Hello 3D Printing Friends! Today on the BV3D Channel, I'm gonna have an update on
my Ender 3 Pro review. Stick around and we'll get into it, right after this.
I'm Bryan, and you... are watching BV3D!
Hi everyone welcome back. In my recent Ender 3 Pro
review video, I mentioned that thermal protection features were enabled
on the printer and it turns out that that's true to a degree, but not to the
degree that I thought. I had a comment on the video which said, "To test for thermal
runaway protection you have to heat the hot end up, and then remove the
thermistor. If thermal runaway protection is enabled, it should trigger a thermal
runaway error in less than a minute. It's not the same as a MINTEMP error."
And that comment is absolutely correct. What I tested was the ability of the printer
to respond to a situation where there's no longer thermistor input coming into
the mainboard at all. But that's not the same as being able to detect a thermal
runaway condition. A thermal runaway condition is one where the ability of
the printer to accurately measure the temperature of the of the hot end is
compromised in some way. So for example, as the commenter pointed out, pulling the
thermistor out of the heater block is going to cause the temperature reported
to the main board to drop. If thermal runaway protection is enabled, the
printer should recognize the fact that although it's providing power to that
heater cartridge (and is it's actually heating up) it doesn't feel it heating up.
the thermistor doesn't tell it that it's getting hot. And so in that situation, if
a certain short amount of time elapses where it's trying to heat up and it
doesn't see the temperature increasing as rapidly as it should increase, it
should shut the hot end down and declare a thermal runaway condition. So I'm going
to test thermal runaway protection in the firmware of the Ender 3 Pro. I'm not
going to do it by removing the thermistor from the hot end. Instead what
I'm going to do, is I'm going to unplug the heater cartridge from the mainboard,
and connect in its place a voltmeter. And so what I want to find out is, if we
tell the printer to heat up, and it can't get above 30-something degrees, which is
the ambient temperature in the room that I'm in, will it throw an error, and will
it cut power. And we'll be able to see it cut power, because we'll be watching the
voltage that it's outputting. When it's trying to heat the cartridge,
it'll be outputting 24 volts, and we'll be watching for that. The reason I'm
doing that is I don't want my hot end to overheat and melt down, if I let this sit
for five minutes or so. If the hot end has power for five solid minutes, it's
probably going to be a smoking mess. I don't want to have to replace anything
on it, so I'm gonna do this. I have removed the mainboard from the box,
it's sitting out on the side, and I've got my ancient voltmeter here. So I'm
gonna go ahead take my screwdriver, and I'm going to unscrew the terminals. And
these are the wires that go to the heater cartridge on the hot end. The
printer will no longer be able to heat that up.
And so in place of the heater wires, I have inserted the probes from my
voltmeter. We're gonna have fan noise; we're just going to have to deal with that.
So the printer is reporting the hot end at 29 degrees. And so I'm going to
set it to 200, and we're gonna watch this. I'm gonna zoom in on this stuff. So we're
gonna watch that.
Going to control, then going to temperature, and going to
nozzle. And I'm setting that to 200 degrees... well, 199, close enough. All right
so I'm recording a close-up video with my iPhone here and this has actually
been going for quite a while. It's been going for a minute that I've been
recording, and it was going for 2 or 3 minutes before that as I was trying to
get the camera aligned. And we're still pushing 24 volts to what would be the
heater cartridge; at the moment that's a voltmeter. And the printer is showing no
signs of wanting to shut anything down, even though its trying to get to a 199
degrees set point, and its thermistor is only
reading 29 degrees. Well, there you have it.
Definitive proof that thermal runaway protection is not enabled on the Ender 3 Pro.
That makes me sad, for a couple of reasons. One, I expected better from
Creality; and two, I expected better from myself.
I tested for MINTEMP, but I didn't test the full thermal runaway protection
scenario, and I should have. And so for that, I apologize.
Well, that's about all the time I've got for this quick update video. Thank you
very much for making it all the way to the end, and thank you very much to those of
you who subscribe, who like, comment, and share these videos. I really
appreciate that, especially... ESPECIALLY that comment on the Ender 3 Pro
review video, that pointed me in this direction. So, like I said, that's about
it. If you liked the video, give it a thumbs up. If not, give it a thumbs down,
but either way, please leave your thoughts in the comments. And if you like the content
that I'm producing, please consider supporting the channel with a one-time
micropayment. You could buy me a coffee, or leave a little something in the PayPal
tip jar. Links for both are in the description. Well, now that I know I don't
have thermal runaway protection enabled on my Ender 3 Pro, time to research
getting Marlin on there. I'm gonna go do that, you go print something cool, and I
will see you next time!