werid z starting printing much higher than anticipated...

[otaku521]

M122
=== Diagnostics ===
Used output buffers: 3 of 32 (13 max)
=== Platform ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 1.21 running on Duet WiFi 1.02 or later
Board ID: xxxxxxxxxxxxxxxxxxxx
Static ram used: 16152
Dynamic ram used: 100648
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Last software reset at 2018-04-13 14:39, reason: User, spinning module GCodes, available RAM 7760 bytes (slot 3)
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MCU temperature: min 32.8, current 48.2, max 49.7
Supply voltage: min 24.1, current 24.2, max 25.3, under voltage events: 0, over voltage events: 0
Driver 0: ok, SG min/max 0/75
Driver 1: ok, SG min/max 0/16
Driver 2: ok, SG min/max 0/1023
Driver 3: ok, SG min/max not available
Driver 4: ok, SG min/max 0/365
Date/time: 2018-04-14 03:14:00
Slowest main loop (seconds): 1.256110; fastest: 0.000046
=== Move ===
MaxReps: 4, StepErrors: 0, LaErrors: 0, FreeDm: 129, MinFreeDm 120, MaxWait: 3092251824ms, Underruns: 0, 2
Scheduled moves: 233458, completed moves: 233428
Bed compensation in use: mesh
Bed probe heights: -0.850 -1.028 -1.423 -0.223 -0.308
=== Heat ===
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=== Network ===
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• WiFi -
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  WiFi firmware version 1.21
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  === Expansion ===

[otaku521]

Here is a photo of my HEVO

[T3P3Tony]

To confirm. When you command the printer to go to
G1 Z0
Its at a perfect Z0 (by paper feeler gauge)

But when you start a print you have to use -1.35mm of baby stepping to get it to the right height?

Can you post the first bit of a gcode file that you have tried to print that shows this issue please.

[dc42]

Does your slicer start GCode include a G28 homing command, and if so it that altering the Z=0 position?

[otaku521]

@dc42 Yes it does a home before print... is this the problem?? if so I take it out!

[otaku521]

@t3p3tony

Here is the gfile for the above print... (first couple of lines) (using S3D as Slicer)

G90
M82
M106 S0
M140 S85
M190 S85
M104 S235 T0
M109 S235 T0
M582 T3 ; FILAMENT RUNOUT SENSOR TURN ON
G28 ; home all axes <<<<< @dc42 is this the problem???
M106 P1 S0 ; Turn off Parts Fans
G92 E0
G1 E-0.6000 F6000
G1 Z0.250 F1200
; process Process1
; layer 1, Z = 0.250
T0
; tool H0.250 W0.600
; skirt
G1 X51.471 Y88.911 F3000
G1 E0.0000 F1800
G92 E0
G1 X52.456 Y88.293 E0.0711 F600
G1 X52.557 Y88.237 E0.0781
G1 X53.155 Y87.948 E0.1188

[otaku521]

@t3p3tony
Yes when I go G1 Z0 it is a good paper feeler grip (like typical feel when I do paper feeler)
then start print i have to use -1.35mm baby step... this IMHO doesn't make sense...
if it was +/-0.2-0.3 maybe... but -1.35mm made me think there is something really wrong ... but I have no idea what

[T3P3Tony]

@otaku521 if you do a G28 and then G1 Z0, how far above the bed is the nozzle? Is it paper feeler close or~1.35mm above. If it is the latter then you need to adjust oyur config so that it is.

I think is sensible to have a home command in your start gcode.

[otaku521]

@t3p3tony
It is after g28 before print it is paper feeler close
But when start print and re home again it is higher than anticipated

Thus I have to do baby step that large (which results me to perminate to add it in my config file for now on

The bottom of the mini ir sensor there is enough gap that I can see the hex of the nozzle to the tip

Maybe g28 is running too fast on z to get an inaccurate reading?

Note that i am using a 2mm black PEI sheet like I mentioned above

[otaku521]

I have uploaded the video for your reference...

https://youtu.be/p8XtWKYzo_I

[T3P3Tony]

@otaku521 g28 should produce the same results no matter if it is run from the command line or from a gcode file. Can you test it multiple times from the command line to assure repeatability.

[otaku521]

I know... this is why it is weird....
so far I am wondering if my config and other scripts are fine ?

[BPisLife]

@otaku521 Sorry if you already mentioned this, but I was having an strange issue like this to and it turns out my slicer (simplify3D) was setting the Z to be .18 for the first layer. If my z=0 was tuned to approx. .1mm off the bed, then it would be .28mm off the bed and the print wouldn't adhere.

Just a thought, check out your gcode for the first layer and see what it sets Z to, then manually move the Z to the point it says after printing and you may see the gap. If so, then you need to either A adjust your slicer or your leveling. This is of course only assuming you are seeing what I am describing here.

[otaku521]

@bpislife you are 0.1-0.2xx off.. while I am 1.xx off... this made me think otherwise....
the only thing is I think is the 2mm PEI sheet on the bed not being correctly read by mini IR probe... so I am thinking of switching back to BL Touch and see

[T3P3Tony]

If the PEI sheet was not being recognised l would expect that to happen either way. I just had a thought though. Are you probing the bed in your prints but not when doing a normal test of G28?

[SputnikOC3d]

I have the same issues and have been plagued by it since day one. I cannot resolve ... I initially chalked it up to inconsistency of the BL Touch, but the more I deal with the issue it seems to be some arbitrary value created by the firmware.

I have to babystep in EVERY print - using a 5-6 perimeter skirt - and hope I can step it in in time before the actual part starts. Circles are particularly ominous to get right ... in time.

If I dont get adhesion - then I get Elephants Foot [ alot ] as I err on the side of sticking this mother down.

all this to say ... youre not alone.

[otaku521]

@t3p3tony
No... I only probe when everytime I start the machine doing my Macro above which calibrate my leadscrews (from 2... now 3 (just installed a Duex5) and then I do some prints from there on... but I don't start script all my prints to go calibration at the beginning since I got the Mini IR Probe (Switching out the BL touch)... (which was "PITA"...)

[otaku521]

@sputnikoc3d

Thanks! I think it is problem with PEI with IR...
I used to have BL Touch on AnyCubic's Ultrabase... it was inconsistent... then I switch Mini IR with Ultrabase and it was a joy!.... then now with a bigger bed (420x320)... I have to cut my own PEI sheet (2mm) and now it literally drives me nuts!! (but PEI when printed on fine... it is very nice to use!)

I am thinking of installing BL touch back... but I might be plagued by inconsistencies again.... OH THE JOY of 3D printing! XD

[AlexLin]

@otaku521 said in werid z starting printing much higher than anticipated...:

then I switch Mini IR with Ultrabase and it was a joy!

was it? No problems due to the hole-pattern? What color do you have under the Ultrabase?

[otaku521]

@alexlin I never removed the sticker on the bottom... I just put it on top of my old MK3 200x200x3mm Alum bed and clip in with 4 binder clips... never had a problem... I am in process of tearing my old i3 clone and making another corexy