Mid-air Printing with BLtouch and Delta Printer



  • No matter what I do I can't solve this problem. I am seeing 1.75 mm z heigh when Z0 is in config. When changing it to Z1.75, this time I see another different value. When it is changed it to - value, it's still trying to mid-print. The Z-axis limit is 0. But, when I changed it to -3.80 and still the same mid-air print. I tried changing Y and X offset, still the same. Changed Z offset, and still the same.

    Normally, I use my printer without a probe, but I have 2 Bltouch (1 clone and 1 original) so I wanted to try. Both are mid-air printing. My printer is TEVO Little Monster with Duet Wi-Fi 2 and 2.04 firmware.

    Here is my config file and start the script.

    ; Configuration file for Duet WiFi (firmware version 2.04)
    ; executed by the firmware on start-up
    ;
    ; generated by RepRapFirmware Configuration Tool v2 on Tue Aug 27 2019 19:34:39 GMT+0300 (GMT+03:00)
    
    ; General preferences
    G90                                                                      ; Send absolute coordinates...
    M83                                                                      ; ...but relative extruder moves
    M665 R155 L397.19 B155 H520                                              ; Set delta radius, diagonal rod length, printable radius and homed height
    M666 X0 Y0 Z0                                                            ; Put your endstop adjustments here, or let auto calibration find them
    
    ; Network
    
    
    ; Drives
    M569 P0 S1                                                               ; Physical drive 0 goes forwards
    M569 P1 S1                                                               ; Physical drive 1 goes forwards
    M569 P2 S1                                                               ; Physical drive 2 goes forwards
    M569 P3 S1                                                               ; Physical drive 3 goes forwards
    M350 X16 Y16 Z16 E16 I1                                                  ; Configure microstepping with interpolation
    M92 X80.00 Y80.00 Z80.00 E403.00                  			 ; set steps per mm
    M566 X1200.00 Y1200.00 Z1200.00 E1200.00           			 ; set maximum instantaneous speed changes (mm/min)
    M203 X18000.00 Y18000.00 Z18000.00 E1200.00        			 ; set maximum speeds (mm/min)
    M201 X1000.00 Y1000.00 Z1000.00 E1000.00            			 ; set accelerations (mm/s^2)
    M906 X1200 Y1200 Z1200 E1200 I30                   			 ; set motor currents (mA) and motor idle factor in per cent
    M84 S30                                             			 ; Set idle timeout
    
    ; Axis Limits
    M208 Z-3.80 S1                                         			 ; set minimum Z
    	
    ; Endstops
    M574 X2 Y2 Z2 S1                                  			 ; set active high endstops
    
    ; Z-Probe
    M307 H3 A-1 C-1 D-1                              			 ; disable heater on PWM channel for BLTouch
    M558 P9 H5 F120 T6000                             			 ; set Z probe type to bltouch and the dive height + speeds
    G31 P500 X20 Y0 Z-3.70                                			 ; set Z probe trigger value, offset and trigger height
    M557 R125 S45                                     			 ; define mesh grid
    
    ; Heaters
    M305 P0 T100000 B4138 R4700                                              ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120                                                             ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4725 C7.060000e-8 R4700          			 ; set thermistor + ADC parameters for heater 1
    M143 H1 S280                                                             ; Set temperature limit for heater 1 to 280C
    
    ; Fans
    M106 P0 S1 I0 F500 H-1                            			 ; set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P1 S1 I0 F500 H-1                             			 ; set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off
    
    ; Tools
    M563 P0 S"Extruder" D0 H1 F0:1                     			 ; define tool 0
    G10 P0 X0 Y0 Z0                                    			 ; set tool 0 axis offsets
    G10 P0 R0 S0                                    			 ; set initial tool 0 active and standby temperatures to 0C
    ; Automatic power saving
    M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000"                       ; Set voltage thresholds and actions to run on power loss
    
    ; Custom settings are not configured
    
    ; Miscellaneous
    
    
    
    
    Simply3d Start Script
    G28 ;Home
    G1 E35 F900 ; Extrude filament to avoid clog
    M280 P3 S10 I1 ; set bltouch to probing position - to make sure probe is working
    M280 P3 S90 I1 ; set bltouch to idle position - to make sure probe is working
    G32
    
    ; bed.g
    ; called to perform automatic delta calibration via G32
    ;
    ; generated by RepRapFirmware Configuration Tool v2.1.2 on Wed Nov 20 2019 13:17:15 GMT+0300 (GMT+03:00)
    M561 ; clear any bed transform
    G28  ; home all towers
    ; Probe the bed at 6 peripheral and 6 halfway points, and perform 6-factor auto compensation
    ; Before running this, you should have set up your Z-probe trigger height to suit your build, in the G31 command in config.g.
    G30 P0 X0 Y117.5 H0 Z-99999
    G30 P1 X108.01 Y62.36 H0 Z-99999
    G30 P2 X116.91 Y-67.5 H0 Z-99999
    G30 P3 X0 Y-135 H0 Z-99999
    G30 P4 X-116.91 Y-67.5 H0 Z-99999
    G30 P5 X-108.01 Y62.36 H0 Z-99999
    G30 P6 X0 Y52.01 H0 Z-99999
    G30 P7 X49.63 Y28.65 H0 Z-99999
    G30 P8 X58.46 Y-33.75 H0 Z-99999
    G30 P9 X0 Y-67.5 H0 Z-99999
    G30 P10 X-58.46 Y-33.75 H0 Z-99999
    G30 P11 X-49.63 Y28.65 H0 Z-99999
    G30 P12 X0 Y0 H0 Z-99999 S6
    ; Use S-1 for measurements only, without calculations. Use S4 for endstop heights and Z-height only. Use S6 for full 6 factors
    ; If your Z probe has significantly different trigger heights depending on XY position, adjust the H parameters in the G30 commands accordingly. The value of each H parameter should be (trigger height at that XY position) - (trigger height at centre of bed)
    
    
    


  • Please post your full config.g and homedelta.g. Most likely you have something applying an offset that isn't in the parts you have posted.

    Edit: sorry, see you have already posted config.g!

    Ian



  • @sniper23 said in Mid-air Printing with BLtouch and Delta Printer:

    M665 R155 L397.19 B155 H520 ; Set delta radius, diagonal rod length, printable radius and homed height
    M666 X0 Y0 Z0 ; Put your endstop adjustments here, or let auto calibration find them

    these are not the results of the delta calibration, you have to save the values from the delta calibration.
    please read
    https://duet3d.dozuki.com/Wiki/Calibrating_a_delta_printer



  • @Veti Parameters in config override? or this one?

    Calibrated 6 factors using 13 points, deviation before 0.082 after 0.080



  • @sniper23 said in Mid-air Printing with BLtouch and Delta Printer:

    @Veti Parameters in config override?

    You update the parameters in config.g with the results from running bed.g. It should mean you don't have to run bed.g every time. However, if you're going to run bed.g every time you turn the printer on, or you are confident that your delta sizes are correct (my delta constantly tells me to change them, because my bed isn't square to the axes) you don't have to.

    Can you post your homedelta.g?

    Ian



  • @droftarts

    ; homedelta.g
    ; called to home all towers on a delta printer
    ;
    ; generated by RepRapFirmware Configuration Tool v2 on Tue Aug 27 2019 19:34:39 GMT+0300 (GMT+03:00)
    G91                        ; relative positioning
    
    G1 S1 X705 Y705 Z705 F3600 ; move all towers to the high end stopping at the endstops (first pass)
    G1 X-5 Y-5 Z-5 F3600 S2    ; go down a few mm
    G1 S1 X10 Y10 Z10 F360     ; move all towers up once more (second pass)
    G1 Z-5 F6000               ; move down a few mm so that the nozzle can be centred
    G90                        ; absolute positioning
    


  • @sniper23 said in Mid-air Printing with BLtouch and Delta Printer:

    Parameters in config override?

    you have not enabled config overwrite. therefore those settings will get ignored.



  • @sniper23 said in Mid-air Printing with BLtouch and Delta Printer:

    M587 S"Akpa YapI" P"3672436724" I192.168.1.4 J192.168.1.1 K255.255.255.0 ; Configure access point and IP addresses. You can delete this line once connected

    Not related to your problem, but delete or comment out this line from your config.g. As it says in the gcode dictionary:

    Important! Do not use M587 within config.g. As well as being a security hazard, writing the access point parameters to WiFi chip every time you start the Duet may eventually wear out the flash memory. Also, the wifi module does not get enabled until the end of running config.g. It is better to use a macro to send M587 (source: https://forum.duet3d.com/post/42798)

    Ian



  • homedelta.g looks sensible. At what point are you seeing the homing offset problem? Is it after running bed.g? Because you probably need to run G28 after the bed.g to reset the Z home if bed.g is applying a large correction.

    Ian



  • @droftarts Homing offset?

    My printer runs automatically G28 before delta calibration. After calibration results look normal (but can't see the map as with g29). After that print starts and mid printing happens.



  • you still need to save the values from the delta calibration.



  • @sniper23 said in Mid-air Printing with BLtouch and Delta Printer:

    @droftarts Homing offset?

    At some point a different offset is being applied to the homed position of Z=0 when nozzle touches bed.

    My printer runs automatically G28 before delta calibration. After calibration results look normal (but can't see the map as with g29).

    After bed.g calibration, send G28. Then send G1 X0 Y0 Z0. Is the nozzle offset from the bed?

    After that print starts and mid printing happens.

    So it's in the Gcode created by Simply3D (Simplify3D?)? I don't use Simplify3D, but check settings for any Z offset there.

    Ian



  • @droftarts I already did G1 X0 Y0 Z0, the same position happens when bl touch starts probing. After playing with my trigger height. I was able to print properly, but there is another problem. While it is printing fine on one side of the bed, it's not the same for the other side. A little air printing happens. Now, we need to find fix for that.



  • @sniper23 said in Mid-air Printing with BLtouch and Delta Printer:

    I already did G1 X0 Y0 Z0, the same position happens when bl touch starts probing.

    The phrase "the same position happens when bl touch starts probing." should not be a factual statement. Z0 is not the start position for bltouch probing.

    So let's verify: Enter a "G1 X0Y0Z0" manually.

    When that move finishes, is the nozzle just touching the bed?


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