Oozing nozzle while doing bed leveling?  

Page 1 / 4
  RSS
janko.t
(@janko-t)
Active Member

Honestly i'm having issues with my mk3 that appeared out of nowhere. All of the sudden the nozzle is starting to develop this nasty leaking problem, anytime I print, anytime I insert the filament it just leaks like crazy. It's super annoying when it develops a blob of filament after just doing bed levelling calibration at the start of every print [The picture is a blob of filament that came out while bed levelling before a print].  And what's the most annoying problem is it's messing with my prints, since it cant get rid of it with the purge strip, because there's to much filament glued to the nozzle that it  just grabs the first layer with it while printing and completely destroys any chances of that print even starting.

And yes the nozzle temperature is 215°c, the filament is Prusament galaxy black, and it really liked this settings so far!

If anyone knows how to fix this mess please I beg help me 😀

Posted : 15/06/2019 2:14 pm
david.a66
(@david-a66)
Honorable Member

easy solution is modify your before print gcode block. only preheat the hotend to around 160. the add a pinda temp check , then bedlevel, then raise the hotend tep to printing temp before the purge

 

something like this

M83 ; extruder relative mode
G28 W ; MUST FIRST home all without mesh bed level or else risk nozzle crash!
G0 X70 Y70 Z0.2 F2000; PINDA warms faster near bed
M140 S[first_layer_bed_temperature] ; set bed temp
M104 S160 ; preheat extruder to no ooze temp to help warm PINDA
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S160 ; wait for extruder temp
M860 S36 ; wait for PINDA temp. For most stable PINDA temp during mesh, set temp here 1-2 deg below your actual PINDA temp at end of mesh cal.
M104 S100 ; drop extruder to lower temp to minimize PINDA temp rise during mesh
G80 N7 R1 ; mesh bed leveling with extra points but this requires 3.6.0c firmware
G1 Y-3.0 F1000.0 ; go outside print area
G92 E0.0
G1 Z3 ; raise head safely clear of bed before heating extruder
M104 S[first_layer_temperature] ; we heat extruder AFTER mesh to minimize ooze
M109 S[first_layer_temperature] ; wait for extruder temp
G1 Z0.7 ; move slightly above bed for easy clean intro line
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line
G1 E-0.8 F2100; bobstro anti-stringing retract and wipe
G1 X99.0 E0 F1000.0 ; -1mm intro line @ 0.00
G1 X110.0 E0 F1000.0 ; +10mm intro line @ 0.00
G1 Z0 ;lower head back to normal Z after intro line
G92 E0.0
M221 S{if layer_height==0.05}100{else}95{endif}

 

Posted : 15/06/2019 3:27 pm
janko.t
(@janko-t)
Active Member

I mean I appreciate the help but I do still wonder what the root of the problem is in the first place. Maybe I can resolve the issue in the first place without modifying the Gcode. Cause it was working just fine only a couple of days earlier.

 

Posted : 15/06/2019 6:14 pm
Tim
(@tim-m30)
Illustrious Member

I use 185c as my preheat.

And the command G80 N7 R1  only works with custom firmware.  With 3.7.x you can  select the 7x7 mesh level via the LCD menus, under settings.  G80 is now suffiecient with stick firmware.

As for other methods to reduce drip and gnat creation, some try to use retraction, but that requires changes with each type and brand and color of filament; whereas reducing nozzle temps works with everything.

 

Root of the problem?  Gravity.   Hot filament - melted filament - flows downhill.

 

 

This post was modified 1 year ago by Tim
It is always wise to get more than one opinion......
Posted : 15/06/2019 6:21 pm
Area51
(@area51)
Honorable Member
Posted by: janko.t

I mean I appreciate the help but I do still wonder what the root of the problem is in the first place. Maybe I can resolve the issue in the first place without modifying the Gcode. Cause it was working just fine only a couple of days earlier.

 

It looks like a moisture problem. Having the same problem with my PETG - helps to dry the filament.

Have a look at my designs on Thingiverse or on PrusaPrinters ;)...
Posted : 15/06/2019 10:53 pm
brian.m22
(@brian-m22)
Active Member

I have the regular problem that sounds similar. As soon as I load the material, it starts to leak out. Then when it does the bed leveling it pushes the leaked material up onto the head. Then it can randomly fall off onto the bed, disrupting the print. Or it can stay on the head and during the head clean, and then fall randomly off during the print. I believe the filament is dry and has no moisture. It is relatively cold here however, maybe that could be significant?

The mmu2s autoloading can help resolve this problem at times, however not for prints I have downloaded pre-sliced that require preloading of a single material.

I have found it helps if I just let it in a continuous flow, then when the head starts moving I can pull the entire thing away in one go. Doesn't seem like the ideal solution however.

Posted : 16/06/2019 11:15 am
jbinfl
(@jbinfl)
Reputable Member

I know what you experiencing and it is maddening...  It leaks a lot and the flow seems faster than normal like when you are loading filament how it comes out fast.  I had that happen in the past as well and fortunately it went away.  At the time, I attributed it to the filament being the cause but you are using Prusament so I do not think that is it.

I would try a cold pull with cleaning filament.  That can help to clean out accumulated bits in the hotend and nozzle.  I always run some cleaning filament between switches of types of filament (e.g PETG to PLA) and brands of the same type (hatchbox PLA to prusament PLA) which seems to help.  I use the Bobstro method and it works.

Does it happen with all types of filament?  e.g. have you tried a different roll of filament and it still happens or not?

last suggestion, change the nozzle and see if it still happens or resolves.

Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!...
Posted : 16/06/2019 2:01 pm
jack
 jack
(@jack)
Trusted Member

I cleaned the exterior of my nozzle with an Exacto knife, which had gotten a lot of gunk on it after 2 months with my new mk3S (maybe 200 hours of printing). Gunk on the exterior seems to play a role in turning the oozing into a rats nest during the bed leveling check. The oozing still happens, but it stays straighter, and wipes off better during the pre-swipe. When I got my printer two months ago (my first), I don't remember seeing any little rats nest, but I can't say if the oozing was happening then. Of course a new, clean nozzle would accomplish the same thing, and make cleaning the gunky nozzle easier, but I haven't changed a nozzle yet, so I tried this first.

...there are only 10 kinds of people in this world--those who know binary and those who don't......
Posted : 19/06/2019 2:35 am
julian.s10
(@julian-s10)
Eminent Member

I noticed that phenomenon too. My MK3 doesn't have this problem in contrast to MK3S. Oozing is noticable during preheating and non printing moves. Does anybody know how to solve this problem? I am printing with Flex so oozing is more noticable but my first printer doesn't have this problem. 

Posted : 19/06/2019 10:40 am
Area51
(@area51)
Honorable Member

Printing PETG I had a lot of gunk on my nozzles as PET tends to stick very well to the brass surface.

I found the solution, using plated nozzles from Micro Swiss. The nozzles have a non-stick coating and is now very easy to keep clean.

Have a look at my designs on Thingiverse or on PrusaPrinters ;)...
Posted : 19/06/2019 11:03 am
bobstro
(@bobstro)
Illustrious Member
Posted by: janko.t

[...] And what's the most annoying problem is it's messing with my prints, since it cant get rid of it with the purge strip, because there's to much filament glued to the nozzle that it  just grabs the first layer with it while printing and completely destroys any chances of that print even starting.

"So much filament glued to the nozzle" makes me think it's sticking on build-up. Are you cleaning your hotend and nozzle exterior regularly? If not, it's not unusual for filament to accumulate, burn and fall off into prints at inopportune moments. Try using a soft brass brush to gently remove any accumulated crud from the exterior. You won't be able to get it shiny and new looking, but you should at least see mostly clean surfaces. Be very careful around the heater cartridge and thermistor wires on the heater block. If you are using a coated nozzle, use a strip of cardboard to remove any accumulation. Consider a silicone sock to avoid excessive build-up.

Also remember that nozzles are expendables. If yours has worn so much that the opening is uneven or over-sized, it can cause a variety of "sudden" problems. Keeping a spare on hand is always recommended. I'd swap in a replacement and see it that improves things.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 19/06/2019 12:46 pm
guy.k2
(@guy-k2)
Noble Member

And the command G80 N7 R1  only works with custom firmware.  With 3.7.x you can  select the 7x7 mesh level via the LCD menus, under settings.  G80 is now suffiecient with stick firmware.

Actually, G80 N7 R1 does work with current release firmware. The parameters are respected. But, yes. If you specify the 7x7 mesh in the printer's settings, you only need G80.

 

Posted : 19/06/2019 4:29 pm
julian.s10
(@julian-s10)
Eminent Member

What it does? G80 - stop steppers, N7 - go to line 7, R1 - temperatura 1 Celcius degree 🙂 : O?  Could you please describe it?

Posted : 19/06/2019 4:34 pm
Sembazuru
(@sembazuru)
Prominent Member
Posted by: julian.s10

What it does? G80 - stop steppers, N7 - go to line 7, R1 - temperatura 1 Celcius degree 🙂 : O?  Could you please describe it?

G80 is the command for Prusa printers to start the mesh bed leveling process. The argument N7 specifies a 7x7 grid (I think N5 and N3 are also supported). The argument R1 specifies a single measurement at each point. I personally use the most number of measurements per point (they are averaged together, hopefully correcting for measurement tolerances). I think it is 5, but I don't recall off the top of my head.

In the current FW, you can specify the grid size and number of repititions that the G80 without arguments will do. If any of the arguments are specified, they will override the settings. So, since I have my printer configured to 7x7 grid with the max number of measurements, if I send to the printer "G80 N3 R1" then it will to the mesh bed leveling measurements on a 3x3 grid with only 1 measurement per point.

See my (limited) designs on:
PrusaPrinters - https://www.prusaprinters.org/social/1448-sembazuru/prints
Thingiverse - https://www.thingiverse.com/Sembazuru/designs...
Posted : 19/06/2019 4:55 pm
david.a66 liked
Tim
(@tim-m30)
Illustrious Member

Gcodes · prusa3d/Prusa

Gcode | Marlin Firmware

 

It is always wise to get more than one opinion......
Posted : 19/06/2019 7:21 pm
Sembazuru
(@sembazuru)
Prominent Member
Posted by: Tim

Gcodes · prusa3d/Prusa

Gcode | Marlin Firmware

 

Unfortunately for the question asker these links aren't useful.

The Prusa Wiki page is severely incomplete (even states that is is WIP). But, it was last edited in October 2017 so I think it is probably abandoned. It does mention G80, but doesn't give any of the newly added arguments.

The Marlin page doesn't even include G80...

A better link would be the announcement for the firmware that started to include the arguments for G80. I quickly scanned the blog and didn't see it (not to say that it wasn't mentioned in the body of one of the past blogs). Found it in the GitHub release notes: https://github.com/prusa3d/Prusa-Firmware/releases/tag/v3.7.0-RC1

This post was modified 1 year ago by Sembazuru
See my (limited) designs on:
PrusaPrinters - https://www.prusaprinters.org/social/1448-sembazuru/prints
Thingiverse - https://www.thingiverse.com/Sembazuru/designs...
Posted : 19/06/2019 8:22 pm
Tim
(@tim-m30)
Illustrious Member

I'd call that info adequately buried and only available to the dedicated reader. lol   Lack of documentation of features is one of the issues I have with Prusa.  They try, but fail in some rather obvious ways, like this.

It is always wise to get more than one opinion......
Posted : 19/06/2019 11:44 pm
james.m79
(@james-m79)
Active Member

I have found that after loading the filament, if I let it set for 4-5 minutes before starting to print it will continue to ooze for a bit and then stop.  This also eliminates or at least reduces the number of little blobs left on the plate during bed leveling.

Posted : 20/06/2019 12:35 pm
julian.s10
(@julian-s10)
Eminent Member

@james_m79 That's exactly what I observed too 🙂 ! But it doesn't solve the problem with oozing permamently. Maybe it's because of no pressure from melted filament after some time of 'leaking'. 

Posted : 21/06/2019 12:01 am
david.a66
(@david-a66)
Honorable Member

really its just adding a couple of lines of g-code to the "start G-Code" under the printer tab in prusaslicer and saving that config. then it's always there.    

 

look at the code sample i posted and compare with whats already in the "start G-Code" 

 

 

Posted : 21/06/2019 12:34 am
Page 1 / 4
Share:

Please Login or Register