Hot end fan - how does/should it work?
Posted by Yamster
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Hot end fan - how does/should it work? August 05, 2013 08:21PM |
I am considering installing a fan for the hot end. I looked at some fan mounts available in Thingiverse, and I am a bit confused.
Some of them seem to be blowing air to the body of the hot end (not sure what it's called - but that black plastic thing in J hot end above the metal part at the bottom). Some other designs, however, seems to be blowing air on to the printed object...
What is the hot end fan for? It may sound silly that I am trying to get one without even knowing what it does - I just read it from somewhere it helps improving the print quality with PLA, especially reducing the warping with overhangs, which by the way is my latest struggle with my printer calibration...
Honestly, I don't know how cooling the hot end and/or printed object can help reducing warping in overhang... Doesn't warping happen when the melted plastic shrinks when it cools down and hardens?? But the again, after spending hours trying everything I know to fight this warping with no real victory, now I am willing to try anything... whether it makes senses or not
To reduce the warping, should I mount a fan to cool off the hot end, or should I install it in a way that it would cool down the printed object? Or, should I have both?
Thank you!
Some of them seem to be blowing air to the body of the hot end (not sure what it's called - but that black plastic thing in J hot end above the metal part at the bottom). Some other designs, however, seems to be blowing air on to the printed object...
What is the hot end fan for? It may sound silly that I am trying to get one without even knowing what it does - I just read it from somewhere it helps improving the print quality with PLA, especially reducing the warping with overhangs, which by the way is my latest struggle with my printer calibration...
Honestly, I don't know how cooling the hot end and/or printed object can help reducing warping in overhang... Doesn't warping happen when the melted plastic shrinks when it cools down and hardens?? But the again, after spending hours trying everything I know to fight this warping with no real victory, now I am willing to try anything... whether it makes senses or not
To reduce the warping, should I mount a fan to cool off the hot end, or should I install it in a way that it would cool down the printed object? Or, should I have both?
Thank you!
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Re: Hot end fan - how does/should it work? August 05, 2013 10:58PM |
Thanks for your reply.
If I understood it correctly, it will be ideal to have both fans, one for the hot end and the other for the printed parts, right?
I really liked it when I saw you saying "dramatically better" results. That's something I sure can use.
Now I have two more questions:
1. How much of air flow would be ideal? Will there be something as "too much" air flow? Or, since the controller will increase the current in the nozzle and keep it at the operating temperature, will more air flow simply the better?
If that's the case, I wonder if I can use a common household fan while printing some test pieces to see the effect....
2. Are there particular fans that are suitable for the job? I haven't been using this feature (because I don't have a fan) but I can see some configuration and settings in Slic3r for fan control. This makes me wonder if I need to get some fancy fan... You know, if I just use a simple DC fan (like CPU cooling fan), how would the controller know how fast it's spinning?
woodencase01 Wrote:
-------------------------------------------------------
> Fans are pushing air on the hotend when it needs
> to print PLA. PLA has a very low vitreous
> transition temperature and if it gets hot enough
> in the hot end, it might jam there. Cooling the
> hotend prevent this from happening. Most all metal
> hotends will need a fan.
>
> Also, when printing relatively small parts, the
> plastic doesn't have time to cooldown and expand
> more than it should every time a new layer is
> added.In other words, more heat get in your part
> than it can dissipate. Adding a fan blowing at the
> part will help it to cool faster. Results are
> dramatically better when using a fan.
>
> Overall, more cooling is better.
If I understood it correctly, it will be ideal to have both fans, one for the hot end and the other for the printed parts, right?
I really liked it when I saw you saying "dramatically better" results. That's something I sure can use.
Now I have two more questions:
1. How much of air flow would be ideal? Will there be something as "too much" air flow? Or, since the controller will increase the current in the nozzle and keep it at the operating temperature, will more air flow simply the better?
If that's the case, I wonder if I can use a common household fan while printing some test pieces to see the effect....
2. Are there particular fans that are suitable for the job? I haven't been using this feature (because I don't have a fan) but I can see some configuration and settings in Slic3r for fan control. This makes me wonder if I need to get some fancy fan... You know, if I just use a simple DC fan (like CPU cooling fan), how would the controller know how fast it's spinning?
woodencase01 Wrote:
-------------------------------------------------------
> Fans are pushing air on the hotend when it needs
> to print PLA. PLA has a very low vitreous
> transition temperature and if it gets hot enough
> in the hot end, it might jam there. Cooling the
> hotend prevent this from happening. Most all metal
> hotends will need a fan.
>
> Also, when printing relatively small parts, the
> plastic doesn't have time to cooldown and expand
> more than it should every time a new layer is
> added.In other words, more heat get in your part
> than it can dissipate. Adding a fan blowing at the
> part will help it to cool faster. Results are
> dramatically better when using a fan.
>
> Overall, more cooling is better.
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