Dealing with ooze during mesh bed leveling?  

Re: Dealing with ooze during mesh bed leveling?

Change your startup gcode so the mesh bed leveling occurs at a lower temp, like 170. Then when the leveling start you can heat the nozzle to your printing temperature. It should be at temp by the time the leveling is complete and does not ooze filament while leveling.

Re: Dealing with ooze during mesh bed leveling?

Here is my initial gcode:

G28 W ; home all without mesh bed level
G1 X0 Y0 Z125; home X axis
M109 S170 T0 ; this will take the layer 1 temperature for extruder 0
M140 S55 ; this will take the layer 1 temperature for bed 0
M190 S55 ; wait for bed temp
M104 S210 T0 ; set extruder temp
G80 ; mesh bed leveling
G1 Y-3.0 F1000.0 ; go outside printing area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

I also move the print head to 125mm off the bed and then bring the bed to the target temperature. I don't use the temp adjustment for the pinda probe in the updated firmware.

Re: Dealing with ooze during mesh bed leveling?

... as discussed here ...

Re: Dealing with ooze during mesh bed leveling?

Here is my initial gcode:

G28 W ; home all without mesh bed level
G1 X0 Y0 Z125; home X axis
M109 S170 T0 ; this will take the layer 1 temperature for extruder 0
M140 S55 ; this will take the layer 1 temperature for bed 0
M190 S55 ; wait for bed temp
M104 S210 T0 ; set extruder temp
G80 ; mesh bed leveling
G1 Y-3.0 F1000.0 ; go outside printing area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

I also move the print head to 125mm off the bed and then bring the bed to the target temperature. I don't use the temp adjustment for the pinda probe in the updated firmware.

Thanks a lot for this James. I was getting tired of wiping the 9 dots each print 😉 I'm just wondering if there was some reason the Slicer/Prusa folks didn't set it this way by default? They are some smart people, so it seems like there would be a reason? Josef?

Re: Dealing with ooze during mesh bed leveling?

I don't really see a reason...

Re: Dealing with ooze during mesh bed leveling?

This was a work-around introduced on these forums by us users. PR may not even be aware of it (although some members of PR staff have had access to my GCode files).

I don't think the Slic3r settings have been changed very much since PR made them work and it's a good introduction for users to figure this one out for themselves and to learn a bit of GCode.

Peter

Re: Dealing with ooze during mesh bed leveling?

Here is how I modified the default that came with the latest version of Prusa slicer. It seems to work pretty well. The extra filament that comes out towards the end of nozzle heating usually wipes off clean with the intro line. It would have been very helpful to have this from the start. Could a moderator pin a post for slicer settings like there is for simplify3d?

Random question, but why are there 2 different thickness intro lines and does it really need to be that long? I just like to know everything works. Thanks!

M115 U3.0.12 ; tell printer latest fw version
M83 ; extruder relative mode
G1 X0 Y0 Z80; home X axis
M109 S170 ; heat nozzle to 170
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
G28 W ; home all without mesh bed level
M104 S[first_layer_temperature] ; set extruder temp
G80 ; mesh bed leveling
G1 X0 Y0 Z40; lift nozzle to 40 while heating
M109 S[first_layer_temperature] ; wait for extruder temp
G1 X0 Y0 Z0.2; lower Z to prepare for intro line
G1 Y-3.0 F1000.0 ; go outside print area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

Re: Dealing with ooze during mesh bed leveling?

Problem there is that you are doing 9 point cal with a cold extruder. Any ooze from the last print will be solid and push the bed down during probing.

You need 170 degrees on the extruder to soften any nozzle blobs.

Peter

Re: Dealing with ooze during mesh bed leveling?

Problem there is that you are doing 9 point cal with a cold extruder. Any ooze from the last print will be solid and push the bed down during probing.

You need 170 degrees on the extruder to soften any nozzle blobs.

Peter

Thanks for catching that Peter! I somehow missed that in the post above, but makes perfect sense.

Re: Dealing with ooze during mesh bed leveling?

M115 U3.0.11 ; tell printer latest fw version
M83 ; extruder relative mode
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
M104 S[first_layer_temperature] ; set extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp
G1 Y-3.0 F1000.0 ; go outside pritn area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

This code will make it so you never have to watch it until it actually starts printing (you should always watch the first layer go down). Ooze problem solved.

and to address PJR, you have to visit the printer between prints so this isn't a concern. while you're there you should be inspecting the nozzle to make sure it's clean, taking two second to snip off the ooze from the end of the previous print should be part of that routine already.

Re: Dealing with ooze during mesh bed leveling?

M115 U3.0.11 ; tell printer latest fw version
M83 ; extruder relative mode
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
M104 S[first_layer_temperature] ; set extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp
G1 Y-3.0 F1000.0 ; go outside pritn area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

This code will make it so you never have to watch it until it actually starts printing (you should always watch the first layer go down). Ooze problem solved.

and to address PJR, you have to visit the printer between prints so this isn't a concern. while you're there you should be inspecting the nozzle to make sure it's clean, taking two second to snip off the ooze from the end of the previous print should be part of that routine already.

1. No point in having M190 immediately following M140. You need an M109 S170 in between
2. "snip off the ooze" - not with a small blob, which is enough (if you have calibrated correctly) to cause the bed to be pushed down when probing.

Sorry.

Peter

Re: Dealing with ooze during mesh bed leveling?

It's far easier to clean a nozzle when it's warmed up to a holding temperature than a cold one.

Given that the bed will heat up more slowly than the extruder, the sane process is:

1. Set the bed temp (non-blocking)
2. Set the extruder to holding temp (blocking)
3. Clean the extruder and bed while the bed continues heating up
4. Once the bed is at temp, run probe
5. Set the the extruder to full temp and start printing

Re: Dealing with ooze during mesh bed leveling?

M115 U3.0.11 ; tell printer latest fw version
M83 ; extruder relative mode
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
M104 S[first_layer_temperature] ; set extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp
G1 Y-3.0 F1000.0 ; go outside pritn area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

This code will make it so you never have to watch it until it actually starts printing (you should always watch the first layer go down). Ooze problem solved.

and to address PJR, you have to visit the printer between prints so this isn't a concern. while you're there you should be inspecting the nozzle to make sure it's clean, taking two second to snip off the ooze from the end of the previous print should be part of that routine already.

1. No point in having M190 immediately following M140. You need an M109 S170 in between
2. "snip off the ooze" - not with a small blob, which is enough (if you have calibrated correctly) to cause the bed to be pushed down when probing.

Sorry.

Peter

1. it's all the original gcode prusa provides, I just moved it around. If you don't need 190 after 140 go tell Joseph he's wrong.
2. there won't be a small blob. why would there be a blob? because you failed a print? then you better be cleaning your nozzle after the failure. If you finish a print successfully then the only thing will be a short string of ooze from it cooling after the previous print. grab the flush cutters and snip it. two seconds, no more problems.
3. this is almost 500 hours of printing with this code, never once has it failed.

Sorry.

Re: Dealing with ooze during mesh bed leveling?

this is almost 500 hours of printing with this code, never once has it failed.

500 hours? Wow that's almost 3 weeks.. Sorry. Next time I will make sure I agree with you.

Peter

Re: Dealing with ooze during mesh bed leveling?

this is almost 500 hours of printing with this code, never once has it failed.

500 hours? Wow that's almost 3 weeks.. Sorry. Next time I will make sure I agree with you.

Peter

I think that's a pretty good trial run of something. 500 hours with this code and not a single failure. Do you require more time testing something? give me a number and I'll get back to when I hit it and let you know if there's any failures.

Do you have any constructive feedback? I've put in a lot of hours testing this and you're just blowing it off because it's not your way. Regardless, it works, try it.

Re: Dealing with ooze during mesh bed leveling?

I've put in a lot of hours testing this and you're just blowing it off because it's not your way. Regardless, it works, try it.

I did try it over 3 years ago. Moved on pretty quickly from that. Incidentally, I have one single model which took over 3 weeks to print, and I have a total of more that 5 years printing on my 3 printers. I don't really care if you wish to ignore my experiences. End of conversation.

Peter

Re: Dealing with ooze during mesh bed leveling?

Guys there is actually totally other way to solve that problem.
do mesh bed leveling on cold.
it solves 2 problems:
1) ooze on mesh bed leveling
2) PINDA probe sensitivity to heat (pinda probe distance detection changes with temperature)

it depends 3 things:
1) check that your nozzle is clean before each print
2) different way of first layer calibration.

one disadvantage:
you need to wait printer cool down between prints.

M83 ; extruder relative mode
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M104 S[first_layer_temperature] ; set extruder temp
M109 S[first_layer_temperature] ; wait for extruder temp
G1 Y-3.0 F1000.0 ; go outside pritn area

calibration routine modification:
1) turn off (if enabled) Temp calibration
2) go V2Calibration gcode
3) fix slicer settings Start gcode
4) prepare gcode of prusa.stl with 200um layer , and print do Z tuning during firstlayer.
5) cancel print after first layer
6) repeat steps 5~6 till first layer will be perfect.

I am using cold calibration because i am printing booth PLA and ABS, and those materials have different bed temperatures, so it was easier to calibrate instead of setting special z offset for abs, as pinda sensitivity vary from temp , it was changing z offset between points as during travel on heated-bed it greting warmer.