UM2's small cooling fan

[coffeecup 1]

It seems the small cooling fan is not strong enough to cool down the steel/aluminum assembly. Did anybody ever try to mount a 2nd cooling fan? Thanks.

Note: I am talking about the small cooling fan, not the two bigger ones.

 

[IRobertI 520]

It's not meant to make the whole assembly cold. The purpose is to create a sharper temperature transition for the filament so that it doesn't clog.

Are you having issues with your prints?

 

[ian 32]

correct as Robert said.. the small fan is blowing a concentrated wall of cool air onto the hotend to stop the heat from traveling from the heating cartridge up the hotend... possibly allowing for the PLA filament to expand in the Bowden tube and stopping the flow of material.

So a bigger fan for this purpose is not needed !

Ian :-)

 

[coffeecup 1]

Thanks for the reply. I suspect that the PLA filament does expand in the isolation teflon part and causes the under-extrusion problem. I do not have any proof yet though.

The performance of the cooling fan, I suspect, will degrade when the printer becomes older. It will complicate the situation.

 

[ian 32]

im not sure that the fan will become worse with age.. but I do know ultimaker is working very hard on developing the teflon part in the hotend !

Ian :-)

 

[coffeecup 1]

Do you mean they are developing a new teflon part to replace the original one? Thanks.

 

[gr5 2,172]

While the UM2 is printing you can place your finger on/inside the head so that the tip of your finger is touching the heat sink and the side of your finger is almost touching that ring with the holes in it. If you "stay loose" you can "surf" the head as it wiggles around. It's not very hot. At all. It's a pleasant temperature, nowhere near the 220C that the nozzle is at. So it seems to work very very well as far as I can tell.