life adjust Z - my way  

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bobstro
(@bobstro)
Illustrious Member


[...]So the first few lines print OK before it starts catching. Can someone please help me identify what's going on here?
I always have a hard time judging from pictures as the results of being too high or too low can start to look the same once it starts to peel up.

One tip: Be sure your sheet is completely clean before trying this. I suggest a quick dunk under the kitchen sink with a bit of dish soap, and avoid touching it!

I always go by the first few lines. If I can rub my finger across it without it becoming dislodged, I'm not too high. I might still be too low. Look for wrinkling or distortion on adjacent lines as it progresses as that usually indicates lines being pressed together from being too low. Of course, being so low as to snag is a problem too.

Looking at your skirt around the square, I'm thinking you've got a bit of adhesion issue going on. The 1st few rows look pretty good but it's lifting. Give it a clean and try again. That skirt line around the perimeter should go down cleanly and stick. Lower it a tad (go more negative - I use 0.02 increments once I'm close).

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 26/09/2018 12:02 pm
neal.w2
(@neal-w2)
Reputable Member

Just a note...the upper left side in the photo still has holes along the perimeter. Could be your Z is still too high.

Neal

...
Posted : 26/09/2018 4:28 pm
perry.t
(@perry-t)
Active Member

The soap worked! I washed the sheet and dialed in in closer and the result was bang on. Thanks for the help!

Posted : 27/09/2018 10:17 am
christian.b13
(@christian-b13)
Eminent Member

I used this method to get a a good first layer for the square... Then i tried to check the whole bed. I am getting a bit rough surface to the touch for the marked area.. the bed doesnt seems warped... i mea it is acceptable but still the plastic is more squishes here... any ideas ?

Posted : 06/10/2018 12:04 am
JeffJordan
(@jeffjordan)
Member Moderator

nice to notice that my thread is still "alive" and helpful.
😎 😛 💡

:geek: by the way: @christian.b13 nice powder-coated steel sheet. hope they'll be available soon as spare parts...

dem inscheniör is' nix zu schwör......
Posted : 08/10/2018 11:04 pm
andy.b15
(@andy-b15)
Active Member


I used this method to get a a good first layer for the square... Then i tried to check the whole bed. I am getting a bit rough surface to the touch for the marked area.. the bed doesnt seems warped... i mea it is acceptable but still the plastic is more squishes here... any ideas ?

When you print this how long are you letting your bed heat up before starting the print. I had issues where some areas of the bed printed better than others and Prusa sent me a new bed and Y carriage but I saw the same issues. I found by letting the bed heat up for about 5 minutes before the print gave me a better (but no perfect) first layer across the bed. I still have random areas which are higher or lower with no explanation to determine why.

Posted : 09/10/2018 12:40 am
toaf
 toaf
(@toaf)
Noble Member



I used this method to get a a good first layer for the square... Then i tried to check the whole bed. I am getting a bit rough surface to the touch for the marked area.. the bed doesnt seems warped... i mea it is acceptable but still the plastic is more squishes here... any ideas ?

When you print this how long are you letting your bed heat up before starting the print. I had issues where some areas of the bed printed better than others and Prusa sent me a new bed and Y carriage but I saw the same issues. I found by letting the bed heat up for about 5 minutes before the print gave me a better (but no perfect) first layer across the bed. I still have random areas which are higher or lower with no explanation to determine why.

I believe you. preheating seems to be key.

I have a Prusa,therefore I research....
Posted : 09/10/2018 1:00 am
andrea.l5
(@andrea-l5)
Eminent Member

Very useful tool. With just zig zag pattern my 1st layer was completely wrong.
With your g-code this is the result at -1122 (PLA):

As you can see, the back left corner is still a little high, while the front right corner starts to be rough.
I have to calibrate better with bed level correction. Maybe -1112 as global value, then -30 back and -30 left.
I'll try tomorrow, very useful tool indeed! 😎

Posted : 20/10/2018 7:13 pm
brian.m10
(@brian-m10)
New Member

Excuse my ignorance but I am definitely a newbie. I rebuilt my hot-end after a clogging problem and tried to calibrate the Z-height using the built-in calibration method. Problem with that is that sitting in front of the machine … most of the time the machine is moving...the print line is hidden by the extruder. (I wonder why Prusa couldn't build this 1st Layer Square print method into the machine instead of the line method??)
But here is my problem..... once I have set up my nozzle to "touch" the PEI sheet and the PINDA height by the Zip-tie method I then run the "Calibrate Z-height line" routine.
Then, while its running I start to vary "Live Z-height" numbers. But if the number increases from, say, -500 to -600...is the nozzle moving "DOWN" towards the bed plate(BP) or from -500 to -400 is the nozzle moving "UP" away from the BP...hence does change of Z-height mean that from -500 to -600 squishes the print line lower/flatter or does from -500 to -400 produce a higher/rounder print line??

One last question: what is the latest version (as of 28/10/2018) of the 1st Layer Square test routine V6 ???

Posted : 28/10/2018 1:44 pm
FaultyLine
(@faultyline)
Trusted Member

I think you are asking 3 things here...
1) Does adjusting the Live Z-Height from -500 to -600 result in the hot end getting closer to the bed
2) Does adjusting the Live Z-Height from -500 to -400 result in the hot end getting further from the bed
3) Is "V6" of the live-z-adjust downloads the latest version.

I have a Prusa i3 MK2.5 (recently upgraded) and my printer does the opposite of yours. if I go from -500 to -1000 then my hot end moves away from the bed (it goes UP), which results in a less "squished" line that's thicker in the "Z" axis. If I were to adjust it from -500 to 0 my hot end would move closer to the bed, which results in a very squished line that is very thin in the "Z" axis but would be very wide in either X or Y axis's.

My understanding is that V6 is the latest version of these test patterns.

Hope that helps.

...
Posted : 28/10/2018 9:29 pm
jonathan.h30
(@jonathan-h30)
New Member

Shout to Jeff and pjr and everyone else for all the information available in this thread. My Mk3 kit arrives tomorrow and I'll definitely be referencing this thread again soon. Keep it up yall!

Posted : 29/10/2018 4:10 am
jbinfl
(@jbinfl)
Reputable Member

Hold on, I am confused as something does not seem right. Just to be sure.


I think you are asking 3 things here...
1) Does adjusting the Live Z-Height from -500 to -600 result in the hot end getting closer to the bed<= yes, this is correct
2) Does adjusting the Live Z-Height from -500 to -400 result in the hot end getting further from the bed<= yes this is correct
3) Is "V6" of the live-z-adjust downloads the latest version. <= yes.

I am not sure I agree with the below info. Moving the live z number more negative (eg from <500> to <525>) moves the nozzle closer to the bed and squishes the filament more or it should. Moving the live z number more positive or less negative (eg from <500> to <475>) moves the nozzle farther away from the thread and less squishes to the filament. Or it should.

I am sure that with my printer a more negative number moves the nozzle closer to the bed and a less negative number moves the nozzle away from the bed. This also corresponds with the Knowledge base information under support. https://help.prusa3d.com/l/en/article/ZhBlGFD9Ah-live-adjust-z .

I am not doubting you if you are saying that is what happens, but are you sure that is what your printer does? I cannot find it right now, but there was a post either earlier in the thread (or in another thread) where someone said the same thing as below (more negative moves nozzle away from the bed) which runs counter to other information earlier in the thread. I thought there was something with their wiring being backwards or something that caused it. Again do not quote me on that i am not 100% sure. I will look for it and if anyone has more info about that it would be helpful.

I have a Prusa i3 MK2.5 (recently upgraded) and my printer does the opposite of yours. if I go from -500 to -1000 then my hot end moves away from the bed (it goes UP), which results in a less "squished" line that's thicker in the "Z" axis. If I were to adjust it from -500 to 0 my hot end would move closer to the bed, which results in a very squished line that is very thin in the "Z" axis but would be very wide in either X or Y axis's.

My understanding is that V6 is the latest version of these test patterns.

Hope that helps.

Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!...
Posted : 29/10/2018 9:11 pm
matthew.g31
(@matthew-g31)
Active Member

I used this file and technique for calibrating my printer and it is fantastic. Thank you so much for making this file available.

Due to an unrelated issue, I have taken the nozzle off my printer and will be screwing it back on. I will also be switching from PLA to PETG for my next print. How can I use this technique for dialing in the printer using PETG. I assume that the temperature settings, etc will need to be different for PETG than the settings currently in the downloadable file.

Do you folks have any advice for how to calibrate using this technique with PETG?

Posted : 10/11/2018 2:10 am
jbinfl
(@jbinfl)
Reputable Member

here is an STL you can put into your slicer and generate a Gcode using temp and filament settings.

There are also Gcodes for PETG and ABS (sorry that is PLA not ABS) at Bobstro's page here: http://projects.ttlexceeded.com/3dprinting_live_z_calibration.html

Thingiverse also has various calibration squares, it is just 1 layer 75X75 @ 0.20MM height.

(edited to correct info for below update)

Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!...
Posted : 10/11/2018 2:43 am
bobstro
(@bobstro)
Illustrious Member


[...] There are also Gcodes for PETG and ABS at Bobstro's page here: http://projects.ttlexceeded.com/3dprinting_live_z_calibration.html
I've got PLA and PETG gcode files in various nozzle sizes, but not ABS. If someone would be willing to test the ABS prints, I'd be happy to generate them (as well as any other desired material).

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 10/11/2018 5:46 am
jbinfl
(@jbinfl)
Reputable Member

Bobstro:

Fixed above.

Just wanted to say, your site has really good information for new users and I use it all the time and appreciate you creating it. It is well written and provides good additional information on various topics. So please keep rockin!

JB

Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!...
Posted : 10/11/2018 3:02 pm
markus.k8
(@markus-k8)
New Member

Hello,

i am new in 3D-printig. I bought the kit and assembled it. The wizard says everything is OK.

BUT on the right side of the bed, seems to me, i have a good first layer and the left side of the bed, it seems to me, i am too high with the nozzle. https://photos.app.goo.gl/fv1vkMPZjbwPrR8X8

What can I do, what should i do?

Posted : 13/11/2018 8:25 pm
nikolai.r
(@nikolai-r)
Noble Member


What can I do, what should i do?

It's already pretty good. I would go even lower. On textured sheet you will see no big difference.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram...
Posted : 13/11/2018 10:21 pm
flashburn
(@flashburn)
Active Member

I could really use some help dialing in my Z. I'm basically a complete noob, just got my i3 Mk3 last week. I've printed out a few things succesfully, but whenever I try to print something larger it winds up failing at some point.

This is my current test print, the bottom right is at -0.68 and the top left is -0.72:
https://imgur.com/a/fGOn4nD

My gut tells me that -0.72 is pretty good, but I really am not sure what I'm looking for, even after looking at others prints.

Thanks!

Posted : 14/11/2018 10:56 pm
toaf
 toaf
(@toaf)
Noble Member

what fails? does it come off the bed, or does something else happen?

I have a Prusa,therefore I research....
Posted : 14/11/2018 11:23 pm
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