MK4 Z Height Adjusment
My MK4 was running great for months then I clogged the nozzle. I put in a new nozzle(hot tip). It was really easy. I ran all of the calibrations. I am running PETG using a textured sheet. The Z height is not correct. It needs to be a bit lower. I have been emailing tech service and waiting for their latest recommendation. It sounds like a lot of people have this issue and change the Z height in the slicer. I tried and am unable to put a negative number in. Yes I am in expert mode.
Thoughts?
RE: MK4 Z Height Adjusment
You don’t change the slicer, once you have calibrated the printer you adjust the live z setting on the lcd menu. Every time you change or adjust the nozzle you need to redo your live z. You don’t need to run the calibration each time but you DO need to adjust the live z.
RE: MK4 Z Height Adjusment
I respectfully have to disagree with @neophyl. I believe what he said is correct for an MK3S, but not for the MK4. You don't have to change anything when you swap out the nozzle. I do it all of the time.
You might have an issue if there is some filament on the tip of the nozzle. Another possibility is a loadcell issue. Did you do the loadcell test after changing the nozzle?
I know that some people have had issues with PETG on the textured sheet. It seems like you didn't before, but I just wanted to mention it. I'm strictly a satin sheet guy.
RE: MK4 Z Height Adjusment
I have a Mini and a MK3S+ I know how to dial in the first layer for these. I prefer the textured sheets for the parts I am making. You need a good squish for it to stick and pick up the texture. Once you find it your golden and every print is good. I was very excited with the MK4 since it should nail the first layer every time. You can't live adjust with the MK4 - you shouldn't need to. But I know it is too high. Filament on the nozzle tip might be it but I have cleaned it and the program will clean it if there is a problem.
I simply need to have the nozzle .02 mm closer.
RE: MK4 Z Height Adjusment
I understand completely. When I had an MK3S I did exactly the same thing. I also liked how the prints came out on the textured sheet.
Are you using the stock nozzle with the nozzle and heatbreak, or the Nextruder V6 Nozzle Adapter?
RE: MK4 Z Height Adjusment
My MK4 was running great for months then I clogged the nozzle. I put in a new nozzle(hot tip). It was really easy. I ran all of the calibrations. I am running PETG using a textured sheet. The Z height is not correct. It needs to be a bit lower. I have been emailing tech service and waiting for their latest recommendation. It sounds like a lot of people have this issue and change the Z height in the slicer. I tried and am unable to put a negative number in. Yes I am in expert mode.
Thoughts?
I have a Mini and a MK3S+ I know how to dial in the first layer for these. I prefer the textured sheets for the parts I am making. You need a good squish for it to stick and pick up the texture. Once you find it your golden and every print is good. I was very excited with the MK4 since it should nail the first layer every time. You can't live adjust with the MK4 - you shouldn't need to. But I know it is too high. Filament on the nozzle tip might be it but I have cleaned it and the program will clean it if there is a problem.
I simply need to have the nozzle .02 mm closer.
Did you adjust Printers > General > Size and coordinates > Z offset? I can enter a negative number, and the discription says it's to correct for an incorrect endstop, and will add or subtract the value from all Z-axis values in the G-code output.
RE: MK4 Z Height Adjusment
Also to add, you can live adjust the MK4. This adjustment is brought up in the Tune menu after a print is started. However, unlike the MK3/Mini, the value doesn't "stick" and resets at the start of the next print. This allows tuning the Z height on a one-shot basis, like if there was some junk and it started too high, but not what you are trying to do by adding a bit more squish for textured sheets on all your prints. For that, I believe the "Z offset" in PrusaSlicer I outlined above is what you want.
RE: MK4 Z Height Adjusment
Yes. I bought one from Prusa direct and one from Amazon. I tried both and found the same results.
RE: MK4 Z Height Adjusment
Hmm I did not see this option in the tune menu?
RE: MK4 Z Height Adjusment
And you tested the loadcell?
RE: MK4 Z Height Adjusment
yes
RE: MK4 Z Height Adjusment
From everything you have written, it appears that something changed when you switched nozzles, and we don't know what it was. I am a little concerned that it might change back to how it was at some point, but I don't think making a 0.02mm adjustment will cause any harm.
Have you tried what @jseyfert3 suggested? Changing the Z-offset in the slicer?
RE: MK4 Z Height Adjusment
I need a negative number but the slicer wont let me.? I ran a first layer test file that prusa sent and it is a square that failed.
RE: MK4 Z Height Adjusment
I need a negative number but the slicer wont let me.? I ran a first layer test file that prusa sent and it is a square that failed.
Where exactly are you trying to enter a negative number and the slicer won't let you enter it? Please give the exact description or post a screenshot.
RE:
If I go to Printer Settings > General > Size and coordinates > Z offset then I can enter a negative number, such as -.02, which is what you said you wanted (click image to see full image):
Then I put a simple box in the slicer, sliced it, and the G-code preview shows the printer is going to a height of 0.18 mm for the first layer. Line 77 in the below image, "G1 Z.18 F720". G1 is a move command, Z means move in Z direction, .18 means move to a height of 0.18 mm.
This should be exactly what you want. You want a bit more squish, this will do that. It uses the mesh bed level to set the 0 point as before, but all z values in the G code have been subtracted by 0.02 mm, so the first layer is printed at a height of 0.18 mm instead of the 0.2 mm. Unlike the First Layer Height (which is set to 0.2 mm in this example), the extrusion isn't adjusted, so this is pretty much exactly like lowering the Live-Z adjustment on the MK3 & Mini printers (I had a Mini before my MK4 so I'm very much aware of how it's adjusted on the Mini/MK3). If the First Layer Height was adjusted instead of the Z offset I am recommending, then the first layer height will be lower, but it won't be more "squish" because the extrusion will be reduced for a layer height of the entered size. Z offset won't change the extrusion of the first layer. Also note you cannot enter a negative First Layer Height, because that wouldn't make any sense.
RE: MK4 Z Height Adjusment
Also realized in my post yesterday I said:
Printers > General > Size and coordinates > Z offset
And today I said:
Printer Settings > General > Size and coordinates > Z offset
The difference is yesterday I was on PrusaSlicer 2.8 with the updated UI, today I was on my work computer over lunch break and was on PrusaSlicer 2.7. They changed the text of the menu option slightly between 2.7 and 2.8, but all sub-menu items are named the same between versions of PrusaSlicer. Also neither 2.7 on Windows or 2.8 on Linux gave me an error about a negative value of Z offset.
Apologies for any possible confusion!