Types of Casting Processes

Casting makes big things and small things. It makes car parts, toys, and many more things. We will learn about all the ways to make things with casting. Let’s see how it works!

What is Casting?

Casting is when you pour hot metal into a hole or space. The metal gets hard. Then you take it out. Now you have a new part!

Casting helps make parts with isotropic properties. This means the part is strong in all ways. Casting can make parts with good dimensional accuracy too.

Many big companies use casting for mass production. This is because they can make lots of parts fast.

How to Pick the Right Casting Process

You need to think about these things:

• What mold do you want? (Expandable or Permanent)
• How many parts do you need? (One or Many)
• What metal will you use? (Aluminum, Steel, Zinc)
• How much money can you spend?
• How exact must the part be?

Here is a table to help you pick:

8 Big Types of Casting

1. Sand Casting

Sand casting uses green sand to make a mold. The cope and drag parts hold the sand. Then hot metal goes in the mold.

Best For: Big parts like car engines and bells.

Good Things:

• Low cost
• Can make big parts
• Works with many metals
• Uses foundry sand

Bad Things:

• Not very exact
• Rough surface
• Slow to make

Metals Used: Iron, aluminum, bronze, brass

Ford Motor Co. uses sand casting for diesel engine blocks because it costs less.

:link: Explore precision grinding services for finishing sand cast parts.

2. Investment Casting

Investment casting is also called lost-wax process. First, make a wax model. Then coat it with ceramic. Heat it up so the wax melts away. Pour in metal.

Best For: Small, exact parts like turbine blades and jewelry.

Good Things:

• Very exact (±0.05mm)
• Smooth surface
• Can make hard shapes
• Uses ceramic molds

Bad Things:

• Costs more than sand casting
• Takes more time
• Size limits

Metals Used: Steel, aluminum, brass

GE Aviation uses investment casting to make turbine blades for jet engines.

3. Die Casting

Die casting uses metal molds. It can be high-pressure or low-pressure. The metal is pushed into the mold with force.

Best For: Many small or medium parts.

Good Things:

• Fast
• Very exact
• Smooth finish
• Makes many parts

Bad Things:

• High tool cost
• Size limits
• Not for high-heat metals

Metals Used: Aluminum, zinc, magnesium

Tesla uses high-pressure die casting for car parts like the Model Y chassis.

:link: Our casting CNC machining service can help finish die cast parts.

4. Centrifugal Casting

Centrifugal casting uses spinning! The mold spins fast while the metal goes in. The centrifugal force makes the metal go to the sides.

Best For: Round, hollow parts like pipes.

Good Things:

• Good for pipe manufacturing
• Less waste (98% yield)
• Clean inside
• Good for hollow shapes

Bad Things:

• Only for round parts
• Heavy machines
• High start cost

Metals Used: Iron, steel, aluminum

Kubota Corp. makes pipes for chemical plants with centrifugal casting.

5. Plaster Casting

Plaster casting is like sand casting but uses plaster instead of sand.

Best For: Thin, smooth parts for art.

Good Things:

• Very smooth (1.6 µm Ra)
• Good for thin walls
• More exact than sand

Bad Things:

• Not for high-heat metals
• Takes time to dry
• Breaks easy

Metals Used: Aluminum, zinc, copper

Art foundries use plaster casting for bronze sculptures and jewelry.

6. Continuous Casting

Continuous casting makes long metal shapes all the time. The metal flows into a mold and comes out as a long piece.

Best For: Steel beams, sheets, and rods.

Good Things:

• Makes long parts
• Less waste
• Saves energy
• Runs all the time

Bad Things:

• Big machines
• High start cost
• Few shapes

Metals Used: Steel, aluminum, copper

ArcelorMittal uses continuous casting to make steel sheets for buildings.

7. Lost Foam Casting

Lost foam casting uses polystyrene patterns that burn away when the metal comes in.

Best For: Engine parts with hard shapes.

Good Things:

• Less cutting after (30-40% less)
• Can make hard shapes
• No split in mold
• Less minimal machining

Bad Things:

• Foam patterns cost more
• Not as exact
• Some gas problems

Metals Used: Iron, aluminum

Harley-Davidson uses lost foam casting for motorcycle engine parts.

8. Squeeze Casting

Squeeze casting is when you squeeze the metal as it gets hard.

Best For: Strong car parts.

Good Things:

• Less bubbles (90% less)
• Stronger parts
• Good look

Bad Things:

• High machine cost
• Hard to do
• Size limits

Metals Used: Aluminum, magnesium

Honda uses squeeze casting for light aluminum parts in hybrid cars.

:link: Check out our automotive CNC machining services for post-casting operations.

Casting Methods Side by Side

How to Choose the Right Casting Way

Think about these things:

1. How much money do you have?
2. How strong must the part be?
3. How hard is the shape?
4. How many parts do you need?
5. Does it need to meet rules like ASTM or ISO 8062?

Example: For car engine blocks, you must pick. Die casting is fast and exact but costs a lot. Sand casting costs less but is not as nice.

Where Casting is Used

Cars

Cars use die casting for engine parts. The global die casting market will grow to $106 billion by 2030!

Planes

Planes use investment casting for engine parts. The parts can be as exact as ±0.05mm.

Art

Art uses plaster casting for statues. It makes very smooth parts (up to 1.6 µm Ra).

:link: Use 5 axis machining to finish cast art pieces.

Pipes and Tubes

Centrifugal casting is best for pipes. It uses less metal and makes good pipes with 98% yield.

Questions People Ask

End

Now you know about the 8 big types of casting. Each has good and bad points. To pick the right one, think about your money, the metal, how many parts you need, and how exact they must be.

Casting helps make many things we use every day. From car parts to art, casting is a big part of how we make things.