Oh, I need a coffee!
What the….?
In today’s video, I’m going to show you
how you can use your 3D prints at higher temperatures.
Guten Morgen everybody, I’m Stefan and welcome
to CNC Kitchen.
So before I start a short disclaimer.
I did not drink the coffee since the material
is not yet rated for being food safe and I
also don’t recommend anyone to 3D print
pressure vessels especially ones that contain
boiling water.
The purpose of this video is to show you that
3D printing is more than printing fidget spinners.
If you know your application and have chosen
the suitable material you can do pretty cool
things with it.
So I’ve been testing the Formfutura Volcano
filament for a couple of months and was looking
for a cool application that can demonstrate
the exciting properties of it.
I’m a hobby barista myself and thought 3D
printing a moka pot would be something really
cool which I’ve never seen so far done by
anyone.
I went for the classic and iconic octagon
design which was designed and invented by
Alfonso Bialetti in the 1930s and mass produced
after WW2.
Even though many people especially here in
Germany call it an espresso cooker it actually
brews moka.
The distinction is that in such a cooker the
brewing pressure is only up to 1.5bars and
not the around 9bars that you need for a real
espresso.
Its design is actually pretty simple.
It consists out of a bottom chamber which
is filled with water, a funnel with a sieve
that contains the ground coffee and a collection
chamber.
When the water is heated and comes to a boil
the steam creates pressure in the bottom chamber
forcing the hot water through the funnel and
the coffee up to the collection chamber.
So when we want to 3D print it we do not only
need to cope with the temperatures but also
the stresses which are created by the pressure.
Also, since it is a multi-part design and
needs to seal, all the parts need to have
tight tolerances.
Formfuturas Volcano filament is a modified
PLA.
Normal PLA severely softens at around 60°C
and that is also the same with the Volcano
filament.
But there is a way to beef up the properties
of actually all PLA filaments, which is called
annealing.
I did make a video about this process a couple
of weeks ago.
There should be a link plopping up in the
upper right corner if you want to learn more
about the details.
Annealing PLA means that you put the printed
part into an oven at a temperature of around
100°C, for the Volcano filament 110°C to
be precise, keep it there for 20 to 60 minutes,
depending on the thickness of your part and
then slowly cool it down to ambient temperatures.
During that time, the material crystalizes
which improves the temperature resistance
a lot.
The PLA can now withstand temperatures up
to 160°C. Way more than most other materials
you can use on an FDM printer.
As usual, there is a downside.
Normal PLA shrinks quite a lot during this
process.
This screws up all of your dimensions, which
can be compensated, but is not optimal.
Formfutura Volcano is modified in a way that
the shrinkage during annealing is minimal
leaving you with a well-fitting part after
the process.
The material does have a lower tensile strength
than normal PLA but on the other hand is much
less brittle and has an impact strength comparable
to ABS.
You also need to store the material at a dry
place because it seems to absorb more moisture
than regular PLA.
I will post a proper review with the mechanical
strength values as soon as I have my test
setup figured out.
So I went into Autodesk Fusion 360 and created
my own 3D printable version of the Bialetti.
I needed to have a thin bottom in order to
work on my induction stove.
Then I knew that there will be pressure building
up in the lower chamber so I did a crude finite
element analysis in Fusion to figure out the
rough stresses that 1 bar of pressure will
create, just to see if it was even possible
to have the thing not explode in my kitchen.
I added fine threads to close the pot and
tried applying all design rules necessary
to have the parts printing with the least
amount of supports.
I printed all of the parts, one by one, on
my Original Prusa i3 at 210°C nozzle and
60°C bed.
I had to add a steel washer to the lower chamber
during the print because otherwise the plastic
part would not heat up on my induction oven.
All the parts do have a very nice, matt surface
finish and also the overall print quality
is very decent.
The design does include two sieves which hold
the ground coffee in place.
They are also 3D printed and I used a neat
technique to print them very nicely.
I deactivated the top and bottom layers in
Slic3r and increased the number of perimeters.
If you use a rectilinear infill pattern and
set an infill density of around 60 to 80%
you get very nice and consistent looking sieves
from your 3D printer.
This might also be interesting for some other
projects.
I preheated my oven to 110°C and put a flat
piece of aluminum in it.
After the preheating was done I quickly put
the parts on the aluminum and set the timer
for 30 minutes at which point the oven slowly
cooled down to ambient temperature.
Just for the fun of it I put the knob, which
I printed in regular black PLA, on the lid
during the annealing process because I knew
that it would shrink and therefore establish
a press fit with the stud on the lid which
perfectly worked.
The parts did assemble beautifully, neither
better nor worse than before the annealing
process.
Then it was time for the test.
I added ground coffee and put it on my induction
stove.
After some tense minutes with me wearing full
safety gear and being afraid that I might
put coffee on all of the walls in the kitchen
the first drops of dark liquid rose through
the tube and a delicious smell of freshly
brewed coffee started filling to room.
I was so happy that this worked out!
Nerdy as this is I had to serve it in this
stormtrooper espresso mug, also printed in
Volcano.
I used the cooker a couple of times more and
did not have any problems with it.
Nothing melted or obviously degenerated.
Really cool.
So if you are looking for a material that
need to withstand higher temperatures definitely
take a look at Formfuturas Volcano filament.
It prints as easy as regular PLA and does
not emit the toxic fumes as most of the other
high temperature filaments.
The material should be available worldwide
at all Formfutura resellers.
If you buy it from formfutura.com and use
the discount code that you can find in the
description below, you will get 17.5% off
your purchase on all of their products.
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Thanks for watching, auf wiedersehen and I
will see you next time!
