If you've ever tried to print
with something like this 70A TPU you'll know that it's not easy or quick, you have to tune your
printer especially for it, and if it will even print it, you have to do it very very slowly.
What if you could get the same result,
but using a stiffer filament like this 95A from noulei? Nonsense, obviously. But here
is a thing that claims it can do that. This is varioshore from colorfabb...let's go.
This video is sponsored by PCBWay.
Colorfabb is nearly impossible to get hold of in the UK and it's not cheap either when you do, I
bought this myself, and that would be with patreon donations, so thank you to those who do support
the channel and allowed me to buy this stuff and the other test equipment you'll see used here
So...what is this stuff? And why am I asking rhetorical questions when
I obviously already know? Or do I? Am I just reading the spec sheet on the fly?
Basically...the claim is that this starts foaming at 230C. So if you
print it at 220C it acts like normal TPU, which it doesn't, but if we're entertaining that idea,
at 230 onwards the stuff foams, which means its volume increases by 40-60 percent.
If you think that through, it's not obvious at first what you would do to leverage that,
because why would you want your part to be 40-60% bigger I'll show you a half printed block that's
40-60% bigger, this is not really ideal is it, but if instead of trying to foam it like that, if
you actually underextruded it by 40-60% then what you have is less material put down but because it
expands to fill the gaps, you get around the same volume. In theory. And colorfabb thinks
that will give you a lower shore reading. And we're going to see if those claims are true.
So I printed varioshore on the sovol SV07. Well, not exactly. I started printing it on the creality
K1 but that idea went...out of the window pretty quickly. The K1 is in my experience a great
printer, review coming soon, shameless affiliate link below..but it's not a TPU machine, at least
not for 92A which this filament states as its off the reel hardness. You see, none of
these corexys really are. They have these silly tubes that go from the reel to the hotend which
for some reason we decided to call reverse bowdens, those increase the incoming friction
a lot. for clarity you can overcome this, this isn't an unsolvable problem, but, this is why
there's still a place for the bed slinger in your printer collection, like the SV07 here,
it prints TPU perfectly, and I used it for all the varioshore tests because I had only one reel
of the stuff, and, full disclosure I do have connections to sovol and they are a sponsor
and patron of the channel, but not one of the I think 30+ test prints I did failed in making this
video. Not one. Shameless...affiliate link below..I will say no more.
We should stop waffling and start testing I suppose, or else this will be another
15 minute video and I hate editing 15 minute videos. To test the shore hardness I have this
impenetrable box, which is practically a meme at this point on the channel...
...if you haven't seen this before, this is a shore durometer, you poke
it into the sample and it tells you the shore hardness in As. That's the unit of measure,
the A. To measure properly you need a fully solid block and you have to push it firmly in
on a flat surface and wait a known amount of time, so I have a test print that is
literally a solid block that complies with the shore hardness test standards,
it's not very exciting, but I did write squishy on the side, what more do you want, these are
printed with 100% infill, and for the control case since TPU always underextrudes by default, it's
printed at 105 percent flow rate at 220C which is supposedly below the foam point of the varioshore.
This is very very solid. We should let the meter do the talking though. It's supposed
to be 92A. It's not. It's about 91 and a half. I'll allow it. I'm feeling generous.
Anyway, this stuff foams at 230 so I did ...a whole bunch of tests..
...a lot of tests. Each of these took an hour to print, so...that was fun.
And then I measured the shore hardness of each one, recorded it, and plotted it.
And that gave us...today's sponsor. Well, no, it didn't, but today's sponsor is PCBway who
can in fact print flexible materials for you, look, flexible resin prints,
without having to get into resin yourself. You can see that for this material, as with all materials,
the flexible properties are available, here you go, 60-75A shore hardness, that's really soft,
this is equivalent to something like filaflex which is a specialist TPU for FDM, that would
be cool to see I think, maybe I'll ask for something made in that and sent to
me, and we can have a literal poke at it with my meter, comment below if you want to see
that and I'll make it happen. You can also get TPU made which is done by SLS not FDM,
so that would be cool to poke at too, that is also 65A, also what's a poisson ratio?
I think you're getting the idea here that PCBWay is giving you all the info you need
to choose the material you want for your own designs, and it's simple to access this data by
just clicking the link that says show material description and there's a tonne of info there,
so all you have to do is upload your stl, choose your options and send,
and they will do the rest while you sit back and watch more of my videos, so it's a win win really.
Check the description below for links to PCBWay and thank you pcbway for sponsoring this episode.
So the plot...here it is. That's some cool glowing lines too, excel has come a long way. The keen
observer, assuming you're still awake, will notice that this is linear. It's always a surprise when
a relationship is linear but I think I know why. Tell me in the comments if you think you know why,
we'll see if we both think we know why for the same reason. But, it is linear.
I also have some new fancy scales that measure some ridiculous fraction of a gram,
so I can plot the weights of the test pieces too. This is probably
going to give you a strong hint as to why the relationship is linear.
Interestingly if you haven't already noticed,
the colour changes as it foams, this is documented, and expected.
The fun thing is, colorfabb's specs claim that the filament has an operating range of between
100% and 60% flow rate which translates to a shore hardness of, well, the claim is a bit
vague. I think the 55A maximum foamed is probably theoretical, I don't know how they've worked that
out, but to achieve that, you need to exceed their operating range a bit, but you can. And you can go
further, you get reasonable layer adhesion and integrity down to maybe 40A in my experience
but it depends on your model, probably depends on overhangs a lot too. I noticed that beyond this,
you can still print, but you start to see the walls delaminate from the infill.
There is a solution to this, the infill overlap... here in cura...can be increased
to compensate. It's easiest to go down to one outer wall so that you don't have to worry
about the walls delaminating, there are ways to fix this but I don't have room in the margin of
this video to explain, and anyway you wouldn't be doing this if you didn't want a softer part,
and a single wall will achieve this. You can surprisingly go right down to 20% flow rate
and retain structural integrity - notably that's on these test blocks - real world use might not
be so forgiving, almost certainly won't. This part is insanely light and soft, for something
that is at least mostly a solid block, using the term solid to mean has been printed with
100% infill. Although I imagine there might be gaps internally. I wouldn't advise printing this
far out of spec for anything functional, but it's interesting to see that you can.
This is kind of a rabbit hole in fact. For curiosity's sake I tried doing some flow
rate reduction with normal TPU and found that even though normal TPU doesn't foam,
it does behave similarly when you reduce flow, you can reduce the
amount of material a fair bit before the same thing happens, with the walls delaminating.
So, I think we can probably assert with some level of confidence that when we look at this graph, you
probably have a foaming section where the foaming TPU is filling the gaps efficiently, and then
a section where integrity is maintained but the additional gaps are being essentially filled with
air. I can't prove it, but I can take some macro shots which kind of proves it, here you go...
In terms of practical uses, well, this is actually huge. You can dial in your shore hardness within
the range of 92A to about 50A by just reading a graph and setting your flow rate and temperature,
this is a game changer, like, an actual game changer not just a youtube thumbnail game
changer that turns out not to be a game changer. Here's two rabbits. Nothing changed other than
one is here on the graph, the other is here. And one is softer. Heres two test pieces with
a weight on them. This is pick your own shore hardness. Not just that, this is printing 50A
shore hardness on FDM. Have you ever tried to print 50A on FDM? No you haven't. Why? because
it would be near impossible. This is recreus filaflex, it's 70A, this stuff goes down to
60A and it is near impossible to print at 60A, it's hard enough at 70A. But now you
can just print it. Like, you can just print it on an ender3 probably. Most direct drive
printers without reverse bowdens will be able to print this reliably.
So there you go, that's varioshore. I normally do a summary but I think
that rant was the summary. What do you think? Let me know in the
comments. Otherwise I will see you next time, thanks for watching!