Strange BLTouch issue. Hightmap it off while printing

RocketPat

this is my home all

; homeall.g
; called to home all axes
; generated by RepRapFirmware Configuration Tool v3.1.4 on Sat Oct 03 2020 22:18:40 

GMT+0200 (Mitteleuropäische Sommerzeit)
G91                     ; relative positioning
G1 H2 Z5 F6000          ; lift Z relative to current position
G1 H1 X-245 Y-285 F1800 ; move quickly to X and Y axis endstops and stop there (first pass)
G1 H2 X5 Y5 F6000       ; go back a few mm
G1 H1 X-245 Y-285 F360  ; move slowly to X and Y axis endstops once more (second pass)
G90                     ; absolute positioning
G1 X118 Y185 F6000      ; home Z
G30                     ; home Z by probing the bed

; Uncomment the following lines to lift Z after probing
;G91                    ; relative positioning
;G1 Z5 F100             ; lift Z relative to current position
;G90                    ; absolute positioning

and this is home z

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Sat Oct 03 2020 22:18:40 GMT+0200 (Mitteleuropäische Sommerzeit)
G91                ; relative positioning
G1 H2 Z5 F6000     ; lift Z relative to current position
G90                ; absolute positioning
G1 X20 Y55.5 F6000 ; go to first probe point
G30                ; home Z by probing the bed

; Uncomment the following lines to lift Z after probing
;G91               ; relative positioning
;G1 Z5 F100        ; lift Z relative to current position
;G90               ; absolute positioning

RocketPat

@Phaedrux in the home all i am using the middle of my bed

Veti

@RocketPat

do you still have the G29 in the start script?

RocketPat

yep right after i home all

M107
;M190 S45	  ;set bed temperature and wait for it to be reached
G28          ;Home axis
G29

M109 S210 ;
M107         ; Turn layer fan off
G21          ; Set to metric change to G20 if you want Imperial
G90          ; Force coordinates to be absolute relative to the origin

G0 X0 Y0 F9000 ; Go to front
G0 Z0.15 ; Drop to bed
G92 E0 ; zero the extruded length
G1 X80 E6 F780.000 ; Extrude filament in a 8cm line
G92 E0 ; zero the extruded length
G1 E-1 F780.000 ; Retract a little
G1 X80 F4000 ; Quickly wipe away from the filament line
G1 Z0.3 ; Raise and begin printing.

Veti

@RocketPat

while printing use M122 to check if mesh compensation is active

RocketPat

So i think its on, but i am not sure why the offset is 0

M122
=== Diagnostics ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 3.1.1 running on Duet WiFi 1.02 or later
Board ID: 08DJM-9178L-L4MSJ-6J1F4-3S06M-193YP
Used output buffers: 3 of 24 (7 max)
=== RTOS ===
Static ram: 27980
Dynamic ram: 94072 of which 44 recycled
Exception stack ram used: 576
Never used ram: 8400
Tasks: NETWORK(ready,716) HEAT(blocked,1224) MAIN(running,1632) IDLE(ready,80)
Owned mutexes: WiFi(NETWORK)
=== Platform ===
Last reset 00:02:49 ago, cause: software
Last software reset at 2020-10-25 16:47, reason: User, spinning module GCodes, available RAM 8424 bytes (slot 3)
Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x04417000 BFAR 0xe000ed38 SP 0xffffffff Task MAIN
Error status: 0
MCU temperature: min 29.0, current 29.8, max 30.3
Supply voltage: min 11.8, current 12.0, max 12.4, under voltage events: 0, over voltage events: 0, power good: yes
Driver 0: ok, SG min/max 0/517
Driver 1: standstill, SG min/max 0/495
Driver 2: ok, SG min/max not available
Driver 3: ok, SG min/max 0/432
Driver 4: ok, SG min/max not available
Date/time: 2020-10-25 16:50:37
Cache data hit count 279758463
Slowest loop: 154.49ms; fastest: 0.12ms
I2C nak errors 0, send timeouts 0, receive timeouts 0, finishTimeouts 0, resets 0
=== Storage ===
Free file entries: 9
SD card 0 detected, interface speed: 20.0MBytes/sec
SD card longest read time 3.4ms, write time 2.2ms, max retries 0
=== Move ===
Hiccups: 0(0), FreeDm: 166, MinFreeDm: 157, MaxWait: 15080ms
Bed compensation in use: mesh, comp offset 0.000
=== MainDDARing ===
Scheduled moves: 99, completed moves: 88, StepErrors: 0, LaErrors: 0, Underruns: 0, 0  CDDA state: 3
=== AuxDDARing ===
Scheduled moves: 0, completed moves: 0, StepErrors: 0, LaErrors: 0, Underruns: 0, 0  CDDA state: -1
=== Heat ===
Bed heaters = 0 -1 -1 -1, chamberHeaters = -1 -1 -1 -1
Heater 0 is on, I-accum = 0.0
Heater 1 is on, I-accum = 0.5
=== GCodes ===
Segments left: 1
Movement lock held by null
HTTP is idle in state(s) 0
Telnet is idle in state(s) 0
File is doing "G1 X13.453 Y68.416 E30.30764" in state(s) 0
USB is idle in state(s) 0
Aux is idle in state(s) 0
Trigger is idle in state(s) 0
Queue is idle in state(s) 0
Daemon is idle in state(s) 0
Autopause is idle in state(s) 0
Code queue is empty.

Veti

@RocketPat said in Strange BLTouch issue. Hightmap it off while printing:

Bed compensation in use: mesh, comp offset 0.000

that is fine. why do you think its not working?

RocketPat

i was just wondering about the 0.000, but still i have that strange issue that my map is kinda flipped around. The right side is too far up and the left side is too far down... its doing the opposite of what the mesh is giving out.

Veti

another possibility could be sagging linear rods causing a tilt in the hotend carriage.

RocketPat

hm, the hotend shoud be fine i didnt notice any sagging there. I will now rebuild my old stock hotend (cr-10) and see if its causing the same problem. If not, the bracket that i am using to hold my Titan Aero is very bad. I will give an update in a few hours.

RocketPat

so, i rebuild my entire extrudersetup and i still have that issue.

Veti

can you measure the z offset twice

once on the left and once on the right?

RocketPat

yep i followed that tutorial: https://duet3d.dozuki.com/Wiki/Test_and_calibrate_the_Z_probe
and on the left side its 1.294 and on the right side its 0.935

i think this is not good, becuase the offset should be the same on every side right?

Veti

@RocketPat said in Strange BLTouch issue. Hightmap it off while printing:

1.294 and on the right side its 0.935

that would indicate rotation of the carriage.

this could be the problem. but its a mechanical problem.

RocketPat

For my X-Axis i am using a modified version of the Prusa printable parts. But i noticed that my left side is broken, where the smooth rods come into the plastic part.

RocketPat

Hey guys, so i printed out some new X-Axis holders and now there is much tighter fit as before and i measured 0.726 and 0.658 on both sides, so far its much better then before but still not perfect. But i did a few test prints and they came out with a perfect first layer. And i dont have any more issues with the rotation of my X-Axis. Thank you for all of your help to find out what was causing that issue

habitoti

Hi,
while this is an older thread, the problem itself is very current, unfortunately
While I had it for an Anycubic Mega S printer, it was basically the same root cause. I solved it w/o having to replace any hardware, but with some additional mathematics to compensate for the rod twist. I wrote something up explaining the issue and also provide there a little online tool to create appropriate compensation GCode commands. This works great for me and I have no more issues with the bent hardware, so maybe it is a proper resolution for some of you also...

Regards, habitoti