Sand casting is a metal casting manufacturing technique that involves using sand to create mould. This process is used to create metal products in various sizes and shapes. In sand casting, there are two main types: green sand cast and dry sand cast. The green sand cast consists of clay; silica sand additives.
Dry sand is a mixture of sand and fast-curing sticking. There are countless patterns in sand casting, but nowadays, few are only in use. They are single-piece patterns, two-piece patterns, match-pate patterns, gate patterns, sweep patterns, and loose-piece patterns.
Why is Sand Casting?
Castings are produced by pouring liquid metal into a mould cavity. For a successful casting, the mould cavity must retain its shape until the metal has cooled and fully solidified. Pure sand is not good for making the casting. But moulding sand contains bonding materials that increase its ability to resist heat and hold the shape.
The sand casting method has been used for thousands of years and remains one of the best methods for casting metal today. It is pouring molten metal into a form made from condensed sand. Sand is inexpensive and can also withstand high temperatures.
Sand casting also serves a large size range of parts. Compared to the other types of casting, sand casting is cheap and budget-friendly. Sand casting is to be used to produce products quickly, and it’s a great option for limited runs. Sand casting supports various alloys and metals, including steel, iron, zinc and tin. This is the reason why sand is good for casting.
What Type of Sand is Used for Sand Casting?
Green sand is widely used for sand casting. It refers to the sand moulds from wet sand and is sometimes called clay. Green sand is a quick and inexpensive way of making a sand casting. We cannot use all the sand because it will break the sand casting and disappoint us. People think green sand is accurately green in colour, but it is not.
The sand is not green in colour, nor does the mould use greensand. This refers to a greenish colour stone. Green sand casting is popular in the market. You can also find the green sand casting in everything from the engine blocks and parts of the ships.
- Water glass or sodium silicate
These water glasses are also used to create mould casting. Sodium silicate can rapidly go from a liquid to a solid by passing carbon dioxide through it. This will cause the sodium silicate to dehydrate. Sodium silicate casting is also called water glass casting. This water-casting process is very similar to investment casting.
Water glass cast components are majorly used where stronger or heavier, more complex shapes are required. Nowadays, water glass casting is very popular among casters. It is used to make the heavy and strongest metal for the cast. This water glass gives superior finishing through sand casting. Water glass cast gives you a perfect finish to the sand cast.
- Resin sand
Once you mix and heat, resin sand becomes a solid mould with a smooth surface. A solid mould means fewer defective castings, but the drawback is that it has a higher cost and slower production rate. Compared to other sands, this resin sand will be quick to create.
The resin sand is relatively cheap. It is very expensive in today’s market because of its popularity and quality. And also, it is the type of quartz sand that is mixed with resin material. This chemical reaction created by the resin helps to bind the quartz sand to make hard and strong moulds.