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shaun.k2
(@shaun-k2)
Eminent Member
Topic starter answered:
Re: First layer issues



Okay so still no luck printing, seems like the moment the printer heats up, all the Live-Z values go out of whack. So I went back to Calibrate XYZ and started again. This time I measured the live-Z values at which the paper stops resisting for each of the 9 points around the bed....

but you still know that the meshbed levelling only works during a print, not when you move the extruder through the menu (either through the axis menu or the live z adjustment level) ?

so what you've "measured" with your values is only of limited usage... and only gives you the information, that your right "bumper" at the top of the z-axis is slightly lower than the left one.... so "calibrate z" delivers a slightly askew x-axis.

I had thought measuring these 9 values gives a good basis for a ballpark estimation of the hyperfine bed correction values. I should add that I flashed the hyperfine firmware, set a live Z of - 0.500mm to get the centre printing fine, and managed to get the rear left corner dialed in, but when it got to the middle left square (the one with - 770), the nozzle was printing into thin air even at +99 bed correction. So I might try to adjust the PINDA slightly to not get such a low value for that point on the bed.

Should I be worried that the bumper on one of the Z axes is higher than the other? Is this an assembly fault and something I should fix before I go any further?

Posted : 05/09/2017 4:00 am
JeffJordan
(@jeffjordan)
Moderator
Re: First layer issues


...
Should I be worried that the bumper on one of the Z axes is higher than the other? Is this an assembly fault and something I should fix before I go any further?

not essentially necessary, because the meshbed levelling should correct the slight skew of the axis, but it would make things easier to dial in the 8 values for the hyperfine bed correction.

ps. I'm going to make a proposal on how to dial in the values at the hyperfine meshbed levelling thread later on...

dem inscheniör is' nix zu schwör...

Posted : 05/09/2017 3:26 pm
shaun.k2
(@shaun-k2)
Eminent Member
Topic starter answered:
Re: First layer issues


ps. I'm going to make a proposal on how to dial in the values at the hyperfine meshbed levelling thread later on...

I'd still be interested in your process, will you post it here or in another thread?

Posted : 07/09/2017 10:05 pm
JeffJordan
(@jeffjordan)
Moderator
Re: First layer issues



ps. I'm going to make a proposal on how to dial in the values at the hyperfine meshbed levelling thread later on...

I'd still be interested in your process, will you post it here or in another thread?

I will post it at the hyperfine bed levelling thread, as soon as I've tested it here at my printers personally.
I've already prepared a set of tweaked gcodes, with a tiny test patch for every calibration point.

here in advance my idea on how to determine the required correction levels most efficient:

the idea is to dial in the center first with the live z adjustment. then note down the value and proceed with printing single patches for every edge/corner without starting another meshbed levelling (G80), without disabling the steppers and without cooling down the hotend completely (bed remains heated as well).
then dialing in the correct z-height with the live z adjustment again for each corner/edge patch and writing down the determined value for the corresponding spot.
so you'll get 9 "live z adjustment values" in total. subtract the value of the center adjustment level from the remaining 8 and you'll get the 8 correction values to dial in for the 8 meshbed correction points.
and: don't forget the set the live z adjustment level back to the value you've determined for the center spot.
🙄

dem inscheniör is' nix zu schwör...

Posted : 08/09/2017 8:29 am
walter.v4
(@walter-v4)
Active Member
Re: First layer issues

Thanks for the details

Just to make sure I understood the math behind this calibration:

Suppose I have set the "live Z adjustment value" at -350 in the bed center point.
I want now to adjust the "a" corner. My live Z adjustment for that corner is -500.
Am I right I need to enter -150 for "a" ? -500 -(-350)
When finished with the 8 points, I will set back -350 for my live Z adjustment value.

Hope that makes sense!
Thanks

Posted : 08/09/2017 7:26 pm
JeffJordan
(@jeffjordan)
Moderator
Re: First layer issues

just provided a detailed description and a special set of gcodes on how to dial in the hyperfine bed levelling.
it took a little bit longer than expected, because my first attempt with the gcodes didn't work as expected. but now it should be easy to understand and to use.

@walter: you can only go for max. +/-99 µm when using the altered firmware with the 8 correction values for the meshbed levelling through menu.
150 would be to much. but from the maths and the principle you are right.
if you need values between +/- 100 and 200, you've to use the G80 command and need to parse the values through the gcode to your printer, as proposed by PJR.

dem inscheniör is' nix zu schwör...

Posted : 11/09/2017 10:11 am
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