Sand casting and gravity die casting are two popular methods of producing metal parts, particularly in the OEM (Original Equipment Manufacturer) industry. Both processes involve the use of a mold or pattern to shape the molten metal into the desired shape, but there are some key differences between the two. In this comprehensive guide, we’ll take a closer look at OEM sand casting and OEM gravity die casting, including the advantages and disadvantages of each process, the materials they are best suited for, and the industries that commonly use them.

What is OEM Sand Casting?

Sand casting, also known as green sand casting, is a metal casting process that has been used for centuries. It involves the use of a mold made of compacted sand to shape the molten metal into the desired shape. The mold is created by packing a mixture of sand, clay, and water around a pattern, which is a replica of the part to be cast. The pattern is then removed, leaving a cavity in the mold that will be filled with the molten metal.

There are several steps involved in the OEM sand casting process:

  1. Pattern creation: The first step is to create a pattern of the part to be cast. This is typically done using wood, metal, or plastic.
  2. Mold creation: Once the pattern has been created, the mold is made by packing the sand mixture around it. The sand mixture, known as the “green sand,” is made up of sand, clay, and water. The clay helps to bind the sand together, while the water helps to cure the clay and create a stronger mold.
  3. Melting and pouring: The next step is to melt the metal and pour it into the mold. This is typically done using a furnace. The molten metal is then poured into the mold through a channel called a “sprue.”
  4. Cooling and solidification: As the molten metal cools and solidifies, it takes on the shape of the mold cavity.
  5. Shakeout: Once the metal has cooled and solidified, the mold is broken apart, or “shakeout,” to reveal the cast part.
  6. Finishing: The cast part may require additional finishing steps, such as grinding, sanding, or polishing, to achieve the desired surface finish.

Sand casting is a relatively simple and cost-effective process, making it a popular choice for producing large or complex parts. It is also well-suited for OEM producing parts in low to medium quantities. However, it is not as precise as other casting methods and may require additional finishing steps to achieve the desired tolerances and surface finish.

What is OEM Gravity Die Casting?

Gravity die casting, also known as permanent mold casting, is a metal casting process that involves the use of a mold made of metal to shape the molten metal into the desired shape. The mold, or “die,” is created by machining a cavity into a block of metal, typically aluminum or iron. The die is then heated to a high temperature to allow the molten metal to flow into it under the force of gravity.

There are several steps involved in the OEM gravity die casting process:

  1. Die preparation: The first step is to prepare the die by heating it to the desired temperature. This is typically done using a furnace.
  2. Melting and pouring: The next step is to melt the metal and pour it into the die. This is typically done using a furnace or an induction heater.
  3. Cooling and solidification: As the molten metal cools and solidifies, it takes on the shape of the die cavity.
  1. Ejection: Once the metal has cooled and solidified, the die is opened and the cast part is removed, or “ejected.”
  2. Finishing: The cast part may require additional finishing steps, such as grinding, sanding, or polishing, to achieve the desired surface finish.

Gravity die casting is a faster and more precise process than sand casting, as the metal mold allows for closer tolerances and a smoother surface finish. It is also well-suited for producing medium to high quantities of parts, as the die can be used multiple times before it needs to be replaced. However, it is a more expensive process due to the cost of machining the metal die and the need for precise temperature control.

Advantages and Disadvantages of OEM Sand Casting

One of the main advantages of OEM sand casting is that it is a simple and cost-effective process, making it a popular choice for producing large or complex parts. It is also well-suited for producing parts in low to medium quantities. Additionally, sand casting allows for the use of a wide range of metals, including aluminum, brass, bronze, iron, and steel.

Some of the disadvantages of sand casting include:

  • Lower precision: Sand casting is not as precise as other casting methods, and may require additional finishing steps to achieve the desired tolerances and surface finish.
  • Limited size: Sand casting is not well-suited for producing small parts, as the sand grains can interfere with the details of the part.
  • Limited production: Sand casting is not as efficient as other casting methods, and is not well-suited for high volume production.

Advantages and Disadvantages of OEM Gravity Die Casting

One of the main advantages of OEM gravity die casting is that it is a faster and more precise process than sand casting, as the metal mold allows for closer tolerances and a smoother surface finish. It is also well-suited for producing medium to high quantities of parts, as the die can be used multiple times before it needs to be replaced. Additionally, gravity die casting allows for the use of a wide range of metals, including aluminum, brass, bronze, and zinc.

Some of the disadvantages of gravity die casting include:

  • Higher cost: Gravity die casting is a more expensive process than sand casting due to the cost of machining the metal die and the need for precise temperature control.
  • Limited size: Gravity die casting is not well-suited for producing very large or very small parts, as the die may be too heavy or the details may be too fine to capture accurately.
  • Limited production: Gravity die casting is not as efficient as other casting methods, such as pressure die casting, and is not well-suited for very high volume production.

Which Process is Best Suited for Your Needs?

Both sand casting and gravity die casting have their own set of advantages and disadvantages, and the best process for your needs will depend on a variety of factors, including the size, complexity, and quantity of the parts to be produced, as well as the materials and tolerances required. Here is a summary of the key differences between the two processes:

  • Sand casting is a simple and cost-effective process that is well-suited for producing large or complex parts in low to medium quantities. It allows for the use of a wide range of metals and is not as precise as other casting methods.
  • Gravity die casting is a faster and more precise process that is well-suited for producing medium to high quantities of parts. It allows for the use of a wide range of metals, but is more expensive and not as efficient as other casting methods, such as pressure die casting, for very high volume production.

Materials and Industries Commonly Using OEM Sand Casting and OEM Gravity Die Casting

Both sand casting and gravity die casting can be used to produce parts from a wide range of metals, including aluminum, brass, bronze, iron, and steel. However, each process has its own set of limitations and is best suited for certain materials and industries.

Sand casting is commonly used to produce parts for a variety of industries, including:

  • Automotive: Sand casting is commonly used to produce engine blocks, transmission cases, and other large and complex parts for the automotive industry.
  • Aerospace: Sand casting is used to produce large and complex parts for the aerospace industry, such as landing gear and wing components.
  • Construction: Sand casting is used to produce parts for the construction industry, such as pipes, valves, and fittings.
  • Energy: Sand casting is used to produce parts for the energy industry, such as turbines and generators.

Gravity die casting is commonly used to produce parts for a variety of industries, including:

  • Automotive: Gravity die casting is commonly used to produce automotive parts, such as wheels, cylinder heads, and transmission cases.
  • Aerospace: Gravity die casting is used to produce parts for the aerospace industry, such as landing gear and wing components.
  • Electronics: Gravity die casting is used to produce parts for the electronics industry, such as heat sinks and enclosures.
  • Consumer goods: Gravity die casting is used to produce parts for consumer goods, such as appliances and sporting goods.

Conclusion

Sand casting and gravity die casting are two popular methods of producing metal parts in the OEM industry. Each process has its own set of advantages and disadvantages, and the best process for your needs will depend on a variety of factors, including the size, complexity, and quantity of the parts to be produced, as well as the materials and tolerances required. Sand casting is a simple and cost-effective process that is well-suited for producing large or complex parts in low to medium quantities, while gravity die casting is a faster and more precise process that is well-suited for producing medium to high quantities of parts.

If you are looking for OEM sand casting or OEM gravity die casting service, you are welcome to contact us.