First layer issues? Look here!  

Re: First layer issues? Look here!

Awesome, got some of these on the way: https://www.amazon.com/gp/product/B00PGHX67Q/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

What graphing software is that? Looks nice. 🙂

you would think an M3 washer would be easier to find on amazon, sheesh. thanks for the link.

I'm still not quite understanding why the probe can't compensate for offsets larger than .2 or why it doesn't tell you if its that bad, but my prints have taken a quantum leap in quality so far.

I have half a mind to find a source for the stock standoffs and superglue together a bunch of pre-sized standoffs to swap out for leveling.

Re: First layer issues? Look here!

What graphing software is that? Looks nice. 🙂

Thanks but it's standard Excel actually. 2010 I think. One of the many graph style options and the one that's a bit nicer on the eyes with all the chart colours. Also less 'shine in your face' when you're inevitably doing this stuff late at night 🙄

I'm still not quite understanding why the probe can't compensate for offsets larger than .2 or why it doesn't tell you if its that bad, but my prints have taken a quantum leap in quality so far.

I have half a mind to find a source for the stock standoffs and superglue together a bunch of pre-sized standoffs to swap out for leveling.

I don't understand either why a larger bed offset is problematic for the sensor designed to compensate for that exact thing. Maybe Prusa is playing it on the safe side to prevent the nozzle scraping the bed when the curve is erroneously estimated. We'll get there eventually 🙂

Still haven't had time to try the firmware with the corrected temperature compensation unfortunately. Looking forward to getting past this first layer inconsistency and focus on the second layer issues

Re: First layer issues? Look here!

In what order do you read the measured Z level values?
The measurement is done from left to right in front and rear row, but from right to left in the middle row.
There is a risk place the shim washers in wrong place if you do not know how to read the readings.
So what is correct reading?

Re: First layer issues? Look here!

Just wanted to say that I'm using stahlfabrik's patched firmware and the first layer is much more consistent now. I hope the change makes it into the next official release!

Re: First layer issues? Look here!

Just wanted to say that I'm using stahlfabrik's patched firmware and the first layer is much more consistent now. I hope the change makes it into the next official release!

AWESOME! Thank you!

Re: First layer issues? Look here!

I am currently working on new gcodes to fine tune the temperature calibration table. The stock values work great for me for PINDA temps that are encountered when printing PLA. But for ABS I have quite some temperature drift which comes from over compensation

There is the build in (experimental) temperature calibration which I can not recommend at all.

The build in temperature calibration yields really bad results for me. After it, PLA was bad again and ABS still, too.:-)

So I will write a forum post and maybe do one or even two new pull requests.

Sadly I am quite inexperienced in writing Gcodes. If anybody can help please contact me.

I have a gcode written that waits until the PINDA has exactly a specific temperature. Super awesome for "living with the bug" on current stock firmware but in my case also super awesome to find alternative ways to do the temperature compensation table tuning.

Another gcode that I am still working on is for reading, zeroing, resetting and setting the temp compensation table. I wish there was a UI in the printer for that...

Re: First layer issues? Look here!

In what order do you read the measured Z level values?
The measurement is done from left to right in front and rear row, but from right to left in the middle row.
There is a risk place the shim washers in wrong place if you do not know how to read the readings.
So what is correct reading?


it matches the layout of the bed, from your your perspective.

Back of BedREAD: 0.29839 0.26785 0.23314 0.19427 0.15124 0.10404 0.05268
READ: 0.26925 0.22683 0.18099 0.13172 0.07904 0.02293 -0.03660
READ: 0.24237 0.18976 0.13590 0.08080 0.02445 -0.03315 -0.09199
Middle READ: 0.21775 0.15664 0.09789 0.04150 -0.01253 -0.06419 -0.11349
READ: 0.19540 0.12747 0.06694 0.01382 -0.03189 -0.07019 -0.10108
READ: 0.17532 0.10225 0.04306 -0.00223 -0.03364 -0.05116 -0.05479
Front of BedREAD: 0.15750 0.08097 0.02625 -0.00667 -0.01778 -0.00709 0.02540

Re: First layer issues? Look here!

I'm currently running some tests with the Stahlfabrik version without LA. Did anyone else have to change their live Z values to figures never seen before?

I used to run anything between -.220 and -.265 but I'm now playing around -.400. I redid the PID calibration and mesh bed levelling before starting my 3x3 patch pattern.

Re: First layer issues? Look here!

Hmm, going to run some more tests but I'm struggling with consistency here. Initial patch started way high, immediately had to turn Z down to -0.440 to stop seeing line gaps. Next patch was low and have been raising live Z continuously throughout the print, ending at -0.280 which looks to be on the high side again.

Going to do more tests and investigate further but it's a preliminary no for me unfortunately.

Re: First layer issues? Look here!

Hi all,
I installed Stahlfabrik's patch (Thanks for spotting this!) and did the complete xyz calibrations again. I already saw a difference then: the nozzle was slightly touching the paper where it did not do that before. Tuning live z value results in -50u less than before (now -590u, was -640u). Printing the 9 squares full bed test layer, the difference between left and right has reduced, but is not completely gone.
I guess the next step is to manually adjust left or right a bit with an offset. Only if the required adjustment is out of range, I should be thinking about shimming, right?

Re: First layer issues? Look here!

I'm currently running some tests with the Stahlfabrik version without LA. Did anyone else have to change their live Z values to figures never seen before?

I used to run anything between -.220 and -.265 but I'm now playing around -.400. I redid the PID calibration and mesh bed levelling before starting my 3x3 patch pattern.

Hi!

It is expected that you have to change the live Z value lower with the patch. Do you mean that you did XYZ calibration?

I also wonder why your values are so low in general. Jo talked about it in his getting started video that -1-000 would be normal. With mine it is in the -0.800 range.

Re: First layer issues? Look here!

Hmm, going to run some more tests but I'm struggling with consistency here. Initial patch started way high, immediately had to turn Z down to -0.440 to stop seeing line gaps. Next patch was low and have been raising live Z continuously throughout the print, ending at -0.280 which looks to be on the high side again.

Going to do more tests and investigate further but it's a preliminary no for me unfortunately.

Lowering live z is natural thing that happens when installing my version.

What material are you printing? I found for PLA the bug fix seems to work great. For ABS, which prints at 100C bed and such the PINDA gets a lot warmer and warmer quicker I experience a temperature drift so my running theory is that the stock temperature compensation values might not go well with my real, physical, PINDA probe.

Did you do a temperature calibration? Currently I would advise against it. The results I got from that (officially experimental) routine were worse than the stock compensation values.
So I still am in the process to find optimal compensation values... I will report back

Re: First layer issues? Look here!

Hi all,
I installed Stahlfabrik's patch (Thanks for spotting this!) and did the complete xyz calibrations again. I already saw a difference then: the nozzle was slightly touching the paper where it did not do that before. Tuning live z value results in -50u less than before (now -590u, was -640u). Printing the 9 squares full bed test layer, the difference between left and right has reduced, but is not completely gone.
I guess the next step is to manually adjust left or right a bit with an offset. Only if the required adjustment is out of range, I should be thinking about shimming, right?

As far as I am aware my code change has nothing to do with the XYZ calibration? Not 100% sure, but yeah, quite sure!!!

Do you get consistent readings when you do a G80, G81 lets say three time quickly with a cooled down printer? Just want to make sure that your pinda is fixed and working consistently

And also my fix is not generally about the flatness of the bed - just if the temperature of your PINDA fluctuates during mesh bed leveling. I see that my pindas temperature reading are like +-0.1 from one second to the next - so one should do the maths if my fix is able to make "beds more flat" - I think if my fix it is doing the right thing that is the consequence mathematically - I just do not know if the effect is strong enough to make an observable difference. I hope though!

Re: First layer issues? Look here!

Lowering live z is natural thing that happens when installing my version.

What material are you printing? I found for PLA the bug fix seems to work great. For ABS, which prints at 100C bed and such the PINDA gets a lot warmer and warmer quicker I experience a temperature drift so my running theory is that the stock temperature compensation values might not go well with my real, physical, PINDA probe.

Did you do a temperature calibration? Currently I would advise against it. The results I got from that (officially experimental) routine were worse than the stock compensation values.
So I still am in the process to find optimal compensation values... I will report back

I lowered the Pinda probe some time ago and got better printing results across the bed. As far as I know it's still in the ok range but feel free to correct me 🙂

I did indeed redo the temperature calibration thinking that would fit the correct values to the changed equation. That may be what makes it malfunction for me while it works for others. Is it possible a sign change is required in the temperature compensation algorithm as well somewhere?

Re: First layer issues? Look here!

I have tried this firmware but when i go print ABS, bed at 120ºc i have to reajust Z value on fly, also sometimes calibration fails with message: Pinda probe reading is to high", so i had to reset printer and then reprint the file, it works at second try.
Same happen with the original firmware, if i don't ajust Z value it will print 10mm from the bed, like print on air.
I think we need better approach for 3d printers, inductor sensors are not the right option, even with a perfect temperature compensation algorithm there will be some flaws... Like readings vary from sensor to sensor, and this relly into two sensors (Induction + Temp sensor) so two sensors = more error.
I think manual set compensation would be far better, so it will always perform good since it respect our values, one time calibration with the help of PINDA and some tests, of course this can do some problems... So we can merge pinda and manual, when pinda detect a not safe value or too near bed it should stop there to prevent touch the bed.

For example: Print PLA at no heatbed and calibrate to found the best compensation values, set on settings and we are always good!

Re: First layer issues? Look here!

Several commits in MK3 since 3.1.2 the other day. Rebuilt firmware (with and without LA) with this fix applied. Interesting stuff included is a change on temperature calibration in relation to the steel sheet, an extrusion multiplier regression fix, and slight change in LA:

Re: First layer issues? Look here!

Several commits in MK3 since 3.1.2 the other day. Rebuilt firmware (with and without LA) with this fix applied. Interesting stuff included is a change on temperature calibration in relation to the steel sheet, an extrusion multiplier regression fix, and slight change in LA:

03-07-18-NO-LA-testing-pull-514.zip
03-07-18-WITH-LA-testing-pull-514.zip

I was using that extrusion fix before, and i can tell is much better

Re: First layer issues? Look here!

Several commits in MK3 since 3.1.2 the other day. Rebuilt firmware (with and without LA) with this fix applied. Interesting stuff included is a change on temperature calibration in relation to the steel sheet, an extrusion multiplier regression fix, and slight change in LA:

03-07-18-NO-LA-testing-pull-514.zip
03-07-18-WITH-LA-testing-pull-514.zip

Thank you!

The old temperature calibration was a mess. The results I got were very wrong. I will try this improved version soon. Maybe it comes in handy. I currently invest my time in doing a manual temperature calibration.

So far my manual values are very different to the stock values AND to the values I got from the build in old version of temperature calibration. I now need to test them if they work as I intended. Then I will finally know if I am heading in the right direction...

Man the time and effort I am putting into this issue... 😯

Re: First layer issues? Look here!

Hi all,
I installed Stahlfabrik's patch (Thanks for spotting this!) and did the complete xyz calibrations again. I already saw a difference then: the nozzle was slightly touching the paper where it did not do that before. Tuning live z value results in -50u less than before (now -590u, was -640u). Printing the 9 squares full bed test layer, the difference between left and right has reduced, but is not completely gone.
I guess the next step is to manually adjust left or right a bit with an offset. Only if the required adjustment is out of range, I should be thinking about shimming, right?

As far as I am aware my code change has nothing to do with the XYZ calibration? Not 100% sure, but yeah, quite sure!!!

Do you get consistent readings when you do a G80, G81 lets say three time quickly with a cooled down printer? Just want to make sure that your pinda is fixed and working consistently

And also my fix is not generally about the flatness of the bed - just if the temperature of your PINDA fluctuates during mesh bed leveling. I see that my pindas temperature reading are like +-0.1 from one second to the next - so one should do the maths if my fix is able to make "beds more flat" - I think if my fix it is doing the right thing that is the consequence mathematically - I just do not know if the effect is strong enough to make an observable difference. I hope though!

I did not try the G80/G81 commands yet. But I was wondering: during xyz calibration the PINDA searches not only in x/y direction but also the optimal z-height where it can detect the build plate targets. I assume this z sensing is equally affected by your patch, no?
Anyhow, maybe I just got a wrong impression during xyz calibration. The end result is an improved first layer consistency, so I'm happy with it 😉

I do find it a bit suspicious that PR did not give a reaction on the bug patch yet. A simple "yes, you're right - the sign of the temperature correction was wrong" or "no, you made a mistake" would be appreciated.

Re: First layer issues? Look here!

I do find it a bit suspicious that PR did not give a reaction on the bug patch yet. A simple "yes, you're right - the sign of the temperature correction was wrong" or "no, you made a mistake" would be appreciated.

I agree. Is there something more we can do to bring this to their attention?