Re: Improved fan shroud / nozzle
... I think PJR's smaller approach design is the key (air pressure), while using a scientific approach like in Sebastian's shroud is what will seal the deal.
Clarify please. Smaller design is key, scientific approach will seal the deal.
Are you saying you like the small design format but would like to see it actually engineered? ie: flow rates, from each side. cooling potential etc.
Or are they so close in performance, you don't really have a clear preference?
Re: Improved fan shroud / nozzle
... I think PJR's smaller approach design is the key (air pressure), while using a scientific approach like in Sebastian's shroud is what will seal the deal.
Clarify please. Smaller design is key, scientific approach will seal the deal.
Are you saying you like the small design format but would like to see it actually engineered? ie: flow rates, from each side. cooling potential etc.
Or are they so close in performance, you don't really have a clear preference?
I think PJR's design is smaller and has better air pressure (I can't really test the flow rate but it feels a bit faster), but Sebastian's shroud has the ideal curves for optimal air flow.
I've kind of given up hope as far as making the stock fan perform better. Maybe something super small (about the same size as the stock) that diverts the air so it flows on both sides would be good. If you look around most of the heavily modified printers that have really good cooling use two fans aimed quite a bit away from the hotend, so perhaps the designs in this thread are also too close to the hotend. Then again, I'm not sure if these shroud designs would make a big difference or not with higher temp materials as my testing was done with Prusa's Silver PLA.
After a few days of obsessing over this it felt like too much effort for too little a thing.
Re: Improved fan shroud / nozzle
I've kind of given up hope as far as making the stock fan perform better. Maybe something super small (about the same size as the stock) that diverts the air so it flows on both sides would be good. If you look around most of the heavily modified printers that have really good cooling use two fans aimed quite a bit away from the hotend, so perhaps the designs in this thread are also too close to the hotend. Then again, I'm not sure if these shroud designs would make a big difference or not with higher temp materials as my testing was done with Prusa's Silver PLA.
After a few days of obsessing over this it felt like too much effort for too little a thing.
You maybe want to try this one. https://www.thingiverse.com/thing:2578649
Works pretty well, for me at least.
I have to say that my hotend is equipped with a silicone sock which in any case is a good idea.
There is a nice mold available on thingiverse to make those yourself.
Have a look at my make https://www.thingiverse.com/make:384804 where I made a picture of the silicone stuff.
Should be available by some other brand everywhere...
Re: Improved fan shroud / nozzle
You maybe want to try this one. https://www.thingiverse.com/thing:2578649
Works pretty well, for me at least.
I have to say that my hotend is equipped with a silicone sock which in any case is a good idea.
There is a nice mold available on thingiverse to make those yourself.
Have a look at my make https://www.thingiverse.com/make:384804 where I made a picture of the silicone stuff.
Should be available by some other brand everywhere...
I won't get a sock right now, but for future reference have you compared your mold sock vs an ordered one? I feel cheap for saying this but the molding stuff would cost me $30+ but a premade one (this one https://e3d-online.com/v6-sock-3pack ) would cost me quite a bit less, even if the shipping is insane. I could use the silicone molding stuff for other things too I guess.
Re: Improved fan shroud / nozzle
The self made sock should be no big difference to the bought ones.
And the fan duct should even work well without sock although in this case
a PID calibration with the fan running would be no bad idea.
Re: Improved fan shroud / nozzle
I have made my own tests with different air outlets on my printers.
I have tested the air outlet that you guys have come up with for almost a year now on my E3D Titans on my MK2s.
S+E had made this quite some time ago, and i've been using it since. https://www.thingiverse.com/thing:2065461
But S+E's outlet that is similar to yours is not optimal as well.
S+E's outlets point directly at the nozzle frem left and right, and work well fro some overhangs, but not all.
I have tried adding a front air outlet to this cooling part, as seen here:
https://www.thingiverse.com/thing:2728443
still not optimal
Im having some overhang problems with this:
https://imgur.com/a/PiijE
It seems the extruder moved away too fast before the cooling was done. Slowing down the print to a crawl didn't help either.
From what i can see there needs to be two things for cooling the plastic as quickly as possible:
- a small pressure outlet directed at the nozzle opening. this helps cooling the plastic drown from lets say 220 degrees to 150 or so degrees.
This air from the pressure outlet is gone when the extruder moves away. Edges will warp and filament layers will curl upwards towards where the most heat is, the extruder block.
- a wide air outlet that takes over when the print head moves away to cool down the plastic even more, to the point where it stiffens.
now there is a wide and constant airflow around the nozzle that cools the plastic that has been layed down a few seconds ago.
A guy has come to the same conclusion here:
http://www.desiquintans.com/coolingtests
http://www.desiquintans.com/coolingtests2
A 'sharp' and a 'wide' air outlet should be used, there is nothing better.
Prusa's stock MK2 air outlet is pretty good, because it's wide open and has some good pressure.
The stock MK3 should even be better, because it's wider and there are still areas that point directly at the nozzle opening. Sadly, all of the MK3 air outlets melt from a design failure on Prusa's part.
After i had problems with 45 degree overhangs i have taken a wirecutter to my own fan nozzle remix to widen the air outlet on the air outlet.
As seen in the picture, i went from directed pressure outlets to a wide airflow.
From what i can see, it works better than before, but i am still testing.
I can now print a few things better that gave me dented in overhangs before.
Re: Improved fan shroud / nozzle
@devilhunter
It is interesting the notion of wake cooling (don't know what else to call it). Lets see, filament in nozzle is in expanded state. It extrudes molten plastic in an orderly fashion at a prescribed speed. As thermal buildup avoidance isn't part of firmware, only strategy is to cool just away from the nozzle then gradually taper off. In a perfect world, with infinite funds and too much time on one's hands...best would be to have an articulated "wake" cooling just behind motion of nozzle. Why? Shrinkage is unavoidable due to material science of plastics. Everything shrinks when cooled, everything. But, you can mitigate bulk shrinkage which we see as curling by flash cooling so thermal build-up won't allow large areas to cool and accumulate shrinking forces. So, localizing wake cooling/shrinkage means only small areas "curl" but as successive layers correct prior, overall, the print looks fine. Something like that?
MK2S kit owner since 8/15/2017
Re: Improved fan shroud / nozzle
[/quote]
I won't get a sock right now, but for future reference have you compared your mold sock vs an ordered one? I feel cheap for saying this but the molding stuff would cost me $30+ but a premade one (this one https://e3d-online.com/v6-sock-3pack ) would cost me quite a bit less, even if the shipping is insane. I could use the silicone molding stuff for other things too I guess.
[/quote]
Has anyone fitted this option to the MK3 to see if it fits or if it hampers the MK3 in any way?
Re: Improved fan shroud / nozzle
I took the extruder cover for the mk3 and merged it with the mk2 one, so that you can use the mk3 fan shroud on the mk2. Here's a thingiverse link
Re: Improved fan shroud / nozzle
How has this conversion been working? How is the visibility of the nozzle from the sides?