Sand Casting Core Types

Sand Casting is a widely used form of casting. As the name suggests, the mold is made from sand. Sand Casting requires placing a finished part model or a wooden model (pattern) in the sand, then filling the sand around the pattern, and taking the pattern out of the box to form a mold. So what is the type of sand core for Sand Casting? Let's take a look next.

Here is the content list:

l Oil sand core

l Resin sand core

l Water glass sand core

Oil sand core

The core is made of core sand with dry oil or semi-dry oil as a binder is widely used. The viscosity of the oil is low, the mixed core sand has good fluidity, and it is easy to be compacted during the core making. However, the strength of the newly made Sand Casting parts core is very low, and it is generally accepted by a profiled core board, and then baked in an oven at 200 to 300 ° C for several hours, and the oil is oxidized by air to harden it. The disadvantage of this core-making method is that the core is easily deformed during demolding, handling, and baking, resulting in a reduction in the dimensional accuracy of Sand Castings; long baking time, and high energy consumption.

Resin sand core

Sand Casting cores are made from resin sand. The core is hardened in the core box and then taken out to ensure the tolerance of the shape and size of the core. According to different hardening methods, the manufacture of resin sand cores is generally divided into three methods: hot core box core making, shell core making, and cold-core box core making.

①Hot box method core: Appeared in the late 1950s. Usually, furan resin is used as a core sand binder, and latent hardener (such as ammonium chloride) is also added to it. When the core is made, the core box is kept at 200-300 °C. After the core sand is injected into the core box, the ammonium chloride reacts with the free formaldehyde in the resin at a higher temperature to generate acid, so that the core hardens quickly. It takes about 10 to 100 seconds to build de-mold strength. Using the hot core box method to make the core, the dimensional accuracy of the core is relatively high, but the processing device is complex and expensive, the energy consumption is high, and the irritating gas is discharged.

②The shell core is made by the hot method of over-molding sand, and the Sand Casting sand core has high strength and good quality;

Water glass sand core

Sand cores made of water glass as binder can be divided into the following types: ester hardened water glass self-hardening method, water glass methyl formate cold core box method.

The above is the relevant content about Sand Casting's sand core types, if you are interested in Sand Casting and Sand Casting parts, you can contact us, our website is https://www.compass-casting.com/.