[What is your U2 printhead rear/back fan behavior ?]

The future modification will only be in new printers. (Current fan is wired straight to the 5V, no way to control it) But the update is a bit delayed due to some problems with a tiny layout change causing changes on the motor current.

Funny how small things can have so much effect.

The fan control is already in the firmware now:

https://github.com/Ultimaker/Ultimaker2Marlin/commit/d85409f22204c606a331f49a83d31745b3d961ba

I understand the fan is a 2pin 5v fan ?

Can you provide me with the dimension of the fan, 25mm x 25mm x7mm ?

 

The easiest way to control the fan is with a PWM signal so I probably need to replace the fan for a 3pin fan.

 

Thanks

 

[What is your U2 printhead rear/back fan behavior ?]

Why would you want to go to the trouble of doing this? Daid already mentioned that UM is likely to change the fan to be controlled at some point in the future... but what's the advantage to not just leaving the fan on full time? Especially as a non-standard modifcation?

Yes but as Daid mentioned you need to upgrade your electronics board for the newer revised version, and I guess that electronics board will not be cheap.

Also I want to do this upgrade because my fan is making a annoying high pitched sound (I'm in the same room as my printer). During printing this is not so much a problem but when a printed object is cooling down it is some what annoying. I can shut off the printer but most of the time I want to run another print job and I'n not a big van of setting devices on, of, on, of all the time. The fan probably needs some lubrication or I can simply replace it, but I also want to experiment with some Arduino based microcontroller boards so I find this a nice project for that.

The idea is to program a Trinket microcontroller that reads the temp from a NTC thermistor and translates this into an appropriate fan speed or even completely shuts of the fan (when your not printing). And this will be much cheaper and more fun than replacing the main electronics board

 

[What is your U2 printhead rear/back fan behavior ?]

Why is your font small?

The back fan keeps the upper portion of the head at a cooler temperature. There are parts there that can't withstand temps of 260C. But the more important reason is if PLA gets over 50 or 60C it gets soft and can expand under the very high pressures (around 3-5kg) and will fill the area and cause a clog or jam.

Every time you retract, you move heat upwards a little bit - each time you retract filament it moves the previously moved heat a little higher. Plus hot air rises. Plus everything conducts heat somewhat. So you have to keep the upper part of the head below 50C.

Not as important for ABS which has a glass temp of around 100C.

Thanks for your quick reply!

I ask this because I'm considering making a independent temp sensor driven back fan.

The idea is to add a NTC thermistor (temp sensor) to the printhead frame that will adjust the fan speed according to the temperature and also turns the fan off if the temperature is low, like when there is no print job running.

Can you tell me if the 3mm (M3) screw hole between the print nozzles wil be used in the future (for example dual extrusion kit) because that would be a perfect spot for a M3 screw-type NTC thermistor?

Thanks!

 

[What is your U2 printhead rear/back fan behavior ?]

Can someone explain the purpose of the back fan on the printhead.

By the looks of it keeps the main printhead frame on the right (low) temperature ?

 

[What is your U2 printhead rear/back fan behavior ?]

Ok thanks for the reply’s, I think that the fan on my first U2 was indeed not working properly than.

 

[What is your U2 printhead rear/back fan behavior ?]

I have received a replacement printer (Ultimaker 2) after my original broke down (great service).

 

One thing I noticed about my new U2 is that the small fan on the rear/back of the printhead is always on full speed from the moment I turn on my printer. On my first Ultimaker 2 this was not the case, it went only on when I started a new print and went of when my print was finished. And even during printing it was not always on full speed. It looked like it was self controlling through a sensor or something.

 

I contacted the Ultimaker support and they said it’s normal that this fan is on full speed from the moment you turn on your printer. Because I’m 100% sure this was not the case on my first U2 I have my doubts, so are there more Ultimaker 2 owners that can confirm that the small fan on the back of the printhead is always on full speed from the moment you turn on your printer ?

 

Thanks!!