1st layer problems - in depth look at software PINDA problems (and solutions!)  

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Thank you so much! The RC2 firmware and the modified start code has resolved my first layer issues! I had layer variations all over the bed. Now I have a consistent first layer over nine test points across the bed. I love this open source community! Thank you for your time, effort, and dedication.

Awesome!

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Hi Stahlfabrik.

Made a big square to do your manual temperature calibration but had problems to evaluate what the exact height is when the gaps between lines vanishes.

Seems my spring-steel bed is not perfectly even. There is probably a 50µm difference between "two lines closed all the way start to finish" and "two lines open all the way start to finish". As the compensation for 40°C and 45°C is usually within a 5 - 30µm range, that difference is ways too big to be neglected.

Second problem is, that these high and low areas shift a bit during the test. It helps a bit to concentrate on an imaginary line pependicular to the actual infill for evaluating the gaps but only if the test doesn't run too long because then variations of the bed height along this imaginary line come into play.

Did you face the same problem and how did you compensate for this?

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

I used a ellipsis that took roughly a fourth or less of the total bed. I guess it takes five to ten minutes to print the first layer.

For me, I concentrated on the middle of the bed, maybe a five by five centimeters area. I wanted to have it perfect there. I rarely finished the first layer prints. I usually stopped after that center area was done.

Remember that you do need just the same result every time, it does not have to be perfect over the entire bed. Focus on the bed middle.

So I concentrated on the sweet spot, where the gaps between the lines are just not happening anymore.

When you have your absolute live z values for all the different temperature levels then you all relate them to the 35C temp to get the offsets.

If you then choose to change the live z value for 35C that is ok as your temperature calibration is relative to whatever live z at 35C.

Just try to identify the sweet spot that you are able to reproduce for each pinda temperature.

After temp calibration you may change - as just described - the base live z value. Your relative offsets will still be valid!

Edit: Here is what I measured and the offsets that I put in EEPROM:


Temp Live Z EEPROM index EEPROM value
35C -0,822 N/A N/A
40C -0,810 0 -5
45C -0,795 1 -11
50C -0,795 2 -11
55C -0,787 3 -14
60C -0,790 4 -13


Edit2:
AFTER you have done your PINDA calibration, you can go to menu/calibration /"Bed level correct" and try to compensate for remaining unevenness in the four bed directions - for me that has not been necessary as most prints I did until now where not THAT big and my bed seems to be OKishly flat. But that is why I tell you to concentrate on the MIDDLE of the bed:-)

Edit3:
So if the values get "less negative" compared to the base values @35C you want to have the offset negative - that just got possible with 3.2.0-RC2:-)

Edit4:
As an example - here is attached the gcode that I used to calibrate the 45C

Edit5:

Remember that you put "usteps" into EEPROM not um. As I wrote in the beginning:
Example:
35C is the reference, easy: ustep is 0
40C the difference to 35C is 0.012mm. Multiply that by 400 (steps per millimeter the MK3 uses) and you will get 4.8 which rounds up to 5 usteps.

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

stahlfabrik, I have been following this thread and Github since a little before I got my printer and obviously since then. Just wanted to say you did an amazing job diagnosing and fixing the issue. Really quite astonishing really. I was disheartened when the first RC of 3.2.0 came out and your fixes weren't included more or less wholesale. To have someone fix your software in a comprehensive manner like that is such a golden ticket and I'd have bitten your hand off to get at it. Anyway, with RC2 including the fixes and improving upon them (your words!) I finally got to try out the fixes myself and they've been great so far.

So thanks again for spending the time to diagnose, fix, and then contribute back to the community.

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Hi Daniel,

thank you VERY much for the kind words.

As this problem was driving me (nearly) insane and even a replacement of the printer did not help I had to dig into this problem to be able to hang to my sanity:-)

I learned a lot about how this thing/aspect works - and I really am happy that I bought an open source machine.

I still have not touched my live adjust Z value since I fixed that issues and created the gcodes to work with the problem. So I am quite confident that it will help a lot of Prusa's customers:-) (Well OK, with 3.2.0-RC2 I had to change live adjust Z from -0.822 to -0.825;-))

Best regards

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

So completed my first manual temperature calibration according to your recommendation.

To check für gaps between the lines for me it worked best to

Here is the resulting matrix:

index temp z-offset µm µstep
n/a 35 -0,992 0
0 40 -0,970 -22,0 -9
1 45 -1,007 15,0 6
2 50 -1,022 30,0 12
3 55 -1,060 68,0 27
4 60 -1,155 163,0 65

Strange the offset for 40°C is in the opposite direction! 😯

And the values are very different from those I receive with automatic temperature calibration via the menu. But that was expected according to Stahlfabrik's findings. 😉

Here is the result of the automatic temperature calibration:

Send: M861 ?
Recv: PINDA cal status: 1
Recv: index, temp, ustep, um
Recv: n/a, 35, 0, 0.00
Recv: 0, 40, 27, 67.50
Recv: 1, 45, 35, 87.50
Recv: 2, 50, 40, 100.00
Recv: 3, 55, 55, 137.50
Recv: 4, 60, 96, 240.00
Recv: ok

For now I stick with the manual values and check the results in my next prints.

Cheers

Pete

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Hej Pete! You did it! Great!

Thank you for your tips on how to find the sweet spot you could compare!
I really have Freak pinda with only negative values:-) but yours is interesting too;-)

The print based approach has the huge benefit of calibration of the whole system. With heat, pinda triggers differently, nozzle enlarges, plastics too, the bed bulges.

I really hope you will like it!

You could test your setup very easy: choose a temperature level that you dialed in. With the live z value of 35C first layer should be perfect for the temperature you test:-)

Do not forget to enable temperature calibration in settings;-)

Please report back!!

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Hej Pete! You did it! Great!

Thank you for your tips on how to find the sweet spot you could compare!
I really have Freak pinda with only negative values:-) but yours is interesting too;-)

The print based approach has the huge benefit of calibration of the whole system. With heat, pinda triggers differently, nozzle enlarges, plastics too, the bed bulges.

I really hope you will like it!

You could test your setup very easy: choose a temperature level that you dialed in. With the live z value of 35C first layer should be perfect for the temperature you test:-)

Do not forget to enable temperature calibration in settings;-)

Please report back!!

Thanks for this. I finally got some time to do this calibration today and want to make sure I fully understand the results before I update the firmware.


Temp Live Z Dif uSteps
35 -.395 0 0
40 -.385 .01 4
45 -.4 -.005 -2
50 -.41 -.015 -6
55 -.49 -.095 -38
60 -.575 -.18 -72


My pattern is the opposite of yours (Live Z gets lower as temperature goes up) and matches the pattern from @pete above. However, you mention your uSteps as being negative and he shows his as being positive. Maybe I am thinking about this wrong, but it makes sense to me that if the Live Z goes lower, the uSteps would need to go lower and would be negative. Is that accurate?

Just for fun, here are the values the auto calibration gave me:


SENDING:M861 ?
PINDA cal status: 1
index, temp, ustep, um
n/a, 35, 0, 0.00
0, 40, 73, 182.50
1, 45, 136, 340.00
2, 50, 151, 377.50
3, 55, 173, 432.50
4, 60, 213, 532.50


Thanks!

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Thanks for this. I finally got some time to do this calibration today and want to make sure I fully understand the results before I update the firmware.


Temp Live Z Dif uSteps
35 -.395 0 0
40 -.385 .01 4
45 -.4 -.005 -2
50 -.41 -.015 -6
55 -.49 -.095 -38
60 -.575 -.18 -72


My pattern is the opposite of yours (Live Z gets lower as temperature goes up) and matches the pattern from @pete above. However, you mention your uSteps as being negative and he shows his as being positive. Maybe I am thinking about this wrong, but it makes sense to me that if the Live Z goes lower, the uSteps would need to go lower and would be negative. Is that accurate?

Just for fun, here are the values the auto calibration gave me:


SENDING:M861 ?
PINDA cal status: 1
index, temp, ustep, um
n/a, 35, 0, 0.00
0, 40, 73, 182.50
1, 45, 136, 340.00
2, 50, 151, 377.50
3, 55, 173, 432.50
4, 60, 213, 532.50


Thanks!

Are you using the official 3.2.0-RC2 as I do? I suggest to not use my custom firmware anymore that flipped the sign to make it work for my MK3. Please use the official 3.2.0 release So now that is out of the way:-)

I think your sign is switched around - you need to flip all - to + and + to -: Here are my values that prove to work perfectly:
Temp Live Z EEPROM index EEPROM value
35C -0,822 N/A N/A
40C -0,810 0 -5
45C -0,795 1 -11
50C -0,795 2 -11
55C -0,787 3 -14
60C -0,790 4 -13

So you see that my live Z values get "higher" (less negative). So for me, the ustep values stored to eeprom have to be negative. That you have to take just as a fact (you need to study the source code to make sense of it)

Here are Pete's values. His live Z values get "lower" (more negative). So he has to use positive ustep values in EEPROM. He also has an exception with the 40C value, that has to have the negative offset


index temp z-offset µm µstep
n/a 35 -0,992 0
0 40 -0,970 -22,0 -9
1 45 -1,007 15,0 6
2 50 -1,022 30,0 12
3 55 -1,060 68,0 27
4 60 -1,155 163,0 65

So after you update your eeprom, do not forget to enable "temp. calibration" in the settings menu - if it is still "off".

And if you want to test your calibrations I suggest to start prints with PINDA temperature of for example 35 C, 40C and 45C - if you have calibrated correctly you will find that all PINDA temperatures now lead to perfect first layers without touching live Z. (Obviously you need to set live Z to -.395. aka the 35C value)

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Thanks for this. I finally got some time to do this calibration today and want to make sure I fully understand the results before I update the firmware.


Temp Live Z Dif uSteps
35 -.395 0 0
40 -.385 .01 4
45 -.4 -.005 -2
50 -.41 -.015 -6
55 -.49 -.095 -38
60 -.575 -.18 -72


My pattern is the opposite of yours (Live Z gets lower as temperature goes up) and matches the pattern from @pete above. However, you mention your uSteps as being negative and he shows his as being positive. Maybe I am thinking about this wrong, but it makes sense to me that if the Live Z goes lower, the uSteps would need to go lower and would be negative. Is that accurate?

Just for fun, here are the values the auto calibration gave me:


SENDING:M861 ?
PINDA cal status: 1
index, temp, ustep, um
n/a, 35, 0, 0.00
0, 40, 73, 182.50
1, 45, 136, 340.00
2, 50, 151, 377.50
3, 55, 173, 432.50
4, 60, 213, 532.50


Thanks!

Are you using the official 3.2.0-RC2 as I do? I suggest to not use my custom firmware anymore that flipped the sign to make it work for my MK3. Please use the official 3.2.0 release So now that is out of the way:-)

I think your sign is switched around - you need to flip all - to + and + to -: Here are my values that prove to work perfectly:
Temp Live Z EEPROM index EEPROM value
35C -0,822 N/A N/A
40C -0,810 0 -5
45C -0,795 1 -11
50C -0,795 2 -11
55C -0,787 3 -14
60C -0,790 4 -13

So you see that my live Z values get "higher" (less negative). So for me, the ustep values stored to eeprom have to be negative. That you have to take just as a fact (you need to study the source code to make sense of it)

Here are Pete's values. His live Z values get "lower" (more negative). So he has to use positive ustep values in EEPROM. He also has an exception with the 40C value, that has to have the negative offset


index temp z-offset µm µstep
n/a 35 -0,992 0
0 40 -0,970 -22,0 -9
1 45 -1,007 15,0 6
2 50 -1,022 30,0 12
3 55 -1,060 68,0 27
4 60 -1,155 163,0 65

So after you update your eeprom, do not forget to enable "temp. calibration" in the settings menu - if it is still "off".

And if you want to test your calibrations I suggest to start prints with PINDA temperature of for example 35 C, 40C and 45C - if you have calibrated correctly you will find that all PINDA temperatures now lead to perfect first layers without touching live Z. (Obviously you need to set live Z to -.395. aka the 35C value)

Thanks for the clarification, I compiled using latest code from Github as of Saturday afternoon. I couldn't use the released RC2 because I was hitting the bug with the stall guard sensitivity breaking bed leveling. Looking forward to not having to adjust my live z every time I switch from PLA to PETG. 🙂

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Thanks for the clarification, I compiled using latest code from Github as of Saturday afternoon. I couldn't use the released RC2 because I was hitting the bug with the stall guard sensitivity breaking bed leveling. Looking forward to not having to adjust my live z every time I switch from PLA to PETG. 🙂

Ah Ok, newer than 3.2.0-RC2 and self compiled is of course fine, too:-) Just do not work in any of my old Pull Requests as everything you need is present in 3.2.0-RC2.

Please let me know how it works for you:-)

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Thanks for the clarification, I compiled using latest code from Github as of Saturday afternoon. I couldn't use the released RC2 because I was hitting the bug with the stall guard sensitivity breaking bed leveling. Looking forward to not having to adjust my live z every time I switch from PLA to PETG. 🙂

Ah Ok, newer than 3.2.0-RC2 and self compiled is of course fine, too:-) Just do not work in any of my old Pull Requests as everything you need is present in 3.2.0-RC2.

Please let me know how it works for you:-)

Updated my EEPROM and ran tests at 55C and 40C without changing my Live Z. Both first layers looked great. Thanks!

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Updated my EEPROM and ran tests at 55C and 40C without changing my Live Z. Both first layers looked great. Thanks!

Super awesome!

I am happy that it works for others too 😆

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

I must chime in and thank you, stahlfabrik, for your excellent work. With RC2, I get perfect first layers every time.

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

I must chime in and thank you, stahlfabrik, for your excellent work. With RC2, I get perfect first layers every time.

Great to hear! Did you also adjust the EEPROM ustep values? What did you do for that? What does "M861 ?" return? Do you even have temperature calibration enabled?:-)

So many questions 😆

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

Thanks for the clarification, I compiled using latest code from Github as of Saturday afternoon. I couldn't use the released RC2 because I was hitting the bug with the stall guard sensitivity breaking bed leveling. Looking forward to not having to adjust my live z every time I switch from PLA to PETG. 🙂

What is this stall guard sensitivity bug you are mentioning?

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

https://github.com/prusa3d/Prusa-Firmware/pull/701

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

So with this bug Z calibration fails on some printers right? I assume you get an error when this happens.

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

So with this bug Z calibration fails on some printers right? I assume you get an error when this happens.

Yeah, mesh bed leveling was failing consistently at random points, stopping my print. I think the message said something about checking for debris. I grabbed the latest code (which included the fix) and the issue went away for me.

Re: 1st layer problems - in depth look at software PINDA problems (and solutions!)

I must chime in and thank you, stahlfabrik, for your excellent work. With RC2, I get perfect first layers every time.

Great to hear! Did you also adjust the EEPROM ustep values? What did you do for that? What does "M861 ?" return? Do you even have temperature calibration enabled?:-)

So many questions 😆

Hehe. I didn't really have that many problems before, except for having to fiddle with Live Z a little too often. Actually, all I really needed was the 860 gcode to wait for PINDA to reach 35 degrees. I haven't even performed a temp calibration. 🙂 I just think you deserve credit for your hard work.