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slic3r / Slic3r

Open Source toolpath generator for 3D printers
https://slic3r.org/
GNU Affero General Public License v3.0
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Feature request: Fan slow (gradual) start after first layer #3366

Open bssstudio opened 8 years ago

bssstudio commented 8 years ago

I would like to have the fan gradually gain speed when starting the second layer. The motivation for that is the fact that turning the fan on can cause a significant drop in hotend temperature. When printing difficult materials, this can cause a jam or under-extrusion. It would be nice to gradually ramp up the fan speed so that the hotent control loop can compensate for the additional power requirement caused by the part cooling fan.

lordofhyphens commented 8 years ago

Are you sure that your fan shroud is designed and/or positioned properly? I would not think it was supposed to be able to do that.

I had a post processing script for fan kickstart that may be adapted to this.

mrvn commented 8 years ago

I had my firmware report thermal runaway and lock up when the fan kicked in because of the temperature drop. Very annoying.

Mikk36 commented 8 years ago

A better solution is to insulate your hotend.

bubnikv commented 8 years ago

Maybe your firmware needs an adjustment to make the temperature feedback loop faster. Another solution, again on the firmware side, is to bump the speed of the temp feedback loop when the firmware kicks the fan on or off. There is really a lot, which may be done at the firmware side.

mrvn commented 8 years ago

All good ideas. All harder, sometimes impossible, too do than being nice in the gcode. As for speeding up the feedback loop that partly depends on the hardware. There is a delay between the nozzle cooling down and the temperature sensor noticing given the distance between the two. Can't speed up the feedback loop faster than that, probably needs to be a magnitude slower to work.

VanessaE commented 6 years ago

Something I would like to see is a gradual speed-up of the fan over some height. The user could, for example, tell Slic3r to start off at 10% speed on layer 5, and gradually increase to 50% speed over the course of the next 20 or so layers, staying there for the rest of the print (unless layer time or bridging demands a higher speed, as usual).

This wouldn't be to avoid excessive hotend cooling (because PID should handle that), but to avoid excessive bed cooling. Most heated beds are slow to respond to a temperature drop, no matter how well-tuned they are, and too much cooling in the first layers can cause lifting/warp.

f11h commented 5 years ago

Any news on this topic?

lordofhyphens commented 4 years ago

@f11h Nobody has decided to take it up