Add extruder fan min_temp: option

Currently the Extruder fan comes on the instant you start the extruder heating. I would like to see the option to set the min_temp before it kicks the fan on. I already see min_temp for other fan configurations but not for the extruder. This would probably help reduce the nozzle temp time by a few seconds each print since the nozzle isn’t fighting the fan right off the bat but will have a few seconds to heat up.

There is a value that you can set in [heater_fan]:

#heater_temp: 50.0
#   A temperature (in Celsius) that the heater must drop below before
#   the fan is disabled. The default is 50 Celsius.

#Configuration reference - Klipper documentation

Maybe you picked the wrong fan setting

i am asking for it not to kick on before that temp, not after

You would need to do tests showing a noticeable difference in heating times. Since the fan should only be blowing on the heatsink, I would be surprised if the difference in heating time is more than a second or two. That makes it hard to justify investing time writing a PR and going through the process to get it merged.

Just set it to a lower temp…

ok, lets say it’s a 3 sec difference to get up to temp with and without fan, now let’s say someone has 5 printers and they print parts all day, that’s 15 sec wasted per part, on an average day they can print 60 parts 60*15=900 sec, 900sec/60 15min, so 15 min a day wasted, 15min *7 days is just over 1.5hrs a week wasted, some people have more than 5 so it can be exponentially greater. That being said, the solution already exists under generic fan, the sanity checks just need to allow it under nozzle_fan.

that would only turn if off later

When the hotend is so much influenced by the heat brake fan, then either consider to optimize this cooling or try a hotend silicone sock.

Then provide empirical data showing this time savings, and find a developer interested in writing the code. I’m just saying it’s going to be tough to find someone interested, and also to get it merged. See #2 at this link to understand why it likely won’t get merged without actual data.

If I was in a production environment where I was concerned about every second, I would leave my hotends heated just below the temperature where filament would ooze so the next print could start immediately.

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Thank you for your input but you are obviously not comprehending what I am saying.

So it seems this Discourse is only for giving reasons why things can’t progress. not for discussing why things should. I am simply asking for something that is already implemented to be carried over to another setting, not to reinvent the wheel.

All I did is tell you what information you would need to provide to get this idea considered for merging into Klipper. Simply asking for something to be added without evidence that it provides a benefit won’t result in any progress.

I personally don’t see this as a “high impact” addition, but it’s not my decision to make.

Well, it is open source. Just do it. Hand in a PR, keep it for yourself, whatever you like.

If progress means, that someone else should spend his free time and develop a feature that you would like, then as @jakep_82 already pointed out, you will need to convince this person

And he further pointed out, that it would most likely considered a niche feature with little to no impact for the common hobbyist users at which this project is targeted at.

And last but not least, my personal opinion: Features targeted at people who use open source projects commercially but usually not giving back a single penny are ranging somewhere on the very last position that I can imagine.
Here we have commercial / professional machines with maintenance and support contracts. Go for it, if every second counts.

meh. no biggie, just offering up something many have asked for that would make Klipper more intuitive and friendly than it currently is…