- [Instructor] You may ask yourself,
"have I already done anything like this?"
I bet you have.
We're going to look at common use kitchen examples
and relate them to manufacturing.
We're already defined casting, which at its core,
is filling a pre-made cavity with material
that undergoes a physical change from semi-liquid to solid.
That sounds like waffles, to me.
But first, let's look at the process breakdown
of an ice cube tray.
You take a semi-flexible tray,
the most common of which has cubes,
then you fill it most of the way with water,
place it in the freezer,
and hours later, voila!
Due to physics, the water reached a cold enough temperature
to expand and solidify into the ice you want.
Did it keep the shape?
Were there bubbles or voids?
Did you get them all out in one piece?
Think about it.
Modern ice cube trays now come in silicone,
which could be extremely flexible.
Having a pliable mold can expand
the shapes that you can make.
This is an easy analogy for one part, pour-over molds
because you need to make sure
you have room for the material to expand.
The mold needs to be flexible,
or come apart enough for you to get consistent ice cubes,
hopefully in one piece.
Speaking of breaking the mold, another everyday casting
you might have done is hard boiling eggs.
Seems strange to think about this as casting,
but bear with me.
If you aren't using a fancy kitchen gadget
to make your boiled eggs look like stars or clouds,
the interior of the egg will go from liquid to semi-solid,
taking the shape of the handy container it's in.
Unfortunately, you'll have to crack the shell
to get the egg out of there,
and I would be extremely impressed
if you could get it off in one piece.
This would be an example of destructive molding,
where the shape of the mold is a very specific geometry,
but in order to get the part inside,
you'll have to break a few eggs.
If we're going to talk about a full breakfast,
let's talk about waffles.
Yes, waffles.
But really, the waffle iron makes some delicious sense.
As in molding, once a correct consistency
of batter is poured into the iron,
under pressure, it fills the entire iron.
Too much batter, and it flows out of the sides,
too little batter, and it doesn't fill the iron completely.
The waffle changes consistency from batter
to buttery-goodness where it contacts
the heat from the iron,
which cooks the outside faster than the inside.
With the right timing,
the entire waffle will fill the iron
and be completely done throughout,
with the wrong timing and temperature settings,
the inside could be underdone, the outside can burn,
and you won't be happy with the results.
If you've ever looked closely at an iron,
you'll notice the squares aren't exactly cubes.
We'll come back to why that matters in a later chapter.
The closest manufacturing method
to this would be compression molding.
The last food example that helps explain molding processes
would be lollipops.
The lollipop product is only complete
with the candy and stick elements.
Let's say you want to make some candy for your sweetie,
what are the steps?
You gather all of your materials together and combine them,
whether that involves heating or simple addition.
While you're waiting,
you place the sticks carefully in the mold.
Once your candy material is ready,
you pour or inject it into the mold
and allow the candy to cool until it's ready
to be demolded and wielded with this handy stick.
This is a simple version of overmolding
because you've completed the product
with more than one kind of material,
with the initial part being molded over with hard candy.
You've combined materials together,
changed their temperature and consistency
and reshaped them to your design.
In injection molding,
the initial and interior part is often a harder material,
with added softer, rubberized, or textured material
to the outside for added visual and tactile value.
Like the toothbrush you'll need later on.
Now that we've got a better idea
of the casting you've already done,
take some time to look at the processes and items around you
and start making connections on your own.
Try to think of processes you already do on a regular basis
and how that fits into the cycle process loops.
Think about how the things you use everyday are made.