- F1 engines are the creme de la creme of engines.
They're designed by the best engineers
using the best materials
and manufactured using a 3000 year old process.
Hold on, what?
As it turns out, they've been building their engine blocks
by way of an old-school method with a new age trick.
It's 3D sand printing
and today we're gonna see how it works.
Let's go.
(upbeat music)
This is the engine block from the Money Pit Miata.
Now the block might be one of the least sexy items
when it comes to modifying your car.
But in terms of making sure your engine works,
it's the most important stationary part.
It's the biggest part of the engine
and its purpose is to not only support all the components
like the pistons and cranks and all that good stuff,
but it also transfers heat.
And the fascinating thing about a block like this
is that it's been made using the same way
for a very long time.
Engine blocks are primarily made by machining
or casting.
Now machining, ooh, it's sexy.
(slow music)
You take a big old hunk of aluminum alloy
and you start cutting away material
to shape the engine block how you want it.
It's called subtractive manufacturing,
since you're subtracting or removing material
and it's typically done by a CNC machine.
Any machine part on a car is pretty nifty.
But an entire machine block,
that is super nifty.
Okay, the scale's like this, okay.
Not nifty, pretty nifty, super nifty.
These blocks are stronger, lighter,
they're guaranteed to make your people say,
"Pretty nifty."
Now there are few downsides to machining a block.
It's more expensive and you're limited
to the internal cutouts and shapes you can make.
If you have certain internal passageways
or pockets for cooling a CNC might not be able to do it.
You're limited to the physical limitations
of having to cut away material.
For example, say I wanna make this hallow thermostat
that I pulled off of Jope's Miata.
He didn't know I took it, but I did,
'cause I needed an example.
From Jope's Miata.
Jope's Miata.
He didn't know I took it.
Now if I wanted to CNC this part,
it would be very difficult.
One, because it has a lot of complex bends in it.
And two, it's hollow.
Now CNC wouldn't be able to do the inside cuts
that I would need to make this piece.
I could do it in halves and then weld it together
or do it in sections and clamp it together.
But that takes more time
and it's more expensive.
So, how was this part made?
Well, this piece was made using casting.
And now my hands are freaking dirty.
Clean your thermostat, Jope.
(upbeat music)
Casting metal has been around for thousands of years.
The oldest surviving cast part isn't even a tool.
It was a toy.
You know what we should do,
maybe we should make our own toy.
Something like maybe a Miata.
Maybe we'll make it.
Casting is a process in which you take metal,
you heat it up until it liquefies
and then you pour that liquid metal into the mold
that's in the shape of your part.
You let the metal cool inside the mold
where it solidifies
and then you have your nice, shiny cast part.
When we're talking about casting engine blocks,
there's specifically two main methods.
There's die casting,
which you take your mold and metal and you inject it
into dies under high pressure.
And there's sand casting,
which you have a mold made from sand
and then you pour your liquid metal into that mold.
The molds have these outer walls that define the shape
of the outside of the block
with other cores that define the shape
of the internal cavities.
The molds are made out of glue, sand and a hardener.
When you mix these three together,
it creates a material that could withstand the heat
from liquid metal being poured into them.
Or as I call it, liquid hot magma.
Each mold is made up of multiple cords that fit together
like a puzzle.
And to make each sand mold a machine blows
that sand-glue mixture into an iron mold
and it injects a gas to activate the hardener
so the molds solidifies.
And once you have your base core mold,
you assemble all the other cores onto it
to build an entire system that is your engine block.
Once the mold and metal is poured in and has solidified,
the part goes into an oven
where the sand-glue mixture breaks down
and the sand is shaken out.
Leaving you with your engine block.
Take our cast aluminum thermostat for example.
So the mold for this would have a few parts.
The first is the two halves of the exterior
of this thermostat.
But how do we create the internal cavity
so that the piece is hollow?
Well, we create a second core
that sits in between the two exterior halves.
So when the metal flows into the mold,
the internal core blocks the liquid metal
from filling the inside of the part.
Leaving you with a hollow space.
(pretending to blow a trumpet)
We still cast a lot of parts today.
Not only in the automotive world,
but in things like cooking pans, tools, boat propellers,
patio furniture, mail boxes.
There's tons of stuff out there made
using the casting process.
And there are a few reasons why.
One, you can cast extremely large parts
or parts with complicated shapes.
Shapes outside the capabilities of a CNC machine,
like my thermostat here.
Two, you can use casting when you need a part
made out of a specific alloy.
You can mix different metals to formulate an alloy specific
to your application.
And three, casting is cheaper than machining.
When you're trying to cut down costs,
this is a good way to do it.
Once you have the mold made,
you can essentially duplicate your parts much quicker.
So if you need to make a lot of something,
casting is a really good way
to pump out a lot of identical parts.
But what about when you don't want
to mass manufacture parts?
What if you want to quickly change your block design
to implement better features that improve your race engine?
You wanna make some tweaks, 'cause you're a tweaker.
You want the ability to quickly change your part design
like you would with the machine part,
but use the casting process to create the unique shape
that your block requires.
If only there was such a technology
that would solve these problems.
(phone ringing)
Oh my God, my phone's ringing.
Hello.
(animated voice)
3D sand printing.
Oh yeah, you did write this episode.
Okay, I'll see you this weekend.
Love you, Mom.
My mom wrote this.
(laughing)
Sand printing is similar to 3D printing.
But instead of printing the part you print the mold.
You have layers of 0.25 millimeter thick sand
that are printed with a layer of chemical binder
in between each layer.
You begin with a thin layer of sand.
Then the printer head sprays binder on the areas
that will take shape of the mold.
Another thin layer of sand is evenly distributed
on top of the previous printed layer
and then the printer head sprays more glue.
And you gradually create your mold, slice by slice,
layer by layer.
By building up a mold this way,
not only is it faster, it allows for you
to have some unique casting geometry
that you couldn't get in a typical casting process.
So the million dollar question,
"How does it work?"
Well, it's a simple five-step process.
The first step is generating a 3D CAD model.
Typically this is done by first creating the 3D image
of the parts.
That's something I would do.
And then I would send it to a company
that specializes in 3D sand printing.
Where they would take that CAD file
and create a usable inversion for the mold.
Just like with traditional sand casting
we have to create the reversed image of our part
for the metal to take shape of.
Gotta start thinking,
you gotta be an invert.
Can you do that?
It's really hard.
Once you have the CAD file for the mold,
it's time to use the 3D printer to manufacture it.
And there's two ways in which it's done.
The first is a cold curing process.
The binder gets sprayed from the print head
at ambient temperatures.
That's why it's called cold,
'cause it's just normal temp.
Once the part is finished it is already glazed
which makes it robust.
And suitable for larger molds.
But for the more intrigued cords you need a stiffer,
more accurate sand.
So you need to use a hot curing process.
An infrared lamp in the printer heats the layers
of binder in between the sand to initiate the curing process
and evaporate off any moisture
before the parts are placed in a microwave
for their final cure.
The sand itself is a critical piece in making the mold.
And there are multiple types of sand
that can be used.
The sand has to be strong enough
to withstand the thermal loads
of 700 degrees C liquid metal.
But also be weak enough to be shaken out of the mold.
And when in contact with the mold and metal,
the sand would want to expand by about one percent.
And that one percent might not seem like that much.
But this is an engine block we're talking about.
Their precise tolerance is that need to be maintained.
So for the sections that need more precision,
there are different types of sand
that use different chemistries and curing mechanisms.
Let's take our thermostat for example.
Now say we want the thickness of this thermostat
to be two millimeters.
A standard grain of sand is about 0.2 millimeters.
So we would only have about 10 layers of sand build
into our mold.
Not only is this weak,
but the liquid metal could penetrate between these grains,
creating a thicker part than we specked out.
So to combat this, we would use a synthetic sand
that is half the size, 0.1 millimeters thick,
and we would hot cure it during the printing process.
This will increase the amount of grains
in those thinner sections.
The more grains, the more surface area
for the glue to attach to.
And the more layers we have.
20 versus 10.
Now, when I mentioned before that 3D sand printing allows
for more unique casting geometry,
this is what I'm talking about.
We can get aways with making more intrigued shapes
with finer tolerances.
(upbeat music)
Once the mold is printed up
it's time to pour in our nice, hot metal.
During the pouring process the metal can splash around
which introduces turbulence in the liquid metal.
And when you have a turbulent pour the quality of metal,
once it solidifies, is of a lesser quality.
The molds, they're filled from the bottom to the top uphill,
meaning there are holes in the bottom of the mold
and the liquid metal gets pushed in from the bottom,
rather than pouring it into the top of the mold.
Now if we were to pour from the top,
you expose the metal to air more.
The surface area of the metal being exposed
to the air with a top pour is much more
than if we were to gradually fill the mold up
from the bottom.
So why does all that matter?
Well, aluminum oxide forms when the liquid aluminum reacts
with oxygen in the air.
It forms a ceramic
and that ceramic blocks the metal molecules
from binding properly.
This can lead to different materials distributed
in the casting.
If you have a nonuniform casting, you have weak spots.
That's a no brainer, you want buff spots,
like my arms, okay.
You don't want weak spots.
You don't want to hear about the weak relationship I have
with my sister.
I want my truck back, Christina.
I want it back now.
You could only hide behind that boyfriend
that you married for so long, Christina.
(laughing)
So we want to minimize the amount of contact the metal has
with air during the pour.
When the liquid metal cools, it forms a solid.
And the rate at which it cools is important
because you achieve certain functional properties
out of that metal, depending on how fast or slow it cools.
Mold and metal solidifies by transferring heat
to its surroundings, which in this case is the sand.
And certain areas of the casting can either be insulated
to keep the metal in its liquid state
or placed next to a heat sink
that pulls the heat away,
so the metal solidifies faster.
By adding heat sinks at various spots
along the mold,
you could precisely control the rate of cooling.
And when you control the rate of cooling,
you control the crystal instructure of the part
as it transitions from a liquid to a solid.
Man, we should do a material science episode.
'Cause it's pretty cool stuff.
Different areas of the engine block
experience different stresses.
The head of an engine is going
to experience different forces acting on it
than an engine mound for example.
The combustion process is going to fatigue the head.
So if we cool that section of the mold faster,
it will create a smaller microstructure
in the metal with smaller grains.
And those smaller grains are better
at minimizing the effects of fatigue,
due to the combustion process.
Tight little grains.
Once the part has been cast
and has gone through a series of machining
and heat treatments,
the analysis begins.
This is all fun stuff.
Most parts goes straight into a CT scanner
where a beam of X-rays is passed through the part
and a line detector builds up the images
in these various small sizes.
That data is then imported into a software program
which reconstructs the image into a 3D model
of the actual part.
So then they take that 3D model
and they overlay it with the CAD model
to verify if the casting came out correctly.
Then after that, you got your freaking engine block, baby.
A sweet, sexy F1 cast engine block.
Wroom-wroom.
So the benefits of 3D sand printing are pretty obvious.
One of them is you get to make mini iterations
in a quicker time.
If you wanted to modify a part
using older traditional casting methods,
it would take you weeks, sometimes months,
'cause you'd have to create a new mold
and that takes time.
But with 3D sand printing you can make minute,
intrigued changes and get your part delivered
in only a couple of days.
This is great, for say, someone who's in the F1 world.
Thank you guys so much for watching this episode of B2B.
I think we're gonna do an episode where I make a forge
and I actually cast my own parts.
Maybe we'd do some special one-off key chains,
B2B key chains or emblems.
Maybe a freaking chain.
I don't know if it will make a B2B episode
but maybe we'll put it out on the underground.
So comment down below, see if that's something
that you would like to see.
Follow us here at Donut on Instagram @donutmedia.
Follow me @jeremiaburton.
Until next week.
Bye for now.