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Resin Cores for Sand Casting

Mostly used in China's sand casting foundries, resin cores have a typical yellow appearance. Being one of the best resin casting companies in China today, ChinaSavvy specializes in various casting processes, including resin sand casting.

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Resin sand casting cores are made by blending fine sand and resin to different proportion, each proportion resulting in a different shrinkage rate. Resin sand cores are also subject to moisture absorption, resulting in an effect on the dimension as well as the surface finish and quality of the final sand casted part. It is thus necessary to store resin cores in a dry environment.

Below you will find information concerning:

  1. How Resin Cores Are Made
  2. The Resin Casting Process


How Are Resin Sand Cores Made?

Resin sand cores are produced by making use of molds. With similarities to a die casting mold, sand core injection molds is most commonly made from carbon steel. The cavity along with its features are used to produce all the necessary features, while an attaching system will facilitate the fixing of the core to the pattern or metal die.

In cases where a more complex sand core injection mold is required, costs of production will rise, sometimes to be equal to that of the sand casting mold, or even higher.

There are a number of sand core injection machines applied within the resin sand casting process, each with a different tonnage. The horizontal injection machines usually have the capability of producing larger pattern sizes when compared to the vertical injection machines.

The Resin Casting Process

Simply put, the resin sand is injected into a metal mold (commonly made of carbon steel) and then heated, allowing for the resin to cure and harden the core. The resin sand core is now taken from the mold and can be immediately used.

The Cold Box Process

Capable of producing cured cores in a matter of seconds at room temperature, cores produced using this process shows a good tensile strength, a good resistance to abrasion, a low gas evolution, a high density, a high dimensional accuracy and an exceptional collapsibility.

Aluminum, steel, magnesium, brass and grey and ductile-iron are all excellently casted when using the molds and cores produced with the cold box resin sand casting process.

This particular process also leads to:

  1. A reduction in production cost.
  2. A reduction in core production time.
  3. The opportunity to enabled the use of unskilled labor.
  4. A reduction in energy consumption.


The cold box process enables resin casting companies to automate the core production process, resulting in a reduction of core and casting scrap, the need for fewer personnel and a high production rate.

Some of the other benefits associated with the cold box process includes:

  1. No heat is used for curing the cores, thus leading to a lower foundry energy consumption. This also means that the need of core ovens are eliminated.
  2. Fewer workers are required to produce the cores, resulting in a lower labor cost.
  3. It is an effective process for the production of both cores and molds used in the resin casting process.
  4. With no thermal related expansion present during the core making process, it delivers a precise core with no warpage or shrinkage.
  5. The binders used in this process is suitable for both low and high production volumes.
  6. Dense cores are produced as a result of the excellent flowability provided by this process, in turn lowering core scrap.


You can also learn more about hollow core sand casting and the use of binders in core sands.

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