Fan speed?

[chrisr 18]

At small fan speeds like 20%, the fans won't start at that %

If I give them a little encouragement (with my finger) they'll spin up and then stay turning.

Or, I'll very briefly dial them in the UM2 tune menu to 40% as a "kick" to get them turning and then drop back to 20% where they happily keep going.

Suggestion:

Could Cura incorporate a very brief power "kick" to get low fan speeds reliably started?

 

[mnis 11]

I think some kind of Kickstart is already integrated in Cura v14.09 and the fans should already run below 25 percent. Anyway, in previous Cura software it seemed to me rather that the fans only started above 25 percent.

Markus

 

[chrisr 18]

Ah. I'll try 14.09, I was using 14.07 for some reason & I forget why... (something about retractions?)

Perhaps the "kick" duration needs to be made just a little bit longer then to get the fans reliably started? They will spin at 10% quite happily (on my UM2) but just need encouragement to get going. Perhaps the "kick" time just needs to be extended by a little bit? 2 or 3 seconds perhaps?

Edit: 14.09, 14.11 no different

 

[mnis 11]

I think for such low rpm there is really no need, or is it?

But in the Cura-Expert Settings> "Cool", it is possible to set the minimum starting speed, for example, to xx percent.

With these settings I am quite satisfied:

Fan full on at height 3mm

Fan speed minimum 25%

Fan speed maximum 85% (... because otherwise it rattles at 100 percent)

The other settings I have left as Default.

Probably a kickstart for low rpm will not work reliably on each machine, because of the fan-manufacturing tolerances.

Markus

 

[opit78 0]

I think for such low rpm there is really no need, or is it?

But in the Cura-Expert Settings> "Cool", it is possible to set the minimum starting speed, for example, to xx percent.

With these settings I am quite satisfied:

Fan full on at height 3mm

Fan speed minimum 25%

Fan speed maximum 85% (... because otherwise it rattles at 100 percent)

The other settings I have left as Default.

Probably a kickstart for low rpm will not work reliably on each machine, because of the fan-manufacturing tolerances.

Markus

 

I think you don't understand what minimum and maximum fan speeds are doing.

"Fan speed minimum" is regular speed at which your fans gonna spin all the time till "minimal layer time (sec)" is reached, then they gonna speed up (to 85% in your case).

"Kick" could be fully customisable. Duration of "fan kick" and speed % needed so everybody could tweak that to its own printer.

That would be very handy IMO. We're using two UM2 printer, each printer has different fans fitted, one starts spinning at 15% were other need at least 35%. We're getting different results while using the same gcode.

 

[mnis 11]

Thank you opit78

I had thought that fan speed minimum, is a setting to allow the fans never run below the set value. But fan speed maximum always limited the maximum fan speed, so perhaps the mental confusion.

Markus :oops:

 

[opit78 0]

Not you only have got confused with this, no worries