In this video I'm going to prove to you beyond all reasonable doubt that this stuff here
is absolutely not household dust that gets trapped in the wheels, and I'm going to explore
what it is, and why it is, and also take a look at these.
Let's go.
Nearly all printers these days have these wheels on them somewhere, and all ender clones
do.
Of course there's other ways to propel your printer's parts along each axis but these
are popular because they're cheap, reliable, and cheap.
For those of you who don't realise they're not liquorice, they are in fact made of a
thermoplastic called polyoxymethylene which is also called delrin by those who use brand
names all the time.
Because it's a thermoplastic, interestingly, it can also be used for 3d printing, although
it rarely is, probably because it's toxic when heated and apparently is hard to get
to stick to the bed.
It's used in a lot of places you wouldn't realise though, like apparently your standard
issue clothes zipper.
Anyway - the first premise is that the wheels are somehow not the cause of the dust, which
I feel like I shouldn't waste my time proving because obviously it's not dust, how would
dust get UNDER the bed?
But let's have a look at this stuff under the microscope.
I collected the dust off the gantry where it's most likely to at least contain the most
environmental dust if the assertion is correct.
Here's the result, it kind of looks like snot after a day trip to london, but hey, we have
no measure of what normal dust looks like, so I also collected some of that off the parts
of the printer that are above the gantry, and here's that, as you can see it bears very
little resemblance to the stuff we got off the gantry.
So there we go, within what, a minute, I'm not timing it, but I've already proven that
this isn't dust.
We can pack up and go home.
But what IS it if it isn't dust?
Obviously it's from the wheels?
Yes, but no, but also yes.
I also swabbed the area on the filament reel holder which just happens to be above the
gantry, and when you look at that under the microscope?
Oh what do you know, it looks the same.
So we can't really say with a clear conscience that this is ONLY dust from the wheels, can
we?
Obviously under the bed is another matter, but this is easily solved with the second
part of the experiment anyway.
The take home here so far is that this dust is probably a combination of unknown proportions
of shaved filament reel plastic, and POM wheel plastic.
Enough of that though, let's pull this to bits and put some new wheels on.
These are brand new official creality wheels, and I have to say that if your wheels aren't
worn, which they probably aren't as you'll hopefully understand by the end of this video,
don't bother changing them.
They are an absolute pain to change.
I've also removed the filament holder and filament so it proves any dust isnt from that,
New wheels on, it's testing time.
I have a program that cycles the x axis back and forth, its the same tool as I used for
the last video where I was shaking the wheels off, but just running slower so you just go
back and forth for 4 hours.
It only took a few minutes to start seeing what I suspected, and before you jump in to
tell me the wheels were too tight, no they aren't too tight, we'll get to that.
Within a very short time they start to show this dust, a lot of it.
At the end of the first 4 hours you can see there's a lot of this stuff, and if we look
under the microscope, yep, same stuff as before.
No surprises here.
Next a simple task of cleaning up, and running another 4 hours.
At the end, same again but I think there was less of the stuff.
But, rinse and repeat, and each time there was less and less, until about the 5th run,
so about 20 hours in, I noticed there wasn't really much dust being produced.
So...why?
Well, if I bring out the fancy macro lens, and show you this cross section of an unused
wheel against the profile, you can see what you probably don't expect.
First of all, the profile matches better than we are expected to believe, both are a really
good fit.
But what you can see as you get really close is that the aluminium profile isn't actually
that well made, to put it mildly.
So what I believe is going on here, it doesn't take a genius to work it out, is that the
two surfaces are wearing into each other, or rather, the wheel is wearing in to match
the profile because it's by far the softer.
And this explains why the effect is huge at first, and slows over a very short time.
Let's have a look at the wheel after 20 hours or so under the microscope.
You can see the bottom wheel especially has a distinct line, as I move the light you can
see the ridge has a shadow.
The upper wheels have a more smooth wear profile.
The takeaway from this part, I guess, is that new wheels will wear to match the profile,
and how much that entails possibly depends on the quality of the profile, I've noticed
enders are particularly prone to it, whereas my artillery has hardly shown any POM scratchings
at all, so it does imply that the profile is more accurate, but testing that is outside
the scope of this video.
Either way, seeing a ridge on your POM wheel or wear marks, is NOT a sign they need to
be changed, unless you like changing them weekly.
Final part of the video, I took the POM wheels off and replaced them with polycarbonate wheels.
I am sure, like me, you're wondering whether these are better or worse than POM.
They are probably a lot more brittle.
They are probably a bit more brittle.
Apparently they're really not brittle.
What I found though from running the same set of tests, was largely the same pattern,
although the dust looked totally different, it looked like chalk marks on the bar.
Weird.
But again it gradually decreased over the course of hours.
Are these wheels better?
Nope, I dont get that impression.
Are they worse?
Nope, I dont get that impression either.
I didn't see, smell or hear any difference.
The only two things I think these wheels have that POM ones dont, is perhaps a longer life,
and a hatred of certain chemicals.
The former doesn't matter much as the POM ones last for absolutely ages unless you're
running a print farm, though the latter point is very important I guess if you use especially
acetone to clean your bed then maybe not use polycarbonate.
They don't mix.
I've heard it cracks after IPA exposure too but I don't use it, and I don't trust anything
I see on the internet.
Well - I think that just about wraps up this episode.
Have you changed your wheels ever?
If so, why?
Comment below.
See the description as always for discord, patreon, and any corrections as usual, oh
and speaking of patreon - from this point I'm going to trial a change that lets patreon
members see videos first without ads, I am going to experiment with it and see how it
goes so it's not an official perk, we'll see how it goes.
Otherwise I will see you next time!