PrusaSlicer, Windows 10
PRUSA MINI+ Prusalink + Prusa Connect
RE:
I see little point in putting this into a slicer profile in Prusaslicer or in a sheet profile in the Mini firmware. The next time you swap a nozzle, you'll have to update live Z again and Live Z may or may not be the same as it was the first time around with that nozzle. You can actually do the experiment and calibrate live Z for a nozzle. then remove it and put it back in again. In theory, Live Z should stay the same but in reality, with the tolerances of the nozzle assembly, this may or may not be the case.
TL;DR: I'd just do a quick print with a calibration strip like this https://www.prusaprinters.org/prints/105404 a bit up and down around the previous Live Z and you should be in a good range in no time.
RE: Different Z-Offsets for Different Layer Heights?
@bje
Interesting. So I'm using the Revo Six, which behaves almost identically to the stock hotend in terms of z-height. I was printing with the 0.4mm nozzle and everything is great and I switched to the 0.6mm nozzle (correctly tightened and everything which is easy with Revo) and when printing the first layer, it was obvious that it was too close so I raised the z-height by a bit and everything was peachy. Any idea why this would be the case? You're right that the 1st layer height is the same regardless...
It's also known that E3D has been having issues with the tolerances of their press together nozzles manufacturing, among other things, it's possible that your 0.6mm nozzle is slightly out of tolerance. I don't own one but I have been following the development of their products closely. E3d has a lot of trouble shooting ahead, I'm sure they'll work it out sooner or later.
Regards
Swiss_Cheese
The Filament Whisperer