- 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.
Quick summary from a 3D printing guy-
Sand molds are 3D printed so they can make internal passageways and features they couldn't otherwise machine or cast with traditional methods. Plus you can easily make one-off geometries.
How does this specific type of 3D printing work? Not all that different from your standard inkjet 2D printer. Except instead of paper there is a layer of sand and instead of color ink a binder/glue is jetted. Wherever you jet, deposits glue and binds the sand together. After each layer a new layer of sand is spread on top and the process is repeated. Afterwards you can remove all the unglued sand and you have your mold!
Surprising to a lot of people, this technology was first invented in 1993- https://en.wikipedia.org/wiki/Powder_bed_and_inkjet_head_3D_printing
Listening to this guy was very annoying. Basically, F1 engines are made the same way 99% of the other engines are made.
I know these guys like to “dumb it down” for the new American fans but as an American I’m insulted lmao
I hate Donut’s content so much. “Cream de la cream..” I turned it right off.
It's course and rough and irritating and it gets everywhere, including F1 engines.
I don't like sand. It's all coarse, and rough, and irritating. And it gets everywhere.
Donut is doing more f1 content and I love it