SOLVED UMO print starts in mid air???

[joergen 2]

[UPDATE]
"prehistoric" also refers to the state of the grease along the lead screw and the z nut. it was all caked up and dried and made the z stepper loose steps. removing it, a deep clean and some new high-quality oil solved the problem.

Amazing to see a decade old UM still working great.

 

------------------- 

 

My (ancient) UM2 heated bed just gave up yesterday (separate topic), and I am trying to reactivate my (prehistoric) UMO, which i haven't used since I got the UM2 in 2015. A lot of the finessing and how to tweak gcode knowledge has been lost since then.

 

Problem: i need to get something printed today...

 

I got the GMO to home and heat up, and theoretically print again. home (0) is set to paper sheet thickness under the nozzle. I think the FW is a marlin flavor from 2014, but if there is a newer one, I can flash it (open to suggestions). I would prefer to not change the FW, because I am sure I tweaked a lot of parameters (dim, accel, pid etc) to a T for productions prints between 2011 and 2013)

 

something is wrong in the starting gcode, and the UMO prints mid air (about 15mm above the print bed). I used the original start gcode I found in Cura5, and also tried to change it, but no luck. would appreciate some pointers how to fix the start and end gcode, as well as what settings/flavors i should change in cura5 (i.e. relative or absolute E? etc). it appears the line "G1 Z0 Y50 F9000 ;move the bed and the head" doesn't move the bed back to 0. Help please

 

Quote

;start g-code

G21 ;metric values

G90 ;absolute positioning

M82 ;set extruder to absolute mode

M107 ;start with the fan off

G28 X0 Y0 ;move X/Y to min endstops

G28 Z0 ;move Z to min endstops

G1 Z15.0 F9000 ;move the platform down 15mm

G92 E0 ;zero the extruded length

G1 F200 E6 ;extrude 6 mm of feed stock

G92 E0 ;zero the extruded length again

G1 Z0 Y50 F9000 ;move the bed and the head

;Put printing message on LCD screen

M117 Printing...

 

Quote

;end g-code

M104 S0 ;extruder heater off

G91 ;relative positioning

G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure

G1 Z+5 E-5 X-20 Y-20 F9000 ;move Z up a bit and retract filament even more

G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way

M84 ;steppers off

G90 ;absolute positioning

 

Quote

;print starts here

G92 E0
G92 E0
G1 F1500 E-6.5
;LAYER_COUNT:298
;LAYER:0
M107
G0 F3600 X44.098 Y38.408 Z0.3
G0 X41.786 Y41.69
;TYPE:SKIRT
G1 F1500 E0
G1 F3000 X42.09 Y40.816 E0.02611

...

 

Edited April 26, 2022 by joergen
updated

[dailyworkshare 0]

4 hours ago, joergen said:

[UPDATE]
"prehistoric" also refers to the state of the grease along the lead screw and the z nut. it was all caked up and dried and made the z stepper loose steps. removing it, a deep clean and some new high-quality oil solved the problem.

Amazing to see a decade old UM still working great.

 

------------------- 

 

My (ancient) UM2 heated bed just gave up yesterday (separate topic), and I am trying to reactivate my (prehistoric) UMO, which i haven't used since I got the UM2 in 2015. A lot of the finessing and how to tweak gcode knowledge has been lost since then.

 

Problem: i need to get something printed today...

 

I got the GMO to home and heat up, and theoretically print again. home (0) is set to paper sheet thickness under the nozzle. I think the FW is a marlin flavor from 2014, but if there is a newer one, I can flash it (open to suggestions). I would prefer to not change the FW, because I am sure I tweaked a lot of parameters (dim, accel, pid etc) to a T for productions prints between 2011 and 2013)

 

something is wrong in the starting gcode, and the UMO prints mid air (about 15mm above the print bed). I used the original start gcode I found in Cura5, and also tried to change it, but no luck. would appreciate some pointers how to fix the start and end gcode, as well as what settings/flavors i should change in cura5 (i.e. relative or absolute E? etc). it appears the line "G1 Z0 Y50 F9000 ;move the bed and the head" doesn't move the bed back to 0. Help please

 

 

 

 

Always share some amazing and informative information with us, Thank you for sharing the detail.

[gr5 2,177]

The code looks fine.  I think your Z speed or your Z jerk or your Z acceleration is faulty.  Or too much friction on the Z.  Try moving the Z up and down by 10mm movements to see how it does.  You can do this from the menu system.

[joergen 2]

41 minutes ago, gr5 said:

The code looks fine.  I think your Z speed or your Z jerk or your Z acceleration is faulty.  Or too much friction on the Z.  Try moving the Z up and down by 10mm movements to see how it does.  You can do this from the menu system.

yes, a sticky/dirty z axis was the problem