Many people have asked me if I've tested different cooling ducts on the filament
cooling fan of my Ender three or of the CR 10's and I have. And I don't see a
major improvement. In fact I'm not sure you need a cooling fan at all if you get
the settings right in your slicer. I'll show you what I mean
on today's Filament Friday.This episode of Filament Friday is brought to you by
these patreon supporters. I've seen other YouTube videos where they print a Marvin
keychain with fan and then no fan and compare the two and saw a big difference.
So I'm going to use the same file. Everything in red is underneath or
overhang where it could be a problem so I'm going to use my magic 0.2 profile in
Cura 4.0. 3 outer layers 3 top and bottom layers, 10% infill. I'm going to
print at a 50 millimeters per second which will automatically make the wall
speed 25 millimeters per second. The cooling section of my profiles where
some of the magic happens. Cooling is where you set the fan speed. 100 percent
is what I typically use and you can turn it on and off with that checkbox. Minimum
layer time is a key parameter. I have it set to 10 seconds and what this means is
each layer has to take at least 10 seconds. That gives it time for the
filament to cool if it projects it's gonna take less than that. Because it's a
small print or a small area, it'll slow down the print and when it slows down at
what speed does a print? Well it depends on how long it takes to get to that 10
seconds. I'm printing at 50 millimeters per second, outer wall 25 millimeters per
second but if it's gonna take longer than that it'll slow down. But I set a
minimum to never drop below 10 millimeters per second. That's what minimum speed
does. If you check the lift head box it'll actually move to the side and wait
but I don't recommend that, that'll just give you some stringing. Now that we have
those let's slice this guy and see how it looks. It says it's only going to take
22 minutes to print and when I go into the preview mode you can see a lot of
this is blue or 10 millimeters per second which is my minimum print time.
Inside it's green where it's closer to the 50 millimeters per second but this
outer area and also the little hook is going to hit that minimum time because
is a very small print. I'll print one with the fan on and then I'll uncheck
the box and slice another one with the fan turned off but you notice minimum a
later time and minimum speed are both still enabled. So they're still used even
when the fan is turned off. So I'll print one of each and see how they compare and
if you're not familiar with which fan I'm talking about it's the one here on
the side. Notice the fan is not spinning on this print. This is the one that's
turned off and here's the results. The one on the left is no fan the one on the
right fan at 100%. And I'm telling you I can't tell these two apart. They look
identical. Even underneath they're the same. Now those were very small prints so
they hit that minimum layer time. Let's up size it to 300% so it's much bigger
and hopefully we don't hit those minimum layer times and we'll see what it does.
So I'm gonna slice it, obviously takes longer to print now. When we look at
preview mode you see it's a lot of green for the outer layer so that is our 25
millimeters per second outer wall. The top here, the hook is still blue so
that's hitting the minimum time but everywhere else is basically our inner
wall speed. And inside we're seeing closer to the 50 millimeters per second.
And now let's compare these no fan on the Left, fan on the right and once again
I don't see any difference between these two. The slicer has taken care of it. At
the bottom of it, sags about the same amount. The fans not helping me that much.
Bridging is another area where fan comes into play more often so this is a
hundred millimeter spread test print. I'm gonna use my point two magic layer
height. I'm gonna do six top and bottom layers so a little bit thicker. 10% fill
same speeds fifty millimeters per second and twenty five millimeters per second
outer wall. And I'll use the same cooling parameters and I'll have one with a fan
on and one with the fan off. And we'll see if there's any difference. And here's
the first one. This is the one with no fan and there's definitely some sagging
in this 100 millimetre bridge. It's really not that bad though. I've seen
worse where it sags all the way down to the bottom. So these settings are working
pretty good but now let's compare it to the one with the fan. And here's the one
with the fan. I notice it's a little bit better but not a lot better. I'm still
getting some sagging. It just seems to start a little bit later but it's still
not acceptable to me. I would use supports like what I've showed in a previous video
ow I do supports and I'll run through it quickly here. I'm gonna go just from
touching the build plate I'm gonna use a zig-zag pattern. I'm gonna use a Z
distance of point two or one layer height between the top of the support
and the bottom of the print and I'm also going to use a roof and a bottom layer.
So I'm gonna pinch the zig zag between the two layers and then when I slice it
you can see here's my supports and you can see there's a zigzag. And then as I
go up you'll see it creates a nice roof and then there's a gap from here up to
the actual bridge itself so it should support it but still be easy to remove.
So let's print this and see how it looks. And here's the result and literally this
is the way it came off the bed. They came right apart I didn't have to break
anything off. That support structure is strong it held itself and look at the
bottom of this thing nice and smooth no sagging at all. So why rely on a fan when
I can do the same thing with supports. I know the Creality fan isn't
the best. And I can get a better fan with those dual ductwork and get more
air blowing down on the filament but my point is if you're really relying on
that to get better prints maybe check out the slicer settings. And I share all
my slicer settings, there's a link in the description below. And I also have a