Inconsistent first layer calibration after 3.08 fw upgrade  

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Hi Antonio

I have running the 3.08 for some days now and could not see an issue in Z high coming from the firmware.
What I noticed though that the advice to loctite the PINDA probe is pretty true 😉
Stupid me did not do that and my PINDA "readjusted" itself during several hours of printing. 😯

I have marked it now the position so I can easier fixe back to old position and I hope I find soon a shop with loctite blue 😀

All the Best
Frank

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Hello everyone!
Today I upgraded the firmware of my Prusa I3 MK2 to 3.08. I ran the Z calibration routine and the V2 Calibration gcode. Everything was fine and no further live Z calibration was needed. I printed an ABS, 200um resolution object without any issue. When I tried to print the same object again , I had an inconsistent first layer that forced me to lower the extruder from -1,152 to -1,420!!! 😮

Is that inconsistency an issue related to firmware?

Thanks for help!

I wouldnt say 0,3mm is a really big deal? I'm adjusting my Z height manually (around) -0.4 to -0.15 depending on material, and how the model looks. If I'm printing FilaFlex or PETG and a big surface area I'm almost air-printing for example.

I havnt seen any issues with the Z height after upgrading.

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Despite having fixed the PINDA probe already, I decided to lower it a little bit more just to confirm that the problem was independent from its height. After several tests it seems that changing material needs Z adjusting.
Considering that , as mentioned in previous topics, the number of Z adjusting is limited by the EEPROM write cycles I wonder how long it will take to end the RAMP's life...

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Huh, and here I thought I was doing something wrong because I also have to adjust the z-height when changing materials. Glad to know it's not something that's just me.

Re: Inconsistent first layer calibration after 3.08 fw upgrade

number of Z adjusting is limited by the EEPROM write cycles I wonder how long it will take to end the RAMP's life...
You're talking about Arduino EEPROM, not RAMPS.
Number of write/erase cycles is 100,000 (100k).

Re: Inconsistent first layer calibration after 3.08 fw upgrade

number of Z adjusting is limited by the EEPROM write cycles I wonder how long it will take to end the RAMP's life...
You're talking about Arduino EEPROM, not RAMPS.
Number of write/erase cycles is 100,000 (100k).

You're right! I should probably have said RAMBo. Being that said, Z adjusting would need decades before we need to replace the board. 😀

Re: Inconsistent first layer calibration after 3.08 fw upgrade

FWIW, I am having the same issue.

I do not recall having to re-adjust my Z-adjustment every time I printed something new. My guess is that the calibration routine was modified somehow, and now it has somehow become more inconsistent.

Re: Inconsistent first layer calibration after 3.08 fw upgrade

I'm glad I'm not the only one who's seeing this happen.

I'm noticing that I can print PLA and the nozzel is very close, and then without adjustment, print something else (using the same slicer settings) in a different material, and it's either too close, or too far away!

The live Z adjust makes it easier to fix, but i find it strange that this is normal.

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Yes well, black magic is never a perfect art... 😉

Seriously though, I hope this bug gets isolated and fixed in an upcoming release. It's driving me nuts to have to re-check the live-z EVERY SINGLE TIME.

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Hi Ho

Is it only if you change materials, i.e. from PLA to ABS?
I am asking because till now I only print PLA on my MK2 with 3.08 and have no issues that I have to readjust.
On my other Printer (Lulzbot Mini) I am changing Materials pretty often. For that I have done quite some tests for Z hight and learned that the first layer is not only depending on the distance nozzle to heat bed.
I still do not 100% understand why, but i guess it hass to do with different viscosities of the molten material.

To cut it short: If your troubles are due to different Materials, it might be that it is not the firmware, it might be that the Materials do their part!?

All the Best
Frank

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Hi Ho

Is it only if you change materials, i.e. from PLA to ABS?
I am asking because till now I only print PLA on my MK2 with 3.08 and have no issues that I have to readjust.
On my other Printer (Lulzbot Mini) I am changing Materials pretty often. For that I have done quite some tests for Z hight and learned that the first layer is not only depending on the distance nozzle to heat bed.
I still do not 100% understand why, but i guess it hass to do with different viscosities of the molten material.

To cut it short: If your troubles are due to different Materials, it might be that it is not the firmware, it might be that the Materials do their part!?

All the Best
Frank

No, certainly not. I have varying z-adjust on every consecutive print, even with the same material and identical settings. In fact, I can print the same gcode five times in a row and get five slightly different first layers. It's quite annoying, and it does not seem to be isolated to just me, so I'm hoping it can be resolved in firmware.

Re: Inconsistent first layer calibration after 3.08 fw upgrade

I have varying z-adjust on every consecutive print, even with the same material and identical settings.

That really does sound like a hardware issue (such as moving probe). If it were firmware, then it should be happening to everyone.

Peter

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Hi Ho,

PJR was faster, but I also think that there is a hardware issue.
If there would be a firmware issue with the 3.08 that should show up in all the printers using it.
Just now I finished testing repeatability on Z and after 3 * 25 running up and down (3 times due to 3 different speeds) the µm gauge that I fixed on the X Axis always shows the value.

There for I believe some thing is loose on your machine and I agree to PJR the first thing that comes in mind is the PINDA.
Never the less I am looking on my MK2 right now trying to think about more options.

Some Ideas that came to my mind:
- Is there a chance that you are loosing steps on the Z Steppers in fast moving up or down?
- Is there some thing loose in the extruder assembly?
- is there some thing loose in the X assembly?

As you say it is an issue that the first layer only fails...
Any chance that the heated bed does not heat equal?

All the Best Frank

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Yes well, black magic is never a perfect art... 😉

Seriously though, I hope this bug gets isolated and fixed in an upcoming release. It's driving me nuts to have to re-check the live-z EVERY SINGLE TIME.

Did you run a complete a V2Calibration after your last XYZ or Z calibration? I, too thought I had to run the Live -Z adjust before every print, until I realized I had been re-calibrating, and therefore the Z-level was zeroed. Be sure to run the V2Calibration through to the end. Also - be sure you have downloaded a recent V2Calibration.gcode (mine is from September).

Good luck!

John

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Yes well, black magic is never a perfect art... 😉

Seriously though, I hope this bug gets isolated and fixed in an upcoming release. It's driving me nuts to have to re-check the live-z EVERY SINGLE TIME.

Did you run a complete a V2Calibration after your last XYZ or Z calibration? I, too thought I had to run the Live -Z adjust before every print, until I realized I had been re-calibrating, and therefore the Z-level was zeroed. Be sure to run the V2Calibration through to the end. Also - be sure you have downloaded a recent V2Calibration.gcode (mine is from September).

Good luck!

John

Oh yes, quite sure about following all of the steps. 🙂

Probe is tight and I always run V2Calibration. In fact, I was able to run it several times and get slightly different results on each. I would say that in general the swing seems to be between 20um and 40um. Sometimes it's fine, sometimes it not.

I've also noticed that the sometimes one side is more offset than another, which makes using the "bed level correct" feels somewhat useless.

I agree that the symptoms all point to hardware, but either by coincidence or happenstance I started observing the problem after the latest upgrade. I guess I should got back to a previous firmware version and see if the problem goes away or changes.

Re: Inconsistent first layer calibration after 3.08 fw upgrade

Yeah, i seem to get a couple good prints out of it, and then I have to adjust it again.

Re: Inconsistent first layer calibration after 3.08 fw upgrade

This post solves most of the issues we have being talking about..
Have a look!

http://shop.prusa3d.com/forum/improvements-f14/pinda-probe-live-z-calibration-z-offset-and-temper-t2048.html