UM2+ Heat creep problems

[Emonster997 0]

Hi all,

 

I've been having issues with my new ultimaker 2 go since it arrived. I think I have pinpointed the problem to be heat creep but don't really know how to proceed.

 

I'm using:

- Ultimaker silver metalic pla

- 200 degrees print temperature

- 40mm/s print speed

 

Last night my print failed halfway and after a few searches this seems to be an indication of heat creep. The air in the nozzle as seen in the atomic pulls supports this.

 

In the first week I already experienced these problems and replaced the heat block, nozzle and ptfe coupler. Two weeks later the ptfe coupler looks just as bad as the one I replaced.

 

The fan that cools the heatsink appears to work fine and switches on as soon as the temperature reaches 40 degrees. It is also clean and not obstructed. When holding my hand near it however I don't feel any air blowing so I suspect it might not be powerful enough. It is however the fan that the printer shipped with so I expect that it should work.

 

If anyone can point me in the right direction that would be greatly appreciated!

Edited January 18, 2022 by Emonster997
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[geert_2 557]

That coupler definitely needs replacement. It is hard to see on photo, but it looks like its outside has swollen too? Normally it is only the inside that gets deformed by the pressure and temp of the molten plastic, and the contact surface that gets burnt from contact to the hot end.

 

I think you should have a closer look at the fan again? Nothing blocking the air flow? No piece of plastic or other obstruction blocking the air flow? You should feel some flow.

 

Else, also try to check the nozzle temperature? Is the nozzle temp okay, not too hot? For example if the sensor would be sitting too loose and not make good contact with the block? (Be carefull, don't pull on the sensor wires, they might break.)

 

[my3DBr 4]

I would check the feeder.

[Emonster997 0]

20 hours ago, geert_2 said:

That coupler definitely needs replacement. It is hard to see on photo, but it looks like its outside has swollen too? Normally it is only the inside that gets deformed by the pressure and temp of the molten plastic, and the contact surface that gets burnt from contact to the hot end.

 

I think you should have a closer look at the fan again? Nothing blocking the air flow? No piece of plastic or other obstruction blocking the air flow? You should feel some flow.

 

Else, also try to check the nozzle temperature? Is the nozzle temp okay, not too hot? For example if the sensor would be sitting too loose and not make good contact with the block? (Be carefull, don't pull on the sensor wires, they might break.)

 

Thank you for your advice.

 

The coupler is only 2 weeks old though and I can't figure out why it gets so bad so quickly. I replaced the previous one that looked pretty much the same and was also only 2 weeks old so I'm getting the feeling there might be some other problem.

 

Having taken another look at the fan it appears to be just fine. Paying a bit more attention I do feel some flow so that all seems to be working.

 

The temperature sensor also appears to be working correctly. When idle it displays room temperature, I'm able to do atomic pulls at 90 degrees and filament starts melting and drooping a little at 220 degrees. I was also printing at 200 degrees which is on the lower end for this pla (195 - 240) so I don't think the nozzle could be too hot to cause problems.

 

If you have any other insights I would very mucha appreciate it!

[geert_2 557]

Is that an Ultimaker coupler? If not, if third party, maybe it is not temperature resistant enough? Or a bad batch? It should not deform that fast. So that could also be a possibility?

 

The newer couplers (TMF, MTF, or whatever their name...?) do also fit and should be a bit more temperature resistant. They have a slightly different color, a bit more translucent.

 

If the flow of a fan is difficult to feel, you can often show it by holding a thin paper in front of it: the paper should deflect or blow away, or be sucked onto the fan, depending on its flow direction.

 

But I am still thinking in the direction of the sensor not right, or giving bad contact. At room temp it could still indicate the correct value because everything is at room temp then. But if it does not give good enough contact, it might not feel the heat. Just guessing of course, I don't have "remote viewing"... If you could find a multimeter with thermocouple that you could insert into an empty nozzle, it could show if the sensor is working correctly. Otherwise I don't know how to exactly verify it?