Sand Casting vs. Permanent Mold Casting

Two popular metal casting methods are sand casting and permanent mold casting. While both manufacturing processes can produce high-quality castings, they differ in several key ways.

Know which manufacturing method is best for your product! Here are the differences between sand casting and permanent mold casting.

What's Sand Casting?

Sand casting molds are one-time use, made by mixing sand and a binder. Metal is static poured into the mold, solidifies, then the mold is broken to remove the casting.

Within sand casting, there are 4 types of processes: green sand, nobake, coldbox, and shell.

Sand Casting Pros

- Low-cost tooling
- Suitable for low-volume production and prototyping
- Can accommodate a variety of sizes and shapes

Sand Casting Cons

- Requires more secondary finishing work after casting (heat treat, machining, polishing, etc.)
- Lower dimensional accuracy when compared to permanent mold
- Greater risk of high porosity and sand inclusion defects

What's Permanent Mold Casting?

Permanent mold casting uses a reusable steel mold. Most castings are tilt poured, which is a gravity-fed, machine-controlled method of filling the mold.

Permanent Mold Pros

- High dimensional accuracy and repeatability, especially for complex parts
- Consistent quality and high-end surface finish
- Suitable for medium-volume production
- Low porosity and less risk of other casting defects

Permanent Mold Cons

- Higher tooling costs when compared to sand casting
- Strict design standards for optimal manufacturability

Which one should I use?

When it comes down to making a decision, look at your EAU and quality standards to determine which manufacturing method will give you the best ROI.

EAU

Sand casting tooling is relatively low-cost, making it the ideal choice for low-volume production runs (a couple hundred a year) and even prototyping.

Permanent mold casting has a moderate tooling cost (between sand and die casting), making it the ideal choice for moderate-volume production (a couple thousand).

Die casting is on the opposite end of the spectrum, with typically the highest tooling cost. It's quick pressure-fed process is reserved for high-volume production (tens or hundreds of thousands), such as automotive castings.

Quality

Permanent mold casting is a high-precision method that can produce complex parts with consistent quality and accuracy. Permanent mold has a better surface finish and lower porosity than sand casting, which eases secondary operations like machining or powder coating.

Low porosity is ideal for pressure-tight vessels, medical equipment, and food equipment.

Metal Casting Experts

Still not sure which manufacturing method is best for your product? Send us a picture and we'll point you in the right direction! https://batesvilleproducts.com/reques...