[Recurring problem] Clogged PTFE tube at heatsink  

Re: [Recurring problem] Clogged PTFE tube at heatsink

Anyone?

Re: [Recurring problem] Clogged PTFE tube at heatsink

When does it happen? Without description it's hard to guess the issue. Is only a small part stuck?

Re: [Recurring problem] Clogged PTFE tube at heatsink

I had the same problem when unloading the filament - but only when I left the printer for a few minutes before unloading.

So my solution was to amend the end G-code section to unload the filament immediately after a print. Problem solved.

Peter

Re: [Recurring problem] Clogged PTFE tube at heatsink

I had the same problem when unloading the filament - but only when I left the printer for a few minutes before unloading.

So my solution was to amend the end G-code section to unload the filament immediately after a print. Problem solved.

Peter

A full unload, or just a large retraction? I'd be interested in this, since my printer seems to jam if I let it sit and then try to unload or go into another print.

Re: [Recurring problem] Clogged PTFE tube at heatsink

Full unload in end G-code section (KISS):

; Postfix GCode

G1 Z<Z+1.0> E-4 F7200 ; Lift and retract
G1 X0 Y200 F3600 ; move bed for easy removal
G1 E5 F2100 ; feed a bit
G1 E-100 F3000 ; unload
G4 S1 ; pause 1 second
M107 ; turn off fan
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
M84 ; disable motors


This will need amending for other slicers.

Peter

Re: [Recurring problem] Clogged PTFE tube at heatsink

Hi PJR

How should the code be used? I'm a layman without experience in editing codes.

Re: [Recurring problem] Clogged PTFE tube at heatsink

How should the code be used? I'm a layman without experience in editing codes.

Probably better that you don't change anything then, at least until you learn a bit about G-code.

Basically, all slicers (and I presume you use Slic3r) have sections which allow you to enter G-code at certain point on a model. That includes at the start, at the end, at the change of a tool or at the change of a layer.

What we are talking about here is the Postfix (at the end) section.

In Slic3r, select the "Printer Settings" tab at the top left of the window. Then from the list down the left, select "Custom G-code". You will now see several sections in the main body of the window, including "Start G-code" and a"End G-code"

Have a look at the "End G-code" section, I have no idea what will be in yours, because I only have the Mk2+MMU profiles installed but if you can paste your End G-code section here, I will tell you how to modify it...

Peter

Re: [Recurring problem] Clogged PTFE tube at heatsink

Next time before you unload filament, go into the settings menu, move axis menu, extruder option, then extrude a few mm of filament. THEN unload filament. Should come out freely every time. I have added this to my routine when unloading. I imagine someone can come up with a way to do it automatically but it works.

Re: [Recurring problem] Clogged PTFE tube at heatsink

I imagine someone can come up with a way to do it automatically but it works.

That's exactly what my G-code (above) does...

Peter

Re: [Recurring problem] Clogged PTFE tube at heatsink

Sorry, early in the morning and I was skimming. Thanks. 🙂

Re: [Recurring problem] Clogged PTFE tube at heatsink

Sorry, early in the morning and I was skimming. Thanks. 🙂

😀 Not a problem...

Peter

Re: [Recurring problem] Clogged PTFE tube at heatsink

How should the code be used? I'm a layman without experience in editing codes.

Probably better that you don't change anything then, at least until you learn a bit about G-code.

Basically, all slicers (and I presume you use Slic3r) have sections which allow you to enter G-code at certain point on a model. That includes at the start, at the end, at the change of a tool or at the change of a layer.

What we are talking about here is the Postfix (at the end) section.

In Slic3r, select the "Printer Settings" tab at the top left of the window. Then from the list down the left, select "Custom G-code". You will now see several sections in the main body of the window, including "Start G-code" and a"End G-code"

Have a look at the "End G-code" section, I have no idea what will be in yours, because I only have the Mk2+MMU profiles installed but if you can paste your End G-code section here, I will tell you how to modify it...

Peter

My "End G-code":

G4 ; wait
M221 S100
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
M107 ; turn off fan
G1 X0 Y200; home X axis
M84 ; disable motors

Re: [Recurring problem] Clogged PTFE tube at heatsink

My "End G-code":

G4 ; wait
M221 S100
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
M107 ; turn off fan
G1 X0 Y200; home X axis
M84 ; disable motors

OK, so you can modify it slightly to this:

M221 S100 ; Set extrude factor to 100%
G91 ; Set to relative positioning
G1 Z5 F1200 ; Lift Z (relative)
G90 ; Set to absolute positioning
G1 E-2.5 F3000 ; Retract
G1 X0 Y200 F3600 ; move bed for easy removal
G1 E5 F2100 ; feed a bit
G1 E-100 F3000 ; unload
G4 S1 ; pause 1 second
M107 ; turn off fan
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
M84 ; disable motors

This will completely unload the filament and theory is, it should be a relatively "clean" unload.

Peter

Re: [Recurring problem] Clogged PTFE tube at heatsink

I would submit that if you have to unload filament after every print- there is still something wrong with your heat break or PTFE tube. I never have to unload filament- and can later unload without issue.

Re: [Recurring problem] Clogged PTFE tube at heatsink

Nothing is wrong. This issue is by MK3 design. In my opinion the unload procedure in the firmware need to be adjusted slightly.

You can reproduce it on your machine. Preheat PLA, let it stand for 5 minutes, so the filament rinse out a little bit.
Try to unload and in most cases it will get stuck. The filament end is deforming uneven during unload, if it wasn't compressed before in the nozzle. Second ptfe tube doesn't have much tolerance.

MK2 is working fine, because you can pull out almost everything, once it left the ptfe tube.

Re: [Recurring problem] Clogged PTFE tube at heatsink

Nothing is wrong. This issue is by MK3 design. In my opinion the unload procedure in the firmware need to be adjusted slightly.

You can reproduce it on your machine. Preheat PLA, let it stand for 5 minutes, so the filament rinse out a little bit.
Try to unload and in most cases it will get stuck. The filament end is deforming uneven during unload, if it wasn't compressed before in the nozzle. Second ptfe tube doesn't have much tolerance, so you can't pull it out.

MK2 is working fine, because you can pull out almost everything, once it left the ptfe tube.

Re: [Recurring problem] Clogged PTFE tube at heatsink

I have done this very test several times by accident- pre-heat wanting to change filament and forget about it for 10 minutes. It always unloads, without issue. I have even left it on for 10-15 minutes, then cool down- then later come back and pre-heat and unload. No issues...

Re: [Recurring problem] Clogged PTFE tube at heatsink

I have done this very test several times by accident- pre-heat wanting to change filament and forget about it for 10 minutes. It always unloads, without issue. I have even left it on for 10-15 minutes, then cool down- then later come back and pre-heat and unload. No issues...

Yeah, this problem does not appear to affect all Mk3 printers. Mine is one with the problem. And yes, it may well be down to PTFE being badly formed or installed, but not everyone is capable of dismantling the extruder and changing it properly and without doing damage elsewhere.

Peter