GREEN CASTING SERVICES

Bringing 35 years of metal casting expertise

The Super Vac Foundry offers green sand casting services, a process that uses green sand — a combination of olivine sand and bentonite clay — to create molds for metal castings. Green sand casting is ideal for both low- and high-volume specialty parts, and while extremely custom, more than 80% of all metal castings are produced using this process.

Casting Metal Types

The Sand Casting Process

Part Examples

Casting Metals

We use the following casting metals in the green sand casting process:

Aluminum Foundry

The go-to in aluminum sand casting:
• 319 Aluminum (319SR)
• 356 Aluminum (356.2)
• 535 Aluminum (535.2)
• 713 Aluminum (713.1)
• 771 Aluminum (771.2)

Brass Foundry

Offering brass alloy components:
• Red Brass Alloy (115)
• Manganese Bronze (421)
• Silicon Bronze (500)

The Metal Sand Casting Process

Clay molding is an ancient art that dates back to China’s ancient Shang Dynasty. Today, the green sand casting process requires much of the same handcrafted precision. Here’s a look at the process:

STEP 1A THE SAND MOLD IS CREATED

First we source a 3D printed pattern, a replica of the part that will be cast. This pattern is placed into the molding box, also known as a casting flask. Sand is then packed around the pattern through a vibratory process, called ramming. Eventually, the pattern is removed, leaving behind the sand mold.

STEP 1B OPTIONAL “CORES” ARE CREATED

To produce parts with hollow components, a cavity must be made within the casting. To create this cavity, a CO2 core is made by packing silica sand into a core molding box. The sand is then exposed to carbon dioxide, creating a chemical reaction between the CO2 and the sand’s sodium silicate, which results in a hardened sand core. The core is inserted into the casting flask to create the sand mold and eventually, hollow component.

STEP 2 THE MOLTEN METAL IS POURED

Once the sand mold has been made, aluminum or brass is melted in the furnace. Super Vac'S largest furnace can hold up to 600 lbs. of metal while reaching 1,200-2,200° F. The molten metal is then poured into the mold using a ladle and left to cool for 10 minutes. After cooling, the mold is broken to reveal the casting, and the sand is recycled through the process again.

STEP 3 EACH PART IS THEN “FINISHED”

The final step in the sand casting process often involves grinding, sanding, polishing or machining the component to achieve the desired dimensional accuracies, physical shape and surface finish. The Super Vac Foundry has a dedicated finishing mill to create polished parts, as well as five CNC machining centers to deliver turn-key products. Click here to learn about our machining services.

Sand Casting Examples

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