PLA Suddenly Jamming Mid-Print

[uncle_bob]

Hi

If your fan is cooling off the hot end so it jams ... time for an upgrade.

Bob

[Ryuluce]

Hi

If your fan is cooling off the hot end so it jams ... time for an upgrade.

Bob

An upgrade... on what part? If you're suggesting the entire printer, then no. This printer is only several months old, I know that it functions fine with ABS, and it worked fine with PLA before I switched to ABS.

The theory about the fan over-cooling the nozzle is still just a theory, I haven't the time yet to thoroughly test it.

[uncle_bob]

An upgrade... on what part? If you're suggesting the entire printer, then no. This printer is only several months old, I know that it functions fine with ABS, and it worked fine with PLA before I switched to ABS.

The theory about the fan over-cooling the nozzle is still just a theory, I haven't the time yet to thoroughly test it.

Hi

If the hot end is not doing what it is supposed to do *and* you believe it's properly assembled ..... time to replace the hot end.

I would try it with a couple of different PLA suppliers first.

Bob

[3dex ltd]

We have had issues in the past with a layer fan. The fan is designed to cool the layer just printed which helps with things like bridging. However, we found that the fan was cooling the nozzle to the extent that filament cool and hardened on the nozzle causing a clog half way through the print as you describe. I hope this helps.

[Ryuluce]

Okay, so I can't really give the full details, but through a lot of trial and error I feel that I am close to getting things working fully.

I have one last problem, and it is driving me insane, because I know what I want to do but I can't.

I want to disable the filament cooling fan when the printer prints the HIPS support material, and turn it on only for the PLA.
BUT, when I disable auto-cooling in the HIPS settings, the fan stays on anyways.
I found out that this is because Slic3r uses the M106 or M126 (depending on GCODE flavor) command to turn on the fan during the PLA, but it never triggers M107 or M127 to turn it off when the HIPS starts printing. I also see that most of the time the fan is enabled during the layer change rather than when the GCODE switches between the extruders.

Is there anyway to make the fan turn off for one filament and on for the other? I need to be able to do this.

[uncle_bob]

Hi

A hot end cooling fan should be on pretty much all the time. That is a different fan (in most setups) than a filament post print cooling fan. They make it impossible to turn the first one off. The second one is indeed controllable. You get a problem when the software is a bit confused about which function a specific fan is performing.

Bob

[Ryuluce]

Hi

A hot end cooling fan should be on pretty much all the time. That is a different fan (in most setups) than a filament post print cooling fan. They make it impossible to turn the first one off. The second one is indeed controllable. You get a problem when the software is a bit confused about which function a specific fan is performing.

Bob

I am clearly talking about a post print fan, which I know should be controllable.
My issue is that I can't get the software to turn the dang thing off when I want it too.
Is there a way to fix this in slic3r? That's my question right now.

[uncle_bob]

Hi

The fan setting may be confused in Slic3r or (more likely) it's confused in your Ramps (or equivalent) or your wiring.

Bob

[Ryuluce]

Hi

The fan setting may be confused in Slic3r or (more likely) it's confused in your Ramps (or equivalent) or your wiring.

Bob

Okay, I don't think you're exactly understanding what I mean.

Here's an example part of the GCODE I'm currently producing in Slic3r: https://www.dropbox.com/s/jitinycgas...gcode.txt?dl=0

You can see where the GCODE turns on the cooling fan using M106 at the top.

I've noted each location where I want the code to turn the fan on or off, which is at each tool change. (I also edited out all the repetitive GCODE for brevity's sake)

What you don't see is that several more times in the GCODE file (about 60 times), the GCODE runs the M106 command. This normally happens when the print shifts to a new layer.

With how the GCODE is currently generating, I cannot make the fan only turn on for the PLA and not the HIPS. This needs to change, but I can't figure out how to make it work correctly.

[uncle_bob]

Hi

Ok, I promise I will no longer participate in this thread. Trying to work through a solution in an orderly fashion is obviously annoying you tremendously.

Bob