There are different types of metal casting out there. They are specifically suitable for certain applications. The metal casting process involves melting metal and pouring it into a cavity. Since the invention of part production, casting has been a common practice.
Typically, different industries use metal casting to produce a wide variety of parts. Different types of metal casting lead to the production of certain casting qualities, complexities, properties, manufacturing costs, surface finishes, dimensional accuracies, etc.
All these properties are considered when selecting a suitable type of casting process for an item. Well, in this reading, we’ll explore the four most popular types of metal casting.
Let’s begin!
Related: What is the Difference Between Casting and Forging?
What are the Popular Types of Metal Casting?
The common types of metal casting include sand casting, investment casting, die casting, and evaporative casting.
1. Sand casting
Sand casting processes are manufacturing processes that use sand to create a mold cavity. Sand serves as a refractory material that can resist molten metal. Greensand is usually implied because it has good binding properties, such as sand, clay, silica, and a little amount of water.
Pattern made of either wood or metal is used to create a good replica or model of the item to be produced, leaving the same shape in the mold cavity. Patterns are created to be slightly larger than the original item to contract the molten metal during cooling.
Sand casting is normally used when the larger part is needed to be produced; its production is relatively inexpensive, especially when producing low volume.
You can use both ferrous and nonferrous metals for casting in the sand casting process, which offers a low cost for post-cast tooling.
However, sand casting produces a comparatively rough surface, making it require finishing work. It also yields a lower degree of accuracy. The slowness of sand casting processes stems from the need to break the mold for casting extraction.
Related: What is Sand Casting Sand, its Properties & Types?
2. Die casting
Die metal casting usually involves nonferrous metals and alloys, such as tin, zinc, aluminum, and copper. Its end product offers a better surface finish and excellent dimensional accuracy. We carry out this metal casting process by forcing molten metal into a mold at high pressure.
A lubricant coats the mold to facilitate the easy injection of the molten metal. And to regulate the die’s temperature.
Molten metal is rapidly injected into the die under high pressure. Rapid insertion helps to prevent a segment of the casting from hardening before its remaining part. After the molten metal solidifies, the casting is taken out of the die, and then the scrap materials will be cut off.
Die casting has relatively high tooling costs, making it more cost-efficient when producing high volumes. Porosity defects are common in die casting when producing large items. The solidification of the molten metal traps air before it reaches the die cavity.
3. Investment casting
Investment casting is another type of metal casting process that offers a high degree of accuracy and dimensional results and a relatively high-quality surface finish.
It is capable of creating thin-walled parts with complex geometries. Just as sand casting does, investment casting also has the capacity of casting both ferrous and nonferrous metals.
The metal casting process uses disposable wax, usually beeswax, to create a pattern or model of the casting. The mold receives the pattern or wax.
This wax is pre-coated with a liquid refractory material, dried in the sun, or heated before being placed into the mold, helping the pattern to resist the molten metal for a short amount of time.
After the injection of the coated wax into the mold, molten metal is poured and it takes the position of the pattern. The pattern melts out and the metal solidifies, taking the shape of the melt-out wax.
Investment casting is widely used in the manufacturing of aerospace, automotive, and military parts.
Related: What is Forging, its Applications, Types, and How it Works?
4. Centrifugal casting
Centrifugal casting is a special type of metal casting that is employed when the durability of a product is important, the internal diameter of the casting has fine grains, and generally, where hollow parts are needed.
Centrifugal casting is carried out in a permanent mold that allows molten metal to be poured into it.
The mold spins at high speed around its axes. Due to the centrifugal force, molten metal is thrown toward the mold walls. Once the molten metal solidifies, the mold releases the cast.
The centrifugal casting process is performed when a part such as spherical glass objects, pipes, flywheels, boilers, and television picture tubes is needed.
Conclusion
In conclusion, common casting methods, including sand casting, investment casting, die casting, and centrifugal casting, serve as essential manufacturing techniques that make it possible to produce a wide range of components and goods.
Each approach offers a set of unique benefits and uses that make it a useful tool in various industries, from aerospace to automotive.
To select the best casting process for their unique demands and eventually contribute to the effective and varied manufacturing landscape of today, manufacturers have to fully understand the qualities and capabilities of these casting techniques.
Related: What is Investment Casting? Diagram, & How it Works